Time-reversal frameness and superselection

TL;DR

This paper introduces the concept of time-reversal frameness as a quantum resource, demonstrating how superpositions of motional states can enable communication despite superselection rules, and linking it to entanglement.

Contribution

It identifies time-reversal reference frame states, defines a frameness monotone, and uniquely analyzes an antiunitary representation, advancing understanding of quantum reference frames.

Findings

Superpositions of motional states serve as a resource for breaking time-reversal superselection.

A frameness monotone quantifies the resource and relates to entanglement.

First analysis involving antiunitary representation in quantum reference frames.

Abstract

We show that appropriate superpositions of motional states are a reference frame resource that enables breaking of time -reversal superselection so that two parties lacking knowledge about the other's direction of time can still communicate. We identify the time-reversal reference frame resource states and determine the corresponding frameness monotone, which connects time-reversal frameness to entanglement. In contradistinction to other studies of reference frame quantum resources, this is the first analysis that involves an antiunitary rather than unitary representation.