Comment on "Information flow of quantum states interacting with closed timelike curves"

TL;DR

This paper critiques recent claims about the capabilities of closed timelike curves by highlighting how assumptions about input states influence the conclusions, emphasizing the importance of precise modeling.

Contribution

It demonstrates that the conclusions about closed timelike curves depend on ambiguous assumptions, challenging previous results and stressing the need for careful state specification.

Findings

Different input state assumptions lead to opposite conclusions.

The power of closed timelike curves is sensitive to initial state modeling.

Previous results may be unreliable due to ambiguous state choices.

Abstract

We show that recent results on the interaction of causality-respecting particles with particles on closed timelike curves derived in [Phys. Rev. A 82, 062330 (2010)] depend on ambiguous assumption about the form of the state which is inputted into the proposed equivalent circuit. Choosing different form of this state leads to opposite conclusion on the power of closed timelike curves.