Comment on "Mechanism of Terahertz Electromagnetic Wave Emission from Intrinsic Josephson Junctions"

TL;DR

This paper critiques a recent claim about the mechanism of terahertz wave emission from intrinsic Josephson junctions, arguing that the proposed 'state without kink' is energetically inconsistent and cannot explain experimental observations.

Contribution

It clarifies the energetic considerations of phase states in Josephson junctions and refutes the validity of the 'state without kink' model for terahertz emission.

Findings

The 'state without kink' model is energetically inconsistent with established Josephson junction theory.

The 'state without kink' cannot account for observed terahertz radiation in experiments.

The critique emphasizes the importance of proper energetic analysis in modeling Josephson junction dynamics.

Abstract

In a recent Letter, Tachiki \emph{et al.} argued that the dynamic state of superconductivity phase in multi junctions characterized by $\pm\pi$ kinks is hard to realize from an energetic point of view. Instead, they proposed a so-called "state without kink". In this Comment, we point out that their energetic consideration is inconsistent with the well established treatment for Josephson junctions, and that the results derived for their "state without kink" cannot explain the radiations observed in the recent experiment.