101 research outputs found
Thermal noise and oscillations of photon distribution for squeezed and correlated light
The oscillations of photon distribution function for squeezed and correlated
light are shown to decrease when the temperature increases.The influence of the
squeezing parameter and photon quadrature correlation coefficient on the photon
distribution oscillations at nonzero temperatures is studied. The connection of
deformation of Planck distribution formula with oscillations of distribution
for squeezed and correlated light is discussed.Comment: Latex,7 pages INFN-Na-IV-93/31,DSF-T-93/3
Nonstationary Casimir effect in cavities with two resonantly coupled modes
We study the peculiarities of the nonstationary Casimir effect (creation of
photons in cavities with moving boundaries) in the special case of two
resonantly coupled modes with frequencies and ,
parametrically excited due to small amplitude oscillations of the ideal cavity
wall at the frequency (with ). The
effects of thermally induced oscillations in time dependences of the mean
numbers of created photons and the exchange of quantum purities between the
modes are discovered. Squeezing and photon distributions in each modes are
calculated for initial vacuum and thermal states. A possibility of compensation
of detunings is shown.Comment: 17 pages, 5 ps figures, LaTex, accepted for publication in Physics
Letters
Creation of photons in an oscillating cavity with two moving mirrors
We study the creation of photons in a one dimensional oscillating cavity with
two perfectly conducting moving walls. By means of a conformal transformation
we derive a set of generalized Moore's equations whose solution contains the
whole information of the radiation field within the cavity. For the case of
resonant oscillations we solve these equations using a renormalization group
procedure that appropriately deals with the secular behaviour present in a
naive perturbative approach. We study the time evolution of the energy density
profile and of the number of created photons inside the cavity.Comment: LaTex file, 17 pages, 3 figures, uses epsf.st
Statistical Properties of Schr\"odinger Real and Imaginary Cat States
We study the Photon statistics in the superpositions of coherent states
and named ``Schr\"odinger real and
imaginary cat states''. The oscillatory character of photon distribution
function (PDF) emerging due to the quantum interference between the two
components is shown, and the phenomenon of the quadrature squeezing is observed
for the moderate values of . Despite the quantity
tends to the unit value
(like in the Poissonian PDF) at , the photon statistics is
essentially non-Poissonian for all values of . The factorial moments
and cumulants of the PDF are calculated, and the oscillations of their ratio
are demonstrated.Comment: 13 pages, LaTE
Resonant photon creation in a three dimensional oscillating cavity
We analyze the problem of photon creation inside a perfectly conducting,
rectangular, three dimensional cavity with one oscillating wall. For some
particular values of the frequency of the oscillations the system is resonant.
We solve the field equation using multiple scale analysis and show that the
total number of photons inside the cavity grows exponentially in time. This is
also the case for slightly off-resonance situations. Although the spectrum of a
cavity is in general non equidistant, we show that the modes of the
electromagnetic field can be coupled, and that the rate of photon creation
strongly depends on this coupling. We also analyze the thermal enhancement of
the photon creation.Comment: 13 pages. New section on off-resonance motion is included. To appear
in Physical Review
Strong oscillations of cumulants of photon distribution function in slightly squeezed states
The cumulants and factorial moments of photon distribution for squeezed and
correlated light are calculated in terms of Chebyshev, Legendre and Laguerre
polynomials. The phenomenon of strong oscillations of the ratio of the cumulant
to factorial moment is found.Comment: LATEX, 16 pages,5 figures, INFN-NA-IV-94/22, DSF-T-94/2
Low Energy Wave Packet Tunneling from a Parabolic Potential Well through a High Potential Barrier
The problem of wave packet tunneling from a parabolic potential well through
a barrier represented by a power potential is considered in the case when the
barrier height is much greater than the oscillator ground state energy, and the
difference between the average energy of the packet and the nearest oscillator
eigenvalue is sufficiently small. The universal Poisson distribution of the
partial tunneling rates from the oscillator energy levels is discovered. The
explicit expressions for the tunneling rates of different types of packets
(coherent, squeezed, even/odd, thermal, etc.) are given in terms of the
exponential and modified Bessel functions. The tunneling rates turn out very
sensitive to the energy distributions in the packets, and they may exceed
significantly the tunneling rate from the energy state with the same average
number of quanta.Comment: 14 pages, LaTex type, to appear in Physics Letters
Quantum electromagnetic field in a three dimensional oscillating cavity
We compute the photon creation inside a perfectly conducting, three
dimensional oscillating cavity, taking the polarization of the electromagnetic
field into account. As the boundary conditions for this field are both of
Dirichlet and (generalized) Neumann type, we analyze as a preliminary step the
dynamical Casimir effect for a scalar field satisfying generalized Neumann
boundary conditions. We show that particle production is enhanced with respect
to the case of Dirichlet boundary conditions. Then we consider the transverse
electric and transverse magnetic polarizations of the electromagnetic field.
For resonant frequencies, the total number of photons grows exponentially in
time for both polarizations, the rate being greater for transverse magnetic
modes.Comment: 11 pages, 1 figur
Dynamical Casimir effect without boundary conditions
The moving-mirror problem is microscopically formulated without invoking the
external boundary conditions. The moving mirrors are described by the quantized
matter field interacting with the photon field, forming dynamical cavity
polaritons: photons in the cavity are dressed by electrons in the moving
mirrors. The effective Hamiltonian for the polariton is derived, and
corrections to the results based on the external boundary conditions are
discussed.Comment: 12 pages, 2 figure
Fluctuations, dissipation and the dynamical Casimir effect
Vacuum fluctuations provide a fundamental source of dissipation for systems
coupled to quantum fields by radiation pressure. In the dynamical Casimir
effect, accelerating neutral bodies in free space give rise to the emission of
real photons while experiencing a damping force which plays the role of a
radiation reaction force. Analog models where non-stationary conditions for the
electromagnetic field simulate the presence of moving plates are currently
under experimental investigation. A dissipative force might also appear in the
case of uniform relative motion between two bodies, thus leading to a new kind
of friction mechanism without mechanical contact. In this paper, we review
recent advances on the dynamical Casimir and non-contact friction effects,
highlighting their common physical origin.Comment: 39 pages, 4 figures. Review paper to appear in Lecture Notes in
Physics, Volume on Casimir Physics, edited by Diego Dalvit, Peter Milonni,
David Roberts, and Felipe da Rosa. Minor changes, a reference adde
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