456 research outputs found
Nonlocal effects in the shot noise of diffusive superconductor - normal-metal systems
A cross-shaped diffusive system with two superconducting and two normal
electrodes is considered. A voltage is applied between the normal
leads. Even in the absence of average current through the superconducting
electrodes their presence increases the shot noise at the normal electrodes and
doubles it in the case of a strong coupling to the superconductors. The
nonequilibrium noise at the superconducting electrodes remains finite even in
the case of a vanishingly small transport current due to the absence of energy
transfer into the superconductors. This noise is suppressed by
electron-electron scattering at sufficiently high voltages.Comment: 4 pages, RevTeX, 2 eps figure
Current noise in long diffusive SNS junctions in the incoherent MAR regime
Spectral density of current fluctuations at zero frequency is calculated for
a long diffusive SNS junction with low-resistive interfaces. At low
temperature, T << Delta, the subgap shot noise approaches linear voltage
dependence, S=(2/ 3R)(eV + 2Delta), which is the sum of the shot noise of the
normal conductor and voltage independent excess noise. This result can also be
interpreted as the 1/3-suppressed Poisson noise for the effective charge q =
e(1+2Delta/eV) transferred by incoherent multiple Andreev reflections (MAR). At
higher temperatures, anomalies of the current noise develop at the gap
subharmonics, eV = 2Delta/n. The crossover to the hot electron regime from the
MAR regime is analyzed in the limit of small applied voltages.Comment: improved version, to be published in Phys. Rev.
Long-Range Coulomb Interaction and the Crossover between Quantum and Shot Noise in Diffusive Conductors
Frequency-dependent nonequilibrium noise in quantum-coherent diffusive
conductors is calculated with account taken of long-range Coulomb interaction.
For long and narrow contacts with strong external screening the crossover
between quantum and shot noise takes place at frequencies much smaller than the
voltage drop across the contact. We also show that under certain frequency
limitations, the semiclassical and quantum-coherent approaches to shot noise
are mathematically equivalent.Comment: 13 pages, RevTex, 7 ps figures, more details of derivation give
Quality of life and voice outcome of patients treated with transoral CO2 laser microsurgery for early glottic carcinoma (T1-T2): a 2-year follow-up study
Purpose Longitudinal studies in laryngeal cancer can provide clinicians information about short-term and long-term functional outcomes, like quality of life (QoL) and voice outco
Shot noise of series quantum point contacts intercalating chaotic cavities
Shot noise of series quantum point contacts forming a sequence of cavities in
a two dimensional electron gas are studied theoretically and experimentally.
Noise in such a structure originates from local scattering at the point
contacts as well as from chaotic motion of the electrons in the cavities. We
found that the measured shot noise is in reasonable agreement with our
theoretical prediction taking the cavity noise into account.Comment: 4 pages, 5 figure
Entangled Hanbury Brown Twiss effects with edge states
Electronic Hanbury Brown Twiss correlations are discussed for geometries in
which transport is along adiabatically guided edge channels. We briefly discuss
partition noise experiments and discuss the effect of inelastic scattering and
dephasing on current correlations. We then consider a two-source Hanbury Brown
Twiss experiment which demonstrates strikingly that even in geometries without
an Aharonov-Bohm effect in the conductance matrix (second-order interference),
correlation functions can (due to fourth-order interference) be sensitive to a
flux. Interestingly we find that this fourth-order interference effect is
closely related to orbital entanglement. The entanglement can be detected via
violation of a Bell Inequality in this geometry even so particles emanate from
uncorrelated sources.Comment: International Symposium "Quantum Hall Effect: Past, Present and
Future
Shot Noise at High Temperatures
We consider the possibility of measuring non-equilibrium properties of the
current correlation functions at high temperatures (and small bias). Through
the example of the third cumulant of the current () we demonstrate
that odd order correlation functions represent non-equilibrium physics even at
small external bias and high temperatures. We calculate for a quasi-one-dimensional diffusive constriction. We calculate the
scaling function in two regimes: when the scattering processes are purely
elastic and when the inelastic electron-electron scattering is strong. In both
cases we find that interpolates between two constants. In the low (high)
temperature limit is strongly (weakly) enhanced (suppressed) by the
electron-electron scattering.Comment: 11 pages 4 fig. submitted to Phys. Rev.
Nonequilibrium Josephson effect in short-arm diffusive SNS interferometers
We study non-equilibrium Josephson effect and phase-dependent conductance in
three-terminal diffusive interferometers with short arms. We consider strong
proximity effect and investigate an interplay of dissipative and Josephson
currents co-existing within the same proximity region. In junctions with
transparent interfaces, the suppression of the Josephson current appears at
rather large voltage, , and the current vanishes at
. Josephson current inversion becomes possible in junctions with
resistive interfaces, where the inversion occurs within a finite interval of
the applied voltage. Due to the presence of considerably large and
phase-dependent injection current, the critical current measured in a current
biased junction does not coincide with the maximum Josephson current, and
remains finite when the true Josephson current is suppressed. The voltage
dependence of the conductance shows two pronounced peaks, at the bulk gap
energy, and at the proximity gap energy; the phase oscillation of the
conductance exhibits qualitatively different form at small voltage ,
and at large voltage .Comment: 11 pages, 9 figures, revised version, to be published in Phys. Rev.
Voice outcome after unilateral ELS type III or bilateral type II resections for T1-T2 glottic carcinoma: Results after 1 year
Abstract
Background:
Voice outcome was assessed in patients with extended T1 and limited T2 glottic carcinoma, treated with a unilateral type III or a bilateral type II resection according to the European Laryngological Society (ELS) classification.
Methods:
Objective evaluation (acoustic and aerodynamic parameters), perceptual
evaluation (GRBAS), and patients' self-assessment (voice handicap index [VHI])
were performed before and 1 year after treatment. Results were evaluated according to ELS resection type and the involvement of the anterior commissure.
Results:
The majority of voice parameters in all resection subgroups showed an
improvement of the mean score 1 year postoperatively. Grade of dysphonia varied
between 1.15 and 1.66 postoperatively and VHI score varied from 23.3 to 24.5.
Conclusion:
Voice outcome after ELS unilateral type III or a bilateral type II resection for extended T1 and limited T2 glottic carcinoma is good with mild to very
moderate perceptive dysphonia and low self-reported voice impairment
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