Nonequilibrium Kondo effect in a magnetic field: auxiliary master equation approach

Abstract

We study the single-impurity Anderson model out of equilibrium under the influence of a bias voltage f and a magnetic field B. We investigate the interplay between the shift ( B w ) of the Kondo peak in the spin-resolved density of states (DOS) and the one ( B f ) of the conductance anomaly. In agreement with experiments and previous theoretical calculations we find that, while the latter displays a rather linear behavior with an almost constant slope as a function of B down to the Kondo scale, the DOS shift first features a slower increase reaching the same behavior as. Our auxiliary master equation approach yields highly accurate nonequilibrium results for the DOS and for the conductance all the way from within the Kondo up to the charge fluctuation regime, showing excellent agreement with a recently introduced scheme based on a combination of numerical renormalization group with time-dependent density matrix renormalization group.

Density-wave steady-state phase of dissipative ultracold fermions with nearest-neighbor interactions

“…However, higher number of baths sites in the L-DMFT has not been reached yet. An alternative to the exact diagonalization based solver in the AMEA impurity problem is to use the matrix product states approach [11][12][13]. With this method values of up to N b = 20 have been reached [13].…”

“…An alternative to the exact diagonalization based solver in the AMEA impurity problem is to use the matrix product states approach [11][12][13]. With this method values of up to N b = 20 have been reached [13]. However, currently combining this method and the DMFT self-consistency is not practical, as the computational effort to solve a single impurity problem is too large to be used in a self-consistent approach.…”

“…Nevertheless, using the AMEA within stochastic wave function approach [82] we checked that the discrepancy between the results of the equilibrium and AMEA impurity solvers is decreasing with increasing number of bath sites. Also for other types of impurity magnetic response the value of N b > 10, which might be reached with the matrix product states method, was enough to get accurate results [13].…”

Lead geometry and transport statistics in molecular junctions

“…[63][64][65][66][67][68][69] Promising recent advances combine some of these ideas with auxiliary master equation approaches, allowing for calculations with~10-20 auxiliary lead sites. [70][71][72] The hierarchical equation of motion (HEOM) method [73][74][75] offers an alternative numerically exact scheme that is efficient for regimes in which the coupling-to-temperature ratio Γ/k B T is small. 76,77 This method is different from most of the wavefunction approaches above in that it considers truly infinite leads, but relies on representing the lead density of states in terms of a sum of a small number of Lorentzian functions, making it difficult to study finite or structured bands; nevertheless, recent progress has made significant headway towards structured leads and low temperatures.…”

Dynamics of Kondo voltage splitting after a quantum quench

“…In the presence of a voltage, the Kondo peak is strongly suppressed and splits into two smaller peaks [7][8][9][10][11] . Previous work has argued that the peak-to-peak distance is given by the voltage [12][13][14][15][16][17] and that the split state is significantly less correlated than the equilibrium state 12 . It is therefore natural to examine the establishment of splitting after a quench from an initially uncorrelated state, and to expect that this less correlated state forms on a timescale shorter than that of the equilibrium state.…”