1,473 research outputs found
Geometric Phase and Modulo Relations for Probability Amplitudes as Functions on Complex Parameter Spaces
We investigate general differential relations connecting the respective
behavior s of the phase and modulo of probability amplitudes of the form
\amp{\psi_f}{\psi}, where is a fixed state in Hilbert space
and is a section of a holomorphic line bundle over some complex
parameter space. Amplitude functions on such bundles, while not strictly
holomorphic, nevertheless satisfy generalized Cauchy-Riemann conditions
involving the U(1) Berry-Simon connection on the parameter space. These
conditions entail invertible relations between the gradients of the phase and
modulo, therefore allowing for the reconstruction of the phase from the modulo
(or vice-versa) and other conditions on the behavior of either polar component
of the amplitude. As a special case, we consider amplitude functions valued on
the space of pure states, the ray space , where
transition probabilities have a geometric interpretation in terms of geodesic
distances as measured with the Fubini-Study metric. In conjunction with the
generalized Cauchy-Riemann conditions, this geodesic interpretation leads to
additional relations, in particular a novel connection between the modulus of
the amplitude and the phase gradient, somewhat reminiscent of the WKB formula.
Finally, a connection with geometric phases is established.Comment: 11 pages, 1 figure, revtex
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Safety of guselkumab in hepatitis B virus infection
Reactivation of hepatitis B virus (HBV) following the use of TNF antagonists has been reported and is a contraindication to use of these medications. Although the risk of reactivation of HBV during use of ustekinumab and secukinumab is low in patients with only HBV core antibody positivity, the risk is substantial in patients with chronic HBV infection. Less information is available regarding the use of pure IL-23 antagonists. Herein we discuss the successful treatment with guselkumab of a patient with HBV core antibody positivity, without evidence of HBV reactivation or other liver complications
Coherent Optical Spectroscopy Of Molecules And Molecular Beams
This paper presents our recent work on coherent optical spectroscopy of molecules and molecular beams. The theory for these nonlinear optical effects is summarized and related to the measurements in the gas phase and in the condensed phase. Finally, we discuss the importance of these methods, which disentangle the inhomogeneous optical resonances, in understanding nonradiative and optical dephasing processes
Spin-dependent transport in p+-CdBxF2-x - n-CdF2 planar structures
The CV measurements and tunneling spectroscopy are used to study the
ballistic transport of the spin-polarized holes by varying the value of the
Rashba spin-orbit interaction (SOI) in the p-type quantum well prepared on the
surface of the n-CdF2 bulk crystal. The findings of the hole conductance
oscillations in the plane of the p-type quantum well that are due to the
variations of the Rashba SOI are shown to be evidence of the spin transistor
effect, with the amplitude of the oscillations close to e2/h.Comment: 5 pages, 6 figure
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Comparison of wound strength, histologic, and aesthetic outcomes after microsurgical versus conventional skin closure in a rat model.
The purpose of this study was to compare the healing, strength, and cosmetic outcome of linear incisions after repair with the naked eye, surgical loupes, or a surgical microscope. Two parallel incisions were made on the dorsal skin of Sprague-Dawley rats (n = 36) and the rats randomized into four groups. A single surgeon repaired the incisions using 5-0 poliglecaprone in a running subcuticular pattern using the naked eye (Group I), surgical loupes with 2.5× magnification (Group II), surgical microscope with 5-10× magnification (Group III), and 6-0 poliglecaprone with a surgical microscope (Group IV). Rats were sacrificed at 1, 3, and 6 weeks. At each time point, the tensile strength of each closure was assessed. Macroscopic outcomes were evaluated using the Vancouver Scar Scale (VSS) and histology assessed by a blinded observer. Microscope closure took significantly longer than closure with the naked eye (p < 0.05). There was no significant difference in tensile strength or VSS ratings between the closure methods at any of the time points. On histopathologic analysis, there were a greater number of inflammatory cells and fibroblasts in the 6-0 microscope closure group versus the naked eye closure group at week 3 (p ≤ 0.05). In conclusion, wound repair under magnification did not yield a significant difference in cosmesis or wound tensile strength, but did increase operative time. Moreover, there was a trend toward increased inflammation with microscope-assisted closures, perhaps due to the increased suture burden
The role of the ubiquitination-proteasome pathway in breast cancer: Applying drugs that affect the ubiquitin-proteasome pathway to the therapy of breast cancer
The ubiquitin-proteasome pathway is responsible for most eukaryotic intracellular protein degradation. This pathway has been validated as a target for antineoplastic therapy using both in vitro and preclinical models of human malignancies, and is influenced as part of the mechanism of action of certain chemotherapeutic agents. Drugs whose primary action involves modulation of ubiquitin-proteasome activity, most notably the proteasome inhibitor PS-341, are currently being evaluated in clinical trials, and have already been found to have significant antitumor efficacy. On the basis of the known mechanisms by which these agents work, and the available clinical data, they would seem to be well suited for the treatment of breast neoplasms. Such drugs, alone and especially in combination with current chemotherapeutics, may well represent important advances in the therapy of patients with breast cancer
Radiationless Relaxation in "Large" Molecules: Experimental Evidence for Preparation of True Molecular Eigenstates and Born-Oppenheimer States by a Coherent Light Source
Photon absorption and emission by molecules that undergo radiationless transitions are examined using the single modes of lasers having well-defined coherence properties. Contrary to the usual beliefs, where it is assumed that the molecule is prepared in a Born-Oppenheimer singlet state and then "crosses-over" to other states (vibrationally "hot" singlets and/or triplets), it is shown experimentally that the true eigenstates of the molecule can be prepared, even in "large" molecules, if the laser correlation time is relatively long and the molecular relaxation is made slow. On the other hand, lasers with short (psec) correlation time have yielded effectively the singlet Born-Oppenheimer state, which has a much shorter lifetime than the true eigenstates. Effects of magnetic fields and temperature are also reported. The former changes the amount of mixing amongst the Born-Oppenheimer states. The latter, on the other hand, swings the molecule from being "small" (i.e., sparse vibronic structure with long lifetimes) to being "large" (i.e., dense statistical distribution of levels) since the relaxation between levels is very effective at high temperatures. Finally, the results of this work show that the words fluorescence and phosphorescence in their strict meaning are misleading if the true eigenstates, which may contain both singlet and triplet character, are prepared
How to determine a quantum state by measurements: The Pauli problem for a particle with arbitrary potential
The problem of reconstructing a pure quantum state ¿¿> from measurable quantities is considered for a particle moving in a one-dimensional potential V(x). Suppose that the position probability distribution ¿¿(x,t)¿2 has been measured at time t, and let it have M nodes. It is shown that after measuring the time evolved distribution at a short-time interval ¿t later, ¿¿(x,t+¿t)¿2, the set of wave functions compatible with these distributions is given by a smooth manifold M in Hilbert space. The manifold M is isomorphic to an M-dimensional torus, TM. Finally, M additional expectation values of appropriately chosen nonlocal operators fix the quantum state uniquely. The method used here is the analog of an approach that has been applied successfully to the corresponding problem for a spin system
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