5,424 research outputs found
Semiconductor cavity QED: Bandgap induced by vacuum fluctuations
We consider theoretically a semiconductor nanostructure embedded in
one-dimensional microcavity and study the modification of its electron energy
spectrum by the vacuum fluctuations of the electromagnetic field. To solve the
problem, a non-perturbative diagrammatic approach based on the Green's function
formalism is developed. It is shown that the interaction of the system with the
vacuum fluctuations of the optical cavity opens gaps within the valence band of
the semiconductor. The approach is verified for the case of large photon
occupation numbers, proving the validity of the model by comparing to previous
studies of the semiconductor system excited by a classical electromagnetic
field. The developed theory is of general character and allows for unification
of quantum and classical descriptions of the strong light-matter interaction in
semiconductor structures
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The chamber was a turmoil of ripping, snarling, and tearing as Quesa struggled and swore. She fought back hot tears of pain and rage while the fur flew fast and shrill cries rent the air
3-dimensional Rules for Finite-Temperature Loops
We present simple diagrammatic rules to write down Euclidean n-point
functions at finite temperature directly in terms of 3-dimensional momentum
integrals, without ever performing a single Matsubara sum. The rules can be
understood as describing the interaction of the external particles with those
of the thermal bath.Comment: 12 pages, 4 figures, to appear in Physics Letters
Neutrino emission rates in highly magnetized neutron stars revisited
Magnetars are a subclass of neutron stars whose intense soft-gamma-ray bursts
and quiescent X-ray emission are believed to be powered by the decay of a
strong internal magnetic field. We reanalyze neutrino emission in such stars in
the plausibly relevant regime in which the Landau band spacing of both protons
and electrons is much larger than kT (where k is the Boltzmann constant and T
is the temperature), but still much smaller than the Fermi energies. Focusing
on the direct Urca process, we find that the emissivity oscillates as a
function of density or magnetic field, peaking when the Fermi level of the
protons or electrons lies about 3kT above the bottom of any of their Landau
bands. The oscillation amplitude is comparable to the average emissivity when
the Landau band spacing mentioned above is roughly the geometric mean of kT and
the Fermi energy (excluding mass), i. e., at fields much weaker than required
to confine all particles to the lowest Landau band. Since the density and
magnetic field strength vary continuously inside the neutron star, there will
be alternating surfaces of high and low emissivity. Globally, these
oscillations tend to average out, making it unclear whether there will be any
observable effects.Comment: 7 pages, 2 figures; accepted for publication in Astronomy &
Astrophysic
Comprehensive study of Leon-Queretaro area
There are no author-identified significant results in this report
BCS pairing in fully repulsive fermion mixtures
We consider a mixture of two neutral cold Fermi gases with repulsive
interactions. We show that in some region of the parameter space of the system
the effective attraction between fermions of the same type can appear due to
the exchange of collective excitations. This leads to the formation of BCS
pairing in the case where bare inter-atomic interactions are repulsive
Awareness Of Racial And Ethnic Health Disparities Has Improved Only Modestly Over A Decade
Abstract available at publisher's web site.http://dx.doi.org/10.1377/hlthaff.2010.070
Heisenberg quantization for the systems of identical particles and the Pauli exclusion principle in noncommutative spaces
We study the Heisenberg quantization for the systems of identical particles
in noncommtative spaces. We get fermions and bosons as a special cases of our
argument, in the same way as commutative case and therefore we conclude that
the Pauli exclusion principle is also valid in noncommutative spaces.Comment: 8 pages, 1 figur
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