Fundamental decoherence from quantum gravity: a pedagogical review

TL;DR

This paper reviews how quantum gravity introduces fundamental decoherence in quantum mechanics through real clocks, leading to a loss of unitarity independent of environmental interactions, with implications for theory and experiments.

Contribution

It provides a pedagogical derivation of the modified Schrödinger equation due to real clocks and discusses its implications, highlighting a fundamental decoherence mechanism from quantum gravity.

Findings

Decoherence arises from using physical clocks in quantum mechanics.

The modified Schrödinger equation incorporates a fundamental decoherence term.

Potential experimental signatures of quantum gravity-induced decoherence are discussed.

Abstract

We present a discussion of the fundamental loss of unitarity that appears in quantum mechanics due to the use of a physical apparatus to measure time. This induces a decoherence effect that is independent of any interaction with the environment and appears in addition to any usual environmental decoherence. The discussion is framed self consistently and aimed to general physicists. We derive the modified Schroedinger equation that arises in quantum mechanics with real clocks and discuss the theoretical and potential experimental implications of this process of decoherence.