Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

Posters Tuesday February 5
Poster 42:
Current correlations in the interacting Cooper-pair beam-splitter
Jerome Rech
We propose an approach allowing the computation of currents and their correlations
in interacting multi-terminal mesoscopic systems involving quantum
dots coupled to normal and/or superconducting leads [1]. The formalism
relies on the expression of branching currents and noise crossed correlations in
terms of one- and two-particle Green’s functions for the dots electrons, which
are then evaluated self-consistently within a conserving approximation [2].
We illustrate our method with the Cooper-pair beam-splitter setup recently
proposed [3], which we model as a double quantum dot with weak interactions,
connected to a superconducting lead and two normal ones. Our method
not only enables us to take into account a local repulsive interaction on the
dots, but also to study its competition with the direct tunneling between
dots. Our results suggest that even a weak Coulomb repulsion tends to favor
positive current cross correlations in the antisymmetric regime (where the
dots have opposite energies with respect to the superconducting chemical
potential).
Poster 43:
Controlling entanglement and spin-correlations in double quantum dots using
non-equilibrium currents
Carlos Busser
We study the non-equilibrium dynamics in a parallel double-quantum dot
structure induced by a large bias voltage. By applying both a magnetic flux
and a voltage, it is possible to generate spin-spin-correlations between the two
quantum dots, whose sign and absolute value can be controlled by changing
the bias voltage. Our study is based on the Anderson-impurity model and
we use time-dependent density matrix renormalization group simulations to
obtain currents and spin-correlations in the non-equilibrium regime.
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