Re: quantum darwin?
- Original Message - From: Julia Thompson [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Friday, March 25, 2005 3:33 PM Subject: Re: quantum darwin? A couple of questions about what I believe are typos, but want to make sure: Yup, those are both typos...thanks, Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Dan wrote: For example, we can make a spot on the moon travel faster than the speed of light. Shoot a laser at the moon and change it's angle. One can make the bright spot travel from one side of the moon to the other in a microsecondwhich is many times faster than the speed of light. But, no signal travels from one side of the moon to the other. No information can be sent on this moving point of light. So if I had a rod that reached from here to the moon and was able to manipulate it in the same manner that that beam of light is manipulated, has the tip of that rod exceeded the speed of light? -- Doug Who's probably asked this question before ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Doug Pensinger [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Sunday, March 27, 2005 10:50 PM Subject: Re: quantum darwin? Dan wrote: So if I had a rod that reached from here to the moon and was able to manipulate it in the same manner that that beam of light is manipulated, has the tip of that rod exceeded the speed of light? Yes. But, if you work out the forces you would find that the strength of the rod would have to approach infinity as the speed of the tip approaches the speed of light because the mass of the tip would approach infinity as the tip approaches the speed of light. The torque that needs to be applied also approaches infinity. This can be worked out simplest in the reference frame of the earth's center of mass. Since all reference frames are equally valid for doing physics, I'm allowed to pick the simplest. So, the answer really is that, if you had such a rod, you couldn't do that. :-) Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Richard Baker [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Wednesday, March 23, 2005 11:44 AM Subject: Re: quantum darwin? I've read that book and some more technical articles on string theory. While I couldn't claim to understand even bosonic string theory (let alone superstring theory!) at any more than a cursory level, it doesn't remove quantum indeterminacy. Indeed, it's usual so far as I can tell to treat the two-dimensional string worldsheet as the main spacetime and then to consider the coordinates on our large four dimensional spacetime and the bundle of other smaller dimensions as quantum fields on that spacetime using methods akin to those of quantum field theory. Thanks for the boffin backup, Rich. It's nice to know that even plumbers can get theory correct once in a while. :-) Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
The next step in our consideration is a more detailed look at spacelike correlations and hidden variables. In order to do this, we will use measurements at three angles in the x-y plane (with the direction of travel along the z axis. Using the transfer between Cartesian and polar coordinates where (x=1,y0) is radius 1 at 0 deg, and (x=0,y=1) is radius 1 at 90 degrees, we will consider three measurements. at 0 degrees, 37 degrees, and 74 degrees. We will also need to consider what is required for a local hidden variable theory to be valid for spacelike correlations. It should be clear that such a theory cannot include signals sent from one measurement to the other...since we are specifically considering two measurements that are spacelike from each other. For this reason, hidden variable theories had assumed that these hidden variables were set initially, at the point that the two spin 1/2 particles seperated. Using such a theory, the spin that would be measured at any given angle can be considered pre-set. We don't know what the variables are, but we can posit model of underlying mechanics that includes a number of possible variables that would determine what the measurement of spin would be. So, with a local hidden variable theory, a two-particle system would have pairs of preset spins in all directions. For all angles for which particle 1 is pre-set to be measured in the up direction, particle 2 is pre-set to be measured in the down direction. We can check this at all three angles by setting both measuring devices in the same direction. We could look at one million pairs at 0 deg, one million pairs at 37 deg, and one million pairs at 74 deg. We find that, in each direction, we have half a million times that particle 1 is measured up and particle 2 is measured down, and half a million times that particle 1 is measured down and particle 1 is measured up.** With this, we can see that, when both particles are measured in the same direction, there is perfect anti-correlation between the particles. Thus, using the hidden variable theory, we can make the following conclusion: Whenever particle 2 is measured in the up direction, particle 1 has been preset to be measured in the down direction. Whenever particle 1 is measured in the down direction, particle 1 has been preset to be measured in the up direction. As a shorthand, we will call both the actual measurement of particle 1 as up and the measurement of particle 2 as down particle 1 is up, even though we are really saying particle 1 was preset to be up in both cases. OK, having set this up, let us consider measurements in different directions. First we measure one particle at 0 deg, and one at 37 deg. We find particle 1 being up at 0 and 37 degrees 450,000 out of a million, down at 0 and 37 degrees 450,000 times, and down at one angle and up at the other 100,000 times. Thus, we can say that there is a correlation (two up measurements or two down measurements) 90% of the time, when one measurement is at 0 degrees and one at 37 degrees, and anti-correlations 10% of the time. We repeat the experiment at 37 deg. and 74 deg, and find the same results. (Since the assignment of 0 degrees is arbitrary, it would be shocking if we didn't.) So, now we will predict the % of time that there are correlations between 0 deg. and 74 deg. When particle 1 is up at 37 degrees, it is up at 0 deg. 90% of the time and down at 37 deg. 10% of the time. From our measurements at 37 deg. and 74 deg, we know that when particle 1 is up at 37 degrees, particle 2 is also up 90% of the time. If the anti-correlation between measurements at 0 degrees and 74 degrees is maximized, we have the following: up at zero degrees, up at 37 degrees, up at 74 degrees 40% of the time up at zero degrees, up at 37 degrees, down at 74 degrees 5% of the time down at zero degrees, up at 37 degrees, up at 74 degrees 5% of the time Using similar logic, we also get the following results down at zero degrees, down at 37 degrees, down at 74 degrees 40% of the time down at zero degrees, down at 37 degrees, up at 74 degrees 5% of the time up at zero degrees, down at 37 degrees, down at 74 degrees 5% of the time Adding these up we get correlations between the measurements at 0 degrees and 74 degrees at least 80% of the time, and anti-correlations no more than 20% of the time. We can also calculate this number from QM as cos(74 deg)^2 = 64%. This is far less than the minimum predicted by hidden variable theories. What we requried in order to make these predictions are: 1) The ability to count 2) The distributive law of logic: if A (B or C), then (A B) or (A C). 3) Local hidden variables. Either one of these must be dropped or QM is wrong. But, Aspect and other experimentalists have confirmed the predictions of QM for spacelike correlations. Therefore, one is required to drop one the the three assumptions listed above. While philosophers had toyed with quantum
Re: quantum darwin?
A couple of questions about what I believe are typos, but want to make sure: Dan Minette wrote: We can check this at all three angles by setting both measuring devices in the same direction. We could look at one million pairs at 0 deg, one million pairs at 37 deg, and one million pairs at 74 deg. We find that, in each direction, we have half a million times that particle 1 is measured up and particle 2 is measured down, and half a million times that particle 1 is measured down and particle 1 is measured up.** ^ shouldn't that be 2? So, now we will predict the % of time that there are correlations between 0 deg. and 74 deg. When particle 1 is up at 37 degrees, it is up at 0 deg. 90% of the time and down at 37 deg. 10% of the time. From our measurements ^^ shouldn't that be 0? at 37 deg. and 74 deg, we know that when particle 1 is up at 37 degrees, particle 2 is also up 90% of the time. If the anti-correlation between measurements at 0 degrees and 74 degrees is maximized, we have the following: Everything else looked OK to me, but I'm not an expert. :) Julia ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Dan Minette [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Monday, March 07, 2005 11:02 PM Subject: Re: quantum darwin? - Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Monday, March 07, 2005 7:30 PM Subject: Re: quantum darwin? _The Elegant Universe_, Brian Greene. I glanced at that book and saw a couple of references to how string theory should get rid of infinities. I saw nothing that indicated that he said that quantum indeterminacy would go away. Getting rid of infinities is quite plausible, I think. I'm still working on showing how getting rid of indeterminacy would be a shocking reversal of QMakin to finding the aether. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Dan said: I glanced at that book and saw a couple of references to how string theory should get rid of infinities. I saw nothing that indicated that he said that quantum indeterminacy would go away. Getting rid of infinities is quite plausible, I think. I'm still working on showing how getting rid of indeterminacy would be a shocking reversal of QMakin to finding the aether. I've read that book and some more technical articles on string theory. While I couldn't claim to understand even bosonic string theory (let alone superstring theory!) at any more than a cursory level, it doesn't remove quantum indeterminacy. Indeed, it's usual so far as I can tell to treat the two-dimensional string worldsheet as the main spacetime and then to consider the coordinates on our large four dimensional spacetime and the bundle of other smaller dimensions as quantum fields on that spacetime using methods akin to those of quantum field theory. Rich ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Ray Ludenia [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Monday, March 21, 2005 7:14 AM Subject: Re: quantum darwin? On 21/03/2005, at 3:23 PM, Erik Reuter wrote: * Dan Minette ([EMAIL PROTECTED]) wrote: In reletivistic quantum mechanics, this is stated as Spacelike operators must commute. So, going back to our example of two spin 1/2 particles in a spin zero state, if we have call the operator for measuring the spin of particle 1: A and the operator for measuring the spin of particle 2: B, we find that if we perform A then B on the wavefunction BA(|+- + |-+)/sqrt(2) one gets |+- half of the time and |-+ half of the time. (the operator closest to the ket (which is what |s are called) operates first. If we perform B then A, we obtain exactly the same results. There is no difference in the results if you perform A then B or B then A. So, the operators do commute. I have my doubts whether anyone who hasn't taken quantum mechanics could follow that paragraph. But I imagine serious quantum-less people could follow the rest of the post. Except that no one said anything...h I'll say anything then. Seemed clear enough to me. Well, for those who may not, let me try to give a bit of a background on operators. When you operate, you do something...so operators on a QM state do something to that state. Let's take just 1 particle with unknown spin. Call measuring it in the x direction the operator A, and measuring it in the y direction B (it's traveling in the z direction, so both x y are orthogonal to the direction of travel. So, if we measure the particle in the x direction we either get up or down in the x direction. If we measure it in the y direction, we either get up or down in the y direction. But what happens if we do both. If we measure in the X direction first BA|s, we either first get up in the x direction or down in the x direction. In each case, the odds on getting up or down in the y direction are still 50/50. Then we measure in the y direction and either get up or down. If we measure again in the x direction, we find that we are not assured of the same measurement as we first got. In fact, the measurement in the y direction got what is called an eigenstate (a characteristic state) of spin in y, which is a superposition in x. Well, what does that mean? It means that when we measure in the x direction, we now have a 50/50 chance of getting up or down, no matter what we originally measured. So, we see that, when we measure the same particle twice, the operators don't commute. When we measure BA|s we end up knowing the spin in the y direction, but not the x direction. When we measure AB|s we end up knowing the spin in the x direction but not the y direction. But, if we were to do this with a pair of particles in a superposition, with A being the measurement in the x direction of particle 1 and B being the measurement in the y direction of particle 2, the results of AB|12 and BA|12 are the same. We know the spin of particle 1 in the x direction and we know the spin of particle 2 in the y direction. Since AB|12 and BA|12 give the same answer, we say the operators commute (just as 3+5 =5+3 illustrates that addition commutes). But, with two measurements of the same particle AB|s != BA|s, so the operators don't commute (just as 3-5 != 5-3 illustrates that subtraction does not commute. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On 21/03/2005, at 3:23 PM, Erik Reuter wrote: * Dan Minette ([EMAIL PROTECTED]) wrote: In reletivistic quantum mechanics, this is stated as Spacelike operators must commute. So, going back to our example of two spin 1/2 particles in a spin zero state, if we have call the operator for measuring the spin of particle 1: A and the operator for measuring the spin of particle 2: B, we find that if we perform A then B on the wavefunction BA(|+- + |-+)/sqrt(2) one gets |+- half of the time and |-+ half of the time. (the operator closest to the ket (which is what |s are called) operates first. If we perform B then A, we obtain exactly the same results. There is no difference in the results if you perform A then B or B then A. So, the operators do commute. I have my doubts whether anyone who hasn't taken quantum mechanics could follow that paragraph. But I imagine serious quantum-less people could follow the rest of the post. Except that no one said anything...h I'll say anything then. Seemed clear enough to me. All of these hits are basically non-lethal. It was still possible in the '50s and early '60s to consider his hidden variable theory something that would be a theory of real observables once we probed a bit deeper. But, there was a big development in the mid-60s that eliminated hidden variable theories from serious consideration. That will be in the next installment. Ah, EPR coming? Are you saving these for your forthcoming _Physics for Poets_ book? Hardly seems likely. Dan is from the famous shut up and calculate school after all. More likely to be titled _Physics for Non-Metaphysicians_? Regards, Ray. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
* Ray Ludenia ([EMAIL PROTECTED]) wrote: Hardly seems likely. Dan is from the famous shut up and calculate school after all. Huh? Could've fooled me. -- Erik Reuter http://www.erikreuter.net/ ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
* Dan Minette ([EMAIL PROTECTED]) wrote: In reletivistic quantum mechanics, this is stated as Spacelike operators must commute. So, going back to our example of two spin 1/2 particles in a spin zero state, if we have call the operator for measuring the spin of particle 1: A and the operator for measuring the spin of particle 2: B, we find that if we perform A then B on the wavefunction BA(|+- + |-+)/sqrt(2) one gets |+- half of the time and |-+ half of the time. (the operator closest to the ket (which is what |s are called) operates first. If we perform B then A, we obtain exactly the same results. There is no difference in the results if you perform A then B or B then A. So, the operators do commute. I have my doubts whether anyone who hasn't taken quantum mechanics could follow that paragraph. But I imagine serious quantum-less people could follow the rest of the post. Except that no one said anything...h All of these hits are basically non-lethal. It was still possible in the '50s and early '60s to consider his hidden variable theory something that would be a theory of real observables once we probed a bit deeper. But, there was a big development in the mid-60s that eliminated hidden variable theories from serious consideration. That will be in the next installment. Ah, EPR coming? Are you saving these for your forthcoming _Physics for Poets_ book? -- Erik Reuter http://www.erikreuter.net/ ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
The next step I want to consider is the work from the mid thirties to about the mid 60s. During this time, there were two developments that were important to our discussion of the foundation of QM. The first was the development of quantum field theory, or reletivistic quantum mechanics. The second is the development of Bohm's hidden variable theory of QM. Fortunately for us all, we don't need an expansive review of QED to obtain the points relevant to this discussion. QED is a relativistic quantum theory, consistent with special reletivity. Thus, it must be able to explictly handle the SR requirement that there are no faster than light signals. This might seem very difficult, since we've established that, in QM, the wave function can collapse over spacelike intervals. The answer lies in what is a signal. For example, we can make a spot on the moon travel faster than the speed of light. Shoot a laser at the moon and change it's angle. One can make the bright spot travel from one side of the moon to the other in a microsecondwhich is many times faster than the speed of light. But, no signal travels from one side of the moon to the other. No information can be sent on this moving point of light. That is the key definition of a signal that we need to consider. Can information be sent from one spot to another. With quantum superpositons, can I make a measurement of one of the particles and know whether or not my contemporary at the other end already made a measurement. The reason this is critical is that, for spacelike events, A, and B; A is before B in some reference frames, A and B are simulaneous in at least one reference frame, and B is before A in some reference frames. So,. there is no way one should be able to measure B and tell whether A has been measured...if A and B are spacelike. In reletivistic quantum mechanics, this is stated as Spacelike operators must commute. So, going back to our example of two spin 1/2 particles in a spin zero state, if we have call the operator for measuring the spin of particle 1: A and the operator for measuring the spin of particle 2: B, we find that if we perform A then B on the wavefunction BA(|+- + |-+)/sqrt(2) one gets |+- half of the time and |-+ half of the time. (the operator closest to the ket (which is what |s are called) operates first. If we perform B then A, we obtain exactly the same results. There is no difference in the results if you perform A then B or B then A. So, the operators do commute. If one could pass information, one would have a real working ansible. Fortunately, SF writers are able to modify the rules of QM, or we would have missed out on some pretty good novels. But, such things, like db's Uplift series are good fiction and bad science. :-) This theoretical development was a real step forward in the completeness of modern physics. Two theories of physics (SR and QM) are unified. A significant question about the completeness of QM has been answered. Still, there were a number of aestetic reasons why people wanted a more real theory. One of them who had a hunch that there were hidden variables that underlaid QM was David Bohm. In the '50s he developed a hidden variable theory of QM. It was considered fairly problematic at the time. There are several reasons for this. First of all, a physicist is suspicious of any hidden variable. Quarks were considered to be a mathematical convenience until jets were observed. These high transverse momentum events showed structure within protons and neutrons (the way the high angle scatters showed pointlike electrons in the Rutherford scattering experiment.) Now, quarks were very useful, even if they turned out to be a mathematical convenience. One can see the deucouplet in terms of the combination of three quarks: uuu uud udd udd uus uds dds uss dss sss Where u is the up quark, d is the down quark and s is the strange quark But, the order didn't need to come from structure within these hadrons; it could have been just a property of the system. But, two things happened, then. First, a fourth quark was predicted, and evidence for that fourth quark was found. Second, as mentioned above, jets were found. At this point, quarks became well established. It may seem funny for physicists to worry about something that sounds ontological; especially shut up and calculate physicists. Part of it, is a question of permanence. Mathematical conveniences can be dropped in a split second, when something slightly better comes along. Physicists do not want to say something exists and then say it doesn't, and then say it does, etc. Second, physicists are suspicious of really there, but you can't see it. The reason for this is that it's quite straightforward to develop a mechanism, such as the asymptotic freedom of quarks, to explain why these real things can never bee observed independently. If one allows the unconstrained existence of real but unobserved
Re: quantum darwin?
Since there didn't seem to be objections to the last bit of formalism, let me take the next step. I would like to consider a system of two spin 1/2 particles produced from a spin 0 state. As an aside, actual experiments that have been conducted are a bit more complicated than this idealized experiment. But, this simplified example is useful in the same sense that examples of perfectly elastic collisons are useful in understanding classical mechanics. QM describes two spin 1/2 particles coming out a spin zero state as a superpositon: (|+- + |-+)/sqrt(2). |+- is defined as particle 1 with spin up and particle 2 with spin down |-+ is defined as particle 1 with spin down and particle 2 with spin up. One thing we can immediately see is that if one particle is measured up, the other one should be measured down. This makes sense, if both of them were up in the same direction, angular momentum would not be a conserved quantity, since we would have a spin zero state turning into either a plus 1 or a minus 1 state. And, we can do the experiment, and find that, to within experimental errors, there is 100% anti-correlation between the spin of these particles. Fairly early on, by the mid-30s, the fact that these correlations, according to the formalism of QM, could be spaceline. Einstein Podanski and Rosen pointed this out in their 1935 paper...and arrieved at conclusions concerning the completeness of QM. This work has been generalized, and called the EPR paradox. The paper itself can be found (as .jpg files from scanning) at http://www.burgy.50megs.com/epr.htm It's a bit hard to read, but I was able to go through it. As the paper states, Einstein thought this showed the incompleteness of QM. But, the work of Bell and the experimental work of Aspect and the other experimentalists who have found spacelike correlations show that the spacelike collapse of the wavefunction into eigenstates is not evidence for the incompleteness of QM. Rather, it is an experimentally testable prediction of QM. Experimental observations have been made confirming the predictions obtained when the QM formalism of the spacelike* collapse of the wavefunction occures. But, before going on with that, I'd like to stop again and be sure that Warren, Ray and others who are following along agree with my explaination of this. I'd appreciate a short yes or no on this. Dan M. ** Spacelike is a term that refers to two events in space and time that cannot be connected by a signal. For example, let's say Cassia is suppose to fire it's engines to enter Saturn's orbit at time t. On earth, we cannot know whether this happened before t+d/c, where d is the distance from Saturn to the earth. If d/c is 30 minutes, then the event of the firing/non fireing of the engine and the event of the observer listening to telemetry are spacelikeit is impossible to send a signal from one to the other. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On 13/03/2005, at 9:57 AM, Dan Minette wrote: The best place to start, I think, is spin. My old foundations of QM teacher said that spin was probably the most QMish of all the aspects of QM. So, lets consider a spin 1/2 particle: the electron. Spin is intrinsic angular momentum. It cannot be the real spinning of the electron without the surface of the electron going faster than the speed of light. So, here we have one new feature alreadyintrinsic angular momentum without any observable motion. In any given direction, a measurement of the spin of the electron gives either +1/2 or -1/2. If one measures the spin of the electron as up in a given direction, and then remeasures it at an angle 2x from the original direction, one gets up again cos(x)^2 of the time and down sin(x)^2 of the time. For example, if one measures at 180 degrees, x=90 degrees, cos(x)^2 =0 and sin(x)^2=1. This makes sense, because at 180 degrees, one should always get down. If one measures at 90 degrees, x=45 degrees. At that angle, cos(x)^2=.5, sin(x)^2=.5which also makes sense. To get this, the wave function is given as sin(x)*|d + cos(x)*|u ...a superposition of two eigenstates: |d (spin down) and |u (spin up). The wavefunction itself is not an observable, we only observe the eigenstates. When this was first developed, Einstein accepted that the formalism worked, but he thought that the indeterminacy inherent in this formalism would eventually be replaced by a more deterministic physics. Attempts to develop this has been labeled hidden variable theories, because they assume that there are more classical variables that we don't see yet underlying QM. But, I want to make sure that this step in the formalism is accepted first. If this doesn't make sense, I need to clarify it before going on. (Lurkers are encouraged to unlurk and ask questions if they need clarification.) So far it's at just the right level for me. Not sure how long I'll be able to keep up though! You are bringing back some memories from 35 years ago, so I'm pretty rusty. I don't think I ever really got the idea of eigenstates at the time. Earlier you wrote: Are you familiar with eigenstates and superpositions? For example, if you measure the spin in the x direction, the spin in the y (which is orthogonal to x) is a superposition of up and down. |s = ( |+ + |-)/sqrt(2). which is now much clearer to me than before. Sin(x)^2 and cos(x)^2 refer to probability amplitudes iirc, though why the angle used to remeasure is 2x momentarily escapes me. Anyway, hope you and Warren manage to keep the discussion going as I am finding it most interesting. I'd like to join in some, but time seems to be at a premium. Regards, Ray. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Ray Ludenia [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Sunday, March 13, 2005 7:09 AM Subject: Re: quantum darwin? which is now much clearer to me than before. Sin(x)^2 and cos(x)^2 refer to probability amplitudes iirc, though why the angle used to remeasure is 2x momentarily escapes me. Because it fit the data. :-) Let's look at a particle traveling in the z direction, and treat the xy dimentions in polar coordinates. If we measure at 0 degrees and get up, that is the exact same thing as measuring at 180 degrees and getting down. (use yourself as the pointer, with up as your head and down as your feet. If you were standing on your feet and said something was up, and then stood on your head, if it didn't move, it would now be down in your new coordinate system.) From symmetry, we see that at 90 degrees, (in the y direction) we are equally likely to measure up and down in the y direction after measuring up in the x direction. If we call the angle a, we see that sin(a)^2 and cos(a)^2 do not cut it, because the probability of down is 100% at 90 degrees and 0 % at 180 degrees, after measuring up at 0 degrees. But, sin(a/2)^2 and cos(a/2)^2 do work. So, intermediate values were tried, and they fit. This brings out an important part of sciencethe idea is to find an explaination that first fits and then predicts observations. When the data do not fit established theories, phenomenology is first used. An example of this is the Bohr atom. Electrons really couldn't orbit the nucleus in a classical manner, Bohr knew that. But, he did have a rough model that explained some of the data. Later, with the Copenhaugen school of physicists, he put together the first real quantum theory. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Friday, March 11, 2005 2:17 PM Subject: Re: quantum darwin? On Mar 7, 2005, at 10:02 PM, Dan Minette wrote: [those are some good refs, Dan -- I need some time to digest them though. ;) ] This is getting close to the time where the introduction of a bit of formalism might be helpful. I think I can do it without going too deep into the math. That's probably good. It has been lo many a moon since I've cracked calculus in any depth. But, first let me ask you a question. Are you familiar with eigenstates and superpositions? For example, if you measure the spin in the x direction, the spin in the y (which is orthogonal to x) is a superposition of up and down. |s = ( |+ + |-)/sqrt(2). Is that something you've seen and feel comfortable with discussions that assume that you know it? Not quite yet. Is there anything even approximating a usable metaphor, or something out of more classical physics I could assimilate more readily? The problem with metaphors from classical physics is that they ignore the reasons why the change to QM had to be made. Instead, I think one needs to wade in and actually consider the data as they are. In other words, one has to at least be willing to shut up and calculate. and table any questions about how things could actually be that way. The best place to start, I think, is spin. My old foundations of QM teacher said that spin was probably the most QMish of all the aspects of QM. So, lets consider a spin 1/2 particle: the electron. Spin is intrinsic angular momentum. It cannot be the real spinning of the electron without the surface of the electron going faster than the speed of light. So, here we have one new feature alreadyintrinsic angular momentum without any observable motion. In any given direction, a measurement of the spin of the electron gives either +1/2 or -1/2. If one measures the spin of the electron as up in a given direction, and then remeasures it at an angle 2x from the original direction, one gets up again cos(x)^2 of the time and down sin(x)^2 of the time. For example, if one measures at 180 degrees, x=90 degrees, cos(x)^2 =0 and sin(x)^2=1. This makes sense, because at 180 degrees, one should always get down. If one measures at 90 degrees, x=45 degrees. At that angle, cos(x)^2=.5, sin(x)^2=.5which also makes sense. To get this, the wave function is given as sin(x)*|d + cos(x)*|u ...a superposition of two eigenstates: |d (spin down) and |u (spin up). The wavefunction itself is not an observable, we only observe the eigenstates. When this was first developed, Einstein accepted that the formalism worked, but he thought that the indeterminacy inherent in this formalism would eventually be replaced by a more deterministic physics. Attempts to develop this has been labeled hidden variable theories, because they assume that there are more classical variables that we don't see yet underlying QM. But, I want to make sure that this step in the formalism is accepted first. If this doesn't make sense, I need to clarify it before going on. (Lurkers are encouraged to unlurk and ask questions if they need clarification.) Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 7, 2005, at 10:02 PM, Dan Minette wrote: [those are some good refs, Dan -- I need some time to digest them though. ;) ] This is getting close to the time where the introduction of a bit of formalism might be helpful. I think I can do it without going too deep into the math. That's probably good. It has been lo many a moon since I've cracked calculus in any depth. But, first let me ask you a question. Are you familiar with eigenstates and superpositions? For example, if you measure the spin in the x direction, the spin in the y (which is orthogonal to x) is a superposition of up and down. |s = ( |+ + |-)/sqrt(2). Is that something you've seen and feel comfortable with discussions that assume that you know it? Not quite yet. Is there anything even approximating a usable metaphor, or something out of more classical physics I could assimilate more readily? It appears that there is some interest in the fundamentals of the issues, and I wouldn't mind putting together some stuff on those fundamentals. If there's a way to make QM look less totally outrageous (which means, to me, less metaphysical), I'd certainly be interested in exploring it. :D -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On 08/03/2005, at 8:23 AM, Warren Ockrassa wrote in a fascinating exchange with Dan: Or the suggestion that detecting things a given way once will set pointers such that those things will more naturally tend that way in the future. Seems that is just a more radical expression of the Practice Effect! Regards, Ray. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
My understanding is that physicists who talk about you as the observer who causes a collapse of a wave function, who say that ... observing an experiment is what changes its outcome ... are being solipsistic, since none can prove that there is anything outside of oneself. They try to speak logically and so say only what they are sure of, which in this case is what *you* (not me, themselves, or any third party observer) do, because they can not prove to you that they exist. Others are deists who say that one or more Gods are always observing, both here and near Alpha Centauri.* A few are Tiplerians and figure that probabilistically speaking we are not living in a real universe (since that happens only once) but in a computer simulation (which may happen many times). Most likely, the simulation is run by an AI with antiquarian interests. The AI is the entity who invented the physics for this run and is having fun watching how his beings respond. Yet others figure that things outside of you exist, but know perfectly well they cannot prove that, although they can introduce suggestive arguments. Perhaps I misunderstand, but if someone takes the last position, then might a quantum wave form collapse when enough of the `outside universe' intervenes? Thus, Schrödinger's Cat might not exist in two states for long; but a BEC would. -- Robert J. Chassell [EMAIL PROTECTED] GnuPG Key ID: 004B4AC8 http://www.rattlesnake.com http://www.teak.cc * As Ronald Knox wrote, There once was a man who said God Must think it exceedingly odd If he find that this tree Continues to be When there's no one about in the Quad. To which there came this reply, Dear Sir, Your astonishment's odd: I am always about in the Quad. And that's why the tree Will continue to be, Since observed by Yours faithfully, God ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 5, 2005, at 8:24 AM, Dan Minette wrote: The important thing to take away from this quote is the size of the BEC, several millimeters. That is definitely macroscopic, it's a size that you see on a grade student's ruler. That is compelling, and not something I'd been aware of earlier. I've not kept up with the latest experiments, but I have read papers detailing spacelike correlations over 10 miles, spacelike correlations without inequalities, and spacelike correlations of molecules. This aspect of QM has been rigorously verified. Some of that I've heard of. This is also very compelling, but I'm not sure that it really pulls the plug on my POV. What I mean is that showing something like connection over space between photons or even large-scale indeterminacy effects is very interesting, and I don't doubt the legitimacy of the finds. It's the conclusions that I have trouble with. The elimination of the glass wall is striking but the conclusion many are led to -- that observing an experiment is what changes its outcome -- is what I have trouble with. It imputes a power to consciousness that is, at best, quasi-psychic. To me the more conservative (!) explanation is that there is definitely something going on, but if we think that it's because we're watching, we're guilty of hubris. Hmm, analogy time -- the EM spectrum. How many centuries was it thought that visible light was it? And now we know better -- radio waves, for instance, are not visible at all, but they're on the EM continuum. Until our technology had advanced enough, we simply couldn't possibly have been aware of their existence. So what I'm suggesting is that QM is pointing to something we haven't perceived yet, for some reason or other, sort of like Marie Curie and her fogged film. We'll get there, maybe, but the apparent weirdness in QM is not, I think, a full description of the nature of our universe. Have you had a chance to look into superstring ideas? One thing that goes away with that is the inability to determine a particle's location and motion simultaneously, and it seems superstring theory predicts gravity in a way QM does not. Superstrings could well be a blind alley, but they do seem to more elegantly explain a lot of subatomic interactions. Either you missed most of what I wrote or I didn't express it correctly. I'm not disputing that the equations in QM seem to show the things they seem to show. What I am suggesting is that the wrong conclusions are being reached, and that it could be because we're missing something fundamental. I'm think I see where you are coming from. I've been having this discussion with folks who've made similar comment for years, now. There is one important feature concerning new theories that is fairly evident to those of us who've taken 6+ years of classes in physics, and probably is not apparent to those who haven't had to do that. :D Older theories are not rejected when data requires new theories; they are kept as special limit value cases of the new theories. OK, so an analogy there might be special relativity, in contrast to general relativity? Classical mechanics, as well as classical electrodynamics are still taught in all graduate schools. They are not false in the sense that the caloric theory of heat is false, they are just valid to a certain precision and over certain ranges. This I understand also. There isn't a physicist working in QM today who won't say that QM is incomplete. In other words, we don't yet have the Grand Unified Theory of Everything. Yeah, that's basically it -- and I sometimes wonder if we're any nearer it than we thought we were 100 years ago. To me the very counterintuitive nature of QM is one sign that, no matter how much it works, there's something underneath that we're missing, some key concept or aspect of reality that we're just overlooking. The hard-nosed rationalist in me balks at the idea of of observation affecting reality, and the qD approach is, to me at least, the latest fanciful expression of a theoretical structure that's getting a bit overtaxed. I mean there are too many conclusions being drawn, too fast, about what QM means when we don't even really fully understand QM. That's not a safe approach to take. it has no provision for gravity, and there are (last I checked) eleven possible and totally different interpretations of what QM means in the universal context. Well, I know of four main groups: Copenhaguen, MWI, one that involves backwards in time signals, and one that involves FTL signals in some unknown fixed reference frame. With variants, though I can't list them because my reference materials are (or not! ;) in storage right now. But the dozen or so number sticks out to me. But, that is a comment on the meta-physical position of the physicists. Since each interpreation, by definition, is a description of the exact same data, the differences between the interpreations are philosophical, not
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Monday, March 07, 2005 3:23 PM Subject: Re: quantum darwin? A quick reply with a question. Have you had a chance to look into superstring ideas? One thing that goes away with that is the inability to determine a particle's location and motion simultaneously, Given the fact that local realistic hidden variable theories have been falsified (both in the sense that they have formally been shown to result in predictions at odds with the predictions of QM and in the sense that the QM predictions for spacelike correlations have been experimentally verified), I tend to doubt any claims that a new theory is a local realistic hidden variable theory. To refresh my memory (I first heard about string theory about 25 years ago when the founder gave a physics colloquium at Wisconsin) I went and looked at a few websites. None mention non-locality or indicate that superstring theory is a realistic hidden variable theory. None indicate that it is nonlocal. All indicate that, at small enough scales, the indetermancy is in the structure of spacetime itself. Can you point out where you got this impression? One problem with popular explainations is that it is very easy to write an explaination that gives the lay reader the wrong impression on a key point. I'm guessing that happened here. BTW, I did see the site on the slits in time and I'll reply in some depth later. A quick response is that this is a neat experiment, but the results it gives are very standard and should be expected from elementary QM. I'd be shocked if it didn't turn out that way. :-) Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 7, 2005, at 5:46 PM, Dan Minette wrote: Have you had a chance to look into superstring ideas? One thing that goes away with that is the inability to determine a particle's location and motion simultaneously, Can you point out where you got this impression? _The Elegant Universe_, Brian Greene. He portrays the problem, IIRC, of particle interactions, describing how a pair of loops would interact in a way different from two particles -- they'd join for a while, forming one loop with different properties, and then separate once again into individual loops. Since we see this as a point-particle interaction, my understanding is that we have a hard time determining when or where the interaction actually takes place. Unfortunately the book is, like 99 44/100% of my life, in storage. So I can't dig up the reference or backcheck it. :\ And Greene is obviously a partisan, so whatever alternate explanations exist might get short shrift in his own arguments. Nova/PBS did a program a while back: http://www.pbs.org/wgbh/nova/elegant/ But I don't recall this part of it being discussed. Maybe it was deemed too deep for the audience. Or too abstract! -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Warren Ockrassa wrote: On Mar 7, 2005, at 5:46 PM, Dan Minette wrote: Have you had a chance to look into superstring ideas? One thing that goes away with that is the inability to determine a particle's location and motion simultaneously, Can you point out where you got this impression? _The Elegant Universe_, Brian Greene. I've read the book but got exactly the opposite impression. Greene himself admits that String Theory is far from unifying QM, GR, and SR. There is a lot of interesting hypothesising in the book, and it is a great read indeed, but for the greatest part it is a well organized collection of untested ideas. Worthy ideas I am sure, but not past the test of falsifiability. xponent Loved It Maru rob ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Monday, March 07, 2005 7:30 PM Subject: Re: quantum darwin? On Mar 7, 2005, at 5:46 PM, Dan Minette wrote: Have you had a chance to look into superstring ideas? One thing that goes away with that is the inability to determine a particle's location and motion simultaneously, Can you point out where you got this impression? _The Elegant Universe_, Brian Greene. He portrays the problem, IIRC, of particle interactions, describing how a pair of loops would interact in a way different from two particles -- they'd join for a while, forming one loop with different properties, and then separate once again into individual loops. Since we see this as a point-particle interaction, my understanding is that we have a hard time determining when or where the interaction actually takes place. OK, I think there may be a problem with making a conclusion from a metaphor, then. If you look at a decent fairly non-technical explanation at: http://www3.sympatico.ca/brianfp/topics/essays/444/html/doc.html which seems to be a senior physics project, we see the following quote: quote Although the Heisenberg Uncertainty Principle ensures that we will never measure a particle's exact position in space, space itself is considered in the standard model to be continuous. This idea may be incompatible with superstring theory. Since quantum mechanics already dictates an uncertainty in a particle's coordinates in space and time, as well as its energy, why not extend this idea further, and hypothesize that space itself may not be continuous on the microscopic scale? This is in fact a prediction of superstring theory, which we will consider later. end quote In short, superstring theory, as is stated elsewhere has more indeterminacy than standard QM. Another site which has a better explanation of superstring theory is: http://www.superstringtheory.com/ which is a sorta official site of folks involved in it. This is getting close to the time where the introduction of a bit of formalism might be helpful. I think I can do it without going too deep into the math. But, first let me ask you a question. Are you familiar with eigenstates and superpositions? For example, if you measure the spin in the x direction, the spin in the y (which is orthogonal to x) is a superposition of up and down. |s = ( |+ + |-)/sqrt(2). Is that something you've seen and feel comfortable with discussions that assume that you know it? It appears that there is some interest in the fundamentals of the issues, and I wouldn't mind putting together some stuff on those fundamentals. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Dan Minette wrote: ... Looking at the web, experiments are now ongoing to have superpositions of macroscopic currents, using a Josephine junction. It is always possible that QM will break down at this point, and that there is exciting new physics somewhere around mesoscopic physics. I would rate it as improbable, because one would have thought that the BEC work would not have followed theoretical expectations if some a macroscopic effect existed. Yet, as an experimentalist, I strongly support pushing things as far as we can go in hopes of finding new physics. ... Is that similar to a Josephson junction? ~Maru ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
At 04:11 PM Sunday 3/6/2005, maru wrote: Dan Minette wrote: ... Looking at the web, experiments are now ongoing to have superpositions of macroscopic currents, using a Josephine junction. It is always possible that QM will break down at this point, and that there is exciting new physics somewhere around mesoscopic physics. I would rate it as improbable, because one would have thought that the BEC work would not have followed theoretical expectations if some a macroscopic effect existed. Yet, as an experimentalist, I strongly support pushing things as far as we can go in hopes of finding new physics. ... Is that similar to a Josephson junction? The distaff version, no doubt . . . Me Too Maru --Ronn! :) ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Thursday, March 03, 2005 11:25 PM Subject: Re: quantum darwin? Also, its worth noting, that there have been experimental confirmation of macroscopic quantum statesnot just macroscopic effects. Do you mean the electron-slit thing, or are you referring to something else here? Definitely something else. The two slit experiments were, goodness, 80 years ago. A great deal has been done since then. I was specifically thinking about Bose-Einstein condensates. An article on this is given at: http://www.strangehorizons.com/2001/20011210/bose-einstein.shtml The essay is a bit pop-scienceish, so some of the stuff shouldn't be taken literallybut it's better than most, the discussion of intrinsic spin, for example, is a pretty good layman's description. Anyways, a relevant quote, referring to my point is: quote One of the problems physicists run into when teaching quantum mechanics is that the principles are just counter-intuitive. They're hard to visualize. But videos of BEC blobs several millimeters across show wave-particle duality at a level we can comprehend easily. We can watch something that acts like an atom, at a size we could hold in our hands. MIT researchers have produced visible interference fringe patterns from sodium BECs, demonstrating quantum mechanics effects on the macroscale. That alone is worth notice. end quote The important thing to take away from this quote is the size of the BEC, several millimeters. That is definitely macroscopic, it's a size that you see on a grade student's ruler. The most important work on the foundations of QM, until perhaps the most recent work on a QM theory of QM measurement, has been Bell-Wigner. Einstein, Podansky, and Rosen showed in the '30s that QM predicted the existence of space-like correlations. In the '60s, Bell and Wigner showed that these correlations could not be the result of local hidden variables. The only way for these correlations to be supported by a more deterministic set of variables is if these variables either went faster than light in some ultimate fixed reference frame (which we might as well call the aether), or if they went backwards in time. It was always possible, of course, that these spacelike correlations did not occur. We could see QM break down in that regimeno one thought it likely, but it was possible. In the last 20 years or so, a number of experiments have been done with spacelike correlations. I've not kept up with the latest experiments, but I have read papers detailing spacelike correlations over 10 miles, spacelike correlations without inequalities, and spacelike correlations of molecules. This aspect of QM has been rigorously verified. Looking at the web, experiments are now ongoing to have superpositions of macroscopic currents, using a Josephine junction. It is always possible that QM will break down at this point, and that there is exciting new physics somewhere around mesoscopic physics. I would rate it as improbable, because one would have thought that the BEC work would not have followed theoretical expectations if some a macroscopic effect existed. Yet, as an experimentalist, I strongly support pushing things as far as we can go in hopes of finding new physics. Finally, I'll address in another post a common fallacy concerning the ways that old theories are supplanted by newer theories (i.e. Classical Electrodynamics being replaced by QED). I've seen that misconception lead to a lot of difficulties for alternate thinkers on sci.physics, alt.sci.physics, etc. Dan M. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Friday, March 04, 2005 12:09 PM Subject: Re: quantum darwin? On Mar 3, 2005, at 11:24 PM, Dan Minette wrote: But, you miss why QM is defended as it is. The reaction is as though you said but evolution is just a theory. What would be helpful in thinking about this is asking why Feynman's response was to say shut up and calculate instead of pursuing the same intuative path Einstein didand why his sucessors agreed with that assessment. Either you missed most of what I wrote or I didn't express it correctly. I'm not disputing that the equations in QM seem to show the things they seem to show. What I am suggesting is that the wrong conclusions are being reached, and that it could be because we're missing something fundamental. I'm think I see where you are coming from. I've been having this discussion with folks who've made similar comment for years, now. There is one important feature concerning new theories that is fairly evident to those of us who've taken 6+ years of classes in physics, and probably is not apparent to those who haven't had to do that. Older theories are not rejected when data requires new theories; they are kept as special limit value cases of the new theories. Let me give one example. As you know energy of an object in a reference frame, according to classical mechanics is (1/2)mv^2. In relativistic mechanics, the total energy is mc^2, where m is the relativistic mass. How does this work out. Well, the relativistic mass is m0/sqrt(1-(v/c)^2), where m0 is the invarient mass, or the rest mass. Expanding that into a series we have mr= m0 + 1/2m(v/c)^2.. For low v, higher order terms are negligable. So, dropping those higher order terms, we have for the total energy, (m0 + 1/2m(v/c)^2)*c^2 =m0c^2 + 1/2mv^2. The second term is classical kinetic energy. Classical mechanics, as well as classical electrodynamics are still taught in all graduate schools. They are not false in the sense that the caloric theory of heat is false, they are just valid to a certain precision and over certain ranges. In the same manner, when Electroweak was developed, QCD was not regulated to the trashbin. Rather, people just looked for small effects of the mixing between electromagnetic and weak forces. They even found them in atomic physics, which I thought was neat. So, I would certainly hope that John Baez and friend's work in foamy space continues to pay off and that we will have a rough outline of quantum gravity in the next 5-25 years. When that happens, present theories will be seen as special cases of the new, more general theory. It will probably take a lot longer to formally derive them, but I would guess that is doable. But, when it happens, you can bet that the present theories will survive as special cases of the new theories. Over the ranges of precision, energies, size, etc. that they have been valid, they will continue to be valid. While nothing in the future is absolutely certain, it would be akin to going back to the caloric theory of heat or electromagnetic waves propegating in a material aether to go back to classically behaving particles. The most important reason for this is the fact that local hidden variable theories have been experimentally falsified. Thus, numerous experiments would have had to have gotten the wrong results for there to be local hidden variable theories. There isn't a physicist working in QM today who won't say that QM is incomplete. In other words, we don't yet have the Grand Unified Theory of Everything. Sure, no one will claim that we have QM gravity, for example, or that we've nailed down QCD like we have QED. It's inelegant, It's extremely elegant, IMHO. For example, Classical Electrodynamics has been formally deduced from QED. But, I can see how popular descriptions will not be elegant. it has no provision for gravity, and there are (last I checked) eleven possible and totally different interpretations of what QM means in the universal context. Well, I know of four main groups: Copenhaguen, MWI, one that involves backwards in time signals, and one that involves FTL signals in some unknown fixed reference frame. The biggest group among physicists are the interpretation agnostics: shut up and calculate. After that, its Copenhaguen and MWI that has the vast majority, with only a few professionals in the last two groups. But, that is a comment on the meta-physical position of the physicists. Since each interpreation, by definition, is a description of the exact same data, the differences between the interpreations are philosophical, not scientific. There are apparent self-contradictions as well. I referred earlier to the slit experiment's being reproduced on the time axis. I've looked the abstracts for papers on quantum effects with moving detectors, and I don't think that's
Re: quantum darwin?
Warren Ockrassa wrote: What's funny is that I regularly sense a strong commitment to QM (not just in you), one that isn't comfortable with conceding that, since QM is incomplete, it's possible that some of its conclusions are false. Almost as though it's a religion. So what about indeterminacy? xponent More Questions Maru rob ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 3, 2005, at 11:24 PM, Dan Minette wrote: But, you miss why QM is defended as it is. The reaction is as though you said but evolution is just a theory. What would be helpful in thinking about this is asking why Feynman's response was to say shut up and calculate instead of pursuing the same intuative path Einstein didand why his sucessors agreed with that assessment. Either you missed most of what I wrote or I didn't express it correctly. I'm not disputing that the equations in QM seem to show the things they seem to show. What I am suggesting is that the wrong conclusions are being reached, and that it could be because we're missing something fundamental. There isn't a physicist working in QM today who won't say that QM is incomplete. It's inelegant, it has no provision for gravity, and there are (last I checked) eleven possible and totally different interpretations of what QM means in the universal context. There are apparent self-contradictions as well. I referred earlier to the slit experiment's being reproduced on the time axis. If there really is such a thing as qD and state pointers, how can the slit experiment along the time axis work? Wouldn't a particle's emission *history* be enough to set the later state pointers such that all later particles emit in the same way? You'd think so, if there were real meat to quantum Darwinism, yet experiment indicates otherwise. An incomplete set of equations with multiple interpretations and apparently contradictory outcomes is not a basis on which to judge larger issues about the universe. You seem to think I'm taking a great leap of faith here, but I'm not the one acting on faith, or at least I don't see how I am. Not by pointing out that QM is probably telling us more than we realize about *ourselves* than it ever will about the universe we live in. Which, for the record, we do not make up as we perceive it. I can think of at least two very practical thought experiments to prove that assertion beyond reasonable argument. -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 4, 2005, at 4:26 AM, Robert Seeberger wrote: Warren Ockrassa wrote: What's funny is that I regularly sense a strong commitment to QM (not just in you), one that isn't comfortable with conceding that, since QM is incomplete, it's possible that some of its conclusions are false. Almost as though it's a religion. So what about indeterminacy? I've been ruminating that one for a while. Indeterminacy sure does look like it's there (though superstring proponents believe they've explained that one, and I'm half inclined to agree), but TTBOMK we only see indeterminacy with subatomic particles, and then only some of them, such as electron or photon wavicles. When you're looking at a macroscopic item -- sure, why not, Buckingham Palace -- indeterminacy is overwhelmed by other, much larger effects. That's why, for instance, all the particles in your body don't just randomly decide to vaporize at once. You might get some state changes on the subatomic level because of indeterminacy, but think of it as a finite chance of any one indeterminacy effect happening at any one point in any one entity, and then in fairly ordered ways, as in electron shells -- where exactly in the shell the electron is is indeterminate; but it's proximally certain that it is *someplace* within that shell zone. So you do get indeterminacy in a human body, but if at any one point the likelihood of loss of a single electron to it is, say, 1:1,000,000 (I don't know at all what the odds are of various indeterminate effects happening, but it wouldn't surprise me to know that someone has calculated it), you'd have to poll one million electrons each moment before you were reasonably sure of losing *one* to indeterminacy. That's a lot of electrons, and if your odds of losing one are balanced out by similar odds of gaining one, you still get an outcome that is simply too small to notice. The net effect is toward coherence, not randomization. QM's indeterminacy effects are really quite small. If it were otherwise, we'd have a pretty interesting cosmos, with stochastic tunneling taking place all the time on the macroscopic scale and things spontaneously passing through other things. (As just one example.) -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 3, 2005, at 2:50 AM, d.brin wrote: FYI Natural Selection Acts on the Quantum World - (Nature - December 23, 2004) http://www.nature.com/news/2004/041220/pf/041220-12_pf.html I saw the same idea floated a couple months back on another list. My reaction then is what it is now: What a load of anthropocentric crap. Here's why. The article has this statement: Because, as Zurek says, the Universe is quantum to the core, this property seems to undermine the notion of an objective reality. In this type of situation, every tourist who gazed at Buckingham Palace would change the arrangement of the building's windows, say, merely by the act of looking, so that subsequent tourists would see something slightly different. Yet that clearly isn't what happens. == Yeah? Prove it. The suggestion that the universe is as it is because we see it that way -- and that what exists around us is somehow inherited from some predecessor consciousness -- is no different from the assertion that we shape the universe each moment by our simple interaction with it. IOW until I woke up this morning nothing else in the world existed. In fact I never even woke up. I only came into existence a fraction of a second ago, with a collection of false memories of a history that never happened. I certainly can't think of a way to prove, beyond any shadow of possible doubt, that Buckingham Palace has not been changed by observation; in fact, I bet it can't be proved totally that it *exists*. This is such a blatant load of horse dung that it should go a long way toward driving a coffin nail or two into the entire QM paradigm. I'm not trying to suggest that QM is 100% wrong. But when you're studying something that leads you to such a clearly bizarre assertion -- that we've observed the universe into existence, essentially -- either the underpinning of QM is fundamentally flawed, or our perceptions of reality are. Or, at the very least, understanding of QM is faulty. The strange effects that take place on the quantum level don't have to manifest on the grosser levels, after all. Indeterminacy for a single quark in a brick doesn't cause an entire palace's façade to change. The other problem I have with the idea of quantum Darwinism is that you more or less have to assume a god. That's actually *more* likely to be true, in my mind, than quantum Darwinism. It's much more likely that the fault lies in our ability to perceive, not in what it is we are observing. -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Thursday, March 03, 2005 1:32 PM Subject: Re: quantum darwin? On Mar 3, 2005, at 2:50 AM, d.brin wrote: FYI Natural Selection Acts on the Quantum World - (Nature - December 23, 2004) http://www.nature.com/news/2004/041220/pf/041220-12_pf.html I saw the same idea floated a couple months back on another list. My reaction then is what it is now: What a load of anthropocentric crap. Here's why. The article has this statement: Because, as Zurek says, the Universe is quantum to the core, this property seems to undermine the notion of an objective reality. In this type of situation, every tourist who gazed at Buckingham Palace would change the arrangement of the building's windows, say, merely by the act of looking, so that subsequent tourists would see something slightly different. Yet that clearly isn't what happens. == Yeah? Prove it. Are scientific proofs acceptable to you? Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 3, 2005, at 1:56 PM, Dan Minette wrote: Are scientific proofs acceptable to you? Possibly. If you read the rest of my criticism of the underlying principles, you'll see there's far too much wiggle room. I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Erik Reuter [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Thursday, March 03, 2005 3:10 PM Subject: Re: brin:quantum darwin? Did I imagine the _Nature_ reference (Dec 2004) right at the top of the post and collaspe the wave function? No, Nature is not a physics journal. I read the news reference and wanted to see if there was a physics publication, which would go into more of the detail I was interested in. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Warren Ockrassa wrote: On Mar 3, 2005, at 1:56 PM, Dan Minette wrote: Are scientific proofs acceptable to you? Possibly. If you read the rest of my criticism of the underlying principles, you'll see there's far too much wiggle room. I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. So.in your opinion Schrodringers Cat is a false or unfalsified theory? The weak or strong anthropic theories? (Be warned..I may want to use your argument for a story I am outliningG) xponent Scanning Tunneling Organ Of Love Maru rob ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
Warren Ockrassa wrote: On Mar 3, 2005, at 1:56 PM, Dan Minette wrote: Are scientific proofs acceptable to you? Possibly. If you read the rest of my criticism of the underlying principles, you'll see there's far too much wiggle room. I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf So I take it you don't like the Copenhagen interpretation, Warren. But, what do you think of the other interpretations, like the Tegmark multiverse? ~Maru ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
[two replies combined here, one to RS and one to maru] On Mar 3, 2005, at 4:18 PM, Robert Seeberger wrote: Warren Ockrassa wrote: I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. So.in your opinion Schrodringers Cat is a false or unfalsified theory? Schrödinger's Cat is not a theory; it's a model to illustrate one of the more unusual effects of QM at a subatomic level. It's a kind of real-world interpretation of (example) the electron slit experiment (BTW, apparently that experiment has been replicated in a modified way, this time along the time axis -- and it still happens.) I know that there are various tests that confirm observation appears to cause some events to collapse into realities that, until the observation is made, don't exist (or exist equally, which amounts to the same thing). I'm not questioning that the math behind QM, the science, appears to work. I am simply suggesting that there are some very wrong conclusions being drawn about how the universe happens, and they're based in QM. Or rather, we are vastly miscomprehending what QM is telling us about ourselves. The weak or strong anthropic theories? Those aren't valid either, IMO; I think they're inverses of the situation. That is, we seem to think this universe is ideal for (weak:life || strong:human life) because we happen to live in it. Well, obviously if nothing lived in a given universe, one conclusion to be drawn would be that it's nonoptimal for life, but there wouldn't be anyone there to figure that out. It's only the inhabited universe/s where you get life saying, Huh, how interesting; if things weren't just so, we wouldn't be here... Let me express that in a slightly different way. Imagine a gingerbread man looking at the cookie cutter that has just cut him out of the dough. He thinks to himself, Gosh, it sure is amazing how well that cutter mold fits around me -- obviously this cutter has to exist in this way. That would be the strong piskotothropic principle. Or he might think, If the conditions of this oven weren't just right, I couldn't be baking here in this pan right now. That would be the weak piskotothropic principle. But his reasoning is inverted; he seems to fit the cutter so well only because he has been so precisely molded by it. That's what I think is happening in this universe; the anthropic principles -- either one of them -- are a bit like the gingerbread man fantasizing that his presence somehow implies rules about how the cookie cutter can be shaped, or how the oven, eggs, flour, sugar and pan can work. Or he might think By seeing the cutter, I've caused it to come into existence. My observation has shaped the cutter, and in fact observation has caused the oven, the heat, *and* the pan to all come into existence. Until I and my kind saw these things, they simply weren't there at all. That's the quantum Darwin principle, and it is by far the most ridiculous conclusion the gingerbread man can reach. The objections I have to quantum Darwinism are certainly emotional, or maybe you could call them philosophical. From the perspective of an atheist, I don't like what qD suggests about the history of this universe or the way it leaves a big gaping hole for a deity to appear. From the perspective of a pragmatist or realist, I don't like what qD suggests about history; it might render history meaningless. Ethically and philosophically, don't like what qD suggests about *us* -- if we're really shaping the universe, then starvation, genocide and general human and animal suffering must exist only because we've dreamt them up, and every moment we let it endure is another moment of needless suffering foisted off on millions. We die only because we believer we do? Horseshit. Worst of all, that qD would mean the rock-fondlers are correct in their blatherings about consensual reality and other inane, feel-good drivel. But I *also* don't think quantum Darwinism is particularly parsimonious. It suggests there *must have been* observers (other than us) in the past, which is not necessarily false but a tall thing on which to hang one's hat; or it suggests that our observance of the past -- possibly by the lightyear delay in astronomy, who knows -- has affected the history of the universe even as we observe it, and frankly I think prior observers are more likely in this case. Otherwise, again, all of history is useless. It is rendered, to quote Ford, bunk. qD suggests that consciousness has a deep underlying effect on all of what might be called objective reality; and at its core it seeks to re-enthrone humanity in a way that hasn't been viable since the Copernican revolution. That said, there
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Thursday, March 03, 2005 3:12 PM Subject: Re: quantum darwin? On Mar 3, 2005, at 1:56 PM, Dan Minette wrote: Are scientific proofs acceptable to you? Possibly. If you read the rest of my criticism of the underlying principles, you'll see there's far too much wiggle room. What wiggle room? Do you realize what you are saying? You are saying that you trust your feeling about how things should be better than a scientific understanding of the universe. Science is our best means of understanding how the universe works. Aristotle got things very wrong when he used gut level feel. The models that best fit observations are, by definition, the best descriptions of what we observe. Since the universe, the totality of phenomenon, is what we observe, how can you say that the universe is different than what our best models of it give us. What special source of information do you have, other than observation and the ability to model that observation. I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. No, there is a much better explanation than this. The universe is phenomenon, not a collection of things-in-themselves. If you only drop your insistence that the universe must fit your beliefs, then what we observe is quite understandable from a variety of metaphysical viewpoints. Indeed, it makes sense that we observe QM effects as we do. Also, its worth noting, that there have been experimental confirmation of macroscopic quantum statesnot just macroscopic effects. In short, once you drop realism...which is hard to reconcile with the results of QM, and accept that the objects of our senses are not a separate reality but the interface between that separate reality and our minds, a lot of things fall into place rather nicely. Quasi-realism is extremely messy and virtually every effort to come up with quasi-realism has fallen apart very quickly. (I'm not talking about MWI.that is personally distasteful to me, and I don't consider it realism, but it does not collapse upon itself.) Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 3, 2005, at 10:05 PM, Dan Minette wrote: Are scientific proofs acceptable to you? Possibly. If you read the rest of my criticism of the underlying principles, you'll see there's far too much wiggle room. What wiggle room? Do you realize what you are saying? Yes, I do. I am saying that QM is incomplete, that our understanding is incomplete, and that it's unwise to use an incomplete understanding to purport anything like total comprehension of a thing. As to the wiggle room -- did you read what I wrote? There's plenty of it. ;) You are saying that you trust your feeling about how things should be better than a scientific understanding of the universe. Not at all. I am saying that it is the height of folly to use an incomplete theoretical system to posit *anything* about the universe as anything *except* conjecture. Science is our best means of understanding how the universe works. Aristotle got things very wrong when he used gut level feel. So tell me again why you think this god idea is valid...? The models that best fit observations are, by definition, the best descriptions of what we observe. Since the universe, the totality of phenomenon, is what we observe, how can you say that the universe is different than what our best models of it give us. What special source of information do you have, other than observation and the ability to model that observation. Dan, are you aware of how many interpretations there are of QM? Are you aware that all those interpretations are valid? In what specific best model do you think I should place my trust? Which one of those interpretations is the correct one? Isn't it just possible that none of them are correct, that we've got only the vaguest clue what's going on out there, that QM is just the latest phantom idea? Before we start assuming that we know how things operate, doesn't it make sense to see if our ideas are leading us to silly conclusions? I really don't think QM is a valid assessment of our universe. It's partially correct, sure, but it leads to really outrageous conclusions, and to me the most parsimonious explanation is that it's our perceptions of the universe that are just plain wrong, that the universe does *not* shape itself to an observer's will. No, there is a much better explanation than this. The universe is phenomenon, not a collection of things-in-themselves. There is no such thing as a thing in itself; I'm very aware of that. If you only drop your insistence that the universe must fit your beliefs, then what we observe is quite understandable from a variety of metaphysical viewpoints. You, like some other QM defenders, have it inverted. It is QM that states the universe fits our beliefs. I'm saying hogwash. By supporting QM you are the one declaring that the universe operates according to people's observations, that consciousness alters outcomes. That is one of the key tenets of QM. And it's a key reason I think *some* of the conclusions reached via QM are dead wrong. Indeed, it makes sense that we observe QM effects as we do. How? Also, its worth noting, that there have been experimental confirmation of macroscopic quantum statesnot just macroscopic effects. Do you mean the electron-slit thing, or are you referring to something else here? In short, once you drop realism...which is hard to reconcile with the results of QM, and accept that the objects of our senses are not a separate reality but the interface between that separate reality and our minds, a lot of things fall into place rather nicely. Sure, even more so if you accept the mumbo-jumbo that wishing something is true is sufficient to make it so. That's what really lies at the core of strong QM defense, I think. What's funny is that I regularly sense a strong commitment to QM (not just in you), one that isn't comfortable with conceding that, since QM is incomplete, it's possible that some of its conclusions are false. Almost as though it's a religion. Quasi-realism is extremely messy and virtually every effort to come up with quasi-realism has fallen apart very quickly. I'm not sure what you're referring to here. -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
On Mar 3, 2005, at 10:25 PM, I wrote: In short, once you drop realism...which is hard to reconcile with the results of QM, and accept that the objects of our senses are not a separate reality but the interface between that separate reality and our minds, a lot of things fall into place rather nicely. Sure, even more so if you accept the mumbo-jumbo that wishing something is true is sufficient to make it so. That's what really lies at the core of strong QM defense, I think. What's funny is that I regularly sense a strong commitment to QM (not just in you), one that isn't comfortable with conceding that, since QM is incomplete, it's possible that some of its conclusions are false. Almost as though it's a religion. That reads a little harsher than I intended. I was thinking of the nonspecific you in that first graf; I should have written it as ...even more so if one accepts the mumbo-jumbo that... The second graf isn't meant to be a slam on religion, but rather on the fervor with which I have seen *some* people defend QM. (That's not targeted at Dan either, BTW, and neither is the following.) Sometimes I feel like Sinead O'Connor ripping up a picture of the Pope -- there's a vast outcry from a throng of individuals, not all of whom seem to have thought fully about what QM's suggestions really mean; the analogy is to the huge number of holiday Catholics who were up in arms because of Sinead's gesture, all of whom seemed to forget that they were really *Christians*, and not particularly devout ones either. When there are nearly a dozen possible equally sensible interpretations of QM's effects on the universe, isn't it just a little odd? When QM says that the universe is the way it is because of how it's been observed in the past, doesn't anyone else get a yellow light? Can the universe really be that plastic? Doesn't it seem just a little hubristic to suggest that reality is, quite literally, what we make it out to be? Is that truly the most likely case, or is it instead more feasible that we're not there yet, that we aren't fully clear on everything? Just before Einstein published his paper on relativity, physicists were saying that there was virtually no research left to be done in physics, that it was soon to be a dead science. Boy were they wrong. Isn't it feasible that we're just as wrong to assume that QM is really a fully legitimate, deeply descriptive and entirely accurate model of reality? Particularly when there still isn't agreement about how to interpret what QM tells us? -- Warren Ockrassa, Publisher/Editor, nightwares Books http://books.nightwares.com/ Current work in progress The Seven-Year Mirror http://www.nightwares.com/books/ockrassa/Flat_Out.pdf ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: quantum darwin?
- Original Message - From: Warren Ockrassa [EMAIL PROTECTED] To: Killer Bs Discussion brin-l@mccmedia.com Sent: Thursday, March 03, 2005 11:45 PM Subject: Re: quantum darwin? Sometimes I feel like Sinead O'Connor ripping up a picture of the Pope -- there's a vast outcry from a throng of individuals, not all of whom seem to have thought fully about what QM's suggestions really mean; the analogy is to the huge number of holiday Catholics who were up in arms because of Sinead's gesture, all of whom seemed to forget that they were really *Christians*, and not particularly devout ones either. I'll answer your earlier post with work that has been done in the last 50 years after I've slept. But, you miss why QM is defended as it is. The reaction is as though you said but evolution is just a theory. What would be helpful in thinking about this is asking why Feynman's response was to say shut up and calculate instead of pursuing the same intuative path Einstein didand why his sucessors agreed with that assessment. Dan M. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
