No Time Asymmetry from Quantum Mechanics

TL;DR

The paper argues that the apparent time asymmetry in quantum mechanics may be an artifact of the decoherence functional, suggesting the universe could be fundamentally CPT-symmetric with no intrinsic time asymmetry.

Contribution

It challenges the conventional interpretation of time asymmetry in quantum mechanics by proposing CPT invariance as a fundamental symmetry.

Findings

Probabilities of histories and their CPT reverses are equal under CPT-invariant conditions.

Decoherence functional asymmetry may not imply fundamental time asymmetry.

Supports CPT symmetry as a basis for understanding quantum universe.

Abstract

With CPT-invariant initial conditions that commute with CPT-invariant final conditions, the respective probabilities (when defined) of a set of histories and its CPT reverse are equal, giving a CPT-symmetric universe. This leads me to question whether the asymmetry of the Gell-Mann--Hartle decoherence functional for ordinary quantum mechanics should be interpreted as an asymmetry of {\it time} .