0000000000132318
AUTHOR
A. Vaglica
Non-markovian dynamics and spectrum of a moving atom strongly coupled to the field in a damped cavity
Abstract We study the internal dynamics of an atom entering in its excited state in a damped cavity and strongly coupled to the field. We show that the time evolution of its dipole operator is described by a second order Langevin-like equation with time dependent coefficients. We use this equation to investigate the time dependence of the average population inversion and the spectrum of the emitted radiation. We discuss how Rabi oscillations are modified by the motion of the atom and how the spectrum changes from the vacuum Rabi doublet to a more complex structure having new lines, different frequency localizations and modified widths.
Irreversible decay of nonlocal entanglement via a reservoir of a single degree of freedom.
Recently, it has been realized that nonlocal disentanglement may take a finite time as opposite to the asymptotic decay of local coherences. We find in this paper that a sudden irreversible death of entanglement takes place in a two atom optical Stern-Gerlach model. In particular, the one degree non dissipative environment here considered suddenly destroys the initial entanglement of any Bell's states $\ket{\phi^{\pm}}$ superposition.
On the observability of Bell's inequality violation in the two-atoms optical Stern-Gerlach model
Using the optical Stern-Gerlach model, we have recently shown that the non-local correlations between the internal variables of two atoms that successively interact with the field of an ideal cavity in proximity of a nodal region are affected by the atomic translational dynamics. As a consequence, there can be some difficulties in observing violation of the Bell's inequality for the atomic internal variables. These difficulties persist even if the atoms travel an antinodal region, except when the spatial wave packets are exactly centered in an antinodal point.
Jaynes-Cummings model with atomic position distribution
The position as well as the width of the atomic wave packet passing through an optical cavity may affect the matter-field interaction. As a result, the internal dynamics of a two-level atom, such as the Rabi oscillations or the collapse and revival phenomenon, may be strongly modified with respect to the standard Jaynes-Cummings model. In particular, for a sufficiently large spread of the atomic position, the atomic population inversion displays the characteristic ringing behavior of the Bessel function ${\mathit{J}}_{0}$ differently from the usual full Rabi oscillation.
Correlations between Rabi oscillations and atomic translational dynamics
We analyze some aspects of the internal and translational dynamics of a two-level atom interacting with a resonant standing wave of an ideal cavity. We show that the cavity vacuum field can split the incoming wave packet of the excited two-level atom into two parts, whose scalar product in the Hilbert space determines the behavior of the Rabi oscillations. The state of the whole system is derived and allows us to study the correlations between the internal and the translational atomic dynamics. We find that these correlations become negligible when the two parts are sufficiently away from each other in the space.
One-sided atomic deflection in the optical Stern-Gerlach effect and coherent trapping
In the optical Stern-Gerlach effect, the interaction of a traveling two-level atom with the electromagnetic field of an optical cavity causes a splitting of the atomic trajectory. One may ask if it is possible to single out particular initial configurations of the system that will lead to selective scattering, in which the atoms follow only one trajectory. We show that these configurations consist of a coherent superposition of the atomic internal states, and of a field phase state or a field coherent state, with a precise phase relation between the two subsystems: The same configurations which produce the so-called atomic coherent trapping in the Jaynes-Cummings model.
Translational dynamics effects on the non-local correlations between two atoms
A pair of atoms interacting successively with the field of the same cavity and exchanging a single photon, leave the cavity in an entangled state of Einstein-Podolsky-Rosen (EPR) type (see, for example, [S.J.D. Phoenix, and S.M. Barnett, J. Mod. Opt. \textbf{40} (1993) 979]). By implementing the model with the translational degrees of freedom, we show in this letter that the entanglement with the translational atomic variables can lead, under appropriate conditions, towards the separability of the internal variables of the two atoms. This implies that the translational dynamics can lead, in some cases, to difficulties in observing the Bell's inequality violation for massive particles.
The non dissipative damping of the Rabi oscillations as a "which-path" information
Rabi oscillations may be viewed as an interference phenomenon due to a coherent superposition of different quantum paths, like in the Young's two-slit experiment. The inclusion of the atomic external variables causes a non dissipative damping of the Rabi oscillations. More generally, the atomic translational dynamics induces damping in the correlation functions which describe non classical behaviors of the field and internal atomic variables, leading to the separability of these two subsystems. We discuss on the possibility of interpreting this intrinsic decoherence as a "which-way" information effect and we apply to this case a quantitative analysis of the complementarity relation as intro…
Quantum erasure within the optical Stern-Gerlach model
In the optical Stern-Gerlach effect the two branches in which the incoming atomic packet splits up can display interference pattern outside the cavity when a field measurement is made which erases the which-way information on the quantum paths the system can follow. On the contrary, the mere possibility to acquire this information causes a decoherence effect which cancels out the interference pattern. A phase space analysis is also carried out to investigate on the negativity of the Wigner function and on the connection between its covariance matrix and the distinguishability of the quantum paths.
Resection of a giant mediastinal leiomyosarcoma
ABSTRACT Primary leiomyosarcomas of the lung are rare tumors. We report a case of 49-year-old female with history of cough, breathless at rest, right sided chest pain. Chest CT showed a huge (16 cm) mediastinal mass located on the right mediastinum encasing the right main pulmonary artery and infiltrating the main right bronchus and pericardium. The tumor was resected with combined pericardiectomy and pnemonectomy via hemiclamshell incision. This surgical access provided an adequate exposure of the chest “blind zones” and it allowed a radical and safe surgical resection of lung, pleura, pericardium and diaphragm. The final diagnosis showed a low grade differentiation leiomyosarcoma.
ROUTINARY USE OF FIBRIN SEALANTS TO PREVENT PROLONGED AIR LEAK IN THORACIC SURGERT: OUR EXPERIENCE
Introduction: prolonged air leak (PAL) is one of the most common postoperative complications after lung surgery. It is associatred with increased significant morbidity, lower quality of life, longer hospital stay and higher hospital costs. Since its great clinical and economic burden, it is important to establish the feasibility and the effectiveness of the routinary preventive use of a fibrin sealant in order to reduce the incidence of prolonged air leaks. Patients and methods: this is a randomized study on 189 adult patients - 118 men (62,4%) and 71 women (37,6%) aged from 39 to 87 y.o. (mean age 68,3 y.o.) - who underwent lung surgery (lobectomy or bilobectomy) with intraoperatory detect…