The Decoherent Arrow of Time and the Entanglement Past Hypothesis

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Al-Khalili, Jim, Chen, Eddy Keming
Format: Preprint
Published: 2024
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911963172306944
author Al-Khalili, Jim
Chen, Eddy Keming
author_facet Al-Khalili, Jim
Chen, Eddy Keming
contents If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future according to the Second Law of Thermodynamics, then tracing this back to the time around the Big Bang means the universe must have started off in a state of very low thermodynamic entropy: the Thermodynamic Past Hypothesis. In this paper, we consider another boundary condition that plays a similar role, but for the decoherent arrow of time, i.e. the quantum state of the universe is more mixed in the future than in the past. According to what we call the Entanglement Past Hypothesis, the initial quantum state of the universe had very low entanglement entropy. We clarify the content of the Entanglement Past Hypothesis, compare it with the Thermodynamic Past Hypothesis, and identify some challenges and open questions for future research.
format Preprint
id arxiv_https___arxiv_org_abs_2405_03418
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Decoherent Arrow of Time and the Entanglement Past Hypothesis
Al-Khalili, Jim
Chen, Eddy Keming
Quantum Physics
General Relativity and Quantum Cosmology
History and Philosophy of Physics
If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future according to the Second Law of Thermodynamics, then tracing this back to the time around the Big Bang means the universe must have started off in a state of very low thermodynamic entropy: the Thermodynamic Past Hypothesis. In this paper, we consider another boundary condition that plays a similar role, but for the decoherent arrow of time, i.e. the quantum state of the universe is more mixed in the future than in the past. According to what we call the Entanglement Past Hypothesis, the initial quantum state of the universe had very low entanglement entropy. We clarify the content of the Entanglement Past Hypothesis, compare it with the Thermodynamic Past Hypothesis, and identify some challenges and open questions for future research.
title The Decoherent Arrow of Time and the Entanglement Past Hypothesis
topic Quantum Physics
General Relativity and Quantum Cosmology
History and Philosophy of Physics
url https://arxiv.org/abs/2405.03418