Research profile

11The main scientific interest of Quantum Systems and Modeling group lies in modeling of nano- and macro-scoping systems. This includes studies of high-temperature copper-based superconductors, solid hydrogen phases (molecular and its metallization), heavy-fermion materials, organic superconductors and selected nanoscale systems (nanolayers, nanowires, quantum dots, etc.). As part of our work we study the stability of unconventional phases, such as the superconducting and topological-superconducting phases, charge-density-wave phase, pair-density wave phase, Fulde-Ferrell-Larkin-Ovczynnikov phase, coexistence of superconductivity and magnetism, as well as the Mott insulator phase and its transformation to the metallic state. Particular emphasis in the research is placed on the inclusion of inter-electronic correlations with the use of the the renormalized mean field theory (RMFT), the diagrammatic expansion of the Gutzwiller wave function method (DE-GWF), as well as the Exact Diagonalization Ab-Initio approach (EDABI) and Quantum Variational Monte Carlo method. These tools allow to determine physical quantities characterizing the given material or system (e.g. electron structure, superconducting gap value, effective mass, Fermi velocity, condensation energy). The group also studies phenomena related to electron transport in nanoscopic semiconductor and semiconductor-superconductor structures in the context of understanding the fundamental properties of systems that hosts exotic quasiparticles or that can serve as building blocks of new-generation electronics.

Field of expertise

  • Formulation of new models as well as application of the existing ones in order to theoretically describe the unconventional phases induced by the electronic correlations in solid state (models based on the Hubbard Hamiltonian, t-J, t-J-U, and related)
  • Application of advanced programming techniques in order to carry out numerical calculations characterized by a high level of complexity.
  • Exact Diagonalization Ab Initio Approach (EDABI) and its application to the nano- and macro-scopic systems.
  • Calculations dedicated to strongly correlated electron systems with the use of the diagrammatic expansion of the Gutzwiller wave function (DE-GWF) approach.
  • Calculations based on the Quantum Variational Monte Carlo method within many body wave function correlated in terms of the Jastrow operator
  • Calculations based on the Renormalized Mean field Theory which allows to take into account the correlation effects.
  • Quantum transport calculations through the solution of stationary Schroedinger equation
  • Modeling of semiconductor and superconductor nanostructures within exact diagonalization approach

Head of the group

  • Prof. Józef Spałek

Group Members

  • Dr. Andrzej Biborski (quantum systems team)
  • Dr. hab. Michał Zegrodnik (quantum systems team)
  • Dr. hab. Michał Nowak (theory and modeling of nanostructures team)