Evolving Realities for Quantum Measure Theory

2019-09-25 Thread Philip Thrift

*Evolving Realities for Quantum Measure Theory*
Henry Wilkes*
Imperial College, London
September 28, 2018
https://arxiv.org/abs/1809.10427

We introduce and explore Rafael Sorkin's \textit{evolving co-event scheme}: 
a theoretical framework for determining completely which events do and do 
not happen in evolving quantum, or indeed classical, systems. The theory is 
observer-independent and constructed from discrete histories, making the 
framework a potential setting for discrete quantum cosmology and quantum 
gravity, as well as ordinary discrete quantum systems. The foundation of 
this theory is Quantum Measure Theory, which generalises (classical) 
measure theory to allow for quantum interference between alternative 
histories; and its co-event interpretation, which describes whether events 
can or can not occur, and in what combination, given a system and a quantum 
measure. In contrast to previous co-event schemes, the evolving co-event 
scheme is applied in stages, in the stochastic sense, without any 
dependence on later stages, making it manifestly compatible with an 
evolving block view. It is shown that the co-event realities produced by 
the basic evolving scheme do not depend on the inclusion or exclusion of 
zero measure histories in the history space, which follows non-trivially 
from the basic rules of the scheme. It is also shown that this evolving 
co-event scheme will reduce to producing classical realities when it is 
applied to classical systems.

* Henry Wilkes is a graduate student at Imperial College
https://www.imperial.ac.uk/media/imperial-college/research-centres-and-groups/theoretical-physics/2018-19-Theory-PhD-student-photos-.pdf


@philipthrift

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/everything-list/b2c9205a-c5fb-403c-99ad-d3a0b4697cd4%40googlegroups.com.


Quantum Measure Theory

2019-08-08 Thread Philip Thrift


video:

*The quantum measure (and how to measure it)*
Rafael Sorkin 
https://www.youtube.com/watch?v=fJb47yt9hgc


references:

*Quantum Mechanics as Quantum Measure Theory*
Rafael D. Sorkin
https://arxiv.org/abs/gr-qc/9401003

The additivity of classical probabilities is only the first in a hierarchy 
of possible sum-rules, each of which implies its successor. The first and 
most restrictive sum-rule of the hierarchy yields measure-theory in the 
Kolmogorov sense, which physically is appropriate for the description of 
stochastic processes such as Brownian motion. The next weaker sum-rule 
defines a {\it generalized measure theory} which includes quantum mechanics 
as a special case. The fact that quantum probabilities can be expressed 
``as the squares of quantum amplitudes'' is thus derived in a natural 
manner, and a series of natural generalizations of the quantum formalism is 
delineated. Conversely, the mathematical sense in which classical physics 
is a special case of quantum physics is clarified. The present paper 
presents these relationships in the context of a ``realistic'' 
interpretation of quantum mechanics.


*Quantum Measure Theory and its Interpretation*
Rafael D. Sorkin 
https://arxiv.org/abs/gr-qc/9507057

We propose a realistic, spacetime interpretation of quantum theory in which 
reality constitutes a *single* history obeying a "law of motion" that makes 
definite, but incomplete, predictions about its behavior. We associate a 
"quantum measure" |S| to the set S of histories, and point out that |S| 
fulfills a sum rule generalizing that of classical probability theory. We 
interpret |S| as a "propensity", making this precise by stating a criterion 
for |S|=0 to imply "preclusion" (meaning that the true history will not lie 
in S). The criterion involves triads of correlated events, and in 
application to electron-electron scattering, for example, it yields 
definite predictions about the electron trajectories themselves, 
independently of any measuring devices which might or might not be present. 
(So we can give an objective account of measurements.) Two unfinished 
aspects of the interpretation involve *conditonal* preclusion (which 
apparently requires a notion of coarse-graining for its formulation) and 
the need to "locate spacetime regions in advance" without the aid of a 
fixed background metric (which can be achieved in the context of 
conditional preclusion via a construction which makes sense both in 
continuum gravity and in the discrete setting of causal set theory).


*Dynamical Wave Function Collapse Models in Quantum Measure Theory*
Fay Dowker, Yousef Ghazi-Tabatabai
https://arxiv.org/abs/0712.2924
The structure of Collapse Models is investigated in the framework of 
Quantum Measure Theory, a histories-based approach to quantum mechanics. 
The underlying structure of coupled classical and quantum systems is 
elucidated in this approach which puts both systems on a spacetime footing. 
The nature of the coupling is exposed: the classical histories have no 
dynamics of their own but are simply tied, more or less closely, to the 
quantum histories.


other references:

*Quantum measure theory*
Stan Gudder
https://www.degruyter.com/view/j/ms.2010.60.issue-5/s12175-010-0040-8/s12175-010-0040-8.xml

*Quantum measure and integration theory*
Stan Gudder
https://aip.scitation.org/doi/10.1063/1.3267867



@philipthrift

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/everything-list/66cd7523-f875-485f-858c-e6277878981c%40googlegroups.com.