We construct an exact map between a tight-binding model on any bipartite lattice in presence of dephasing noise and a Hubbard model with imaginary interaction strength. In one dimension, the exact many-body Liouvillian spectrum can be obtained by application of the Bethe ansatz method. We find that both the non-equilibrium steady state and the leading decay modes describing the relaxation at late times are related to the eta-pairing symmetry of the Hubbard model. We show that there is a remarkable relation between the time-evolution of an arbitrary k-point correlation function in the dissipative system and k-particle states of the corresponding Hubbard model.
COBISS.SI-ID: 3000420
Using state-of-the-art numerical simulations we have resolved an outstanding problem about transport properties of the Heisenberg chain in the ergodic phase. We have showed theoreticlly that for small disorder strength the scattering length is large and therefore previous small-system studies are not reliable. We identifies a phase transition from a subdiffusive to diffusive transport at finite values of disorder.
COBISS.SI-ID: 3010404
The calculation of transport in correlated electron systems is a very challenging problem. We have successfully calculated the in-plane Seebeck coefficient of Sr2RuO4 within a framework combining electronic structure and dynamical mean-field theory methods. We have shown that its temperature dependence can be explained within entropic considerations based on the Kelvin formula and that the Seebeck coefficient provides a meaningful probe of the crossover out of the Fermi liquid regime into an incoherent metal. This crossover proceeds in two stages: The entropy of spin degrees of freedom is released around room temperature, while orbital degrees of freedom remain quenched up to much higher temperatures. This is confirmed by a direct calculation of the corresponding susceptibilities and is a hallmark of "Hund’s metals.” We have also calculated the c-axis thermopower and predicted that it exceeds substantially the in-plane one at high temperature, a peculiar behavior which originates from an interlayer “hole-filtering” mechanism.
COBISS.SI-ID: 30007591
We address a long-standing problem concerning the origin of bosonic excitations that strongly interact with charge carriers. We show that the time-resolved pump-probe experiments are capable of distinguishing between regular bosonic degrees of freedom, e.g., phonons, and the hard-core bosons, e.g., magnons. The ability of phonon degrees of freedom to absorb essentially an unlimited amount of energy renders relaxation dynamics nearly independent of the absorbed energy or fluence. In contrast, the hard core effects pose limits on the density of energy stored in the bosonic subsystems resulting in a substantial dependence of the relaxation time on the fluence and/or excitation energy.
COBISS.SI-ID: 3041124
We have explored the nature of fluctuations of Barkhausen noise that accompanies the process of the magnetization reversal in disordered ferromagnets at hysteresis loop. We have shown that in the experimentally relevant conditions of pinning and rate of change of the external magnetic field, this noise has multifractal properties, which significantly limit the possibilities for the controlled motion of domain walls on which a new group of memory elements builds.
COBISS.SI-ID: 29578535