7 research outputs found
Prepotential and the Seiberg-Witten Theory
Some basic facts about the prepotential in the SW/Whitham theory are
presented. Consideration begins from the abstract theory of quasiclassical
-functions , which uses as input a family of complex spectral curves with
a meromorphic differential , subject to the constraint , and gives as an output a homogeneous
prepotential on extended moduli space. Then reversed construction is discussed,
which is straightforwardly generalizable from spectral {\it curves} to certain
complex manifolds of dimension (like and families). Finally,
examples of particular SUSY gauge models are considered from the point of
view of this formalism. At the end we discuss similarity between the
-\-Calabi-\-Yau model with and the
Calogero/Ruijsenaars model, but stop short of the claim that they
belong to the same Whitham universality class beyond the conifold limit.Comment: 50 pages, Late
Integrability and Seiberg-Witten Theory: Curves and Periods
Interpretation of exact results on the low-energy limit of SUSY YM
in the language of integrability theory is reviewed. The case of elliptic
Calogero system, associated with the flow between and SUSY in ,
is considered in some detail.Comment: 26 page
Nonequilibrium stabilization of charge states in double quantum dots
We analyze the decoherence of charge states in double quantum dots due to
cotunneling. The system is treated using the Bloch-Redfield generalized master
equation for the Schrieffer-Wolff transformed Hamiltonian. We show that the
decoherence, characterized through a relaxation and a dephasing time
, can be controlled through the external voltage and that the
optimum point, where these times are maximum, is not necessarily in
equilibrium. We outline the mechanism of this nonequilibrium-induced
enhancement of lifetime and coherence. We discuss the relevance of our results
for recent charge qubit experiments.Comment: 5 pages, 5 figure
Nonlinear cotunneling through an artificial molecule
We study electron transport through a system of two lateral quantum dots
coupled in series. We consider the case of weak coupling to the leads and a
bias point in the Coulomb blockade. After a generalized Schrieffer-Wolf
transformation, cotunneling through this system is described using methods from
lowest-order perturbation theory. We study the system for arbitrary bias
voltages below the Coulomb energy. We observe a rich, non-monotonic behavior of
the stationary current depending on the internal degrees of freedom. In
particular, it turns out that at fixed transport voltage, the current through
the system is largest at weak-to-intermediate inter-dot coupling.Comment: 4 pages, 5 figure