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Main Authors: Engineer, Sophie, Rivlin, Tom, Wollmann, Sabine, Malik, Mehul, Lock, Maximilian P. E.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2403.18016
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author Engineer, Sophie
Rivlin, Tom
Wollmann, Sabine
Malik, Mehul
Lock, Maximilian P. E.
author_facet Engineer, Sophie
Rivlin, Tom
Wollmann, Sabine
Malik, Mehul
Lock, Maximilian P. E.
contents The challenge of understanding quantum measurement persists as a fundamental issue in modern physics. Particularly, the abrupt and energy-non-conserving collapse of the wave function appears to contradict classical thermodynamic laws. The contradiction can be resolved by considering measurement itself to be an entropy-increasing process, driven by the second law of thermodynamics. One such resolution explains the apparently irreversible emergence of objective outcomes in an isolated, unitarily-evolving quantum system via the theory of closed-system equilibration. Working within this framework, we construct the set of \textit{`objectifying observables'} that best encode the measurement statistics of a system in an objective manner, and establish a measurement error bound to quantify the probability an observer will obtain an incorrect measurement outcome. Using this error bound, we show that the objectifying observables readily equilibrate on average under the set of Hamiltonians which preserve the outcome statistics on the measured system. Using a random matrix model for this set, we numerically determine the measurement error bound, finding that the error only approaches zero with increasing environment size when the environment is coarse-grained into so-called observer systems. This indicates the necessity of coarse graining an environment for the emergence of objective, classical measurement outcomes.
format Preprint
id arxiv_https___arxiv_org_abs_2403_18016
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Equilibration of objective observables in a dynamical model of quantum measurements
Engineer, Sophie
Rivlin, Tom
Wollmann, Sabine
Malik, Mehul
Lock, Maximilian P. E.
Quantum Physics
The challenge of understanding quantum measurement persists as a fundamental issue in modern physics. Particularly, the abrupt and energy-non-conserving collapse of the wave function appears to contradict classical thermodynamic laws. The contradiction can be resolved by considering measurement itself to be an entropy-increasing process, driven by the second law of thermodynamics. One such resolution explains the apparently irreversible emergence of objective outcomes in an isolated, unitarily-evolving quantum system via the theory of closed-system equilibration. Working within this framework, we construct the set of \textit{`objectifying observables'} that best encode the measurement statistics of a system in an objective manner, and establish a measurement error bound to quantify the probability an observer will obtain an incorrect measurement outcome. Using this error bound, we show that the objectifying observables readily equilibrate on average under the set of Hamiltonians which preserve the outcome statistics on the measured system. Using a random matrix model for this set, we numerically determine the measurement error bound, finding that the error only approaches zero with increasing environment size when the environment is coarse-grained into so-called observer systems. This indicates the necessity of coarse graining an environment for the emergence of objective, classical measurement outcomes.
title Equilibration of objective observables in a dynamical model of quantum measurements
topic Quantum Physics
url https://arxiv.org/abs/2403.18016