Some Integrable Systems in Nonlinear Quantum Optics

In the paper we investigate the theory of quantum optical systems. As an application we integrate and describe the quantum optical systems which are generically related to the classical orthogonal polynomials. The family of coherent states related to these systems is constructed and described. Some applications are also presented.Comment: 27 page

Dynamic effects of electromagnetic wave on a damped two-level atom

We studied the dynamic effects of an electromagnetic(EM) wave with circular polarization on a two-level damped atom. The results demonstrate interesting ac Stark split of energy levels of damped atom. The split levels have different energies and lifetimes, both of which depend on the interaction and the damping rate of atom. When the frequency of the EM wave is tuned to satisfy the resonance condition in the strong coupling limit, the transition probability exhibits Rabi oscillation. Momentum transfer between atom and EM wave shows similar properties as the transition probability under resonance condition. For a damped atom interacting with EM field, there exists no longer stable state. More importantly, if the angular frequency of the EM wave is tuned the same as the atomic transition frequency and its amplitude is adjusted appropriately according to the damping coefficients, we can prepare a particular 'Dressed State' of the coupled system between atom and EM field and can keep the system coherently in this 'Dressed state' for a very long time. This opens another way to prepare coherent atomic states.Comment: latex, 2 figure

Collisional decay of a strongly driven Bose-Einstein condensate

We study the collisional decay of a strongly driven Bose-Einstein condensate oscillating between two momentum modes. The resulting products of the decay are found to strongly deviate from the usual s-wave halo. Using a stochastically seeded classical field method we simulate the collisional manifold. These results are also explained by a model of colliding Bloch states.Comment: 4 pages, 4 figure

Multiplicity distributions in gravitational and strong interactions

The multiplicity distributions produced by the variation of time-dependent gravitational fields in a conformally flat background geometry belong to the same class of infinitely divisible distributions found, for fixed centre of mass energies and symmetric (pseudo)rapidity intervals, in charged multiplicities produced in $pp$, $p\overline{p}$ and in heavy ion collisions. Apparently unrelated multiplicity distributions are classified in terms of the (positive) discrete representations of the $SU(1,1)$ group. The gravitational analogy suggest a global high-energy asymptote for the distributions measured in $pp$ and $p\overline{p}$ collisions. Second-order cross correlations between positively and negatively charged distributions represent a relevant diagnostic for a closer scrutiny of the multiparticle final state.Comment: 11 pages, 2 included figures; to appear in Physics Letters

Threshold of a random laser based on Raman gain in cold atoms

We address the problem of achieving a random laser with a cloud of cold atoms, in which gain and scattering are provided by the same atoms. In this system, the elastic scattering cross-section is related to the complex atomic polarizability. As a consequence, the random laser threshold is expressed as a function of this polarizability, which can be fully determined by spectroscopic measurements. We apply this idea to experimentally evaluate the threshold of a random laser based on Raman gain between non-degenerate Zeeman states and find a critical optical thickness on the order of 200, which is within reach of state-of-the-art cold-atom experiments

Quantum properties of the parametric amplifier with and without pumping field fluctuations

The parametric amplifier with and without the pumping fluctuations of coupling function is considered when the fields are initially prepared in coherent light. The pumping fluctuations are assumed to be normally distributed with time-dependent variance. The effects of antibunching and anticorrelation of photons on the photon distribution, correlation between modes and factorial moments are demonstrated. A possible enhancement of photon antibunching for certain values of initial mean photon numbers is shown and discussed. We have shown also that new states (called modified squeezed vacuum states or even thermal states) can be generated from such an interaction. Further, we have demonstrated that the sum photon-number distribution can exhibit collapses and revivals in the photon-number domain somewhat similar to those known in the Jaynes-Cummings model.Comment: 17 pages, 6figure

Fattening Austerity

This essay presents “fattening austerity” as a new conceptual framework that will enable a collective resistance to austerity politics and fat oppression. Austerity and fatphobia have not, to our knowledge, been analyzed in tandem. But the discourses that uphold both punitive austerity measures and the pathologization of fat people’s bodies are deeply imbricated. Austerity and anti-fat stigma each invoke a language of crisis to authorize social practices that inflict hunger and bodily injury upon people who are fat and/or poor. In addition, anti-‘obesity’ rhetoric and pro-austerity arguments each utilize the neoliberal values of “personal responsibility” and corporeal “choice” to further marginalize people who are poor, fat, or both. We argue that it is incumbent upon the political Left—which thus far has been remiss in challenging the anti-fat prejudice that often animates its own movements—to make fat justice a central part of its critique of austerity

Quantum key distribution using non-classical photon number correlations in macroscopic light pulses

We propose a new scheme for quantum key distribution using macroscopic non-classical pulses of light having of the order 10^6 photons per pulse. Sub-shot-noise quantum correlation between the two polarization modes in a pulse gives the necessary sensitivity to eavesdropping that ensures the security of the protocol. We consider pulses of two-mode squeezed light generated by a type-II seeded parametric amplification process. We analyze the security of the system in terms of the effect of an eavesdropper on the bit error rates for the legitimate parties in the key distribution system. We also consider the effects of imperfect detectors and lossy channels on the security of the scheme.Comment: Modifications:added new eavesdropping attack, added more references Submitted to Physical Review A [email protected]

Unraveling quantum dissipation in the frequency domain

We present a quantum Monte Carlo method for solving the evolution of an open quantum system. In our approach, the density operator evolution is unraveled in the frequency domain. Significant advantages of this approach arise when the frequency of each dissipative event conveys information about the state of the system.Comment: 4 pages, 4 Postscript figures, uses RevTe

Conditional resonance-fluorescence spectra of single atoms.

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