Polder Interaction Research Articles

Nonlocal field correlations and dynamical Casimir–Polder forces between one excited- and two ground-state atoms

The problem of nonlocality in the dynamical three-body Casimir–Polder interaction between an initially excited and two ground-state atoms is considered. It is shown that the nonlocal spatial correlations of the field emitted by the excited atom during the initial part of its spontaneous decay may become manifest in the three-body interaction. The observability of this new phenomenon is discussed.

Causality, non-locality and three-body Casimir–Polder energy between three ground-state atoms

The problem of relativistic causality in the time-dependent three-body Casimir–Polder interaction energy between three atoms, initially in their bare ground-state, is discussed. It is shown that the non-locality of the spatial correlations of the electromagnetic field emitted by the atoms during their dynamical self-dressing may become manifest in the dynamical three-body Casimir–Polder interaction energy between the three atoms.

Optically induced inter-particle forces: from the bonding of dimers to optical electrostriction in molecular solids

The quantum electrodynamical formulation of the Casimir–Polder interaction invites a consideration of optically induced inter-particle forces, which arise in the same level of perturbation theory. For the observation of such effects, quantitative assessments of the coupling mechanism suggest levels of intensity that are now routinely available from pulsed lasers. In this paper, a theoretical analysis of the principal mechanism is followed by a development for two specific systems, chosen to illustrate the broad significance and the range of systems in which such effects might be manifest. The first system is a van der Waals dimer, a loosely bound and essentially isolated molecular pair in which a small optically induced shift in the equilibrium bond length proves to be well within the limits of measurement by microwave rotational spectroscopy. The second system illustrates the opposite extreme, where an optically induced modification of the forces between densely packed molecules in the condensed phase is shown to produce anisotropic patterns of laser-induced compression and expansion, an effect termed optical electrostriction. Again, such an effect should be readily measurable, although the necessary conditions are such that a number of secondary effects might also be likely to arise. The experimental challenge of precluding those secondary effects in the condensed phase and unequivocally identifying optically induced intermolecular forces is discussed. Possible applications are also entertained, including optical actuators for nanoscale electromechanical systems.

Casimir–Polder interaction between an atom and a cylinder with application to nanosystems

Recently the Lifshitz theory of dispersion forces was extended for the case of an atom (molecule) interacting with a plane surface of a uniaxial crystal or with a long solid cylinder or cylindrical shell made of isotropic material or uniaxial crystal. The obtained results are applicable to nanosystems. In particular, we investigate the Casimir-Polder interaction between hydrogen atoms (molecules) and multi-wall carbon nanotubes. It is demonstrated that the hydrogen atoms located inside multiwall carbon nanotubes have a lower free energy compared to those located outside. We also perform comparison studies of the interaction of hydrogen atoms between themselves and with multi-wall carbon nanotube. The obtained results are important for the problem of hydrogen storage.

Dependence of the Casimir–Polder interaction between an atom and a cavity wall on atomic and material properties

The Casimir-Polder and van der Waals interactions between an atom and a flat cavity wall are investigated under the influence of real conditions including the dynamic polarizability of the atom, actual conductivity of the wall material and nonzero temperature of the wall. The cases of different atoms near metal and dielectric walls are considered. It is shown that to obtain accurate results for the atom-wall interaction at short separations, one should use the complete tabulated optical data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom. At relatively large separations in the case of a metal wall, one may use the plasma model dielectric function to describe the dielectric properties of wall material. The obtained results are important for the theoretical interpretation of experiments on quantum reflection and Bose-Einstein condensation.

Born expansion of the Casimir–Polder interaction of a ground-state atom with dielectric bodies

Within leading-order perturbation theory, the Casimir–Polder potential of a ground-state atom placed within an arbitrary arrangement of dispersing and absorbing linear bodies can be expressed in terms of the polarizability of the atom and the scattering Green tensor of the body-assisted electromagnetic field. Based on a Born series of the Green tensor, a systematic expansion of the Casimir–Polder potential in powers of the electric susceptibilities of the bodies is presented. The Born expansion is used to show how and under which conditions the Casimir–Polder force can be related to microscopic many-atom van der Waals forces, for which general expressions are presented. As an application, the Casimir–Polder potentials of an atom near a dielectric ring and an inhomogeneous dielectric half space are studied and explicit expressions are presented that are valid up to second order in the susceptibility.

Polarization propagator calculations of the polarizability tensor at imaginary frequencies and long-range interactions for the noble gases and n-alkanes

The linear polarization propagator has been computed at imaginary frequencies for He, Ne, Ar, and Kr as well as for the n-alkanes including heptane and its smaller members. It is shown that an effective and direct evaluation of the polarization propagator using standard electronic structure first principle methods can be achieved on the whole imaginary axis without expanding the polarizability in a series of the Cauchy moments. The linear response equation will be complex in this case, but an effective algorithm can be constructed so that the computational cost parallels that of the real propagator. Calculations of the polarizability tensor are used to determine the Casimir–Polder interaction potentials for the molecules under consideration. Theoretical results for the C6 dispersion coefficient are compared with accurate experimental data, and it is shown that results for the extended n-alkanes obtained with density functional theory and the hybrid B3LYP exchange correlation functional are in excellent agreement with experiment. At the same level of theory, on the other hand, there are significant discrepancies for the noble gas atoms. The electron correlation contribution to C6 is less than 9% for the n-alkanes and decreases with the size of the system.

Concepts for near-field interferometers with large molecules

We study the theory behind a Talbot–Lau interferometer. This consists of three gratings in each other’s Fresnel near field and accepts spatially incoherent illumination. Our formalism gives a clear physical picture and permits efficient numerical simulations. We concentrate on the case of matter waves and provide an adequate description of recent fullerene experiments taking into account the Casimir–Polder interaction between a molecular beam and mechanical gratings. For more massive molecules, the influence of this interaction is more drastic and leads to a forbiddingly narrow velocity distribution requirement for future experiments with very massive molecules. This problem can be avoided by configurations where at least one mechanical grating is replaced with an optical grating, i.e. a standing light wave. Such interferometers show improved scaling behaviour. Magnifying or demagnifying interferometer variants are also discussed.

Small object limit of the Casimir effect and the sign of the Casimir force

We show a simple way of deriving the Casimir Polder interaction, present some general arguments on the finiteness and sign of mutual Casimir interactions and finally we derive a simple expression for Casimir radiation from small accelerated objects.

Quantum electrodynamics of an atom in front of a non–dispersive dielectric half–space. II. Effects of finite temperature

Restricted accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Wu Shin-Tza and Eberlein Claudia 2000Quantum electrodynamics of an atom in front of a non–dispersive dielectric half–space. II. Effects of finite temperatureProc. R. Soc. Lond. A.4561931–1951http://doi.org/10.1098/rspa.2000.0595SectionRestricted accessQuantum electrodynamics of an atom in front of a non–dispersive dielectric half–space. II. Effects of finite temperature Shin-Tza Wu Shin-Tza Wu Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK Google Scholar Find this author on PubMed Search for more papers by this author and Claudia Eberlein Claudia Eberlein Sussex Centre for Optical and Atomic Physics, University of Sussex, Falmer, Brighton BN1 9QH, UK Google Scholar Find this author on PubMed Search for more papers by this author Shin-Tza Wu Shin-Tza Wu Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK Google Scholar Find this author on PubMed Search for more papers by this author and Claudia Eberlein Claudia Eberlein Sussex Centre for Optical and Atomic Physics, University of Sussex, Falmer, Brighton BN1 9QH, UK Google Scholar Find this author on PubMed Search for more papers by this author Published:08 August 2000https://doi.org/10.1098/rspa.2000.0595AbstractThe energy–level shifts of an atom located at a distance Z outside a dielectric half–space are calculated at finite temperatures. The refractive index of the medium is real and frequency independent; the limiting case of perfect reflectors is also considered. The analytic expressions for the energy–level shifts are analysed in various regimes of temperature and of the distance of the atom from the surface. The significance of thermal corrections in comparison with zero–temperature effects is analysed in each regime and discussed for recent experiments. Previous ArticleNext Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Haug T, Buhmann S and Bennett R (2019) Casimir-Polder potential in the presence of a Fock state, Physical Review A, 10.1103/PhysRevA.99.012508, 99:1 Zhou W and Yu H (2018) Boundarylike behaviors of the resonance interatomic energy in a cosmic string spacetime, Physical Review D, 10.1103/PhysRevD.97.045007, 97:4 Bimonte G and Emig T (2015) Interplay of curvature and temperature in the Casimir–Polder interaction, Journal of Physics: Condensed Matter, 10.1088/0953-8984/27/21/214018, 27:21, (214018), Online publication date: 3-Jun-2015. Sernelius B (2014) Electromagnetic normal modes and Casimir effects in layered structures, Physical Review B, 10.1103/PhysRevB.90.155457, 90:15 Wu P and Yu H (2014) Thermal dispersion potential of a diamagnetic atom, Physical Review A, 10.1103/PhysRevA.90.032502, 90:3 Zhou W and Yu H (2014) Energy shift and Casimir-Polder force for an atom out of thermal equilibrium near a dielectric substrate, Physical Review A, 10.1103/PhysRevA.90.032501, 90:3 Zhu Z, Yu H and Wang B (2012) Temperature-dependent Casimir-Polder forces on polarizable molecules, Physical Review A, 10.1103/PhysRevA.86.052508, 86:5 Ellingsen S, Buhmann S and Scheel S (2012) Casimir-Polder energy-level shifts of an out-of-equilibrium particle near a microsphere, Physical Review A, 10.1103/PhysRevA.85.022503, 85:2 Buhmann S (2012) Introduction: Dispersion Forces Dispersion Forces I, 10.1007/978-3-642-32484-0_1, (1-43), . Buhmann S (2012) Thermal Casimir–Polder Forces Dispersion Forces II, 10.1007/978-3-642-32466-6_7, (213-262), . Ellingsen S, Buhmann S and Scheel S (2010) Casimir-Polder potential and transition rate in resonating cylindrical cavities, Physical Review A, 10.1103/PhysRevA.82.032516, 82:3 Ellingsen S, Buhmann S and Scheel S (2010) Temperature-Independent Casimir-Polder Forces Despite Large Thermal Photon Numbers, Physical Review Letters, 10.1103/PhysRevLett.104.223003, 104:22 Ellingsen S, Buhmann S and Scheel S (2009) Enhancement of thermal Casimir-Polder potentials of ground-state polar molecules in a planar cavity, Physical Review A, 10.1103/PhysRevA.80.022901, 80:2 Zhu Z and Yu H (2009) Modification of energy shifts of atoms by the presence of a boundary in a thermal bath and the Casimir-Polder force, Physical Review A, 10.1103/PhysRevA.79.032902, 79:3 Rosenblit M, Japha Y, Horak P and Folman R (2006) Simultaneous optical trapping and detection of atoms by microdisk resonators, Physical Review A, 10.1103/PhysRevA.73.063805, 73:6 Eberlein C and Wu S (2003) Methods of asymptotic analysis in cavity quantum electrodynamics, Physical Review A, 10.1103/PhysRevA.68.033813, 68:3 Henkel C, Joulain K, Mulet J and Greffet J (2002) Radiation forces on small particles in thermal near fields, Journal of Optics A: Pure and Applied Optics, 10.1088/1464-4258/4/5/356, 4:5, (S109-S114), Online publication date: 1-Sep-2002. This Issue08 August 2000Volume 456Issue 2000 Article InformationDOI:https://doi.org/10.1098/rspa.2000.0595Published by:Royal SocietyPrint ISSN:1364-5021Online ISSN:1471-2946History: Published online08/08/2000Published in print08/08/2000 License: Citations and impact Keywordsenergy-level shiftsfinite temperaturecavity quantum electrodynamicsCasimir{Polder effectLamb shifts

Moment theory bounds on long-range casimir—polder interactions

Quantum-mechanical sum rules and results from the theory of moments are employed in the construction of rigorous bounds on the long range Casimir—Polder interactions of atoms and molecules.