arXiv subjects

Valery N. Marachevsky

Publications and source records attributed to Valery N. Marachevsky.

At least 19 recordsLinked to original sources

arXiv2023

Casimir-Polder interaction with Chern-Simons boundary layers

Green functions scattering method is generalized to consider mixing of electromagnetic polarizations after reflection from the plane boundary between different media and applied to derivation of the Casimir-Polder potential in systems with Chern-Simons plane boundary layers. The method is first applied to derive the Casimir-Polder potential of an anisotropic atom in the presence of a Chern-Simons plane boundary layer on a dielectric half-space. Then a general result for the Casimir-Polder potential of an anisotropic atom between two dielectric half-spaces with Chern-Simons plane parallel boundary layers is derived. The Casimir-Polder potential of an anisotropic atom between two Chern-Simons plane parallel layers in vacuum is expressed through special functions. Novel P-odd three-body vacuum effects are discovered and analyzed in the system of two Chern-Simons plane parallel layers and a neutral atom in its ground state between the layers. Remarkably, P-odd three-body vacuum effects arising due to 180 degree rotation of one of the Chern-Simons layers can be verified in experiments with neutral atoms having QED dipole interaction with an electromagnetic field.

hep-th↗

arXiv2019

Giant Casimir torque between rotated gratings and the $θ=0$ anomaly

We study the Casimir torque between two metallic one-dimensional gratings rotated by an angle $θ$ with respect to each other. We find that, for infinitely extended gratings, the Casimir energy is anomalously discontinuous at $θ=0$, due to a critical zero-order geometric transition between a 2D- and a 1D-periodic system. This transition is a peculiarity of the grating geometry and does not exist for intrinsically anisotropic materials. As a remarkable practical consequence, for finite-size gratings, the torque per area can reach extremely large values, increasing without bounds with the size of the system. We show that for finite gratings with only 10 period repetitions, the maximum torque is already 60 times larger than the one predicted in the case of infinite gratings. These findings pave the way to the design of a contactless quantum vacuum torsional spring, with possible relevance to micro- and nano-mechanical devices.

cond-mat.mes-hall↗

arXiv2018

Casimir interaction of two dielectric half spaces with Chern-Simons boundary layers

A diffraction problem for a flat Chern-Simons layer at plane boundary of a dielectric half space is solved. The Casimir energy of two dielectric half spaces with Chern-Simons layers at plane-parallel boundaries separated by a vacuum slit is derived. Crossing from the repulsive to the attractive Casimir force is analyzed for two Au and two Si half spaces with boundary Chern-Simons layers. Boundary quantum Hall layers in external magnetic field lead to Casimir repulsion at nanoscales. We discuss features that make systems with boundary quantum Hall layers unique for force measurements and search of long-range interactions beyond electromagnetism.

cond-mat.mes-hall↗

arXiv2018

Charge-Parity violating effects in Casimir-Polder potentials

We demonstrate under which conditions a violation of the charge-parity (CP) symmetry in molecules will manifest itself in the Casimir-Polder interaction of these with a magnetodielectric surface. Charge-parity violation induces a specific electric-magnetic cross-polarisability in a molecule that is not chiral, but time-reversal (T) symmetry violating. As we show, a detection of such an effect via the Casimir-Polder potential requires a material medium that is also sensitive to time-reversal, i.e., it must exhibit a non-reciprocal electromagnetic response. As simple examples of such media we consider a perfectly reflecting non-reciprocal mirror that is a special case of a perfect electromagnetic conductor as well as a Chern-Simons medium. In addition, we show that Chern-Simons and related media can induce unusual atom-surface interactions for anisotropic molecules with and without a chiral response.

quant-ph↗

arXiv2015

Impact of anisotropy on the interaction of an atom with a one-dimensional nano-grating

We study the interaction of an atom with a one-dimensional nano-grating within the framework of macroscopic QED, with special emphasis on possible anisotropic contributions. To this end, we first derive the scattering Green's tensor of the grating by means of a Rayleigh expansion and discuss its symmetry properties and asymptotes. We then determine the Casimir--Polder potential of an atom with the grating. In particular, we find that strong anisotropy can lead to a repulsive Casimir--Polder potential in the normal direction.

quant-ph↗

arXiv2013

Probing atom-surface interactions by diffraction of Bose-Einstein condensates

In this article we analyze the Casimir-Polder interaction of atoms with a solid grating and an additional repulsive interaction between the atoms and the grating in the presence of an external laser source. The combined potential landscape above the solid body is probed locally by diffraction of Bose-Einstein condensates. Measured diffraction efficiencies reveal information about the shape of the Casimir-Polder interaction and allow us to discern between models based on a pairwise-summation (Hamaker) approach and Lifshitz theory.

physics.atom-ph↗

arXiv2012

The Casimir effect: medium and geometry

Theory of the Casimir effect is presented in several examples. Casimir - Polder type formulas, Lifshitz theory and theory of the Casimir effect for two gratings separated by a vacuum slit are derived. Equations for the electromagnetic field in the presence of a medium and dispersion are discussed. Casimir effect for systems with a layer of 2+1 fermions is studied.

quant-ph↗

arXiv2011

Theory of the Casimir effect for graphene at finite temperature

Theory of the Casimir effect for a flat graphene layer interacting with a parallel flat material is presented in detail. The high-temperature asymptotics of a free energy in a graphene-metal system coincides with a Drude high-temperature asymptotics of the metal-metal system. High-temperature behavior in the graphene-metal system is expected at separations of the order of 100 nm at temperature T=300K.

hep-th↗

arXiv2011

Finite temperature Casimir effect for graphene

We adopt the Dirac model for quasiparticles in graphene and calculate the finite temperature Casimir interaction between a suspended graphene layer and a parallel conducting surface. We find that at high temperature the Casimir interaction in such system is just one half of that for two ideal conductors separated by the same distance. In this limit single graphene layer behaves exactly as a Drude metal. In particular, the contribution of the TE mode is suppressed, while one of the TM mode saturates the ideal metal value. Behaviour of the Casimir interaction for intermediate temperatures and separations accessible for an experiment is studied in some detail. We also find an interesting interplay between two fundamental constants of graphene physics: the fine structure constant and the Fermi velocity.

hep-th↗

arXiv2010

Casimir-Polder effect for a plane with Chern-Simons interaction

A novel formalism for the evaluation of the Casimir-Polder potential in an arbitrary gauge of vector potentials is introduced. The ground state energy of a neutral atom in the presence of an infinite two-dimensional plane with Chern-Simons interaction is derived at zero temperature. The essential feature of the result is its dependence on the antisymmetric part of a dipole moment correlation function.

hep-th↗

arXiv2008

Casimir interaction of dielectric gratings

We derive an exact solution for the Casimir force between two arbitrary periodic dielectric gratings and illustrate our method by applying it to two nanostructured silicon gratings. We also reproduce the Casimir force gradient measured recently [1] between a silicon grating and a gold sphere taking into account the material dependence of the force. We find good agreement between our theoretical results and the measured values both in absolute force values and the ratios between the exact force and PFA predictions.

quant-ph↗

arXiv2007

Casimir interaction: pistons and cavity

The energy of a perfectly conducting rectangular cavity is studied by making use of pistons' interactions. The exact solution for a 3D perfectly conducting piston with an arbitrary cross section is being discussed.

hep-th↗

arXiv2007

Casimir interaction of two plates inside a cylinder

The new exact formulas for the attractive Casimir force acting on each of the two identical perfectly conducting plates moving freely inside an infinite perfectly conducting cylinder with the same cross section are derived at zero and finite temperatures by making use of the zeta function technique. The long and short distance behaviour of the plates' free energy is investigated.

hep-th↗

arXiv2006

Casimir energy of two plates inside a cylinder

The new exact formulas for the attractive Casimir force acting on each of the two perfectly conducting plates moving freely inside an infinite perfectly conducting cylinder with the same cross section are derived at zero and finite temperatures by making use of zeta function technique. The short and long distance behaviour of the plates' free energy is investigated.

hep-th↗

arXiv2006

One loop boundary effects: techniques and applications

A pedagogical introduction to the heat kernel technique, zeta function and Casimir effect is presented. Several applications are considered. First we derive the high temperature asymptotics of the free energy for boson fields in terms of the heat kernel expansion and zeta function. Another application is chiral anomaly for local (MIT bag) boundary conditions. Then we rederive the Casimir energies for perfectly conducting rectangular cavities using a new technique. The new results for the attractive Casimir force acting on each of the two perfectly conducting plates inside an infinite perfectly conducting waveguide of the same cross section as the plates are presented at zero and finite temperatures.

hep-th↗

arXiv2004

Spectral functions and their applications

We give an introduction to the heat kernel technique and zeta function. Two applications are considered. First we derive the high temperature asymptotics of the free energy for boson fields in terms of the heat kernel expansion and zeta function. Another application is chiral anomaly for local (MIT bag) boundary conditions.

hep-th↗

arXiv2002

Casimir energy of dielectric systems

A new formula for the Casimir energy of a dispersive dilute dielectric ball is discussed. The formula for the Casimir energy of a polarizable particle situated in a perfectly conducting wedge-shaped cavity is derived by a path-integral coordinate space method in quantum field theory.

cond-mat↗

arXiv2002

Casimir energy of a dilute dispersive dielectric ball: realistic microscopic model

The Casimir energy of a dilute homogeneous nonmagnetic dielectric ball at zero temperature is derived analytically within a microscopic realistic model of dielectrics for an arbitrary physically possible frequency dispersion of dielectric permittivity. Divergences are absent in calculations, a minimum interatomic distance is a physical cut-off. Casimir surface force is proved to be attractive. A physical definition of the Casimir energy is discussed.

quant-ph↗