105 research outputs found
Jahn-Teller systems from a cavity QED perspective
Jahn-Teller systems and the Jahn-Teller effect are discussed in terms of
cavity QED models. By expressing the field modes in a quadrature
representation, it is shown that certain setups of a two-level system
interacting with a bimodal cavity is described by the Jahn-Teller
Hamiltonian. We identify the corresponding adiabatic
potential surfaces and the conical intersection. The effects of a non-zero
geometrical Berry phase, governed by encircling the conical intersection, are
studied in detail both theoretically and numerically. The numerical analysis is
carried out by applying a wave packet propagation method, more commonly used in
molecular or chemical physics, and analytic expressions for the characteristic
time scales are presented. It is found that the collapse-revival structure is
greatly influenced by the geometrical phase and as a consequence, the field
intensities contain direct information about this phase. We also mention the
link between the Jahn-Teller effect and the Dicke phase transition in cavity
QED.Comment: 10 pages, 6 figures. Replaced with final versio
A meta-analysis of randomized double-blind clinical trials in CMT1A to assess the change from baseline in CMTNS and ONLS scales after one year of treatment
International audienceCMT1A is the most common inherited peripheral neuropathy. There is currently no approved treatment. We performed a meta-analysis including four randomized, double-blind, Placebo-controlled clinical trials to assess the disease progression after one year under Placebo, Ascorbic Acid (AA) or PXT3003, a combination of three repurposed drugs. We observed a weak deterioration in patients under Placebo, well below the reported natural disease progression. Patients treated with AA were stable after one year but not significantly different from Placebo. Patients undergoing PXT3003 treatment showed an improvement in CMTNS and ONLS, statistically significant versus Placebo and potentially precursory of a meaningful change in the disease course
Cold Fermi atomic gases in a pumped optical resonator
We study systems of fully polarized ultracold atomic gases obeying Fermi
statistics. The atomic transition interacts dispersively with a mode of a
standing-wave cavity, which is coherently pumped by a laser. In this setup, the
intensity of the intracavity field is determined by the refractive index of the
atomic medium, and thus by the atomic density distribution. Vice versa, the
density distribution of the atom is determined by the cavity field potential,
whose depth is proportional to the intracavity field amplitude. In this work we
show that this nonlinearity leads to an instability in the intracavity
intensity that differs substantially from dispersive optical bistability, as
this effect is already present in the regime, where the atomic dipole is
proportional to the cavity field. Such instability is driven by the matter
waves fluctuations and exhibits a peculiar dependence on the fluctuations in
the atomic density distribution.Comment: Two column, three figures. Replaced with final versio
Breakdown of the classical description of a local system
We provide a straightforward demonstration of a fundamental difference
between classical and quantum mechanics for a single local system; namely the
absence of a joint probability distribution of the position and momentum
. Elaborating on a recently reported criterion by Bednorz and Belzig [Phys.
Rev. A {\bf 83}, 52113] we derive a simple criterion that must be fulfilled for
any joint probability distribution in classical physics. We demonstrate the
violation of this criterion using homodyne measurement of a single photon
state, thus proving a straightforward signature of the breakdown of a classical
description of the underlying state. Most importantly, the criterion used does
not rely on quantum mechanics and can thus be used to demonstrate
non-classicality of systems not immediately apparent to exhibit quantum
behavior. The criterion is directly applicable any system described by the
continuous canonical variables x and p, such as a mechanical or an electrical
oscillator and a collective spin of a large ensemble.Comment: 5 pages, 2 figure
Quantum fluctuations in the mazer
Quantum fluctuations in the mazer are considered, arising either from the
atomic motion or from the quantized intracavity field. Analytical results, for
both the meza and the hyperbolic secant mode profile, predict for example an
attenuation of tunneling resonances due to such fluctuations. The case of a
Gaussian mode profile is studied numerically using a wave packet propagation
approach. The method automatically takes into account fluctuations in the
atomic motion and the dynamics is especially considered at or adjacent to a
tunnel resonance. We find that the system evolution is greatly sensitive to the
atom-field detuning, bringing about a discussion about the concept of
adiabaticity in this model. Further, a novel collapse-revival phenomena is
demonstrated, originating from the quantum fluctuations in the atomic motion
rather from field fluctuations as is normally the case.Comment: 15 pages, 8 figures. Replaced with final versio
Complementarity and the uncertainty relations
We formulate a general complementarity relation starting from any Hermitian
operator with discrete non-degenerate eigenvalues. We then elucidate the
relationship between quantum complementarity and the Heisenberg-Robertson's
uncertainty relation. We show that they are intimately connected. Finally we
exemplify the general theory with some specific suggested experiments.Comment: 9 pages, 4 figures, REVTeX, uses epsf.sty and multicol.st
Acid transport by intracellular vesicles
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106084/1/j.1365-2796.1990.tb01470.x.pd
EMA - A R package for Easy Microarray data analysis
<p>Abstract</p> <p>Background</p> <p>The increasing number of methodologies and tools currently available to analyse gene expression microarray data can be confusing for non specialist users.</p> <p>Findings</p> <p>Based on the experience of biostatisticians of Institut Curie, we propose both a clear analysis strategy and a selection of tools to investigate microarray gene expression data. The most usual and relevant existing R functions were discussed, validated and gathered in an easy-to-use R package (EMA) devoted to gene expression microarray analysis. These functions were improved for ease of use, enhanced visualisation and better interpretation of results.</p> <p>Conclusions</p> <p>Strategy and tools proposed in the EMA R package could provide a useful starting point for many microarrays users. EMA is part of Comprehensive R Archive Network and is freely available at <url>http://bioinfo.curie.fr/projects/ema/</url>.</p
Monoprophylaxis With Cephalosporins for Transrectal Prostate Biopsy After the Fluoroquinolone-Era: A Multi-Institutional Comparison of Severe Infectious Complications
BackgroundTo compare severe infectious complication rates after transrectal prostate biopsies between cephalosporins and fluoroquinolones for antibiotic monoprophylaxis.Material and MethodsIn the multi-institutional cohort, between November 2014 and July 2020 patients received either cefotaxime (single dose intravenously), cefpodoxime (multiple doses orally) or fluoroquinolones (multiple-doses orally or single dose intravenously) for transrectal prostate biopsy prophylaxis. Data were prospectively acquired and retrospectively analyzed. Severe infectious complications were evaluated within 30 days after biopsy. Logistic regression models predicted biopsy-related infectious complications according to antibiotic prophylaxis, application type and patient- and procedure-related risk factors.ResultsOf 793 patients, 132 (16.6%) received a single dose of intravenous cefotaxime and were compared to 119 (15%) who received multiple doses of oral cefpodoxime and 542 (68.3%) who received fluoroquinolones as monoprophylaxis. The overall incidence of severe infectious complications was 1.0% (n=8). No significant differences were observed between the three compared groups (0.8% vs. 0.8% vs. 1.1%, p=0.9). The overall rate of urosepsis was 0.3% and did not significantly differ between the three compared groups as well.ConclusionMonoprophylaxis with third generation cephalosporins was efficient in preventing severe infectious complications after prostate biopsy. Single intravenous dose of cefotaxime and multiday regimen of oral cefpodoxime showed a low incidence of infectious complications <1%. No differences were observed in comparison to fluoroquinolones
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