Comments on "Observation of Fast Evolution in Parity-Time-Symmetric System"

TL;DR

This paper critiques a recent experiment claiming faster-than-Hermitian evolution in a parity-time-symmetric system, clarifying contradictions and addressing issues in the original analysis.

Contribution

It provides a critical analysis of the experimental claims and theoretical assumptions regarding fast evolution in PT-symmetric systems.

Findings

Identifies contradictions with previous quantum brachistochrone results

Highlights problematic aspects in the original experimental interpretation

Clarifies the theoretical limitations of faster-than-Hermitian evolution

Abstract

In the paper "Observation of Fast Evolution in Parity-Time-Symmetric System" the authors propose a physical apparatus for the realization of a faster than Hermitian evolution. This last appears in contrast with the conclusions obtained in our paper "Some Remarks on Quantum Brachistochrone". We will clarify this apparent contradiction and some problematic aspects of the treatment in [1].