We are looking for talented and motivated students doing a bachelor, project or master thesis in our group. Please find below a list of current topics, by whom these are supervised (see AG Held), and what the requirements are. At the bottom of the page you can also find the list of students who are currently working on a project/thesis in the group.

Computational projects

We are developing the w2dynamics quantum Monte Carlo code, have pioneered density functional theory (DFT) plus dynamical mean-field theory (DMFT), and invented new approaches such as the dynamical vertex approximation (DΓA) based on many-body vertices. For the corresponding codes, see here. To test and implement new ideas, further improve, benchmark or parallelize the existing codes, help is always welcome. For computational projects, Computing for TPH or otherwise good coding skills are required.

  • Non-Abelian symmetry in exact diagonalization (MA, GT) supervision: Markus
  • Performance analysis of w2dynamics or exact diagonalization code (PA) supervision: Anna/Markus and Martin/Markus, respectively
  • Machine learning for analytic continuation (PA/MA, ML)  supervision: Markus/Karsten
  • Intermediate representation (machine learning inspired) for solving the parquet equation of the Anderson impurity model (PA, ML)  supervision: Samuel/Markus
  • Improving the exact diagonalization code for DMFT (PA) supervision: Martin

Physics projects

As theoretical solid state physicists, we have to do a lot of detective work, for finding out what is going on in a solid, understanding and predicting new physical phenomena. The projects below aim at this, using existing code or only requiring minor modifications. Physics is at the focus.

  • Hall coefficient in nickelate superconductors  (PA) supervision: Paul/Simone
  • Exploring new thermoelectrics with density functional theory (PA, SSP) supervision: Simone
  • Electron–phonon mediated superconductivity boosted by hydrogen (PA/MA, SSP) supervision: Simone
  • Quantum Fisher information in the pseudogap regime and for quantum critical points (PA)  supervision: Karsten/Anna/Friedrich
  • Topology of the pseudogap phase (PA) supervision: Karsten
  • Weak localization on the triangular lattice (PA/MA, QFT recommended) supervision: Anna/Friedrich
  • Optical conductivity calculated with TUPS (PA/MA, QFT recommended) supervision: Anna
  • Pi-tons (a new polariton) on a six-site ring calculated with exact diagonalization (PA) supervision: Anna/Karsten
  • Pi-tons in a Mott insulator on the level of a (simplified) single-boson exchange (PA) supervision: Juraj/Anna/Karsten
  • Reduced density matrix for two-site Anderson impurity model calculated with exact diagonalization (PA) supervision: Markus/Karsten

Theoretical projects

We do theoretical physics. Sometimes a computer code is at the focus of a project, sometimes it is a physical phenomenon, and sometimes it is the theory as such. For example, when developing new approaches or studying the mathematics behind the objects employed (such as the vertex). The latter projects are listed here.

  • Two-site reduced density matrix for lattice models (PA, QFT is of advantage) supervision: Anna/Karsten
  • High-frequency asymptotics of the Hedin vertex  (PA, QFT is of advantage) supervision: Friedrich
  • Loschmidt amplitude for non-equilibrium optical conductivity  (PA) supervision: Anna

Acronyms

Type of work/thesis:

  • PA: project work (Projektarbeit). Can also be a bachelor thesis if the requirements are met.
  • MA: master thesis

Requirements:

  • QFT: quantum field theory (e.g., elective lecture "Quantum field theory for many body systems")
  • ML: elective lecture "Machine Learning in Physics"
  • SSP: solid state physics (lattice, Brillouin zone, ...)
  • GT: group theory

All our research is fundamentally based on quantum mechanics, hence require the lecture "Quantum Mechanics I".

List of students

Master students:

  • Samuel Badr (supervision: Anna/Markus)
  • Daniel Wieser (supervision: Anna)

Bachelor students:

  • Christoph Kronberger (supervision: Paul)
  • Markus Reichel (supervision: Anna/Markus)

Project students:

  • Constanze Vogel (supervision: Friedrich)

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