Caltech

Abstract: Chaotic dynamics in closed local quantum systems scrambles quantum information, which is manifested quantitatively in the decay of the out-of-time-ordered correlations (OTOC) of local operators. How do we measure OTOC in experiments? How is information scrambling affected when the system is coupled to the environment and suffers from dissipation? We address this question by defining a dissipative version of OTOC and numerically study its behavior in a prototypical chaotic quantum chain in the presence of dissipation. We find that dissipation leads to not only the overall decay of quantum information due to leaking, but also structural changes in the scrambled information so that the `information light cone' can only reach a finite distance even when the effect of overall decay is removed.

报告人简介: After receiving his B.S. in physics from Peking University in 2014, Yong-Liang is a PhD student in the department of physics at Caltech. His research interests lie in the intersection of condensed matter physics and quantum information science. More specifically, he is interested in studying the thermalization, quantum entanglement, and information propagation in quantum many-body systems. Yong-Liang received 41st International Physics Olympiad Gold Medal, in Zagreb, Croatia Jul. 2010.

参考文献：

1.   YL Zhang, Y Huang, and X Chen, Information scrambling in chaotic systems with dissipation", arXiv:1802.04492 (2018).
2.   Y Huang, FGSL Brandao, and YL Zhang, Finite-size scaling of out-of-time-ordered correlators at late times", arXiv: 1705.07597 (2017).
3.   Y Huang, YL Zhang, and X Chen, Out-of-time-ordered correlators in many-body localized systems", Annalen der Physik 529, 7 (2017).
4.   YL Zhang, H Wang, L Jing, LZ Mu and H Fan, Fitting magnetic field gradient with Heisenberg-scaling accuracy", Scientific Reports 4, 7390 (2014).
5. H Fan, YN Wang, L Jing, JD Yue, HD Shi, YL Zhang, and LZ Mu, Quantum cloning machines and the applications", Physics Reports 544 (3), 241-322 (2014).

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