Han Ma

Portrait of a woman wearing a striped shirt standing in an atrium
Research Scientist
Perimeter Institute for Theoretical Physics
Research Scientist
Areas of research:
Quantum Matter
(519) 569-7600 x6621
My research interest lies in the study of quantum phases and phase transitions.

1. I studied exotic phases, such as topological ordered states and fracton phase, have non-trivial entanglement structure resulting in interesting behaviours, such as ground state degeneracy and anyonic statistics of excitations.

2. I am also interested in continuous phase transitions, which can be described by conformal field theories. I am also interested in the pseudo-critical behavior whose universal properties are attributed to the complex fixed point.

3. I am now working on (non-)Fermi liquid which has extensive zero modes. This largely increases the complexity of the system. I use the so-called field theoretical renormalization group to study them.
  • Postdoctoral Researcher, Perimeter Institute for Theoretical Physics, 2019-present
  • PhD student, Department of Physics, University of Colorado Boulder, 2014-2019
  • Block Award, Aspen Center for Physics, 2018
  • Tang, Y., Ma, H., Tang, Q., He, Y. -C., & Zhu, W. (2024). Reclaiming the Lost Conformality in a Non-Hermitian Quantum 5-State Potts Model. Physical Review Letters, 133(7), 076504. doi:10.1103/physrevlett.133.076504
  • Liu, R., Lam, H. T., Ma, H., & Zou, L. (n.d.). Symmetries and anomalies of Kitaev spin-S models: Identifying symmetry-enforced exotic quantum matter. SciPost Physics, 16(4), 100. doi:10.21468/scipostphys.16.4.100
  • Tang, Y., Ma, H., Tang, Q., He, Y. -C., & Zhu, W. (2024). Reclaiming the Lost Conformality in a non-Hermitian Quantum 5-state Potts Model. arxiv:2403.00852v2
  • Liu, R., Lam, H. T., Ma, H., & Zou, L. (2024). Symmetries and anomalies of Kitaev spin-S models. doi:10.21468/scipost.report.8586
  • Liu, R., Lam, H. T., Ma, H., & Zou, L. (2024). Symmetries and anomalies of Kitaev spin-S models. doi:10.21468/scipost.report.8468
  • Liu, R., Lam, H. T., Ma, H., & Zou, L. (2024). Symmetries and anomalies of Kitaev spin-S models. doi:10.21468/scipost.report.8374
  • Ma, H., & Lee, S. -S. (2024). Fermi liquids beyond the forward-scattering limit: The role of nonforward scattering for scale invariance and instabilities. Physical Review B, 109(4), 045143. doi:10.1103/physrevb.109.045143
  • Song, H., Ma, H., Kallin, C., & Lee, S. -S. (2023). Anomalous quasiparticle lifetime in geometric quantum critical metals. arxiv:2310.07539v1
  • Haldar, A., Tavakol, O., Ma, H., & Scaffidi, T. (2023). Hidden Critical Points in the Two-Dimensional O(n>2) Model: Exact Numerical Study of a Complex Conformal Field Theory. Physical Review Letters, 131(13), 131601. doi:10.1103/physrevlett.131.131601
  • Ma, H., & Lee, S. -S. (n.d.). Exact effective action for the O(N) vector model in the large N limit. SciPost Physics, 15(3), 111. doi:10.21468/scipostphys.15.3.111
  • Ma, H. (2023). Z2 Spin Liquids in the Higher Spin-S Kitaev Honeycomb Model: An Exact Deconfined Z2 Gauge Structure in a Nonintegrable Model. Physical Review Letters, 130(15), 156701. doi:10.1103/physrevlett.130.156701
  • Ma, H. (n.d.). Quenched random mass disorder in the large N theory of vector bosons. SciPost Physics, 14(3), 039. doi:10.21468/scipostphys.14.3.039
  • Hsieh, T. -C., Ma, H., & Radzihovsky, L. (2022). Helical superfluid in a frustrated honeycomb Bose-Hubbard model. Physical Review A, 106(2), 023321. doi:10.1103/physreva.106.023321
  • Ma, H., & Lee, S. -S. (n.d.). Constraints on beta functions in field theories. SciPost Physics, 12(2), 046. doi:10.21468/scipostphys.12.2.046
  • Conformality in a non-Hermitian system, KITP, University of California, Santa Barbara, KITP, Santa Barbara, United States, 2024/05/13
  • Z2 spin liquids in the spin-S Kitaev honeycomb model, University of California, Santa Barbara, Kavli Institute for Theoretical Physics, Santa Barbara, California, 93106, United States, 2023/08/22
  • Renormalization group for Metals, Michigan State University, East Lansing, United States, 2023/03/23
  • Renormalization group for Metals, University of Illinois at Urbana-Champaign, Urbana, United States, 2023/02/20
  • Renormalization group for Metals, University of Pittsburgh, Pittsburgh, United States, 2023/02/15
  • Expanding the horizon of Renormalization group in quantum matter, University of Pittsburgh, Pittsburgh, United States, 2023/02/14
  • Renormalization group for Metals, University of Toronto, Toronto, Canada, 2023/02/06
  • Z2 spin liquids in spin-S Kitaev honeycomb model via parton construction, Quantum Matter Workshop, 2022/11/14, PIRSA:22110066
  • Quenched random mass disorder in the large N vector boson model, Centre de recherches mathématiques, Montreal, Canada, 2022/08/29
  • Nonperturbative RG flow and IR effective action of O(N) vector model, National Tsing Hua University, Hsinchu, Taiwan, 2022/03/01