219 research outputs found
Nonequilibrium transport through a quantum dot coupled to normal and superconducting leads
We study the interacting quantum dot coupled to the normal and
superconducting leads by means of a continuous-time quantum Monte Carlo method
in the Keldysh-Nambu formalism. Deducing the steady current through the quantum
dot under a finite voltage, we examine how the gap magnitude in the
superconducting lead and the interaction strength at the quantum dot affect
transport properties. It is clarified that the Andreev reflection and Kondo
effect lead to nonmonotonic behavior in the nonequilibrium transport at zero
temperature.Comment: 6 pages, 3 figures, conference paper of SCES 201
Cluster mean-field approach with density matrix renormalization group: Application to the hard-core bosonic Hubbard model on a triangular lattice
We introduce a new numerical method for the solution of self-consistent
equations in the cluster mean-field theory. The method uses the density matrix
renormalization group method to solve the associated cluster problem. We obtain
an accurate critical value of the supersolid-superfluid transitions in the
hard-core bosonic Hubbard model on a triangular lattice, which is comparable
with the recent quantum Monte Carlo results. This algorithm is applicable to
more general classes of models with a larger number of degrees of freedom.Comment: 6 pages, 4 figures, SCES 201
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