Physics

Editorial

Jump to: Research, Review

11 pages, 282 KiB

Open AccessEditorial

Advances and Prospects in Casimir Physics

by Galina L. Klimchitskaya and Vladimir M. Mostepanenko

Physics 2024, 6(3), 1072-1082; https://doi.org/10.3390/physics6030066 - 22 Aug 2024

Viewed by 3726

Abstract

In the present introductory to the Special Issue “75 Years of the Casimir Effect: Advances and Prospects”, we summarize the state of the art in this field of physics, briefly describe the topics of the contributing papers, formulate several unresolved problems, and outline [...] Read more.

In the present introductory to the Special Issue “75 Years of the Casimir Effect: Advances and Prospects”, we summarize the state of the art in this field of physics, briefly describe the topics of the contributing papers, formulate several unresolved problems, and outline possible pathways towards their resolution. Special attention is given to experiments on measuring the Casimir force, to the known problem of the dissipation of conduction electrons when one compares experiment with theory, and to the Casimir effect in novel materials and non-traditional situations. We conclude that in the future, this multidisciplinary quantum effect will continue to play a crucial role in both fundamental physics and its applications. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

Research

Jump to: Editorial, Review

20 pages, 1428 KiB

Open AccessArticle

First- and Second-Order Forces in the Asymmetric Dynamical Casimir Effect for a Single δ − δ^′ Mirror

by Matthew J. Gorban, William D. Julius, Patrick M. Brown, Jacob A. Matulevich, Ramesh Radhakrishnan and Gerald B. Cleaver

Physics 2024, 6(2), 760-779; https://doi.org/10.3390/physics6020047 - 14 May 2024

Cited by 1 | Viewed by 874

Abstract

Here, we consider an asymmetric

δ - δ^{'}

mirror undergoing time-dependent interactions with a massless scalar field in 1 + 1 dimensions. Using fluctuation-dissipation theory for a mirror in vacuum, we compute the force on a moving

δ - δ^{'}

mirror [...] Read more.

Here, we consider an asymmetric

δ - δ^{'}

mirror undergoing time-dependent interactions with a massless scalar field in 1 + 1 dimensions. Using fluctuation-dissipation theory for a mirror in vacuum, we compute the force on a moving

δ - δ^{'}

mirror with time-dependent material properties. We investigate the first-order forces arising from the two distinct fluctuation sources and calculate the linear susceptibility in each case. We then plot the resulting forces. At the second order, we also find the independent contributions to the total force as well as the force that arises from the interference phenomena between the two fluctuation sources. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

52 pages, 4729 KiB

Open AccessArticle

Force Metrology with Plane Parallel Plates: Final Design Review and Outlook

by Hamid Haghmoradi, Hauke Fischer, Alessandro Bertolini, Ivica Galić, Francesco Intravaia, Mario Pitschmann, Raphael A. Schimpl and René I. P. Sedmik

Physics 2024, 6(2), 690-741; https://doi.org/10.3390/physics6020045 - 7 May 2024

Cited by 4 | Viewed by 1058

Abstract

During the past few decades, abundant evidence for physics beyond the two standard models of particle physics and cosmology was found. Yet, we are tapping in the dark regarding our understanding of the dark sector. For more than a century, open problems related [...] Read more.

During the past few decades, abundant evidence for physics beyond the two standard models of particle physics and cosmology was found. Yet, we are tapping in the dark regarding our understanding of the dark sector. For more than a century, open problems related to the nature of the vacuum remained unresolved. As well as the traditional high-energy frontier and cosmology, technological advancement provides complementary access to new physics via high-precision experiments. Among the latter, the Casimir And Non-Newtonian force EXperiment (Cannex) has successfully completed its proof-of-principle phase and is going to commence operation soon. Benefiting from its plane parallel plate geometry, both interfacial and gravity-like forces are maximized, leading to increased sensitivity. A wide range of dark sector forces, Casimir forces in and out of thermal equilibrium, and gravity can be tested. This paper describes the final experimental design, its sensitivity, and expected results. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

16 pages, 622 KiB

Open AccessArticle

Casimir Energy in (2 + 1)-Dimensional Field Theories

by Manuel Asorey, Claudio Iuliano and Fernando Ezquerro

Physics 2024, 6(2), 613-628; https://doi.org/10.3390/physics6020040 - 17 Apr 2024

Cited by 2 | Viewed by 868

Abstract

We explore the dependence of vacuum energy on the boundary conditions for massive scalar fields in (2 + 1)-dimensional spacetimes. We consider the simplest geometrical setup given by a two-dimensional space bounded by two homogeneous parallel wires in order to compare it with [...] Read more.

We explore the dependence of vacuum energy on the boundary conditions for massive scalar fields in (2 + 1)-dimensional spacetimes. We consider the simplest geometrical setup given by a two-dimensional space bounded by two homogeneous parallel wires in order to compare it with the non-perturbative behaviour of the Casimir energy for non-Abelian gauge theories in (2 + 1) dimensions. Our results show the existence of two types of boundary conditions which give rise to two different asymptotic exponential decay regimes of the Casimir energy at large distances. The two families are distinguished by the feature that the boundary conditions involve or not interrelations between the behaviour of the fields at the two boundaries. Non-perturbative numerical simulations and analytical arguments show such an exponential decay for Dirichlet boundary conditions of SU(2) gauge theories. The verification that this behaviour is modified for other types of boundary conditions requires further numerical work. Subdominant corrections in the low-temperature regime are very relevant for numerical simulations, and they are also analysed in this paper. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

11 pages, 404 KiB

Open AccessCommunication

Rectified Lorentz Force from Thermal Current Fluctuations

by Carsten Henkel

Physics 2024, 6(2), 568-578; https://doi.org/10.3390/physics6020037 - 9 Apr 2024

Cited by 1 | Viewed by 1100

Abstract

In a conducting medium held at finite temperature, free carriers perform Brownian motion and generate fluctuating electromagnetic fields. In this paper, an averaged Lorentz force density is computed that turns out to be nonzero in a thin subsurface layer, pointing towards the surface, [...] Read more.

In a conducting medium held at finite temperature, free carriers perform Brownian motion and generate fluctuating electromagnetic fields. In this paper, an averaged Lorentz force density is computed that turns out to be nonzero in a thin subsurface layer, pointing towards the surface, while it vanishes in the bulk. This is an elementary example of rectified fluctuations, similar to the Casimir force or radiative heat transport. The results obtained also provide an experimental way to distinguish between the Drude and so-called plasma models. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

24 pages, 431 KiB

Open AccessArticle

Casimir Forces in CFT with Defects and Boundaries

by Philippe Brax and Sylvain Fichet

Physics 2024, 6(2), 544-567; https://doi.org/10.3390/physics6020036 - 9 Apr 2024

Cited by 4 | Viewed by 847

Abstract

We investigate the quantum forces occurring between the defects and/or boundaries of a conformal field theory (CFT). We propose to model imperfect defects and boundaries as localized relevant double-trace operators that deform the CFT. Our focus is on pointlike and codimension-one planar defects. [...] Read more.

We investigate the quantum forces occurring between the defects and/or boundaries of a conformal field theory (CFT). We propose to model imperfect defects and boundaries as localized relevant double-trace operators that deform the CFT. Our focus is on pointlike and codimension-one planar defects. In the case of two parallel membranes, we point out that the CFT 2-point function tends to get confined and develops a tower of resonances with a constant decay rate when the operator dimension approaches the free field dimension. Using a functional formalism, we compute the quantum forces induced by the CFT between a variety of configurations of pointlike defects, infinite plates and membranes. Consistency arguments imply that these quantum forces are attractive at any distance. Forces of the Casimir–Polder type appear in the UV (ultraviolet), while forces of the Casimir type appear in the IR (infrared), in which case the CFT gets repelled from the defects. Most of the forces behave as a non-integer power of the separation, controlled by the dimension of the double-trace deformation. In the Casimir regime of the membrane–membrane configuration, the quantum pressure behaves universally as

1 / ℓ^{d}

; however, information about the double-trace nature of the defects still remains encoded in the strength of the pressure. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

19 pages, 412 KiB

Open AccessEditor’s ChoiceArticle

Casimir Interaction of Chern–Simons Layers on Substrates via Vacuum Stress Tensor

by Valery N. Marachevsky and Arseny A. Sidelnikov

Physics 2024, 6(2), 496-514; https://doi.org/10.3390/physics6020033 - 2 Apr 2024

Cited by 1 | Viewed by 944

Abstract

We develop a Green’s functions scattering method for systems with Chern–Simons plane boundary layers on dielectric half-spaces. The Casimir pressure is derived by evaluation of the stress tensor in a vacuum slit between two half-spaces. The sign of the Casimir pressure on a [...] Read more.

We develop a Green’s functions scattering method for systems with Chern–Simons plane boundary layers on dielectric half-spaces. The Casimir pressure is derived by evaluation of the stress tensor in a vacuum slit between two half-spaces. The sign of the Casimir pressure on a Chern–Simons plane layer separated by a vacuum slit from the Chern–Simons layer at the boundary of a dielectric half-space is analyzed for intrinsic

Si

and

{SiO}_{2}

glass substrates. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

12 pages, 305 KiB

Open AccessArticle

Semi-Classical Electrodynamics and the Casimir Effect

by Mathias Boström, Ayda Gholamhosseinian, Subhojit Pal, Yang Li and Iver Brevik

Physics 2024, 6(1), 456-467; https://doi.org/10.3390/physics6010030 - 19 Mar 2024

Cited by 3 | Viewed by 1405

Abstract

From the late 1960s onwards, the groups of Barry Ninham and Adrian Parsegian, and their many collaborators, made a number of essential contributions to theory and experiment of intermolecular forces. In particular, they explored the semi-classical theory: Maxwell’s equations and Planck quantization of [...] Read more.

From the late 1960s onwards, the groups of Barry Ninham and Adrian Parsegian, and their many collaborators, made a number of essential contributions to theory and experiment of intermolecular forces. In particular, they explored the semi-classical theory: Maxwell’s equations and Planck quantization of light leads to Lifshitz and Casimir interactions. We discuss some selected thought-provoking results from Ninham and his group. Some of the results have been conceived as controversial but, we would say, never uninteresting. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

13 pages, 9089 KiB

Open AccessArticle

Casimir Forces with Periodic Structures: Abrikosov Flux Lattices

by Shunashi Guadalupe Castillo-López, Raúl Esquivel-Sirvent, Giuseppe Pirruccio and Carlos Villarreal

Physics 2024, 6(1), 394-406; https://doi.org/10.3390/physics6010026 - 12 Mar 2024

Cited by 2 | Viewed by 972

Abstract

We investigate the influence of the Abrikosov vortex lattice on the Casimir force in a setup constituted by high-temperature superconductors subject to an external magnetic field. The Abrikosov lattice is a property of type II superconductors in which normal and superconducting carriers coexist [...] Read more.

We investigate the influence of the Abrikosov vortex lattice on the Casimir force in a setup constituted by high-temperature superconductors subject to an external magnetic field. The Abrikosov lattice is a property of type II superconductors in which normal and superconducting carriers coexist and the latter define a periodic pattern with square symmetry. We find that the optical properties determined by spatial redistribution of the superconducting order parameter induce Casimir forces with a periodic structure whose minimal strengths coincide with the vortex cores. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

14 pages, 360 KiB

Open AccessEditor’s ChoiceArticle

Mass and Magnetic Moment of the Electron and the Stability of QED—A Critical Review

by Michael Bordag and Irina G. Pirozhenko

Physics 2024, 6(1), 237-250; https://doi.org/10.3390/physics6010017 - 18 Feb 2024

Cited by 1 | Viewed by 852

Abstract

The anomalous magnetic moment of the electron, first calculated by Schwinger, lowers the ground state energy of the electron in a weak magnetic field. It is a function of the field and changes signs for large fields, ensuring the stability of the ground [...] Read more.

The anomalous magnetic moment of the electron, first calculated by Schwinger, lowers the ground state energy of the electron in a weak magnetic field. It is a function of the field and changes signs for large fields, ensuring the stability of the ground state. This has been shown in the past 50 years in numerous papers. The corresponding corrections to the mass of the electron have also been investigated in strong fields using semiclassical methods. We critically review these developments and point out that the calculation for low-lying excited states raises questions. Also, we calculate the contribution from the tadpole diagram, the relevance of which was observed only quite recently. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

12 pages, 992 KiB

Open AccessArticle

Surface Scattering Expansion of the Casimir–Polder Interaction for Magneto-Dielectric Bodies: Convergence Properties for Insulators, Conductors, and Semiconductors

by Giuseppe Bimonte and Thorsten Emig

Physics 2024, 6(1), 194-205; https://doi.org/10.3390/physics6010014 - 9 Feb 2024

Cited by 2 | Viewed by 1230

Abstract

Fluctuation-induced forces are a hallmark of the interplay between fluctuations and geometry. We recently proved the existence of a multi-parametric family of exact representations of Casimir and Casimir–Polder interactions between bodies of arbitrary shape and material composition, admitting a multiple scattering expansion (MSE) [...] Read more.

Fluctuation-induced forces are a hallmark of the interplay between fluctuations and geometry. We recently proved the existence of a multi-parametric family of exact representations of Casimir and Casimir–Polder interactions between bodies of arbitrary shape and material composition, admitting a multiple scattering expansion (MSE) as a sequence of inter-body and intra-body multiple wave scatterings. The approach requires no knowledge of the scattering amplitude (T-matrix) of the bodies. In this paper, we investigate the convergence properties of the MSE for the Casimir–Polder interaction of a polarizable particle with a macroscopic body. We consider representative materials from different classes, such as insulators, conductors, and semiconductors. Using a sphere and a cylinder as benchmarks, we demonstrate that the MSE can be used to efficiently and accurately compute the Casimir–Polder interaction for bodies with smooth surfaces. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

16 pages, 509 KiB

Open AccessArticle

The Normal Casimir Force for Lateral Moving Planes with Isotropic Conductivities

by Nail Khusnutdinov and Natalia Emelianova

Physics 2024, 6(1), 148-163; https://doi.org/10.3390/physics6010011 - 26 Jan 2024

Cited by 2 | Viewed by 930

Abstract

We consider the two planes at zero temperature with isotropic conductivity that are in relative lateral motion with velocity v and interplane distance a. Two models of conductivity are taken into account—the constant and frequency-dependent Drude models. The normal (perpendicular to planes) [...] Read more.

We consider the two planes at zero temperature with isotropic conductivity that are in relative lateral motion with velocity v and interplane distance a. Two models of conductivity are taken into account—the constant and frequency-dependent Drude models. The normal (perpendicular to planes) Casimir force is analyzed in detail for two systems—(i) two planes with identical conductivity and (ii) one plane that is a perfect metal. The velocity correction to the Casimir energy,

Δ_{v} E

\propto

v^{2}

, for small enough velocities is used for all considered cases. In the case of constant conductivity,

η

, the energy correction is

Δ_{v} E

\propto

η / a^{3} {(v / η)}^{2}

for

v ≪ η ≪ 1

. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

18 pages, 3846 KiB

Open AccessArticle

Casimir–Lifshitz Frictional Heating in a System of Parallel Metallic Plates

by George V. Dedkov

Physics 2024, 6(1), 13-30; https://doi.org/10.3390/physics6010002 - 27 Dec 2023

Cited by 1 | Viewed by 976

Abstract

The Casimir–Lifshitz force of friction between neutral bodies in relative motion, along with the drag effect, causes their heating. This paper considers this frictional heating in a system of two metal plates within the framework of fluctuation electromagnetic theory. Analytical expressions for the [...] Read more.

The Casimir–Lifshitz force of friction between neutral bodies in relative motion, along with the drag effect, causes their heating. This paper considers this frictional heating in a system of two metal plates within the framework of fluctuation electromagnetic theory. Analytical expressions for the friction force in the limiting cases of low (zero) temperature and low and high speeds, as well as general expressions describing the kinetics of heating, have been obtained. It is shown that the combination of low temperatures (T < 10 K) and velocities of 10–10³ m/s provides the most favorable conditions when measuring the Casimir–Lifshitz friction force from heat measurements. In particular, the friction force of two coaxial disks of gold 10 cm in diameter and 500 nm in thickness, one of which rotates at a frequency of 10–10³ rps (revolutions per second), can be measured using the heating effect of 1–2 K in less than 1 min. A possible experimental layout is discussed. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

18 pages, 417 KiB

Open AccessArticle

Vacuum Interaction of Topological Strings at Short Distances

by Yuri V. Grats and Pavel Spirin

Physics 2023, 5(4), 1163-1180; https://doi.org/10.3390/physics5040075 - 14 Dec 2023

Cited by 4 | Viewed by 1010

Abstract

The paper provides an extended overview of recent results obtained by the authors in the process of studying the vacuum interaction of topological cosmic strings at short distances, taking into account their transverse size a and the mass m of the quantized field. [...] Read more.

The paper provides an extended overview of recent results obtained by the authors in the process of studying the vacuum interaction of topological cosmic strings at short distances, taking into account their transverse size a and the mass m of the quantized field. We consider the case of a massive real-valued scalar field with minimal coupling. It is shown that at the interstring distances significantly larger than the Compton length,

l_{c} = 1 / m

, the Casimir effect is damped exponentially. On the other hand, at distances smaller than

l_{c}

but much larger than the typical string width, the field-mass influence becomes insignificant. In this case, the partial contribution of a massive field to the Casimir energy is of the same order as the contribution of a massless one. At these distances, the string’s transverse size is insignificant also. However, at the interstring distances of the same order as a string radius, the energy of the vacuum interaction of thick strings may significantly surpass the one for two infinitely thin strings with the same mass per unit length. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

18 pages, 510 KiB

Open AccessArticle

Surface Casimir Densities on Branes Orthogonal to the Boundary of Anti-De Sitter Spacetime

by Aram Saharian

Physics 2023, 5(4), 1145-1162; https://doi.org/10.3390/physics5040074 - 14 Dec 2023

Cited by 1 | Viewed by 899

Abstract

The paper investigates the vacuum expectation value of the surface energy–momentum tensor (SEMT) for a scalar field with general curvature coupling in the geometry of two branes orthogonal to the boundary of anti-de Sitter (AdS) spacetime. For Robin boundary conditions on the branes, [...] Read more.

The paper investigates the vacuum expectation value of the surface energy–momentum tensor (SEMT) for a scalar field with general curvature coupling in the geometry of two branes orthogonal to the boundary of anti-de Sitter (AdS) spacetime. For Robin boundary conditions on the branes, the SEMT is decomposed into the contributions corresponding to the self-energies of the branes and the parts induced by the presence of the second brane. The renormalization is required for the first parts only, and for the corresponding regularization the generalized zeta function method is employed. The induced SEMT is finite and is free from renormalization ambiguities. For an observer living on the brane, the corresponding equation of state is of the cosmological constant type. Depending on the boundary conditions and on the separation between the branes, the surface energy densities can be either positive or negative. The energy density induced on the brane vanishes in special cases of Dirichlet and Neumann boundary conditions on that brane. The effect of gravity on the induced SEMT is essential at separations between the branes of the order or larger than the curvature radius for AdS spacetime. In the considerably large separation limit, the decay of the SEMT, as a function of the proper separation, follows a power law for both massless and massive fields. For parallel plates in Minkowski bulk and for massive fields the fall-off of the corresponding expectation value is exponential. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

13 pages, 3174 KiB

Open AccessEditor’s ChoiceArticle

Dynamical Sensitivity of Three-Layer Micro Electromechanical Systems to the Optical Properties of the Intervening Liquid Layer

by Fatemeh Tajik and George Palasantzas

Physics 2023, 5(4), 1081-1093; https://doi.org/10.3390/physics5040070 - 21 Nov 2023

Cited by 1 | Viewed by 1044

Abstract

Here, we investigate the actuation dynamics of a micro device with different intervening liquids between the actuating components under the influence of Casimir and dissipative hydrodynamic forces. This is enabled via phase space portraits, which demonstrate that by increasing the dielectric response of [...] Read more.

Here, we investigate the actuation dynamics of a micro device with different intervening liquids between the actuating components under the influence of Casimir and dissipative hydrodynamic forces. This is enabled via phase space portraits, which demonstrate that by increasing the dielectric response of the intervening layer the autonomous device may not come into stiction due to the decreasing in magnitude Casmir force. Unlike the micro devices that are placed in vacuum with an intervening liquid, the phase portraits show only a spiral trajectory which eventually stops at a rest position due to the strong energy dissipation by the position dependent hydrodynamic drag forces, even when considering sufficiently strong restoring forces. Moreover, it is feasible to expand the area of motion using intervening liquids with lower dynamic viscosity or increasing the slip length of the intervening fluid. Finally, under the influence of an external driven force, which is the realistic case for possible applications, the system can reach stable oscillation at larger separations with an amplitude higher for the liquid that led to lower Casimir and hydrodynamic forces. Hence, the results presented in this study are essential for studying the dynamical behavior of MEMS and their design in liquid environments. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

18 pages, 1078 KiB

Open AccessArticle

The Casimir Force between Two Graphene Sheets: 2D Fresnel Reflection Coefficients, Contributions of Different Polarizations, and the Role of Evanescent Waves

by Galina L. Klimchitskaya and Vladimir M. Mostepanenko

Physics 2023, 5(4), 1013-1030; https://doi.org/10.3390/physics5040066 - 25 Oct 2023

Cited by 3 | Viewed by 1543

Abstract

We consider the Casimir pressure between two graphene sheets and contributions to it determined by evanescent and propagating waves with different polarizations. For this purpose, the derivation of the 2-dimensional (2D) Fresnel reflection coefficients on a graphene sheet is presented in terms of [...] Read more.

We consider the Casimir pressure between two graphene sheets and contributions to it determined by evanescent and propagating waves with different polarizations. For this purpose, the derivation of the 2-dimensional (2D) Fresnel reflection coefficients on a graphene sheet is presented in terms of the transverse and longitudinal dielectric permittivities of graphene with due account of the spatial dispersion. The explicit expressions for both dielectric permittivities as the functions of the 2D wave vector, frequency, and temperature are written along the real frequency axis in the regions of propagating and evanescent waves and at the pure imaginary Matsubara frequencies using the polarization tensor of graphene. It is shown that in the application region of the Dirac model nearly the total value of the Casimir pressure between two graphene sheets is determined by the electromagnetic field with transverse magnetic (TM) polarization. By using the Lifshitz formula written along the real frequency axis, the contributions of the TM-polarized propagating and evanescent waves into the total pressure are determined. By confronting these results with the analogous results found for plates made of real metals, the way for bringing the Lifshitz theory using the realistic response functions in agreement with measurements of the Casimir force between metallic test bodies is pointed out. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

10 pages, 317 KiB

Open AccessCommunication

Electromagnetic Casimir–Polder Interaction for a Conducting Cone

by Noah Graham

Physics 2023, 5(4), 1003-1012; https://doi.org/10.3390/physics5040065 - 12 Oct 2023

Cited by 3 | Viewed by 1192

Abstract

Using the formulation of the electromagnetic Green’s function of a perfectly conducting cone in terms of analytically continued angular momentum, we compute the Casimir–Polder interaction energy of a cone with a polarizable particle. We introduce this formalism by first reviewing the analogous approach [...] Read more.

Using the formulation of the electromagnetic Green’s function of a perfectly conducting cone in terms of analytically continued angular momentum, we compute the Casimir–Polder interaction energy of a cone with a polarizable particle. We introduce this formalism by first reviewing the analogous approach for a perfectly conducting wedge, and then demonstrate the calculation through numerical evaluation of the resulting integrals. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

16 pages, 482 KiB

Open AccessEditor’s ChoiceArticle

Casimir Effect Invalidates the Drude Model for Transverse Electric Evanescent Waves

by Galina L. Klimchitskaya and Vladimir M. Mostepanenko

Physics 2023, 5(4), 952-967; https://doi.org/10.3390/physics5040062 - 27 Sep 2023

Cited by 9 | Viewed by 1352

Abstract

We consider the Casimir pressure between two metallic plates and calculate the four contributions to it determined by the propagating and evanescent waves and by the transverse magnetic and transverse electric polarizations of the electromagnetic field. The range of interplate separations is considered [...] Read more.

We consider the Casimir pressure between two metallic plates and calculate the four contributions to it determined by the propagating and evanescent waves and by the transverse magnetic and transverse electric polarizations of the electromagnetic field. The range of interplate separations is considered where nearly the whole pressure has its origin in the electromagnetic response of conduction electrons. In the Casimir physics, this response is described either by the dissipative Drude model resulting in contradictions with the measurement data or by the experimentally consistent but dissipationless plasma model. It is shown that the total transverse magnetic contribution to the Casimir pressure due to both the propagating and evanescent waves and the transverse electric contribution due to only the propagating waves, computed by means of the Drude model, correlate well with the corresponding results obtained using the plasma model. We conclude that the disagreement between the theoretical predictions obtained using the Drude model and precision measurements of the Casimir force is not caused by the account of dissipation in itself, but arises from an incorrect description of the response of metals to the low-frequency transverse electric evanescent waves by this model. It is demonstrated that the Drude model has no supporting experimental evidence in the range of transverse electric evanescent waves, so that the above conclusion is consistent with all available information. The alternative test of the Drude model for the transverse electric evanescent waves suggested in the framework of classical electrodynamics is discussed. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

13 pages, 484 KiB

Open AccessArticle

Stabilizing Diamagnetic Levitation of a Graphene Flake through the Casimir Effect

by Norio Inui

Physics 2023, 5(3), 923-935; https://doi.org/10.3390/physics5030060 - 1 Sep 2023

Cited by 2 | Viewed by 1412

Abstract

Graphene exhibits diamagnetism, enabling it to be lifted by the repulsive force produced in an inhomogeneous magnetic field. However, the stable levitation of a graphene flake perpendicular to the magnetic field is impeded by its strong anisotropic of magnetic susceptibility that induces rotation. [...] Read more.

Graphene exhibits diamagnetism, enabling it to be lifted by the repulsive force produced in an inhomogeneous magnetic field. However, the stable levitation of a graphene flake perpendicular to the magnetic field is impeded by its strong anisotropic of magnetic susceptibility that induces rotation. A method to suppress this rotation by applying the Casimir force to the graphene flake is presented in this paper. As a result, the graphene flake can archive stable levitation on a silicon plate when the gravitational force is small. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

9 pages, 310 KiB

Open AccessCommunication

Casimir Forces between a Dielectric and Metal: Compensation of the Electrostatic Interaction

by Vitaly B. Svetovoy

Physics 2023, 5(3), 814-822; https://doi.org/10.3390/physics5030051 - 25 Jul 2023

Cited by 2 | Viewed by 1551

Abstract

The Casimir forces between metals or good conductors have been checked experimentally. Semiconductors and especially dielectrics have not been investigated because of the surface charges, which generate strong electrostatic forces. Here, it is proposed to study the Casimir interaction of a dielectric and [...] Read more.

The Casimir forces between metals or good conductors have been checked experimentally. Semiconductors and especially dielectrics have not been investigated because of the surface charges, which generate strong electrostatic forces. Here, it is proposed to study the Casimir interaction of a dielectric and metal using a thin dielectric layer deposited on an optically thick metallic substrate. If the thickness of the layer is a few tens of nanometers, the electrostatic force due to charging can be compensated for by applying an extra voltage between the metallic plates. On the other hand, the contribution of the dielectric layer to the Casimir force is sufficiently large to extract information about the interaction between the bulk dielectric and metal. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

17 pages, 1053 KiB

Open AccessArticle

Larmor Temperature, Casimir Dynamics, and Planck’s Law

by Evgenii Ievlev and Michael R. R. Good

Physics 2023, 5(3), 797-813; https://doi.org/10.3390/physics5030050 - 18 Jul 2023

Cited by 5 | Viewed by 1507

Abstract

Classical radiation from a single relativistically accelerating electron is investigated where the temperature characterizing the system highlights the dependence on acceleration. In the context of the dynamic Casimir effect with Planck-distributed photons and thermal black hole evaporation, we demonstrate analytic consistency between the [...] Read more.

Classical radiation from a single relativistically accelerating electron is investigated where the temperature characterizing the system highlights the dependence on acceleration. In the context of the dynamic Casimir effect with Planck-distributed photons and thermal black hole evaporation, we demonstrate analytic consistency between the ideas of constant acceleration and equilibrium thermal radiation. For ultra-relativistic speeds, we demonstrate a long-lasting constant peel acceleration and constant power emission, which is consistent with the idea of balanced equilibrium of Planck-distributed particle radiation. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

26 pages, 553 KiB

Open AccessReview

The Casimir Effect in Finite-Temperature and Gravitational Scenarios

by Valdir Barbosa Bezerra, Herondy Francisco Santana Mota, Augusto P. C. M. Lima, Geová Alencar and Celio Rodrigues Muniz

Physics 2024, 6(3), 1046-1071; https://doi.org/10.3390/physics6030065 - 13 Aug 2024

Cited by 1 | Viewed by 1022

Abstract

In this paper, we review some recent findings related to the Casimir effect. Initially, the thermal corrections to the vacuum Casimir energy density are calculated, for a quantum scalar field, whose modes propagate in the (3+1)-dimensional Euclidean spacetime, subject to a nontrivial compact [...] Read more.

In this paper, we review some recent findings related to the Casimir effect. Initially, the thermal corrections to the vacuum Casimir energy density are calculated, for a quantum scalar field, whose modes propagate in the (3+1)-dimensional Euclidean spacetime, subject to a nontrivial compact boundary condition. Next, we analyze the Casimir effect induced by two parallel plates placed in a weak gravitational field background. Finally, we review the three-dimensional wormhole solutions sourced by the Casimir density and pressures associated with the quantum vacuum fluctuations of the Yang-Mills field. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

14 pages, 3805 KiB

Open AccessReview

A Brief Review of Some Recent Precision Casimir Force Measurements

by Madhav Dhital and Umar Mohideen

Physics 2024, 6(2), 891-904; https://doi.org/10.3390/physics6020055 - 13 Jun 2024

Cited by 1 | Viewed by 1002

Abstract

Here, we review recent advances in precision Casimir force measurements with both non-magnetic and magnetic materials. In addition, the measurement of the geometric dependence of the Casimir force, both lateral and normal, using uniformly corrugated surfaces is briefly presented. Finally, the measurement of [...] Read more.

Here, we review recent advances in precision Casimir force measurements with both non-magnetic and magnetic materials. In addition, the measurement of the geometric dependence of the Casimir force, both lateral and normal, using uniformly corrugated surfaces is briefly presented. Finally, the measurement of the thermal Casimir force in graphene is discussed. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

15 pages, 335 KiB

Open AccessReview

Axion Electrodynamics and the Casimir Effect

by Iver Brevik, Subhojit Pal, Yang Li, Ayda Gholamhosseinian and Mathias Boström

Physics 2024, 6(1), 407-421; https://doi.org/10.3390/physics6010027 - 14 Mar 2024

Cited by 1 | Viewed by 1336

Abstract

We present a concise review of selected parts of axion electrodynamics and their application to Casimir physics. We present the general formalism including the boundary conditions at a dielectric surface, derive the dispersion relation in the case where the axion parameter has a [...] Read more.

We present a concise review of selected parts of axion electrodynamics and their application to Casimir physics. We present the general formalism including the boundary conditions at a dielectric surface, derive the dispersion relation in the case where the axion parameter has a constant spatial derivative in the direction normal to the conducting plates, and calculate the Casimir energy for the simple case of scalar electrodynamics using dimensional regularization. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

27 pages, 720 KiB

Open AccessReview

Casimir Physics beyond the Proximity Force Approximation: The Derivative Expansion

by César D. Fosco, Fernando C. Lombardo and Francisco D. Mazzitelli

Physics 2024, 6(1), 290-316; https://doi.org/10.3390/physics6010020 - 27 Feb 2024

Cited by 4 | Viewed by 1196

Abstract

We review the derivative expansion (DE) method in Casimir physics, an approach which extends the proximity force approximation (PFA). After introducing and motivating the DE in contexts other than the Casimir effect, we present different examples which correspond to that realm. We focus [...] Read more.

We review the derivative expansion (DE) method in Casimir physics, an approach which extends the proximity force approximation (PFA). After introducing and motivating the DE in contexts other than the Casimir effect, we present different examples which correspond to that realm. We focus on different particular geometries, boundary conditions, types of fields, and quantum and thermal fluctuations. Besides providing various examples where the method can be applied, we discuss a concrete example for which the DE cannot be applied; namely, the case of perfect Neumann conditions in

2 + 1

dimensions. By the same example, we show how a more realistic type of boundary condition circumvents the problem. We also comment on the application of the DE to the Casimir–Polder interaction which provides a broader perspective on particle–surface interactions. Full article

(This article belongs to the Special Issue 75 Years of the Casimir Effect: Advances and Prospects)

► Show Figures

Figure 1

Journal Menu

Journal Browser

75 Years of the Casimir Effect: Advances and Prospects

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (26 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI