Ralph's equivalent circuit model, revised Deutsch's maximum entropy rule and discontinuous quantum evolutions in D-CTCs

TL;DR

This paper critically examines Ralph's equivalent circuit model of D-CTCs, revealing its limitations in reproducing the maximum entropy rule and proposing revisions that could resolve discontinuous quantum evolutions.

Contribution

It identifies shortcomings in Ralph's model and proposes a revised maximum entropy rule to better describe D-CTCs and address discontinuous evolutions.

Findings

Counterexamples show the model does not always produce the maximal entropy state.

A revised maximum entropy rule is proposed.

Potential elimination of discontinuous quantum evolutions in D-CTCs.

Abstract

We examine Ralph's equivalent circuit model of D-CTCs, which was proposed to derive Deutsch's maximum entropy rule of D-CTCs. By constructing counterexamples we show that the equivalent circuit model does not always reproduce the unique fixed state with the maximal von Neumann entropy. We speculate that the equivalent circuit model remains the correct description of D-CTCs and it can reproduce a revised maximum entropy rule of D-CTCs. We also suggest that the revised maximum entropy rule may eliminate the discontinuous quantum evolutions of D-CTCs.