News

  • 13.03.2023 --  Joint work with Qi Yang, Xing-Yu Zhang, Hai-Jun Liao, and Lei Wang (IOP, CAS) on Projected d-wave superconducting state: A fermionic projected entangled pair state study is published in Phys. Rev. B; see link. Short summary: We have developed a systematic method to convert projected BCS states into PEPS and used it to analyze projected d-wave pairing states as variational ansatz for the t-J model.
  • 28.02.2023 -- In SoSe2023, we will offer a course on Solid State Theory. The course information will be continuously updated in this webpage.

  • 27.02.2023 -- Joint work with Jheng-Wei Li and Jan von Delft (LMU) on U(1)-symmetric Gaussian fermionic projected entangled paired states and their Gutzwiller projection is published in Phys. Rev. B; see link. Short summary: We have devised a systematic method to convert Gutzwiller projected Fermi sea states into PEPS. This makes it possible to calculate physical observables in the thermodynamic limit.

  • 24.10.2022 -- Nico Albert joins our group to work on his Master thesis. Welcome!
  • 03.10.2022 -- Invited talk Tensor networks for fermionic parton wave functions at the Thematic Programme on Tensor Networks: Mathematical Structures and Novel Algorithms (link) at the Erwin Schrödinger International Institute for Mathematics and Physics in Vienna.
  • 01.10.2022 -- Vorlesung in WS2022/23: Rechenmethoden für Lehramt Physik. Auf dieser Webseite finden Sie aktuelle Informationen.
  • 16.09.2022 -- Joint work with Ying-Hai Wu (HUST) on Non-Abelian topological order with SO(5)1 chiral edge states is published in Phys. Rev. B; see link. Short summary: We have revealed an emergent SO(5) symmetry of the edge theory of a spin-1/2 non-Abelian chiral spin liquid.
  • 12.09.2022 -- Joint work with Bin-Bin Chen (HKU), Zi-Yang Meng (HKU), and Meng Cheng (Yale) on Topological disorder parameter: A many-body invariant to characterize gapped quantum phases is published in Phys. Rev. B; see link. As the title suggested, we have introduced topological disorder parameter as a many-body topological invariant for characterizing 2D gapped quantum phases with global internal symmetry.

  • 06.07.2022 -- Congratulations to Anton Hulsch for the successful defense of his Bachelor Thesis on Ising model and conformal field theory!

  • 20.05.2022 -- Joint work with Robijn Vanhove, Laurens Lootens, and Frank Verstraete (Ghent Univ.) on Topological aspects of the critical three-state Potts model is published in J. Phys. A; see link. Short summary: We provide an explicit lattice (!) construction of topological defects in critical three-state Potts model on the torus, Klein bottle, and cylinder, which is an important step in understanding the correspondence between topological field theory and conformal field theory from a lattice setting.
  • 17.05.2022 -- Congratulations to Hua-Chen Zhang for the successful defense of his PhD Thesis on Quantum many-body model wave functions based on conformal field theories at his home institute (Institute of Physics, Chinese Academy of Sciences; supervisor: Prof. Tao Xiang)! Hua-Chen will take up a postdoc position at Aarhus University in July 2022.

  • 11.05.2022 -- Invited talk on Collapsing Schrödinger’s cat: application of anyon eigenbasis in DMRG at the Asian-European workshop on SU(N) physics in condensed matter and cold atoms (link); see slides.

  • 28.04.2022 -- Joint work with Hui-Ke Jin (TUM), Rong-Yang Sun (Kavli ITS -> RIKEN) and Yi Zhou (IOP, CAS) on Unveiling a critical stripy state in the triangular-lattice SU(4) spin-orbital model is published in Sci. Bull.; see link. Short summary: We provide numerical evidence that the SU(4) Kugel-Khomskii model on the triangular lattice has a critical stripy ground state, which preserves the SU(4) symmetry but breaks the translational symmetry by doubling the unit cell along one of the lattice vector directions.

  • 07.03.2022 -- Anton Hulsch joins our group to work on his Bachelor thesis. Welcome!

  • 06.03.2022 -- In SoSe2022, we will offer a specialized lecture on Many Body Theory in Condensed Matter. The course information will be continuously updated in this webpage.

  • 23.02.2022 -- Joint work with Hua-Chen Zhang (IOP, CAS / TU Dresden), Ying-Hai Wu (HUST), and Tao Xiang (IOP, CAS) on Chiral conformal field theory for topological states and the anyon eigenbasis on the torus is published in Nucl. Phys. B; see link. Short summary: We have proposed a method for constructing topologically degenerate ground states on the torus. This approach is conceptually simpler and the wave functions automatically correspond to the anyon eigenbasis.
  • 08.02.2022 -- Felix Kunzmann successfully finished the Master Thesis on Tensor network approach for the algebraic Bethe ansatz. Well done!

  • 01.02.2022 -- Joint work with Hui-Ke Jin (TUM), Rong-Yang Sun (Kavli ITS -> RIKEN) and Yi Zhou (IOP, CAS) on Matrix product states for Hartree-Fock-Bogoliubov wave functions is published in Phys. Rev. B; see link. Short summary: We have designed a new method for converting Hartree-Fock-Bogoliubov (HFB) wave functions into matrix product states. This approach is generally more accurate than previous methods and is also parallelizable. It facilitates the applications of HFB wave functions and can be nicely combined with the DMRG method.

  • 21.12.2021 -- Joint work with Wei Tang (Peking Univ. -> Ghent Univ.), X. C. Xie (Peking Univ.) and Lei Wang (IOP, CAS) on Tensor network simulation of the (1+1)-dimensional O(3) nonlinear σ-model with θ=π term is published in Phys. Rev. D; see link. Short summary: The O(3) nonlinear σ-model (NLSM) with θ=π term is the low-energy effective theory of quantum antiferromagnetic Heisenberg chains with half-integer spins (known as Haldane's conjecture). However, due to the topological term, it's quite difficult to calculate any physical quantities from this non-perturbative field theory. Here we use our recently developed cMPO method to derive a tensor network representation of the O(3) NLSM with θ=π term, reveal its massless nature, and directly calculate the central charge as a function of the coupling constant.
  • 19.10.2021 -- Christoph Schlecht successfully finished the Master Thesis on Microscopic models for Kitaev's sixteenfold way with spontaneous time-reversal symmetry breaking. Congratulations!

  • 27.09.2021 -- Vorlesung in WS2021/22: Rechenmethoden für Lehramt Physik. Auf dieser Webseite finden Sie alle Informationen zu dieser Lehrveranstaltung.

  • 15.07.2021 -- Joint work with Hui-Ke Jin (IOP, CAS -> TUM) and Yi Zhou (IOP, CAS) on Density matrix renormalization group boosted by Gutzwiller projected wave functions is published in Phys. Rev. B; see link. Short summary: We have shown that the performance of DMRG can be dramatically improved by initializing with Gutzwiller projected states. With suitably chosen Gutzwiller ansatz, the notorious “local minimum” issue in DMRG can be circumvented. For systems with topological order, the Gutzwiller-boosted DMRG can also preserve topological sectors, which is convenient for characterizing topological order.
  • 01.04.2021 -- Invited talk on Boosting the performance of DMRG with Gutzwiller projected wave functions at the European Tensor Network Colloquium; see video.
  • 15.03.2021 -- In SoSe2021, we will offer a new lecture on Tensor Networks. The course information will be continuously updated in this webpage.
  • 24.02.2021 -- Joint work with Sreejith Chulliparambil (TU Dresden), Lukas Janssen (TU Dresden), Matthias Vojta (TU Dresden), and Urban Seifert (TU Dresden -> ENS Lyon) on Flux crystals, Majorana metals, and flat bands in exactly solvable spin-orbital liquids is published in Phys. Rev. B; see link. Short summary: We have constructed a family of exactly solvable spin-orbital models. These models exhibit a rich phase diagram with a variety of novel phases.
  • 17.02.2021 -- Joint work with Hua-Chen Zhang (IOP, CAS / TU Dresden), Ying-Hai Wu (HUST), and Tao Xiang (IOP, CAS) on Resonating valence bond realization of spin-1 non-Abelian chiral spin liquid on the torus is published in Phys. Rev. B; see link. Short summary: We have constructed the full set of three-fold degenerate RVB wave functions on the torus, which realize the bosonic Moore-Read-type non-Abelian chiral spin liquid.

  • 14.12.2020 -- Joint work with Urban Seifert (TU Dresden -> ENS Lyon), Xiao-Yu Dong (Ghent Univ.), Sreejith Chulliparambil (TU Dresden / MPI-PKS), Matthias Vojta (TU Dresden), and Lukas Janssen (TU Dresden) on Fractionalized fermionic quantum criticality in spin-orbital Mott insulators is published in Phys. Rev. Lett.; see link. Short summary: We have revealed a new class of quantum phase transitions characterized by fractionalized massless Majorana fermions. Such exotic critical phenomena might be observed in frustrated magnets with spin and orbital degrees of freedom.

  • 11.11.2020 -- Joint work with Sreejith Chulliparambil (TU Dresden / MPI-PKS), Urban Seifert (TU Dresden -> ENS Lyon), Matthias Vojta (TU Dresden), Lukas Janssen (TU Dresden) on Microscopic models for Kitaev's sixteenfold way of anyon theories is published in Phys. Rev. B; see link. Short summary: We have provided, for the first time, a systematic and complete solution to the open problem of constructing Kitaev’s 16-fold way of anyon theories in microscopic models.
  • 23.10.2020 -- Joint work with Wei Tang (Peking Univ.) and Lei Wang (IOP, CAS) on Continuous matrix product operator approach to finite temperature quantum states is published in Phys. Rev. Lett.; see link. Short summary: We have designed a new tensor network method for studying quantum systems at finite temperature. This so-called cMPO approach works directly in the thermodynamic limit and treats short-range and long-range interactions on equal footing, without discretizing the imaginary time. It provides direct access to physical observables such as specific heat, local susceptibility, and local spectral functions.
  • 19.10.2020 -- Felix Kunzmann joins our group to work on his Master thesis. Welcome!
  • 15.10.2020 -- Pleasant surprise: The online teaching for Solid State Theory (SS2020) has brought me the Teaching Award 2020 (Lehrpreis der Gesellschaft von Freunden und Förderern der TU Dresden e. V.). I am very grateful to course participants and the Fachschaftsrat Physik for the nomination, the Gesellschaft von Freuden und Förderern der TU Dresden e. V. for giving me the prize, and colleagues and supervisors (especially Prof. Jan von Delft) who helped me improve teaching.

  • 05.10.2020 -- Hua-Chen Zhang (PhD student at Institute of Physics, Chinese Academy of Sciences) has been awarded a scholarship under the CAS-DAAD-programme and starts his research stay in our group.

  • 23.09.2020 -- Aufgrund der COVID-19-Situation werden die Vorlesungen "Rechenmethoden für Lehramt Physik (WS2020/21)" online abgehalten. Auf dieser Webseite finden Sie aktualisierte Informationen.
  • 26.08.2020 -- Christoph Schlecht joins our group to work on his Master thesis. Welcome!
  • 19.06.2020 -- Joint work with Ying-Hai Wu (HUST) and Lei Wang (IOP, CAS) on Tensor network representations of parton wave functions is published in Phys. Rev. Lett.; see link and recent  slides. Short summary: We have devised a systematic approach to represent parton wave functions (also known as Gutzwiller projected wave functions) as tensor network states and compress them into matrix product states. This nicely combines the advantanges of two methods – tensor networks and variational Monte Carlo – that have been widely used in condensed matter physics and quantum chemistry.

  • 24.04.2020 -- Joint work with Hui-Ke Jin (Zhejiang Univ.) and Yi Zhou (IOP, CAS) on Efficient tensor network representation for Gutzwiller projected states of paired fermions is published in Phys. Rev. B; see link. Short summary: We have developed a systematic approach to represent projected BCS states as tensor networks and compress them into matrix product states. This enables efficient computations of physical quantities and entanglement measures for this important family of variational ansatz.

  • 01.04.2020 -- Due to the COVID-19 situation, the Solid State Theory (SS2020) lectures will be first held online via Zoom until further notice. For enrolment and instructions on how to join the online lectures, please send an email to the lecturer. The course information is being continuously updated in this page.
  • 21.02.2020 -- Talk on Tensor network representations of parton wave functions at Benasque workshop on Entanglement in Strongly Correlated Systems; see slides.
  • 25.11.2019 -- Joint work with Ying-Hai Wu (HUST) on Quantum impurity models from conformal field theory is published in J. High Energ. Phys.; see link. Short summary: This work extends our earlier work on an exactly solvable impurity model to a much larger class, including SU(N) and two-impurity cases. This paves the way for understanding Kondo physics via trial wave functions constructed from conformal field theory.
  • 07.10.2019 -- Course information about Proseminar on Theoretical Physics (WS2019/20) is updated; See this page.
  • 07.10.2019 -- Joint work with Wei Tang (Peking Univ.), X. C. Xie (Peking Univ.) and Lei Wang (IOP, CAS) on Quantized thermal Hall conductance from edge current calculations in lattice models is published in Phys. Rev. B; see link. Short summary: We have proposed a new approach for calculating thermal Hall conductance in 2D lattice models supporting chiral topological order. Our approach greatly simplifies such calculations as only expecation values of local operators in thermal equilibrium are needed (i.e. no need to calculate dynamical quantities).
  • 27.09.2019 -- Sreejith Chulliparambil, enrolled by the International Max Planck Research School for Many-Particle Systems in Structured Environments (IMPRS-MPSSE), joins our group as a PhD student.
  • 09.08.2019 -- Joint work with Ying-Hai Wu (HUST) on Exactly solvable quantum impurity model with inverse-square interactions is published in Phys. Rev. Lett.; see link. Short summary: New insights into the Kondo physics have been obtained by constructing an exactly solvable model with a highly structured ground state. A systematic approach for proposing paradigmatic wave functions for more complicated Kondo problems is provided.
  • 29.07.2019 -- Lectures on Matrix Product States at Beijing Summer School on Quantum Magnetism.
  • 03.04.2019 -- Lecture on Solid State Theory (SS2019) started. See this page for more information.
  • 02.04.2019 -- We are now a partner of the International Max Planck Research School for Many-Particle Systems in Structured Environments (IMPRS-MPSSE). Under the framework of IMPRS, we are offering PhD projects.
  • 05.03.2019 -- Joint work with Wei Tang (Peking Univ.), X. C. Xie (Peking Univ.) and Lei Wang (IOP, CAS) on Klein bottle entropy of compactified boson conformal field theory is published in Phys. Rev. B; see link. Short summary: The Klein bottle entropy can be used for efficiently and accurately extracting Luttinger parameters from microscopic models which describe Tomonaga-Luttinger liquids.
  • 25.02.2019 -- Wei Tang (PhD student at Peking Univ.), who was awarded a scholarship from Peking Univ., starts his 6-month research stay in our group.
  • 23.11.2018 -- The Collaborative Research Center (SFB 1143 "Correlated Magnetism: From Frustration to Topology")  will be funded by the DFG for a second period (2019-2022). Our research is supported by the CRC, and our project A06 (together with Jan Carl Budich) is devoted to the variational description and detection of topological phases.
  • 08.11.2018 -- Joint work with Xiao-Yu Dong (MPI-PKS -> California State Univ.) and Ji-Yao Chen (CNRS Toulouse)  on SU(3) trimer resonating-valence-bond state on the square lattice is published in Phys. Rev. B; see link. Short summary: A soup of resonating SU(3) trimers on the square lattice is found to be a gapped spin liquid with Z3 topological order.
  • 09.10.2018 -- Lecture on Many-Body Theory in Condensed Matter (WS2018/19) started. See this page for more information.
  • 01.10.2018 -- Wei Zhu joins our group as a PhD student.
  • 01.06.2018 -- Wei Tang (PhD student at Peking Univ.) is visiting our group for three months.
  • 10.04.2018 -- Lecture on Solid State Theory (SS2018) started. See this page for more information.
  • 28.12.2017 -- Our work on Universal entropy of conformal critical theories on a Klein bottle is published in Phys. Rev. Lett.; see link. Short summary: When placed on a Klein bottle, conformal field theories are found to have universal entropies, which could be used for characterizing critical theories from finite-size numerics.
  • 01.10.2017 -- Our group started its activity.

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Hong-Hao Tu
Last modified: Jul 21, 2023