9 research outputs found
Higher-order squeezing for the codirectional Kerr nonlinear coupler
In this Letter we study the evolution of the higher-order squeezing, namely,
th-order single-mode squeezing, sum- and difference-squeezing for the
codirectional Kerr nonlinear coupler. We show that the amount of squeezing
decreases when , i.e. the squeezing order, increases. For specific values of
the interaction parameters squeezing factors exhibit a series of
revival-collapse phenomena, which become more pronounced when the value of
increases. Sum-squeezing can provide amounts of squeezing greater than those
produced by the th higher-order () squeezing for the same values of
interaction parameters and can map onto amplitude-squared squeezing. Further,
we prove that the difference-squeezing is not relevant measure for obtaining
information about squeezing from this device.Comment: 13 pages, 3 figure
Quantum phase properties of two-mode Jaynes-Cummings model for Schr\"odinger-cat states: interference and entanglement
In this paper we investigate the quantum phase properties for the coherent
superposition states (Schr\"odinger-cat states) for two-mode multiphoton
Jaynes-Cummings model in the framework of the Pegg-Barnett formalism. We also
demonstrate the behavior of the Wigner () function at the phase space
origin. We obtain many interesting results such as there is a clear
relationship between the revival-collapse phenomenon occurring in the atomic
inversion (as well as in the evolution of the function) and the behavior of
the phase distribution of both the single-mode and two-mode cases. Furthermore,
we find that the phase variances of the single-mode case can exhibit
revival-collapse phenomenon about the long-time behavior. We show that such
behavior occurs for interaction time several times smaller than that of the
single-mode Jaynes-Cummings model.Comment: 23, 8 figure
Single-atom entropy squeezing for two two-level atoms interacting with a single-mode radiation field
In this paper we consider a system of two two-level atoms interacting with a
single-mode quantized electromagnetic field in a lossless resonant cavity via
-photon-transition mechanism. The field and the atoms are initially prepared
in the coherent state and the excited atomic states, respectively. For this
system we investigate the entropy squeezing, the atomic variances, the von
Neumann entropy and the atomic inversions for the single-atom case. We show
that the more the number of the parties in the system the less the amounts of
the nonclassical effects exhibited in the entropy squeezing.
The entropy squeezing can give information on the corresponding von Neumann
entropy. Also the nonclassical effects obtained form the asymmetric atoms are
greater than those obtained form the symmetric atoms. Finally, the entropy
squeezing gives better information than the atomic variances only for the
asymmetric atoms.Comment: 15 pages, 4 figures, comments are most welcom
Quantum properties of the three-mode squeezed operator: triply concurrent parametric amplifiers
In this paper, we study the quantum properties of the three-mode squeezed
operator. This operator is constructed from the optical parametric oscillator
based on the three concurrent nonlinearities. We give a complete
treatment for this operator including the symmetric and asymmetric
nonlinearities cases. The action of the operator on the number and coherent
states are studied in the framework of squeezing, second-order correlation
function, Cauchy-Schwartz inequality and single-mode quasiprobability function.
The nonclassical effects are remarkable in all these quantities. We show that
the nonclassical effects generated by the asymmetric case--for certain values
of the system parameters--are greater than those of the symmetric one. This
reflects the important role for the asymmetry in the system. Moreover, the
system can generate different types of the Schr\"odinger-cat states.Comment: 21 pages, 14 figures; comments are most welcom
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
Quantum properties of the three-mode squeezed operator: triply concurrent parametric amplifiers
In this paper, we study the quantum properties of the three-mode squeezed operator. This operator is
constructed from the optical parametric oscillator based on the three concurrent χ(2) nonlinearities. We give
a complete treatment for this operator including the symmetric and asymmetric nonlinearity cases. The
action of the operator on the number and coherent states is studied in the framework of squeezing, secondorder
correlation function, Cauchy–Schwartz inequality and single-mode quasiprobability function. The
nonclassical effects are remarkable in all these quantities. We show that the nonclassical effects generated by
the asymmetric case–for certain values of the system parameters–are greater than those of the symmetric
one. This reflects the important role for the asymmetry in the system. Moreover, the system can generate
particular types of the superposition states