7,307 research outputs found
Generation of higher order nonclassical states via interaction of intense electromagnetic field with third order nonlinear medium
Interaction of intense laser beam with an inversion symmetric third order
nonlinear medium is modeled as a quartic anharmonic oscillator. A first order
operator solution of the model Hamiltonian is used to study the possibilities
of generation of higher order nonclassical states. It is found that the higher
order squeezed and higher order antibunched states can be produced by this
interaction. It is also shown that the higher order nonclassical states may
appear separately, i.e. a higher order antibunched state is not essentially
higher order squeezed state and vice versa.Comment: 7 pages, no figur
Quasiprobability distributions in open quantum systems: spin-qubit systems
Quasiprobability distributions (QDs) in open quantum systems are investigated
for , spin like systems, having relevance to quantum optics and
information. In this work, effect of both quantum non-demolition (QND) and
dissipative open quantum systems, on the evolution of a number of spin QDs are
investigated. Specifically, compact analytic expressions for the , , ,
and functions are obtained for some interesting single, two and three qubit
states, undergoing general open system evolutions. Further, corresponding QDs
are reported for an N qubit Dicke model and a spin-1 system. The existence of
nonclassical characteristics are observed in all the systems investigated here.
The study leads to a clear understanding of quantum to classical transition in
a host of realistic physical scenarios. Variation of the amount of
nonclassicality observed in the quantum systems, studied here,are also
investigated using nonclassical volume.Comment: 23 pages 13 figure
Quantum phase properties of photon added and subtracted displaced Fock states
Quantum phase properties of photon added and subtracted displaced Fock states
(and a set of quantum states which can be obtained as the limiting cases of
these states) are investigated from a number of perspectives, and it is shown
that the quantum phase properties are dependent on the quantum state
engineering operations performed. Specifically, the analytic expressions for
quantum phase distributions and angular distribution as well as measures of
quantum phase fluctuation and phase dispersion are obtained. The uniform phase
distribution of the initial Fock states is observed to be transformed by the
unitary operation (i.e., displacement operator) into non-Gaussian shape, except
for the initial vacuum state. It is observed that the phase distribution is
symmetric with respect to the phase of the displacement parameter and becomes
progressively narrower as its amplitude increases. The non-unitary (photon
addition/subtraction) operations make it even narrower in contrast to the Fock
parameter, which leads to broadness. The photon subtraction is observed to be a
more powerful quantum state engineering tool in comparison to the photon
addition. Further, one of the quantum phase fluctuation parameters is found to
reveal the existence of antibunching in both the engineered quantum states
under consideration. Finally, the relevance of the engineered quantum states in
the quantum phase estimation is also discussed, and photon added displaced Fock
state is shown to be preferable for the task.Comment: Quantum phase properties of an engineered quantum state has been
studied from various perspective
Lower- and higher-order nonclassical properties of photon added and subtracted displaced Fock states
Nonclassical properties of photon added and subtracted displaced Fock states
have been studied using various witnesses of lower- and higher-order
nonclassicality. Compact analytic expressions are obtained for the
nonclassicality witnesses. Using those expressions, it is established that
these states and the states that can be obtained as their limiting cases
(except coherent states) are highly nonclassical as they show the existence of
lower- and higher-order antibunching and sub-Poissonian photon statistics, in
addition to the nonclassical features revealed through the Mandel
parameter, zeros of Q function, Klyshko's criterion, and Agarwal-Tara
criterion. Further, some comparison between the nonclassicality of photon added
and subtracted displaced Fock states have been performed using witnesses of
nonclassicality. This has established that between the two types of
non-Gaussianity inducing operations (i.e., photon addition and subtraction)
used here, photon addition influences the nonclassical properties more
strongly. Further, optical designs for the generation of photon added and
subtracted displaced Fock states from squeezed vacuum state have also been
proposed.Comment: A comparative study of the nonclassicality present in photon added
and subtracted displaced Fock states shows photon addition is generally
preferable nonclassicality inducing operation, while subtraction also has
advantage in some cases over additio
Spatial-temporal evolution of the current filamentation instability
The spatial-temporal evolution of the purely transverse current filamentation
instability is analyzed by deriving a single partial differential equation for
the instability and obtaining the analytical solutions for the spatially and
temporally growing current filament mode. When the beam front always encounters
fresh plasma, our analysis shows that the instability grows spatially from the
beam front to the back up to a certain critical beam length; then the
instability acquires a purely temporal growth. This critical beam length
increases linearly with time and in the non-relativistic regime it is
proportional to the beam velocity. In the relativistic regime the critical
length is inversely proportional to the cube of the beam Lorentz factor
. Thus, in the ultra-relativistic regime the instability
immediately acquires a purely temporal growth all over the beam. The analytical
results are in good agreement with multidimensional particle-in-cell
simulations performed with OSIRIS. Relevance of current study to recent and
future experiments on fireball beams is also addressed
- …