CMTC Talks
CMTC talks are held in room 4402 Atlantic Building unless an alternate room is indicated

Spring 2020

January 16, Thursday, 2 pm
Fengcheng Wu (CMTC), practice talk for a job interview
Symmetry, Topology, and Many-Body Interactions in Moiré Systems
Van der Waals bilayers with small differences in the lattice constants or orientations of the individual layers have long-period Moiré patterns, which provide vast new opportunities to control material properties. In this talk, I will present our work on Moiré pattern physics that arise from an interplay of symmetry, topology and many-body interactions. First, I will describe our theoretical proposal of using twisted bilayer transition metal dichalcogenides as quantum simulators of Hubbard model [1, 2], and discuss recent experimental realizations. Then I will focus on twisted bilayer graphene (TBG) and show how the interplay between many-body interactions and Bloch band symmetry of TBG can lead to unconventional superconductivity [3, 4]. Finally, I will discuss quantum anomalous Hall insulators in TBG and demonstrate their stability against spin/valley magnon excitations [5]. I will describe the effects of quantum geometry on spin stiffness and show that Berry curvature of Moiré bands helps to stiffen spin magnons.
1. F. Wu, T. Lovorn, E. Tutuc, A. H. MacDonald, Phys. Rev. Lett. 121, 026402 (2018).
2. F. Wu, T. Lovorn, E. Tutuc, I. Martin, A. H. MacDonald, Phys. Rev. Lett. 122, 086402 (2019).
3. F. Wu, A. H. MacDonald, and I. Martin, Phys. Rev. Lett. 121, 257001 (2018).
4. F. Wu, E. Hwang, and S. Das Sarma, Phys. Rev. B 99, 165112 (2019).
5. F. Wu, S. Das Sarma, arXiv:1908.05417 (2019).

February 11, Tuesday, 2:30 pm
Eugene Demler (Harvard), in conjunction with his JQI seminar
Nonlinear optics with collective excitations and photoinduced superconductivity
This talk will review the recent progress in theoretical modeling of nonequilibrium dynamics of electron-phonon systems. There will be an emphasis on understanding experimental observations of photoinduced superconductivity.
Host Jay Sau; last update 2020-1-26 by Victor Yakovenko

SPEAKER (AFFILIATION), NOTES e.g. informal seminar
Host NAME; last update DATE by NAME

CMTC Seminar Committee as of 2020-1-19:
Jay Sau, Maissam Barkeshli, Brian Swingle, Yi-Ting Hsu, and Danny Bulmash

For the earlier CMTC talks, see this page