Talks

 

Titles & Abstracts of Presentations

In the following please find a first compilation of given presentations on the individual topics of the workshop. Please note that at this stage this is only an excerpt of presentations. .

QUANTUM MAGNETISM
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  • Continuous similarity transofrmations for ordered quantum magnets: Dispersion beyond spin wave theory, bound states, and dynamic structure factors
  • Auxiliary filed quantum Monte Carlo study of the interaction electron gas coupled to a cavity
  • Control of Yu-Shiba-Rusinov States through a Bosonic Mode
  • Poisson-Dirichlet distributions and weakly first-order spin-nematic phase transitions
    Abstract:
    Weakly first-order transitions, i.e. discontinuous phase transitions with very large correlation lengths, have become a vivid subject in condensed matter research and beyond in recent years. Therefore, establishing quantum systems in which weakly first-order phase transitions can be robustly demonstrated is of great interest. We present a quantitative characterization of generic weakly first-order thermal phase transitions out of planar spin-nematic states in three-dimensional spin-one quantum magnets, based on calculations using Poisson-Dirichlet distributions within a universal loop model formulation, combined with large-scale quantum Monte Carlo calculations. In contrast to earlier claims, the thermal melting of the spin-nematic state is not continuous, instead we identify a weakly first-order transition. Furthermore, we obtain exact results for the order parameter distribution and cumulant ratios at the melting transition. Our findings establish the thermal melting of planar spin-nematic states as a generic platform for quantitative approaches to weakly first-order phase transitions in quantum systems with a continuous SU(2) internal symmetry.

CORRELATED MATERIALS
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  • Competing interactions and phase transitions of two-dimensional Dirac systems
  • Electron correlations in moiré superlattices and superconductivity in correlated electron systems
  • Quantum Many-Body Methods at work: Insights into complex oxide systems
  • divERGe implements various Exact Renomralization Group examples

NONEQUILIBRIUM DYNAMICS
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  • Non-Equilibrium Dynamics of a Sachdev-Ye-Kitaev Superconductor
  • Theory for ultrafast dynamics in correlated electron systems: Non-equilibrium Dynamical mean-field theory and beyond
  • Light-Induced Unconventional Odd-Parity Superconductivity
  • Fractionalized Prethermalization in a Driven Quantum Spin Liquid

    Abstract:
    Quantum spin liquids subject to a periodic drive can display fascinating non-equilibrium heating behavior because of their emergent fractionalized quasi-particles. We discuss a driven Kitaev honeycomb model and examine the dynamics of emergent Majorana matter and Z2 flux excitations. We uncover a distinct two-step heating profile -- dubbed fractionalized prethermalization -- and a quasi-stationary state with vastly different temperatures for the matter and the flux sectors. This behavior arises from the fractionalization of the excitations. We propose a quantum algorithm for preparing a zero-flux initial state with a low energy density, which can be used to observe fractionalized prethermalization in quantum information processing platforms.

    Reference: [PRL 130, 226701, 2023]

NUMERICAL MANY-BODY APPROACHES
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  • Speeding up quantum-many body physics with monitored quantum circuits
  • The power of Friedel oscillations
  • Simulating Lattice Gauge Theories with Fermionic Tensor Network
    Abstract:

    Quantum field theories (QFTs), especially gauge theories, are at the basis of our understanding of fundamental forces. A common regularization of quantum field theories are lattice gauge theories, a discretization of the QFT on the lattice. With the advent of quantum simulation, Hamiltonian formulations of lattice gauge theories have become more popular. Using tools from condensed matter physics like tensor networks, we can gain further insight into Hamiltonian lattice gauge theories.

    In this talk, I will present recent work about building gauge invariant fermionic Gaussian PEPS (GGPEPS) and use them to simulate pure (2+1) dimensional Z2 lattice gauge theories. We will start with an introduction of lattice gauge theories and give a quick review of tensor networks. Equipped with the necessary basics, we will build gauge invariant states and see how these are used in a variational Monte Carlo procedure to find groundstates throughout the whole coupling region of the theory.

  • Ab initio quantum electrodynamics: lightmatter interactions from first principles

OPEN SYSTEMS
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