Symmetric photon-photon coupling by atoms with Zeeman-split sublevels

We propose a simple scheme for highly efficient nonlinear interaction between two weak optical fields. The scheme is based on the attainment of electromagnetically induced transparency simultaneously for both fields via transitions between magnetically split F=1 atomic sublevels, in the presence of two driving fields. Thereby, equal slow group velocities and symmetric cross-coupling of the weak fields over long distances are achieved. By simply tuning the fields, this scheme can either yield giant cross-phase modulation or ultrasensitive two-photon switching.Comment: Modified scheme, 4 pages, 1 figur

Beyond Gross-Pitaevskii:local density vs. correlated basis approach for trapped bosons

We study the ground state of a system of Bose hard-spheres trapped in an isotropic harmonic potential to investigate the effect of the interatomic correlations and the accuracy of the Gross-Pitaevskii equation. We compare a local density approximation, based on the energy functional derived from the low density expansion of the energy of the uniform hard sphere gas, and a correlated wave function approach which explicitly introduces the correlations induced by the potential. Both higher order terms in the low density expansion, beyond Gross-Pitaevskii, and explicit dynamical correlations have effects of the order of percent when the number of trapped particles becomes similar to that attained in recent experiments.Comment: Revtex, 2 figure

Beyond Gross-Pitaevskii:local density vs. correlated basis approach for trapped bosons

We study the ground state of a system of Bose hard-spheres trapped in an isotropic harmonic potential to investigate the effect of the interatomic correlations and the accuracy of the Gross-Pitaevskii equation. We compare a local density approximation, based on the energy functional derived from the low density expansion of the energy of the uniform hard sphere gas, and a correlated wave function approach which explicitly introduces the correlations induced by the potential. Both higher order terms in the low density expansion, beyond Gross-Pitaevskii, and explicit dynamical correlations have effects of the order of percent when the number of trapped particles becomes similar to that attained in recent experiments.Comment: Revtex, 2 figure

D-dimensional Ideal Quantum Gases in Arn+Br−nAr^{n}+Br^{-n} Potential

The paper is concerned with thermostatistics of both $D$-dimensional Bose and Fermi ideal gases in a confining potential of type $Ar^{n}+Br^{-n}$. The investigation is performed in the framework of the semiclassical approximation. Some physical quantities for such systems are derived, like density of states, density profiles and number of particles. Bose-Einstein condensation (BEC) is discussed in the high and low temperature regimes.Comment: 13 pages, Late

Psicoterapia psicodinamica e formazione universitaria: problematiche e prospettive

This article proposes a reflection on the problem of psychiatric training taking into consideration the current situation present in Italy where, apart from public (university) schools of specialization, there are a number of private post-graduate schools which qualify one to practice the profession of psychotherapist. By keeping separate the more didactic-educational aspect from the training, there is an attempt to verify how much attention is devoted to the latter because within the university schools more and more students ask for a possibility to discuss clinical cases and understand the sense of a therapeutic relationship. Furthermore, it is necessary to verify, not only the didactical learning of students, but also their personal aptitudes during the four years of specialization. There seems to be an incongruity between the statutes that govern the single private specialization schools that regulate the supervision of clinical cases and in some cases prescribe an obligatory didactic analysis for the student, and what happens in a university context

Electromagnetic induced transparency and slow light in interacting quantum degenerate atomic gases

We systematically develop the full quantum theory for the electromagnetic induced transparency (EIT) and slow light properties in ultracold Bose and Fermi gases. It shows a very different property from the classical theory which assumes frozen atomic motion. For example, the speed of light inside the atomic gases can be changed dramatically near the Bose-Einstein condensation temperature, while the presence of the Fermi sea can destroy the EIT effect even at zero temperature. From experimental point of view, such quantum EIT property is mostly manifested in the counter-propagating excitation schemes in either the low-lying Rydberg transition with a narrow line width or in the D2 transitions with a very weak coupling field. We further investigate the interaction effects on the EIT for a weakly interacting Bose-Einstein condensate, showing an inhomogeneous broadening of the EIT profile and nontrivial change of the light speed due to the quantum many-body effects beyond mean field energy shifts.Comment: 7 figure

Self-Trapping, Quantum Tunneling and Decay Rates for a Bose Gas with Attractive Nonlocal Interaction

We study the Bose-Einstein condensation for a cloud of $^7$Li atoms with attractive nonlocal (finite-range) interaction in a harmonic trap. In addition to the low-density metastable branch, that is present also in the case of local interaction, a new stable branch appears at higher densities. For a large number of atoms, the size of the cloud in the stable high-density branch is independent of the trap size and the atoms are in a macroscopic quantum self-trapped configuration. We analyze the macroscopic quantum tunneling between the low-density metastable branch and the high-density one by using the istanton technique. Moreover we consider the decay rate of the Bose condensate due to inelastic two- and three-body collisions.Comment: 5 pages, 4 figures, submitted to Phys. Rev.

From Storage and Retrieval of Pulses to Adiabatons

We investigate whether it is possible to store and retrieve the intense probe pulse from a $\Lambda$-type homogeneous medium of cold atoms. Through numerical simulations we show that it is possible to store and retrieve the probe pulse which are not necessarily weak. As the intensity of the probe pulse increases, the retrieved pulse remains a replica of the original pulse, however there is overall broadening and loss of the intensity. These effects can be understood in terms of the dependence of absorption on the intensity of the probe. We include the dynamics of the control field, which becomes especially important as the intensity of the probe pulse increases. We use the theory of adiabatons [Grobe {\it et al.} Phys. Rev. Lett. {\bf 73}, 3183 (1994)] to understand the storage and retrieval of light pulses at moderate powers.Comment: 15 pages, 7 figures, typed in RevTe

Uno studio sulle caratteristiche di un campione di pazienti internati presso l'Ospedale Psichiatrico Giudiziario di Castiglione delle Stiviere e dimessi nella regione Lazio.

Aim. The aim of this study was: i) To identify socio-demographic and clinical data in a sample of inmates in the Criminal Mental Hospital (CMH) at Castiglione delle Stiviere; ii) to assess the presence of characteristics which could foresee the commission of a crime of psychiatric interest; iii) to assess the frequency of crime repetition. Materials and Methods. This study was carried out on a sample of 38 patients. A descriptive analysis of the sample was carried out and the associations among several variables were analyzed. Results. The sample is characterized by a high frequency of schizophrenia diagnosis (73.0%), the presence of hospitalization before the commission of the crime (68.4%) and the absence of criminal precedents (71.1%). For men the age of the commission of the crime is equal to 33.72±10.6 years and for women to 45.18±11.4 years (p=0.011). The time between the onset and the commission of the crime is longer in patients who have received therapy (treatment) than in those ones with no treatment (p=0.012). About 12% of the sample committed new crimes. Conclusions. The results showed previous criminal acts are not predictive for the commission of new crimes of psychiatric interest. However many patients had previous contacts with community facilities before their first admission to hospital and the treatment extended the interval between the onset of the disease and the commission of the crime. The relapse rate after the discharge was very low if compared with samples coming from other services that offered more custodial rather than rehabilitative facilities