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Public Seminar of PhD Candidate: Quantum Monte Carlo simulations of dimension-tunability phenomena in the quantum spin system

Speaker Mr. Chengkang ZHOU
Affiliation The University of Hong Kong
Date August 18, 2023 (Friday)
Time 9:00 a.m.
Venue [In Person] Room 522, 5/F, Chong Yuet Ming Physics Building, The University of Hong Kong
[Zoom] https://hku.zoom.us/j/9517325726 pwd=dnpkRTc4MmhZbWdIQ1E5OG9DSGFEdz09
Meeting ID: 951 732 5726
Password: 233233233

Abstract

Employ large-scale quantum Monte Carlo (QMC) simulations, I discover the interesting role dimension plays in the quantum magnetic systems, including i) the amplitude mode via the dimension crossovers [1], ii) the subdimesional excitations and their spectrum in fracton orders [2], and iii) the characters of the non-trivial topological phase protected by the subsystem system symmetry [3]. First, to capture a clear amplitude mode signal, we simulate coupled spin chain model and successfully reveal the amplitude mode and identify both the transverse and longitude excitations as the breather of the sine-Gordon theory. Secondly, to see the spectrum of various subdimesional excitations in the fraction order, we simulate the X-Cube model and find the the spectral functions show clear anisotropy exactly caused by the underlying mobility constraints. Finally, we turn to the subsystem symmetry in the 2D-Cluster model and diagnose the non-trivial SSPT phase via the strange correlator, which offers a new tool to detect non-trivial SPT phases. 
References: 
1. Amplitude Mode in Quantum Magnets via Dimensional Crossover, Chengkang Zhou, Zheng Yan, Han-Qing Wu, Kai Sun, Oleg A. Starykh, Zi Yang Meng#, Phys. Rev. Lett. 126, 227201 (2021).
2. Evolution of Dynamical Signature in the X-cube Fracton Topological Order, Chengkang Zhou, Meng-Yuan Li, Zheng Yan#, Peng Ye#, Zi Yang Meng, Phys. Rev. Research 4.033111 (2022).
3. Detecting Subsystem Symmetry Protected Topological Order Through Strange Correlators, Chengkang Zhou*, Meng-Yuan Li*, Zheng Yan, Peng Ye#, Zi Yang Meng#, Phys. Rev. B. 106.214428(2022).
 

Anyone interested is welcome to attend.