Fizikai Tudományok Doktori Iskola
In recent decades there have been great advances in the understanding of the topological properties of weakly interacting electrons. However, much less is known for strongly interacting many-body fermionic systems, like the Mott insulators. In these insulators localized degrees of freedom (e.g. magnetic moments) interact with each other, realizing new states of quantum matter with exotic excitations and unusual ground state properties. Does it lead to new phenomena, especially if we consider the coupling between the spins and the electric polarization due to spin-orbit coupling?
For example, the Hall effect in metals a consequence of the electronic bands having a finite Chern number. In the insulators there are no conducting electrons, but may it happen that a kind of dynamical Hall effect emerges at finite excitation energies, which can be observed by light absorption, e.g. in the SrCu2(BO3)2?
Is it possible to observe spin-quadrupolar excitations in materials suspected to realize spin-nematic ordering, like LiCuVO4?
What is the infrared absorption of skyrmions or other topological defects?
Going beyond ordered materials, does the magnetoelectric effect leads to new physics in spin liquids?
In this Ph.D. project, we will aim to address questions of a similar nature. This is a theoretical study requiring the application of analytical and numerical methods, with the possibility to interact with experimentalists.
The applicant is expected to be proficient in mathematical methods and quantum physics.
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