S. V. Lawande

PANCHARATNAM PHASE FOR A SYSTEM OF A TWO-LEVEL ATOM INTERACTING WITH A QUANTIZED FIELD IN A CAVITY

Abstract We derive an expression for the Pancharatnam phase for the entangled state of a single two-level atom interacting with a single electromagnetic field mode in an ideal cavity with the atom undergoing either a one- or a two-photon transition. It is shown that the Pancharatnam phase explicitly contains information about the statistics of the field and atomic coherence.

Effects of Dipole Interaction on the Collapse-revival Phenomenon of Rabi Oscillations

Abstract The sensitivity of the collapse-revival phenomenon of Rabi oscillations of two identical atoms to dipole-dipole interaction is brought out by deriving the analytical expression of the excitation probability of two interacting atoms in a coherent field. We study this effect in a two-photon model in which the time evolution is exactly periodic.

The effects of negative binomial field distribution on Rabi oscillations in a two-level atom

Abstract The dynamics of excitation of a two-level atom interacting with a single model of electromagnetic field in negative binomial state in an ideal cavity is studied. The squeezing in the cavity field is also investigated. The negative binomial state reduces to a pure thermal state and a pure coherent state in two different limits. Hence it enables one to study how periodic collapses and revivals of Rabi oscillations in a coherent state develop into seemingly chaotic oscillations in a thermal field or vice versa.

Jaynes-Cummings model with stochastic fluctuations

Abstract The dynamical evolution of the Jaynes-Cummings model in the presence of stochastic phase fluctuations in the atom-field coupling is studied. A solution for the phase-averaged density operator is obtained in the secular approximation using the dressed atom approach.

GEOMETRY OF THE HILBERT SPACE AND THE QUANTUM ZENO EFFECT

We show that the quadratic short time behavior of transition probability is a natural consequence of the inner product of the Hilbert space of the quantum system. We provide a relation between the survival probability and the underlying geometric structure such as the Fubini-Study metric defined on the projective Hilbert space of the quantum system. This predicts the quantum Zeno effect even for systems described by nonlinear and nonunitary evolution equations, within the collapse mechanism of the wave function during measurement process.

Existence of stable periodic orbits in the x2y2 potential: a semiclassical approach

The authors use the semiclassical periodic orbit theory to identify the recently discovered one-parameter family of stable periodic orbits in the x2y2 potential occupying an area of 0.005% on the surface of section. They also indicate the presence of another stable family of periodic orbits of higher length. The sensitivity of the method provides hope for ruling out ergodicity in other systems.

Squeezing and quasiprobabilities for a two-photon Jaynes-Cummings model with atomic motion

We study the squeezing and the quasiprobability distribution Q-function for an extended two-photon Jaynes-Cummings model (JCM) that includes atomic motion and the field mode structure. A comparative study of this model with respect to the standard model (in which the atom is at rest) has been presented here to isolate the effect of limited atom-radiation interaction time.

Successive photon emission from a two-level atom in a broadband squeezed vacuum

Abstract The photon statistics of the resonance fluorescence in a broadband squeezed vacuum is studied in terms of the probabilities of emission of any photon and the next photon. These probabilities manifest the inhibition of atomic phase decay in squeezed vacuum.

Optical double resonance spectra under finite bandwidth excitations

Abstract A formalism based on the theory of multiplicative stochastic processes is presented to treat the effects of finite band- with excitations on the optical double resonance spectra. Numerical results for the fluorescent spectra and the second-order intensity correlation functions are presented and discussed.

A DETAILED INVESTIGATION OF THE SPECTRAL RIGIDITY FOR INTEGRABLE HAMILTONIAN SYSTEMS

The authors carry out a detailed analysis of the spectral rigidity for integrable systems with a view towards understanding the deviations from the universal behaviour (L/15) in systems with degeneracies in orbit actions. In the process, they also investigate the saturation region. Their studies show that the energy dependence of Delta 3( infinity ) is a better indicator of the underlying universality in integrable systems.