1,305 research outputs found
Photon and electron spectra in hot and dense QED
Photon and electron spectra in hot and dense QED are found in the high
temperature limit for all |\q| using the Feynman gauge and the one-loop
self-energy. All spectra are split by the medium and their branches develop the
gap (the dynamical mass) at zero momentum. The photon spectrum has two branches
(longitudinal and transverse) with the common mass; but electron spectrum is
split on four branches which are well-separated for any |\q| including their
|\q|=0 limits (their effective masses). These masses and the photon thermal
mass are calculated explicitly and the different limits of spectrum branches
are established in detail. The gauge invariance of the high-temperature spectra
is briefly discussed.Comment: 9 pages, latex, no figure
Ultrasoft Quark Damping in Hot QCD
We determine the quark damping rates in the context of next-to-leading order
hard-thermal-loop summed perturbation of high-temperature QCD where weak
coupling is assumed. The quarks are ultrasoft. Three types of divergent
behavior are encountered: infrared, light-cone and at specific points
determined by the gluon energies. The infrared divergence persists and is
logarithmic whereas the two others are circumvented.Comment: 16 page
Resonant Relaxation in Electroweak Baryogenesis
We compute the leading, chiral charge-changing relaxation term in the quantum
transport equations that govern electroweak baryogenesis using the closed time
path formulation of non-equilibrium quantum field theory. We show that the
relaxation transport coefficients may be resonantly enhanced under appropriate
conditions on electroweak model parameters and that such enhancements can
mitigate the impact of similar enhancements in the CP-violating source terms.
We also develop a power counting in the time and energy scales entering
electroweak baryogenesis and include effects through second order in ratios
of the small and large scales. We illustrate the implications of the
resonantly enhanced terms using the Minimal
Supersymmetric Standard Model, focusing on the interplay between the
requirements of baryogenesis and constraints obtained from collider studies,
precision electroweak data, and electric dipole moment searches.Comment: 30 pages plus appendices, 7 figure
Infrared Behavior of High-Temperature QCD
The damping rate \gamma_t(p) of on-shell transverse gluons with ultrasoft
momentum p is calculated in the context of next-to-leading-order
hard-thermal-loop-summed perturbation of high-temperature QCD. It is obtained
in an expansion to second order in p. The first coefficient is recovered but
that of order p^2 is found divergent in the infrared. Divergences from
light-like momenta do also occur but are circumvented. Our result and method
are critically discussed, particularly regarding a Ward identity obtained in
the literature. When enforcing the equality between \gamma_t(0) and
\gamma_l(0), a rough estimate of the magnetic mass is obtained. Carrying a
similar calculation in the context of scalar quantum electrodynamics shows that
the early ultrasoft-momentum expansion we make has little to do with the
infrared sensitivity of the result.Comment: REVTEX4, 55 page
Fermi spectra and their gauge invariance in hot and dense Abelian and non-Abelian theories
The one-loop Fermi spectra (one-particle and collective ones) are found for
all momenta in the -approximation and their gauge invariance in hot and
dense Abelian and non-Abelian theories is studied. It is shown that the
one-particle spectrum, if the calculation accuracy is kept strictly, is gauge
invariant for all momenta and has two branches as the bare one. The collective
spectrum always has four branches which are gauge dependent including also
their |\q|=0 limit. The exception is the case for which this
spectrum is gauge invariant for all momenta as well.Comment: 16 pages, latex, no figure
Multiexcitons confined within a sub-excitonic volume: Spectroscopic and dynamical signatures of neutral and charged biexcitons in ultrasmall semiconductor nanocrystals
The use of ultrafast gating techniques allows us to resolve both spectrally
and temporally the emission from short-lived neutral and negatively charged
biexcitons in ultrasmall (sub-10 nm) CdSe nanocrystals (nanocrystal quantum
dots). Because of forced overlap of electronic wave functions and reduced
dielectric screening, these states are characterized by giant interaction
energies of tens (neutral biexcitons) to hundreds (charged biexcitons) of meV.
Both types of biexcitons show extremely short lifetimes (from sub-100
picoseconds to sub-picosecond time scales) that rapidly shorten with decreasing
nanocrystal size. These ultrafast relaxation dynamics are explained in terms of
highly efficient nonradiative Auger recombination.Comment: 5 pages, 4 figures, to be published in Phys. Rev.
One-particle and collective electron spectra in hot and dense QED and their gauge dependence
The one-particle electron spectrum is found for hot and dense QED and its
properties are investigated in comparison with the collective spectrum. It is
shown that the one-particle spectrum (in any case its zero momentum limit) is
gauge invariant, but the collective spectrum, being qualitatively different, is
always gauge dependent. The exception is the case for which the
collective spectrum long wavelength limit demonstrates the gauge invariance as
well.Comment: 9 pages, latex, no figure
Radiative heavy quark energy loss in a dynamical QCD medium
The computation of radiative energy loss in a dynamically screened QCD medium
is a key ingredient for obtaining reliable predictions for jet quenching in
ultra-relativistic heavy ion collisions. We calculate, to first order in the
opacity, the energy loss suffered by a heavy quark traveling through an
infinite and time-independent QCD medium and show that the result for a
dynamical medium is almost twice that obtained previously for a medium
consisting of randomly distributed static scattering centers. A quantitative
description of jet suppression in RHIC and LHC experiments thus must correctly
account for the dynamics of the medium's constituents.Comment: 21 pages, 14 figures, submitted to Physical Review
ΠΠ»Π»Π΅ΡΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠΈΠ½ΠΈΡ ΠΈ ΡΠ΅Π½ΠΎΠΌΠ΅Π½ ΡΠ½ΡΠΎΠΏΠΈΠΈ
This article provides a review of the phenomenon of entopy or local atopy from the viewpoint of allergic phenotypesΒ and endotypes. A clinical form of the entopy endotype is local allergic rhinitis, which is still a fertile area for research. The exact mechanisms in the breakdown of allergen tolerance in entopy remain unclear. TheΒ reviewΒ focuses on the pathogenesis, diagnostic algorithm, and the choice of treatment strategies in local allergic rhinitis.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ ΠΎΠ±Π·ΠΎΡ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ, ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π½ΡΡ
Π½Π΅Π΄Π°Π²Π½ΠΎ ΠΎΡΠΊΡΡΡΠΎΠΌΡ ΡΠ²Π»Π΅Π½ΠΈΡ β ΡΠ΅Π½ΠΎΠΌΠ΅Π½ΡΒ ΡΠ½ΡΠΎΠΏΠΈΠΈ (Π»ΠΎΠΊΠ°Π»ΡΠ½ΠΎΠΉ Π°ΡΠΎΠΏΠΈΠΈ), Ρ ΡΠΎΡΠΊΠΈ Π·ΡΠ΅Π½ΠΈΡ Π΅Π³ΠΎ ΡΠ΅Π½ΠΎΡΠΈΠΏΠΎΠ² ΠΈ ΡΠ½Π΄ΠΎΡΠΈΠΏΠΎΠ². ΠΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈΠΌ Π²Π°ΡΠΈΠ°Π½ΡΠΎΠΌ ΡΠ½Π΄ΠΎΡΠΈΠΏΠ°Β ΡΠ½ΡΠΎΠΏΠΈΠΈ ΡΠ²Π»ΡΠ΅ΡΡΡ Π»ΠΎΠΊΠ°Π»ΡΠ½ΡΠΉ Π°Π»Π»Π΅ΡΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠΈΠ½ΠΈΡ, Π½ΠΎΠ²Π°Ρ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΡ, β ΠΎΠ±ΡΠ΅ΠΊΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ Π² ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉΒ ΠΈΠΌΠΌΡΠ½ΠΎΠ»ΠΎΠ³ΠΈΠΈ, Π°Π»Π»Π΅ΡΠ³ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈ ΠΎΡΠΎΡΠΈΠ½ΠΎΠ»Π°ΡΠΈΠ½Π³ΠΎΠ»ΠΎΠ³ΠΈΠΈ. Π’ΠΎΡΠ½ΡΠ΅ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΡ ΡΡΡΠ²Π° ΡΠΎΠ»Π΅ΡΠ°Π½ΡΠ½ΠΎΡΡΠΈ ΠΊ Π°Π»Π»Π΅ΡΠ³Π΅Π½Π°ΠΌ ΠΏΡΠΈ ΡΠ½ΡΠΎΠΏΠΈΠΈΒ ΠΎΡΡΠ°ΡΡΡΡ Π½Π΅ΡΡΠ½ΡΠΌΠΈ. ΠΠ΅ΠΆΠ΄Ρ ΡΠ΅ΠΌ ΡΠ΅Π½ΠΎΠΌΠ΅Π½ ΡΠ½ΡΠΎΠΏΠΈΠΈ ΠΌΠΎΠΆΠ΅Ρ ΡΡΠ°ΡΡ ΠΊΠ»ΡΡΠΎΠΌ Π΄Π»Ρ ΡΠ°ΡΡΠΈΡΡΠΎΠ²ΠΊΠΈΒ Π½Π΅ΡΠ΅ΡΠ΅Π½Π½ΡΡ
Π²ΠΎΠΏΡΠΎΡΠΎΠ² ΡΡΡΠ²Π° Π°Π»Π»Π΅ΡΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΎΠ»Π΅ΡΠ°Π½ΡΠ½ΠΎΡΡΠΈ Π² ΡΠ°Π·Π½ΡΡ
Β Π°Π½Π°ΡΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ°ΠΉΡΠ°Ρ
. ΠΠ±Π·ΠΎΡ ΠΏΠΎΡΠ²ΡΡΠ΅Π½ ΠΏΠ°ΡΠΎΠ³Π΅Π½Π΅Π·Ρ, Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ΅ΡΠΊΠΎΠΌΡ Π°Π»Π³ΠΎΡΠΈΡΠΌΡ ΠΈ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ΅ Π²ΡΠ±ΠΎΡΠ° ΡΠ΅ΡΠ°ΠΏΠ΅Π²ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ΠΎΠ² ΠΏΡΠΈ Π»ΠΎΠΊΠ°Π»ΡΠ½ΠΎΠΌ Π°Π»Π»Π΅ΡΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΌ ΡΠΈΠ½ΠΈΡΠ΅
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