Search results for "Casimir-Polder"

Time-dependent resonance interaction energy between two entangled atoms under nonequilibrium conditions

2018

We consider the time-dependent resonance interaction energy between two identical atoms, one in the ground state and the other in an excited state, and interacting with the vacuum electromagnetic field, during a nonequilibrium situation such as the dynamical atomic self-dressing process. We suppose the two atoms prepared in a correlated, symmetric or antisymmetric, state. Since the atoms start from a nonequilibrium conditions, their interaction energy is time dependent. We obtain, at second order in the atom-field coupling, an analytic expression for the time-dependent resonance interaction energy between the atoms. We show that this interaction vanishes when the two atoms are outside the l…

Dynamical Casimir-Polder effect with Rydberg atoms

2014

We investigate the dynamics of Rydberg atoms trapped in front of an oscillating conducting mirror, that can be simulated by a wall with a periodically driven dielectric constant (dynamical mirror). We focus our attention on the probability of atomic excitation due to a dynamical Casimir-Polder effect, related to the near field of the image atom whose distance periodically changes as a consequence of the mirror's motion. The theoretical analysis of this system also aims to an experimental proposal to detect this new dynamical effect exploiting Rydberg atoms trapped in the vicinity of the dynamical mirror. Our results indicate that the number of excited atoms is high enough to allow detection…

Casimir-Polder forces, boundary conditions and fluctuations

2008

We review different aspects of the atom-atom and atom-wall Casimir-Polder forces. We first discuss the role of a boundary condition on the interatomic Casimir-Polder potential between two ground-state atoms, and give a physically transparent interpretation of the results in terms of vacuum fluctuations and image atomic dipoles. We then discuss the known atom-wall Casimir-Polder force for ground- and excited-state atoms, using a different method which is also suited for extension to time-dependent situations. Finally, we consider the fluctuation of the Casimir-Polder force between a ground-state atom and a conducting wall, and discuss possible observation of this force fluctuation.

Temperature dependence of the magnetic Casimir-Polder interaction

2009

We analyze the magnetic dipole contribution to atom-surface dispersion forces. Unlike its electrical counterpart, it involves small transition frequencies that are comparable to thermal energy scales. A significant temperature dependence is found near surfaces with a nonzero DC conductivity, leading to a strong suppression of the dispersion force at T > 0. We use thermal response theory for the surface material and discuss both normal metals and superconductors. The asymptotes of the free energy of interaction and of the entropy are calculated analytically over a large range of distances. Near a superconductor, the onset of dissipation at the phase transition strongly changes the interac…

Trapping cold atoms using surface-grown carbon nanotubes

2008

We present a feasibility study for loading cold atomic clouds into magnetic traps created by single-wall carbon nanotubes grown directly onto dielectric surfaces. We show that atoms may be captured for experimentally sustainable nanotube currents, generating trapped clouds whose densities and lifetimes are sufficient to enable detection by simple imaging methods. This opens the way for a different type of conductor to be used in atomchips, enabling atom trapping at submicron distances, with implications for both fundamental studies and for technological applications.

Dynamical Casimir-Polder interaction between a chiral molecule and a surface

2016

We develop a dynamical approach to study the Casimir-Polder force between a initially bare molecule and a magnetodielectric body at finite temperature. Switching on the interaction between the molecule and the field at a particular time, we study the resulting temporal evolution of the Casimir-Polder interaction. The dynamical self-dressing of the molecule and its population-induced dynamics are accounted for and discussed. In particular, we find that the Casimir-Polder force between a chiral molecule and a perfect mirror oscillates in time with a frequency related to the molecular transition frequency, and converges to the static result for large times.

Dispersive interactions between atoms and nonplanar surfaces

2009

We calculate the dispersive force between a ground state atom and a non planar surface. We present explicit results for a corrugated surface, derived from the scattering approach at first order in the corrugation amplitude. A variety of analytical results are derived in different limiting cases, including the van der Waals and Casimir-Polder regimes. We compute numerically the exact first-order dispersive potential for arbitrary separation distances and corrugation wavelengths, for a Rubidium atom on top of a silicon or gold corrugated surface. We discuss in detail the inadequacy of the proximity force approximation, and present a simple but adequate approximation for computing the potentia…

Casimir-Polder interaction energy between two atoms in uniformly accelerated motion

2013

Casimir Polder forces between two accelerating atoms and the Unruh effect

2010

The Casimir-Polder force between two atoms with equal uniform acceleration and separated by a constant distance R is considered. We show that, in the low-acceleration limit, while the near-zone R-6 behavior of the interatomic interaction energy is not changed by the acceleration of the atoms, the far-zone interaction energy decreases as R-5 instead of the well-known R-7 behavior for inertial atoms. Possibility of an indirect detection of the Unruh effect through measurements of the Casimir-Polder force between the two accelerating atoms is also suggested. We also consider a heuristic model for calculating the Casimir-Polder potential energy between the two atoms in the high-acceleration lim…

Les interactiones de Casimir hors d'équilibre : effets dynamiques et thermiques

2016

In this thesis, after an introduction where we briefly present the general context of Casimir physics, we present the results obtained during the PhD. At first, we show our work about the van der Waals/Casimir-Polder interactions between two atoms in an out-of-equilibrium condition due to their uniformly accelerated motion. We study the system of two uniformly accelerated atoms in vacuum space, when they are in their ground-state and when they are in a correlated state (one excited and one ground-state atom). We analyze this system both with an heuristic semiclassical model and with a more rigorous method, based on a separation of radiation reaction and vacuum fluctuations contributions, th…