adding seminars

_seminars/2024-03-21.md

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+---
+date: "2024-03-21T15:00:00"
+speaker: Zhaochen Liu
+affiliation:   Fudan University
+title: "Gamma-Valley Moiré Systems"
+type: online-seminar
+abstract: true
+---
+
+Topological flat bands at the Fermi level offer a promising platform to study strongly correlated phases of matter. Diverging from the extensively examined K-valley systems such as graphene and most Transition Metal Dichalcogenides, our study pivots to Gamma-valley moiré systems. We explore various systems including the Dirac surface state of topological insulators, the anisotropic bands of black phosphorus and multi-orbital semiconductors. Within the Dirac surface state, we observe that the interplay between Zeeman and scalar terms within a honeycomb can simulate topological bands in honeycomb lattice. In the twisted bilayer black phosphorus, the system displays giant anisotropic moiré bands, which can further simulate a sliding Luttinger liquid. For the multi-orbital system, the system can support a moiré Kagome lattice and an orbital-active honeycomb lattice, depending on parameters. Finally, we employ the Hartree-Fock method to discuss the impact of Coulomb interactions on the moiré Kagome systems and present phase diagrams for various fillings. Our explorations open up new pathways in the study of Gamma-valley Moiré systems.

_seminars/2024-04-18.md

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+---
+date: "2024-04-18T15:00:00"
+speaker: Linhao Li
+affiliation:   Ghent University
+title: "Lieb-Schultz-Mattis theorem for 1D quantum magnets with magnetic space group symmetries"
+type: lunch-seminar
+abstract: true
+---
+
+The Lieb-Schultz-Mattis theorem is a powerful principle for quantum many-body systems. In this talk, I will discuss 1d LSM theorem in the presence of an exotic antiunitary translation or inversion symmetry involving time reversal. This explains the gaplessness of a class of chiral spin models not indicated by the Lieb-Schultz-Mattis (LSM) theorem and its known extensions. Moreover, I will present symmetry classes with minimal sets of magnetic space group generators that give nontrivial LSM-type constraints. These extended LSM theorems apply to systems with a broader class of spin interactions, such as Dzyaloshinskii-Moriya interactions and triple-product interactions.

_seminars/2024-04-25.md

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+---
+date: "2024-04-18T15:00:00"
+speaker: Laurens Lootens
+affiliation:   Ghent University
+title: "DMRG in the generalised Landau paradigm"
+type: lunch-seminar
+abstract: true
+---
+
+I will talk about some ongoing work on symmetries, phase diagrams and entanglement of ground states that came out of our work on dualities in quantum lattice models, and how one can use these ideas to think about symmetric tensor network codes and improve them.