Geometric phase accumulation-based effects in the quantum dynamics of an anisotropically trapped ion

New physical effects in the dynamics of an ion confined in an anisotropic two-dimensional Paul trap are reported. The link between the occurrence of such manifestations and the accumulation of geometric phase stemming from the intrinsic or controlled lack of symmetry in the trap is brought to light. The possibility of observing in laboratory these anisotropy-based phenomena is briefly discussed.Comment: 10 pages. Acta Physica Hungarica B 200

Zeno Dynamics and High-Temperature Master Equations Beyond Secular Approximation

Complete positivity of a class of maps generated by master equations derived beyond the secular approximation is discussed. The connection between such class of evolutions and physical properties of the system is analyzed in depth. It is also shown that under suitable hypotheses a Zeno dynamics can be induced because of the high temperature of the bath.Comment: 9 pages, 2 figure

Microscopic description of dissipative dynamics of a level crossing transition

We analyze the effect of a dissipative bosonic environment on the Landau-Zener-Stuckelberg-Majorana (LZSM) level crossing model by using a microscopic approach to derive the relevant master equation. For an environment at zero temperature and weak dissipation our microscopic approach confirms the independence of the survival probability on the decay rate that has been predicted earlier by the simple phenomenological LZSM model. For strong decay the microscopic approach predicts a notable increase of the survival probability, which signals dynamical decoupling of the initial state. Unlike the phenomenological model our approach makes it possible to study the dependence of the system dynamics on the temperature of the environment. In the limit of very high temperature we find that the dynamics is characterized by a very strong dynamical decoupling of the initial state - temperature-induced quantum Zeno effect.Comment: 6 pages, 4 figure

Population trapping due to cavity losses

In population trapping the occupation of a decaying quantum level keeps a constant non-zero value. We show that an atom-cavity system interacting with an environment characterized by a non-flat spectrum, in the non-Markovian limit, exhibits such a behavior, effectively realizing the preservation of nonclassical states against dissipation. Our results allow to understand the role of cavity losses in hybrid solid state systems and pave the way to the proper description of leakage in the recently developed cavity quantum electrodynamic systems.Comment: 4 pages, 3 figures, version accepted for publication on Phys. Rev.

Stimulated Raman adiabatic passage in an open quantum system: Master equation approach

A master equation approach to the study of environmental effects in the adiabatic population transfer in three-state systems is presented. A systematic comparison with the non-Hermitian Hamiltonian approach [N. V. Vitanov and S. Stenholm, Phys. Rev. A {\bf 56}, 1463 (1997)] shows that in the weak coupling limit the two treatments lead to essentially the same results. Instead, in the strong damping limit the predictions are quite different: in particular the counterintuitive sequences in the STIRAP scheme turn out to be much more efficient than expected before. This point is explained in terms of quantum Zeno dynamics.Comment: 11 pages, 4 figure

Evaluation of configurational entropy of a model liquid from computer simulations

Computer simulations have been employed in recent years to evaluate the configurational entropy changes in model glass-forming liquids. We consider two methods, both of which involve the calculation of the `intra-basin' entropy as a means for obtaining the configurational entropy. The first method involves the evaluation of the intra-basin entropy from the vibrational frequencies of inherent structures, by making a harmonic approximation of the local potential energy topography. The second method employs simulations that confine the liquid within a localized region of configuration space by the imposition of constraints; apart from the choice of the constraints, no further assumptions are made. We compare the configurational entropies estimated for a model liquid (binary mixture of particles interacting {\it via} the Lennard-Jones potential) for a range of temperatures, at fixed density.Comment: 10 pages, 5 figures, Proceedings of "Unifying Concepts in Glass Physics" Trieste 1999 (to appear in J. Phys. Cond. Mat.

Gastro-intestinal parasites of pigs in Sardinia: a copromicroscopical investigation

This paper illustrates a copromicroscopical investigation carried out in Sardinia to update epidemiological data on diffusion of gastro-intestinal parasites in swine. Results obtained lead to suggest the employment of copromicroscopic exam to monitorate parasites diffusion in swine breedings in order to set up correct prophylactic and therapeutically intervents

Brownian Dynamics Simulation of Polydisperse Hard Spheres

Standard algorithms for the numerical integration of the Langevin equation require that interactions are slowly varying during to the integration timestep. This in not the case for hard-body systems, where there is no clearcut between the correlation time of the noise and the timescale of the interactions. Starting from a short time approximation of the Smoluchowsky equation, we introduce an algorithm for the simulation of the overdamped Brownian dynamics of polydisperse hard-spheres in absence of hydrodynamics interactions and briefly discuss the extension to the case of external drifts

Chronic low back pain patients' use of, level of knowledge of and perceived benefits of complementary medicine: a cross-sectional study at an academic pain center.

Chronic pain patients often use complementary medicine (CM) to alleviate their pain; however, little is known about the use of CM by chronic low back pain (cLBP) patients. We investigated the frequency of use of CM by cLBP patients, the perceived effects of these therapies, patients' knowledge regarding CM, and patient-physician communication regarding CM. A cross-sectional survey was conducted from November 2014 to February 2015. A questionnaire was distributed by physicians to 238 consecutive patients consulting for cLBP at the Pain Center of Lausanne University Hospital, Switzerland. Poisson regression model was used to analyze patients' level of knowledge regarding various CMs, and the logistic regression model was used to assess CM use for cLBP. The questionnaire was returned by 168 cLBP patients (response rate: 70.6%). Lifetime prevalence of CM use for cLBP was 77.3%. The most commonly used therapies were osteopathy (48.8%), massage (45.2%) and acupuncture (31.6%), rated for their usefulness on a 0-10 scale as a mean ± SD of 5.4 ± 2.7, 5.9 ± 2.5 and 3.8 ± 3.2, respectively. The CM treatment best known by patients was osteopathy, followed by massage and acupuncture. If their doctors proposed CM as a treatment for cLBP, 78% of participants reported being very or somewhat likely to try CM. Respondents with CM health insurance were more likely to use CM (OR = 2.26; 95%CI: 1.07-4.78; p = 0.031) for cLBP. Respondents having experienced cLBP for more than five years were more likely to use CM to treat their cLBP than respondents having experienced cLBP for one year or less (OR = 2.84; 95%CI: 1.02-7.88; p = 0.044). More than three-quarters of cLBP patients in our sample did use CM to treat their cLBP. The results showed that the most commonly used therapies were not necessarily the highest rated in terms of perceived usefulness. These results highlight the importance of developing integrative pain centers in which patients may obtain advice regarding CM treatments

Microscopic derivation of the Jaynes-Cummings model with cavity losses

In this paper we provide a microscopic derivation of the master equation for the Jaynes-Cummings model with cavity losses. We single out both the differences with the phenomenological master equation used in the literature and the approximations under which the phenomenological model correctly describes the dynamics of the atom-cavity system. Some examples wherein the phenomenological and the microscopic master equations give rise to different predictions are discussed in detail.Comment: 9 pages, 3 figures New version with minor correction Accepted for publication on Physical Review