Analysis of nonclassical behavior for a two-mode coupled-photon system

We consider a model two-mode coupled-photon system and verify that the photon distribution for this system is exactly super-Poissonian. We calculate the Glauber–Sudarshan diagonal P representation for both the individual photon subsystem and the complete photon–photon complex. We present the detailed analysis on the threshold temperature of the nonclassical behavior for the both cases. We discuss the effect of the interaction between two photons on the threshold temperature.     

A new method for generating nonclassical correlation state of the light in a open-loop LED system

The nonclassical correlation state of the light have been investigated experimentally in re-cent years.After the open-type amplitude squeezed state of the light has been observed experi-mentally,we have generated and observed nonclassical correlation state of the light deep sup-pression in a open-loop LED system with very simple setup.The experimental apparatus isshown in Fig.1.In which,a closed-loop Ch1 is consist of LED1,PD1,A1,A3 and low-noise     

Problem of classical and nonclassical probabilities

A characterization of classical and nonclassical probabilities expressed in terms of some inequalities between multidimensional orS-probability is given. A new criterion (not referring to correlation probabilities) for nonclassicality of the range of a completeS-probability measure on an event system is proposed.     

Symplectic tomography of nonclassical states of a trapped ion

The marginal distribution of squeezed and rotated quadrature for two types of nonclassical states of a trapped ion — squeezed and correlated states and squeezed even and odd coherent states (squeezed Schrödinger cat states) — is studied. The marginal distribution obtained for the two types of states is shown to satisfy a classical dynamic equation equivalent to the standard quantum evolution equation for the density matrix (wave function) derived in a symplectic-tomography scheme.On leave from the P. N. Lebedev Physical Institete, Moscow, Russia.Contribution to the Adriatico Research Conference Interferometry 2 (ICTP, Trieste, March 1–11, 1996), submitted March 13, 1996.     

Quantum-electrodynamic processes in a strong nonclassical electromagnetic field

Quantum-electrodynamic processes that take place in the presence of a squeezed electromagnetic field are discussed. Integral formulas are derived that make it possible to express the probability of any process in a squeezed electromagnetic field in terms of the probability of the same process in a classical electromagnetic field. The main laws that govern processes of first order in the fine-structure constant as functions of the number of photons involved and the quantum fluctuations are examined. Tunneling formulas for the probability of a photon producing an electron-positron pair in a strong squeezed field are derived. Also, resonant electron-electron scattering is examined and the scattering cross section as a function of the statistical properties of the field (the way the field has been squeezed) is investigated. It is found that the quantum fluctuations of the squeezed electromagnetic field give rise to an increase in the scattering cross section, with the probability of the process in a phase-squeezed electromagnetic field always being higher than the probability of the process in an amplitude-squeezed electromagnetic field. Zh. éksp. Teor. Fiz. 112, 1543–1556 (November 1997)     

Generation of nonclassical states of a field with frequency-dependent squeezing

The generation of nonclassical states of light with specified frequency-dependent squeezing by way of introducing a correlation between the phase and amplitude of the input field is considered. Three schemes for measuring amplitude fluctuations of the input beam, based on a nondemolition measurement of the intensity in a nonlinear cubic crystal, the effect of light rectification in a quadratic optical crystal, and the use of a non-degenerate optical parametric oscillator, are proposed. The maximum possible value of noise suppression is estimated for each scheme. The prospects for practical realization of the proposed method for generation of frequency-dependent squeezed states are discussed.     

Darboux transformation and nonclassical orthogonal polynomials

A Darboux transformation of orderN is introduced for the Schrödinger equation. The relation between this transformation and the factorization method is treated in detail forN=2. It is noted that the potential of the new Schrödinger depends on 2N parameters. A new exactly solvable potential is obtained from the harmonic oscillator potential. The polynomials appearing in the new Schrödinger equation are investigated in detail.Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 58–65, April, 1995.     

Phase structure of a two-fluid bosonic system

The phase diagram of a two-fluid bosonic system is investigated. The proton-neutron interacting boson model (IBM-2) possesses a rich phase structure involving three control parameters and multiple order parameters. The surfaces of quantum phase transition between spherical, axially symmetric deformed, and triaxial phases are determined, and the evolution of classical equilibrium properties across these transitions is investigated. Spectroscopic observables are considered in relation to the phase diagram.     

Prolongation structure of a new integrable system

We have obtained the inverse scattering equations associated with a new pair of coupled nonlinear evolution equations in two dimensions. The spectral parameter is introduced by invoking the invariance of the equation set, and imposing those on the Lax pair.     

Generation of nonclassical light upon resonant excitation of a semiconductor microcavity

Strong correlations in the fluctuations of the intensity of emission from a semiconductor microcavity under resonant laser excitation are observed. The intensity correlation function exhibits an unusual oscillatory behavior with an unexpectedly long oscillation period and decay time. The visibility of the correlation function reaches 0.81. Long oscillation times are attributed to the Rabi frequency characterizing weak coupling between the electromagnetic field of the semiconductor microcavity mode and long-lived exciton states localized by the random potential of the quantum well. For a laser excitation power density of 400 W/cm², the power density of the radiation emitted by the microcavity is 12 W/cm², which corresponds to the total flux of nonclassical light of 1.5 × 10¹⁵ photons/s from an excited spot 50 μm in diameter. Thus, a microcavity can serve as a bright emitter of nonclassical light.     

AC stark effect and atomic stabilization in a strong nonclassical electromagnetic field

We consider the dynamics of an atom that interacts with one mode of an electromagnetic field in a microcavity. We discuss the reconstruction of the spectrum of atomic states and the occurrence of a stabilization effect for the case of a nonclassical state of the field mode, in particular, a squeezed vacuum state. We show that, for nonclassical fields, an ionization-suppression effect also arises (stabilization), which is similar to the Kramers-Henneberger stabilization in a classical electromagnetic field, and, for squeezed states of the electromagnetic field, the stabilization threshold is several times smaller than that for the classical electro-magnetic field of the same intensity.