Probing the vicinity of Deconfined Quantum Criticality with Quantum Monte Carlo
by
DrJun Takahashi(Center for Quantum Information and Control, University of New Mexico)
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Asia/Shanghai
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Description
Abstract
Deconfined quantum criticality (DQC) is a beyond-Landau paradigm quantum phase transition predicted to occur in a 2d quantum magnet between a Need phase and a valence bond solid (VBS) phase. Although the two phases are not related in the traditional symmetry-breaking perspective, field theory predicts that at the DQC transition point the order of the phases fractionalizes and creates an emergent gauge field, letting the Neel-VBS transition generically continuous.
By constructing concrete models that could be simulated to a large scale with quantum Monte Carlo methods, we numerically investigate if the Neel-VBS transition truly has no additional relevant fields in the renormalization group sense, as is the implication of the field theoretic prediction. We find that there are a number of new perturbations that were previously overlooked, and show that they lead to a different phase diagram, possibly resolving the previously observed discrepancy between theoretical conformal bootstrap calculation and numerical studies.
J. Takahashi and A. W. Sandvik, Phys Rev Research 2, 033459 (2020)
B. Zhao, J. Takahashi and A W Sandvik, Phys. Rev. Lett. 125, 257204 (2020)
Biography
After getting a PhD at University of Tokyo (東京大学) by studying quantum annealing numerically with Prof. Koji Hukushima (福島孝治), Jun Takahashi (高橋惇) became a postdoc at Chinese Academy of Sciences Institute of Physics (中国科学院物理研究所) and Boston University working with Prof. Anders Sandvik on quantum criticality. He now works at Center for Quantum Information and Control, University of New Mexico in America as a postdoc on more theoretical sides of such numerics such as tackling the sign-problem.
