Resonance energy transfer between two atoms in a conducting cylindrical waveguide

Abstract

We consider the energy transfer process between two identical atoms placed inside a perfectly conducting cylindrical waveguide. We first introduce a general analytical expression of the energy transfer amplitude in terms of the electromagnetic Green's tensor; we then evaluate it in the case of a cylindrical waveguide made of a perfect conductor, for which analytical expressions of the Green's tensor exist. We numerically analyse the energy transfer amplitude when the radius of the waveguide is such that the transition frequency of both atoms is below the lower cutoff frequency of the waveguide, so that the resonant photon exchange is strongly suppressed. We consider both cases of atomic dipoles parallel and orthogonal to the axis of the guide. In both cases, we find that the energy transfer is modified by the presence of the waveguide. In the near zone, that is when the atomic separation is smaller than the atomic transition wavelength, the change, with respect to the free-space case, is small for axial dipoles, while it is larger for radial dipoles; it grows when the intermediate region between near and far zone is approached. In the far zone, we find that the energy transfer amplitude is strongly suppressed by the waveguide, becoming virtually zero. A physical interpretation of these results is discussed. Finally, we discuss the resonance interaction energy and force between two identical correlated atoms in the waveguide, one excited and the other in the ground state, prepared in their symmetric or antisymmetric superposition.

Dispersion Interaction between Two Hydrogen Atoms in a Static Electric Field

“…These ubiquitous interactions have great relevance in many areas of physics, and applications in biology [10,11], chemistry [12] and nanotechnologies [13][14][15]. A striking property of these interactions is that they can be controlled and tailored through the external environment, for example a cavity or a wall [16][17][18][19][20], a waveguide [21][22][23][24][25], or a photonic crystal [26,27]. Of special interest is to investigate the possibility of making Casimir interactions repulsive, in particular for applications in nanotechnological devices, where a repulsive Casimir interaction could help to prevent stiction [28].…”

Spontaneous Emission of an Atom Near an Oscillating Mirror

“…Spontaneous decay of excited atoms in the presence of a driving laser field has been also investigated [15]. Many experiments showing modifications of spontaneous emission of atoms in external environments (a single mirror, optical cavities, photonic crystals and waveguides, for example), have been also performed [16][17][18][19][20].These investigations have shown how a structured environment, such as a cavity or a medium with periodic refractive index, can be exploited to control and tailor the spontaneous decay, as well as energy shifts of atomic levels, resonance and dispersion interactions between atoms, or the resonant energy transfer between atoms or molecules [21][22][23][24][25][26].New interesting features appear when the boundary conditions on the field, or some relevant parameter of the system, change in time. Dynamical environments, whose optical properties change periodically in time, have been recently investigated, in particular in connection with the dynamical Casimir and Casimir-Polder effects [27][28][29][30].…”

Resonance interaction of two entangled atoms accelerating between two mirrors

“…The motivation for the present work is to investigate how radiative properties of entangled atoms change under the combined effect of boundary conditions and acceleration of atoms. Resonance interaction has been studied in case of static atoms in structured environments [44,45]. However, quantum mechanical particles such as atoms can never be absolutely static, but rather undergo accelerations in various confining potentials in realistic scenarios [7,[33][34][35].…”