MU Physics & Astronomy Department's O. M. Stewart Colloquium Series presents: Prof. Xiao Li

Thursday, February 8, 2018 4:00pm

Physics Library, Room 223A, Physics Building

Departments: 

Prof. Xiao Li, University of Maryland

MU Physics & Astronomy Department's O. M. Stewart Colloquium Series presents, "Localization, Quantum Thermalization, and Machine Learning," Thursday, February 8, 4:00 p.m.

Prof. Xiao Li, University of Maryland, writes, "Since the seminal work by P. W. Anderson in 1958 [1], quantum localization has been a central subject of condensed matter physics. In the past decade, this subject has again become an area of intense research activities as people realized that (single-particle) Anderson localization may survive finite interactions [2], leading to a manybody localized phase. More importantly, when an isolated system is manybody localized, it strongly violates the familiar ergodicity hypothesis in quantum statistical mechanics, and fails to thermalize on its own. In this talk I will focus on a one-dimensional mutually incommensurate bichromatic lattice system which has been implemented in ultracold atoms to study quantum localization. We argue that without interactions, there exists a single-particle mobility edge (SPME) in the energy spectrum [3], which is an energy that separates extended eigenstates from localized ones. Our theoretical work subsequently led to a first experimental observation of SPME in one-dimensional systems [4-5]. We further study the properties of manybody localization in such a system when the interaction is turned on, and discuss its implications for a possible manybody mobility edge. In particular, we show that state-of-the-art machine learning techniques can help us understand the phase diagram in this intriguing manybody system."

[1] P. W. Anderson, Phys. Rev. 109, 1492 (1958).

[2] D. M. Basko, I. L. Aleiner, and B. L. Altshuler, Ann. Phys. 321, 1126 (2006).

[3] Xiao Li, Xiaopeng Li, and S. Das Sarma, Phys. Rev. B 96, 085119 (2017).

[4] H. Luschen et al., arXiv: 1709.03478.

[5] T. Kohlert, et al., to be submitted.