Correlated Quantum Matter and Materials

Welcome to CQM² Group!

Strong interactions among atomic particles can lead to materials, such as some high-temperature superconductors, with unusual electronic and magnetic properties. Our research group at ITP and BeihangU is focusing on emergent many-body physics and ultra quantum states of matter due to the intriguing interplay between correlation and topology. We aim to develop quantum many-body simulation techniques, e.g., tensor networks, renormalization group, and deep learning techniques, that provide reliable and accurate numerical access to thermal and dynamical properties of correlated systems. With state-of-the-art methods, we explore novel states of matter and reveal underlying manybody theory, in correlated materials that could possibily lead to intriguing applications in future quantum technology.

Research:

Quantum Many-body Theory and Computations
Ground-State and Thermal Tensor Networks
Frustrated Magnetism and Quantum Spin Liquids
Correlated Electrons and Superconductivity
Magnetocaloric Quantum Materials

Projects:

CAS Project for Young Scientists in Basic Research (Grant No. YSBR-057)
Quantum Many-body Theory and Computation, NSFC Excellent Youngth Project: 12222412
Thermal Tensor Networks for Frustrated Quantum Magnets, NSFC General Project: 11974036
Quantum Manybody Computation Methods and Applications, NSFC Key Project: 11834014
Non-abelian symmetry and tensor networks, NSFC Junior Project: 11504014

News

Our work “Double magnon-roton excitations in the triangular-lattice spin supersolid” is published in Phys. Rev. B 110, 214408, 4-Dec-2024.
Our work “Magnetocaloric effect of topological excitations in Kitaev magnets” is published in Nature Communications 15, 7011 (2024), 15-Aug-2024.
Our work “Orbital-selective superconductivity in the pressurized bilayer nickelate La₃Ni₂O₇: An infinite projected entangled-pair state study ” is published in Phys. Rev. B 110, L041111, 8-Jul-2024.
Our work “Giant magnetocaloric effect in spin supersolid candidate Na₂BaCo(PO₄)₂” is published in Nature 625, 270–275 (2024), 10-Jan-2024.
Our work “Bilayer t-J-J⊥ Model and Magnetically Mediated Pairing in the Pressurized Nickelate La₃Ni₂O₇” is published in Phys. Rev. Lett. 132, 036502, 19-Jan-2024.
Our work “A one-third magnetization plateau phase as evidence for the Kitaev interaction in a honeycomb-lattice antiferromagnet” is published in Nature Physics 10, 1038 (2023) , 25-Sep-2023.
Our work “Plaquette Singlet Transition, Magnetic Barocaloric Effect, and Spin Supersolidity in the Shastry-Sutherland Model” is published in Phys. Rev. Lett. 131, 116702, 14-Sep-2023.
Our work “Possible intermediate quantum spin liquid phase in α-RuCl₃ under high magnetic fields up to 100 T” is published in Nature Communications 14, 5613 (2023) , 12-Sep-2023.
Our work “Tangent Space Approach for Thermal Tensor Network Simulations of the 2D Hubbard Model” is published in Phys. Rev. Lett. 130, 226502, 01-June-2023, and also highlighted as PRL Editors' suggestion.
Our work “High-field quantum spin liquid transitions and angle-field phase diagram of the Kitaev magnet α−RuCl₃” is published in Phys. Rev. B 107, 115124, 10-Mar-2023.
We are very happy to announce that Dr. Han Li has been awarded the KITS fellowship for postdoctoral researchers!
Congratulations to Han Li for being awarded the fellowship of 2022 China National Postdoctoral Program for Innovative Talents (全国博新计划). Grant No. BX20220291.
Congratulations to Junsen Wang for the support from the Fundamental Research Funds for the Central Universities.
Our work “Exciton Proliferation and Fate of the Topological Mott Insulator in a Twisted Bilayer Graphene Lattice Model"is published in Phys. Rev. Lett 128, 157201, 12-Apr-2022.
Our work “Realization of topological Mott insulator in a twisted bilayer graphene lattice model” is published in Nature Communications 12, 5480 (2021) , 16-Sep-2021.
Our work “Learning the Effective Spin Hamiltonian of a Quantum Magnet” is published in Chin. Phys. Lett 38, 097502, 27-Aug-2021. Our code implementation in PyTorch is publicly available at this GitHub repo.
Our work “Identification of magnetic interactions and high-field quantum spin liquid in α-RuCl₃” is published in Nature Communications 12, 4007 (2021) , 29-Jun-2021.
Our work “Symmetry-Protected Topological Edge Modes and Emergent Partial Time-Reversal Symmetry Breaking in Open Quantum Many-Body Systems"is published in Phys. Rev. Lett 126, 237201, 9-Jun-2021.
Our work “Evidence of the Berezinskii-Kosterlitz-Thouless phase in a frustrated magnet” is published in Nature Communications 11, 5631 (2020) , 06-Nov-2020, and also selected as Editor’s Highlight !
Our work “Kosterlitz-Thouless Melting of Magnetic Order in the Triangular Quantum Ising Material TmMgGaO₄” is published in Nature Communications 11, 1111 (2020) , 28-Feb-2020.
Our work “Exponential Thermal Tensor Network Approach for Quantum Lattice Models” is published in Phys. Rev. X 8, 031082, 26-Sep-2018.

Featured

Han Li, Enze Lv, Ning Xi, Yuan Gao, Yang Qi, Wei Li, Gang Su

August, 2024 Nat. Commun.

Magnetocaloric effect of topological excitations in Kitaev magnets

Xing-Zhou Qu, Dai-Wei Qu, Jialin Chen, Congjun Wu, Fan Yang, Wei Li, Gang Su

January, 2024 Phys. Rev. Lett.

Bilayer t-J-J⊥ Model and Magnetically Mediated Pairing in the Pressurized Nickelate La3Ni2O7

Junsen Wang, Han Li, Ning Xi, Yuan Gao, Qing-Bo Yan, Wei Li, Gang Su

September, 2023 Phys. Rev. Lett.

Plaquette Singlet Transition, Magnetic Barocaloric Effect, and Spin Supersolidity in the Shastry-Sutherland Model

Xu-Guang Zhou, Han Li, Yasuhiro H. Matsuda, Akira Matsuo, Wei Li, Nobuyuki Kurita, Gang Su, Koichi Kindo, Hidekazu Tanaka

September, 2023 Nat. Commun.

Possible intermediate quantum spin liquid phase in α-RuCl$_3$ under high magnetic fields up to 100 T

Qiaoyi Li, Yuan Gao, Yuan-Yao He, Yang Qi, Bin-Bin Chen, Wei Li

June, 2023 Phys. Rev. Lett.

Tangent Space Approach for Thermal Tensor Network Simulations of the 2D Hubbard Model

Dai-Wei Qu, Bin-Bin Chen, Hong-Chen Jiang, Yao Wang, Wei Li

October, 2022 Communications Physics

Spin-triplet pairing induced by near-neighbor attraction in the extended Hubbard model for cuprate chain

Xin-Yang Liu, Yuan Gao, Han Li, Wentao Jin, Junsen Xiang, Hai Jin, Ziyu Chen, Wei Li, Gang Su

September, 2022 Communications Physics

Quantum spin liquid candidate as superior refrigerant in cascade demagnetization cooling

Bin-Bin Chen, Ziyu Chen, Shou-Shu Gong, D. N. Sheng, Wei Li, Andreas Weichselbaum

September, 2022 Phys. Rev. B

Quantum spin liquid with emergent chiral order in the triangular-lattice Hubbard model

Yuan Gao, Yu-Chen Fan, Han Li, Fan Yang, Xu-Tao Zeng, Xian-Lei Sheng, Ruidan Zhong, Yang Qi, Yuan Wan, Wei Li

September, 2022 npj Quantum Materials

Spin supersolidity in nearly ideal easy-axis triangular quantum antiferromagnet Na2BaCo(PO4)2

Xiyue Lin, Bin-Bin Chen, Wei Li, Zi Yang Meng, Tao Shi

April, 2022 Phys. Rev. Lett.

Exciton Proliferation and Fate of the Topological Mott Insulator in a Twisted Bilayer Graphene Lattice Model

Bin-Bin Chen, Yuan Da Liao, Ziyu Chen, Oskar Vafek, Jian Kang, Wei Li, Zi Yang Meng

September, 2021 Nature Communications

Realization of topological Mott insulator in a twisted bilayer graphene lattice model

Han Li, H.-K. Zhang, Jiucai Wang, Han-Qing Wu, Yuan Gao, Dai-Wei Qu, Zheng-Xin Liu, Shou-Shu Gong, Wei Li

June, 2021 Nature Communications

Identification of magnetic interactions and high-field quantum spin liquid in α-RuCl3

Zijian Wang, Qiaoyi Li, Wei Li, Zi Cai

June, 2021 Phys. Rev. Lett.

Symmetry-Protected Topological Edge Modes and Emergent Partial Time-Reversal Symmetry Breaking in Open Quantum Many-Body Systems

Bin-Bin Chen, Chuang Chen, Ziyu Chen, Jian Cui, Yueyang Zhai, Andreas Weichselbaum, Jan von Delft, Zi Yang Meng, Wei Li

January, 2021 Phys. Rev. B

Quantum Many-Body Simulations of the Two-Dimensional Fermi-Hubbard Model in Ultracold Optical Lattices

Ze Hu, Zhen Ma, Yuan Da Liao, Han Li, Chunsheng Ma, Yi Cui, Yanyan Shangguan, Zhentao Huang, Yang Qi, Wei Li, Zi Yang Meng, Jinsheng Wen, Weiqiang Yu

November, 2020 Nature Communications

Evidence of the Berezinskii-Kosterlitz-Thouless phase in a frustrated magnet

Han Li, Dai-Wei Qu, Hao-Kai Zhang, Yi-Zhen Jia, Shou-Shu Gong, Yang Qi, Wei Li

October, 2020 Phys. Rev. Research

$Universal thermodynamics in the Kitaev fractional liquid$

Universal thermodynamics in the Kitaev fractional liquid

Han Li, Yuan Da Liao, Bin-Bin Chen, Xu-Tao Zeng, Xian-Lei Sheng, Yang Qi, Zi Yang Meng, Wei Li

February, 2020 Nature Communications

Kosterlitz-Thouless melting of magnetic order in the triangular quantum Ising material TmMgGaO$_4$

TmMgGaO4 is one of a number of recently-synthesized quantum magnets that are proposed to realize important theoretical models. Here the authors demonstrate the agreement between detailed experimental measurements and state-of-the-art predictions based on the 2D transverse field triangular lattice Ising model.

Lei Chen, Dai-Wei Qu, Han Li, Bin-Bin Chen, Shou-Shu Gong, Jan von Delft, Andreas Weichselbaum, Wei Li

April, 2019 Phys. Rev. B (Rapid Commun.)

Two-Temperature Scales in the Triangular-Lattice Heisenberg Antiferromagnet

The anomalous thermodynamic properties of the paradigmatic frustrated spin-1/2 triangular-lattice Heisenberg antiferromagnet (TLH) has remained an open topic of research over decades, both experimentally and theoretically. Here, we further the theoretical understanding based on the recently developed, powerful exponential tensor renormalization group method on cylinders and stripes in a quasi-one-dimensional (1D) setup, as well as a tensor product operator approach directly in 2D.

Bin-Bin Chen, Lei Chen, Ziyu Chen, Wei Li, Andreas Weichselbaum

September, 2018 Phys. Rev. X

Exponential Thermal Tensor Network Approach for Quantum Lattice Models

We speed up thermal simulations of quantum many-body systems in both one- (1D) and two-dimensional (2D) models in an exponential way by iteratively projecting the thermal density matrix $\rho=e^{-\beta H}$ onto itself.