28 research outputs found
Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes-Cummings model: interference and entanglement
In this paper we study the evolution of the two two-level atoms interacting
with a single-mode quantized radiation field, namely, two-atom multiphoton
Jaynes-Cummings model when the radiation field and atoms are initially prepared
in the superpostion of displaced number states and excited atomic states,
respectively. For this system we investigate the atomic inversion, Wigner
function, phase distribution and entanglement.Comment: 18 pages, 17 figure
Marginal and density atomic Wehrl entropies for the Jaynes-Cummings model
In this paper, we develop the notion of the marginal and density atomic Wehrl
entropies for two-level atom interacting with the single mode field, i.e.
Jaynes-Cummings model. For this system we show that there are relationships
between these quantities and both of the information entropies and the von
Neumann entropy.Comment: 13 pages, 3 figures, this is the final versio
The revival-collapse phenomenon in the quadrature field components of the two-mode multiphoton Jaynes-Cummings model
In this paper we consider a system consisting of a two-level atom in an
excited state interacting with two modes of a radiation field prepared
initially in -photon coherent states. This system is described by two-mode
multiphoton (, i.e., ) Jaynes-Cummings model (JCM). For this system
we investigate the occurrence of the revival-collapse phenomenon (RCP) in the
evolution of the single-mode, two-mode, sum and difference quadrature
squeezing. We show that there is a class of states for which all these types of
squeezing exhibit RCP similar to that involved in the corresponding atomic
inversion. Also we show numerically that the single-mode squeezing of the first
mode for provides RCP similar to that of the atomic inversion
of the case , however, sum and difference squeezing give
partial information on that case. Moreover, we show that single-mode, two-mode
and sum squeezing for the case provide information on the
atomic inversion of the single-mode two-photon JCM. We derive the rescaled
squeezing factors giving accurate information on the atomic inversion for all
cases. The consequences of these results are that the homodyne and heterodyne
detectors can be used to detect the RCP for the two-mode JCM.Comment: 18 pages, 6 figure
Linear atomic quantum coupler
In this paper, we develop the notion of the linear atomic quantum coupler.
This device consists of two modes propagating into two waveguides, each of them
includes a localized and/or a trapped atom. These waveguides are placed close
enough to allow exchanging energy between them via evanescent waves. Each mode
interacts with the atom in the same waveguide in the standard way, i.e. as the
Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via
evanescent wave. We present the Hamiltonian for the system and deduce the exact
form for the wavefunction. We investigate the atomic inversions and the
second-order correlation function. In contrast to the conventional linear
coupler, the atomic quantum coupler is able to generate nonclassical effects.
The atomic inversions can exhibit long revival-collapse phenomenon as well as
subsidiary revivals based on the competition among the switching mechanisms in
the system. Finally, under certain conditions, the system can yield the results
of the two-mode JCM.Comment: 14 pages, 3 figures; comments are most welcom
Variance squeezing and entanglement of the XX central spin model
In this paper, we study the quantum properties for a system that consists of
a central atom interacting with surrounding spins through the Heisenberg
couplings of equal strength. Employing the Heisenberg equations of motion we
manage to derive an exact solution for the dynamical operators. We consider
that the central atom and its surroundings are initially prepared in the
excited state and in the coherent spin state, respectively. For this system, we
investigate the evolution of variance squeezing and entanglement. The
nonclassical effects have been remarked in the behavior of all components of
the system. The atomic variance can exhibit revival-collapse phenomenon based
on the value of the detuning parameter.Comment: 19 pages,8 figure
On the evolution of superposition of squeezed displaced number states with the multiphoton Jaynes-Cummings model
In this paper we discuss the quantum properties for superposition of squeezed
displaced number states against multiphoton Jaynes-Cummings model (JCM). In
particular, we investigate atomic inversion, photon-number distribution,
purity, quadrature squeezing, Mandel parameter and Wigner function. We show
that the quadrature squeezing for three-photon absorption case can exhibit
revivals and collapses typical to those occurring in the atomic inversion for
one-photon absorption case. Also we prove that for odd number absorption
parameter there is a connection between the evolution of the atomic inversion
and the evolution of the Wigner function at the origin in phase space.
Furthermore, we show that the nonclassical states whose the Wigner functions
values at the origins are negative will be always nonclassical when they are
evolving through the JCM with even absorption parameter. Also we demonstrate
that various types of cat states can be generated via this system.Comment: 27 pages, 10 figure