3,684 research outputs found
Frequency up-converted radiation from a cavity moving in vacuum
We calculate the photon emission of a high finesse cavity moving in vacuum.
The cavity is treated as an open system. The field initially in the vacuum
state accumulates a dephasing depending on the mirrors motion when bouncing
back and forth inside the cavity. The dephasing is not linearized in our
calculation, so that qualitatively new effects like pulse shaping in the time
domain and frequency up-conversion in the spectrum are found. Furthermore we
predict the existence of a threshold above which the system should show
self-sustained oscillations.Comment: 10 pages, 3 figures, LaTeX, to appear in European Physical Journal
D3, replaced version with few minor grammatical change
Generating photon pulses with an oscillating cavity
We study the generation of photon pulses from thermal field fluctuations
through opto-mechanical coupling to a cavity with an oscillatory motion. Pulses
are regularly spaced and become sharp for a high finesse cavity.Comment: 6 pages, 3 figures, LaTeX, needs EuroPhysics Letters Stylefile, to
appear in Europhysics Letter
Large scale EPR correlations and cosmic gravitational waves
We study how quantum correlations survive at large scales in spite of their
exposition to stochastic backgrounds of gravitational waves. We consider
Einstein-Podolski-Rosen (EPR) correlations built up on the polarizations of
photon pairs and evaluate how they are affected by the cosmic gravitational
wave background (CGWB). We evaluate the quantum decoherence of the EPR
correlations in terms of a reduction of the violation of the Bell inequality as
written by Clauser, Horne, Shimony and Holt (CHSH). We show that this
decoherence remains small and that EPR correlations can in principle survive up
to the largest cosmic scales.Comment: 5 figure
The Scattering Approach to the Casimir Force
We present the scattering approach which is nowadays the best tool for
describing the Casimir force in realistic experimental configurations. After
reminders on the simple geometries of 1d space and specular scatterers in 3d
space, we discuss the case of stationary arbitrarily shaped mirrors in
electromagnetic vacuum. We then review specific calculations based on the
scattering approach, dealing for example with the forces or torques between
nanostructured surfaces and with the force between a plane and a sphere. In
these various cases, we account for the material dependence of the forces, and
show that the geometry dependence goes beyond the trivial {\it Proximity Force
Approximation} often used for discussing experiments.Comment: Proceedings of the QFEXT'09 conference (Oklahoma, 2009
Quantum Effects in the Presence of Expanding Semi-Transparent Spherical Mirrors
We study quantum effects in the presence of a spherical semi-transparent
mirror or a system of two concentric mirrors which expand with a constant
acceleration in a flat D-dimensional spacetime. Using the Euclidean approach,
we obtain expressions for fluctuations and the renormalized value of
stress-energy tensor for a scalar non-minimally coupled massless field.
Explicit expressions are obtained for the energy fluxes at the null infinity
generated by such mirrors in the physical spacetime and their properties are
discussed.Comment: 28 pages, Paper is slightly reorganized, additional references are
adde
Lateral Casimir-Polder force with corrugated surfaces
We derive the lateral Casimir-Polder force on a ground state atom on top of a
corrugated surface, up to first order in the corrugation amplitude. Our
calculation is based on the scattering approach, which takes into account
nonspecular reflections and polarization mixing for electromagnetic quantum
fluctuations impinging on real materials. We compare our first order exact
result with two commonly used approximation methods. We show that the proximity
force approximation (large corrugation wavelengths) overestimates the lateral
force, while the pairwise summation approach underestimates it due to the
non-additivity of dispersion forces. We argue that a frequency shift
measurement for the dipolar lateral oscillations of cold atoms could provide a
striking demonstration of nontrivial geometrical effects on the quantum vacuum.Comment: 12 pages, 6 figures, contribution to QFEXT07 proceeding
The role of Surface Plasmon modes in the Casimir Effect
In this paper we study the role of surface plasmon modes in the Casimir
effect. First we write the Casimir energy as a sum over the modes of a real
cavity. We may identify two sorts of modes, two evanescent surface plasmon
modes and propagative modes. As one of the surface plasmon modes becomes
propagative for some choice of parameters we adopt an adiabatic mode definition
where we follow this mode into the propagative sector and count it together
with the surface plasmon contribution, calling this contribution "plasmonic".
The remaining modes are propagative cavity modes, which we call "photonic". The
Casimir energy contains two main contributions, one coming from the plasmonic,
the other from the photonic modes. Surprisingly we find that the plasmonic
contribution to the Casimir energy becomes repulsive for intermediate and large
mirror separations. Alternatively, we discuss the common surface plasmon
defintion, which includes only evanescent waves, where this effect is not
found. We show that, in contrast to an intuitive expectation, for both
definitions the Casimir energy is the sum of two very large contributions which
nearly cancel each other. The contribution of surface plasmons to the Casimir
energy plays a fundamental role not only at short but also at large distances.Comment: 10 pages, 3 figures. TQMFA200
Casimir energy and geometry : beyond the Proximity Force Approximation
We review the relation between Casimir effect and geometry, emphasizing
deviations from the commonly used Proximity Force Approximation (PFA). We use
to this aim the scattering formalism which is nowadays the best tool available
for accurate and reliable theory-experiment comparisons. We first recall the
main lines of this formalism when the mirrors can be considered to obey
specular reflection. We then discuss the more general case where non planar
mirrors give rise to non-specular reflection with wavevectors and field
polarisations mixed. The general formalism has already been fruitfully used for
evaluating the effect of roughness on the Casimir force as well as the lateral
Casimir force or Casimir torque appearing between corrugated surfaces. In this
short review, we focus our attention on the case of the lateral force which
should make possible in the future an experimental demonstration of the
nontrivial (i.e. beyond PFA) interplay of geometry and Casimir effect.Comment: corrected typos, added references, QFEXT'07 special issue in J. Phys.
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