2,441 research outputs found
Hypergeometric analytic continuation of the strong-coupling perturbation series for the 2d Bose-Hubbard model
We develop a scheme for analytic continuation of the strong-coupling
perturbation series of the pure Bose-Hubbard model beyond the Mott
insulator-to-superfluid transition at zero temperature, based on hypergeometric
functions and their generalizations. We then apply this scheme for computing
the critical exponent of the order parameter of this quantum phase transition
for the two-dimensional case, which falls into the universality class of the
three-dimensional model. This leads to anontrivial test of the
universality hypothesis.Comment: 5 figure
Electron dynamics in graphene with gate-defined quantum dots
We use numerically exact Chebyshev expansion and kernel polynomial methods to
study transport through circular graphene quantum dots in the framework of a
tight-binding honeycomb lattice model. Our focus lies on the regime where
individual modes of the electrostatically defined dot dominate the charge
carrier dynamics. In particular, we discuss the scattering of an injected Dirac
electron wave packet for a single quantum dot, electron confinement in the dot,
the optical excitation of dot-bound modes, and the propagation of an electronic
excitation along a linear array of dots.Comment: revised version, 6 pages, 7 figure
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