123,418 research outputs found
Induced interactions in dilute atomic gases and liquid helium mixtures
In dilute mixtures of two atomic gases, interactions between two minority
atoms acquire a contribution due to interaction with the majority component.
Using thermodynamic arguments, we derive expressions for this induced
interaction for both fermions and bosons for arbitrary strength of the
interaction between the two components. Implications of the work for the theory
of dilute solutions of He in liquid He are discussed.Comment: 7 pages, 1 figure, NORDITA-2012-3
Microwave Nanotube Transistor Operation at High Bias
We measure the small signal, 1 GHz source-drain dynamical conductance of a
back-gated single-walled carbon nanotube field effect transistor at both low
and high dc bias voltages. At all bias voltages, the intrinsic device dynamical
conductance at 1 GHz is identical to the low frequency dynamical conductance,
consistent with the prediction of a cutoff frequency much higher than 1 GHz.
This work represents a significant step towards a full characterization of a
nanotube transistor for RF and microwave amplifiers.Comment: 3 pages, 4 figure
Spin-dependent properties of a two-dimensional electron gas with ferromagnetic gates
A theoretical prediction of the spin-dependent electron self-energy and
in-plane transport of a two-dimensional electron gas in proximity with a
ferromagnetic gate is presented. The application of the predicted
spin-dependent properties is illustrated by the proposal of a device
configuration with two neighboring ferromagnetic gates which produces a
magnetoresistance effect on the channel current generated by nonmagnetic source
and drain contacts. Specific results are shown for a silicon inversion layer
with iron gates. The gate leakage current is found to be beneficial to the spin
effects.Comment: 3 pages, 2 figures, Replaced with revised versio
On bosonic limits of two recent supersymmetric extensions of the Harry Dym hierarchy
Two generalized Harry Dym equations, recently found by Brunelli, Das and
Popowicz in the bosonic limit of new supersymmetric extensions of the Harry Dym
hierarchy [J. Math. Phys. 44:4756--4767 (2003)], are transformed into
previously known integrable systems: one--into a pair of decoupled KdV
equations, the other one--into a pair of coupled mKdV equations from a
bi-Hamiltonian hierarchy of Kupershmidt.Comment: 7 page
Feasibility of Experimental Realization of Entangled Bose-Einstein Condensation
We examine the practical feasibility of the experimental realization of the
so-called entangled Bose-Einstein condensation (BEC), occurring in an entangled
state of two atoms of different species. We demonstrate that if the energy gap
remains vanishing, the entangled BEC persists as the ground state of the
concerned model in a wide parameter regime. We establish the experimental
accessibility of the isotropic point of the effective parameters, in which the
entangled BEC is the exact ground state, as well as the consistency with the
generalized Gross-Pitaevskii equations. The transition temperature is
estimated. Possible experimental implementations are discussed in detail.Comment: 6 pages, published versio
Quantum decoherence of excitons in a leaky cavity with quasimode
For the excitons in the quantum well placed within a leaky cavity, the
quantum decoherence of a mesoscopically superposed states is investigated based
on the factorization theory for quantum dissipation. It is found that the
coherence of the exciton superposition states will decrease in an oscillating
form when the cavity field interacting with the exciton is of the form of
quasimode. The effect of the thermal cavity fields on the quantum decoherence
of the superposition states of the exciton is studied and it is observed that
the higher the temperature of the environment is, the shorter the decoherence
characteristic time is.Comment: 1 figure, 7 page
Effective potential in Lorentz-breaking field theory models
We calculate explicitly the one-loop effective potential in different
Lorentz-breaking field theory models. First, we consider a Yukawa-like theory
and, then, some examples of Lorentz-violating extensions of scalar QED. We
observed, for the extended QED models, that the resulting effective potential
converges to the known result in the limit in which Lorentz-symmetry is
restored. Besides, the one-loop corrections to the effective potential in all
the cases we studied depend on the background tensors responsible for the
Lorentz symmetry violation. This have consequences in physical quantities like,
for example, in the induced mass due to Coleman-Weinberg mechanism.Comment: Version accepted for publication in EPJ
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