AUTHOR=Zhao Wen-Lei , Wang Ru-Ru 

TITLE=Scaling laws of out-of-time-order correlators in a non-Hermitian kicked rotor model

JOURNAL=Frontiers in Physics

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2023.1130225

DOI=10.3389/fphy.2023.1130225

ISSN=2296-424X

ABSTRACT=<p>We investigate the dynamics of the out-of-time-order correlators (OTOCs) <italic>via</italic> a non-Hermitian extension of the quantum kicked rotor model, where the kicking potential satisfies <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math></inline-formula>-symmetry. The spontaneous <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math></inline-formula>-symmetry breaking emerges when the strength of the imaginary part of the kicking potential exceeds a threshold value. We find, both analytically and numerically, that in the broken phase of <inline-formula id="inf3"><mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math></inline-formula> symmetry, the OTOCs rapidly saturate with time evolution. Interestingly, the late-time saturation value scales as a pow-law in the system size. The mechanism of such scaling law results from the interplay between the effects of the nonlocal operator in OTOCs and the time reversal induced by non-Hermitian-driven potential.</p>