共查询到20条相似文献,搜索用时 461 毫秒
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R.S. Decca D. López E. Fischbach G.L. Klimchitskaya D.E. Krause V.M. Mostepanenko 《The European Physical Journal C - Particles and Fields》2007,51(4):963-975
We present supplementary information on the recent indirect measurement of the Casimir pressure between two parallel plates
using a micromachined oscillator. The equivalent pressure between the plates is obtained by means of the proximity force approximation
after measuring the force gradient between a gold coated sphere and a gold coated plate. The data are compared with a new
theoretical approach to the thermal Casimir force based on the use of the Lifshitz formula, combined with a generalized plasma-like
dielectric permittivity that takes into account interband transitions of core electrons. The theoretical Casimir pressures
calculated using the new approach are compared with those computed in the framework of the previously used impedance approach
and also with the Drude model approach. The latter is shown to be excluded by the data at a 99.9% confidence level within
the wide separation range from 210 to 620 nm. The level of agreement between the data and theoretical approaches based on
the generalized plasma model, or the Leontovich surface impedance, is used to set stronger constraints on the Yukawa forces
predicted from the exchange of light elementary particles and/or extra-dimensional physics. The resulting constraints are
the strongest in the interaction region from 20 to 86 nm with a largest improvement by a factor of 4.4 at 26 nm. 相似文献
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I. Antoniadis S. Baessler M. Büchner V.V. Fedorov S. Hoedl A. Lambrecht V.V. Nesvizhevsky G. Pignol K.V. Protasov S. Reynaud Yu. Sobolev 《Comptes Rendus Physique》2011,12(8):755-778
We consider theoretical motivations to search for extra short-range fundamental forces as well as experiments constraining their parameters. The forces could be of two types: 1) spin-independent forces; 2) spin-dependent axion-like forces. Different experimental techniques are sensitive in respective ranges of characteristic distances. The techniques include measurements of gravity at short distances, searches for extra interactions on top of the Casimir force, precision atomic and neutron experiments. We focus on neutron constraints, thus the range of characteristic distances considered here corresponds to the range accessible for neutron experiments. 相似文献
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E. Fischbach G. L. Klimchitskaya D. E. Krause V. M. Mostepanenko 《The European Physical Journal C - Particles and Fields》2010,68(1-2):223-226
We discuss the constraints on the parameters of a Yukawa interaction obtained from the indirect measurements of the Casimir pressure between parallel plates using the sphere–plate configuration. Recently, it was claimed in the literature that the application of the proximity force approximation (PFA) to the calculation of a Yukawa interaction in the sphere–plate configuration could lead to a large error of order 100% in the constraints obtained. Here we re-calculate the constraints both exactly and using the PFA, and arrive at identical results. We elucidate the reasons why an incorrect conclusion was obtained suggesting that the PFA is inapplicable to calculate the Yukawa force. 相似文献
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G. L. Klimchitskaya 《Contemporary Physics》2013,54(3):131-144
Casimir effect is the attractive force which acts between two plane parallel, closely spaced, uncharged, metallic plates in vacuum. This phenomenon was predicted theoretically in 1948 and reliably investigated experimentally only in recent years. In fact, the Casimir force is similar to the familiar van der Waals force in the case of relatively large separations when the relativistic effects come into play. We review the most important experiments on measuring the Casimir force by means of torsion pendulum, atomic force microscope and micromechanical torsional oscillator. Special attention is paid to the puzzle of the thermal Casimir force, i.e. to the apparent violation of the third law of thermodynamics when the Lifshitz theory of dispersion forces is applied to real metals. Thereafter we discuss the role of the Casimir force in nanosystems including the stiction phenomenon, actuators, and interaction of hydrogen atoms with carbon nanotubes. The applications of the Casimir effect for constraining predictions of extra-dimensional unification schemes and other physics beyond the standard model are also considered. 相似文献
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The dependence of the thermal component of the Casimir force and Casimir friction between graphene sheets on the drift velocity of charge carriers in one of the sheets has been analyzed. It has been shown that the drift motion results in the measurable change in the thermal Casimir force owing to the Doppler effect. The thermal Casimir force, as well as Casimir friction, increases strongly in the case of resonant photon tunneling, when the energy of an emitted photon coincides with the excitation energy of an electron-hole pair. In the case of resonant photon tunneling, the dominant contribution to the Casimir friction even at temperatures above room temperature comes from quantum friction caused by quantum fluctuations. Quantum friction can be detected in an experiment on the friction drag between graphene sheets in a high electric field. 相似文献
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《Physics letters. [Part B]》2006,643(6):311-314
The Casimir effect for parallel plates in the presence of compactified universal extra dimensions within the frame of Kaluza–Klein theory is analyzed. Having regularized and discussed the expressions of Casimir force in the limit, we show that the nature of Casimir force is repulsive if the distance between the plates is large enough and the higher-dimensional spacetime is, the greater the value of repulsive Casimir force between plates is. The repulsive nature of the force is not consistent with the experimental phenomena. 相似文献
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The analysis of all Casimir force experiments using a sphere-plate geometry requires the use of the proximity-force approximation (PFA) to relate the Casimir force between a sphere and a flat plate to the Casimir energy between two parallel plates. Because it has been difficult to assess the PFA's range of applicability theoretically, we have conducted an experimental search for corrections to the PFA by measuring the Casimir force and force gradient between a gold-coated plate and five gold-coated spheres with different radii using a microelectromechanical torsion oscillator. For separations z<300 nm, we find that the magnitude of the fractional deviation from the PFA in the force gradient measurement is, at the 95% confidence level, less than 0.4z/R, where R is the radius of the sphere. 相似文献
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CHENG Hong-Bo 《理论物理通讯》2012,58(2):229-236
We discuss the Casimir effect for massless scalar fields subject to the Dirichlet boundary conditions on the parallel plates at finite temperature in the presence of one fractal extra compactified dimension. We obtain the Casimir energy density with the help of the regularization of multiple zeta function with one arbitrary exponent and further the renormalized Casimir energy density involving the thermal corrections. It is found that when the temperature is sufficiently high, the sign of the Casimir energy remains negative no matter how great the scale dimension δ is within its allowed region. We derive and calculate the Casimir force between the parallel plates affected by the fractal additional compactified dimension and surrounding temperature. The stronger thermal influence leads the force to be stronger. The nature of the Casimir force keeps attractive. 相似文献
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A Casimir piston for massless scalar fields obeying Dirichlet boundary conditions in high-dimensional spacetimes within the frame of Kaluza–Klein theory is analyzed. We derive and calculate the exact expression for the Casimir force on the piston. We also compute the Casimir force in the limit that one outer plate is moved to the extremely distant place to show that the reduced force is associated with the properties of additional spatial dimensions. The more dimensionality the spacetime has, the stronger the extra-dimension influence is. The Casimir force for the piston in the model including a third plate under the background with extra compactified dimensions always keeps attractive. Further we find that when the limit is taken the Casimir force between one plate and the piston will change to be the same form as the corresponding force for the standard system consisting of two parallel plates in the four-dimensional spacetimes if the ratio of the plate-piston distance and extra dimensions size is large enough. 相似文献
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JETP Letters - Fluctuation induced interactions originating from electromagnetic fields give rise to the Casimir force. Even though this is a universal interaction, because of the interplay between... 相似文献
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Hongbo Cheng 《International Journal of Theoretical Physics》2013,52(9):3229-3237
The Casimir effect for massless scalar fields satisfying Dirichlet boundary conditions on the parallel plates in the presence of one fractal extra compactified dimension is analyzed. We obtain the Casimir energy density by means of the regularization of multiple zeta function with one arbitrary exponent. We find a limit on the scale dimension like $\delta>\frac{1}{2}$ to keep the negative sign of the renormalized Casimir energy which is the difference between the regularized energy for two parallel plates and the one with no plates. We derive and calculate the Casimir force relating to the influence from the fractal additional compactified dimension between the parallel plates. The larger scale dimension leads to the greater revision on the original Casimir force. The two kinds of curves of Casimir force in the case of integer-numbered extra compactified dimension or fractal one are not superposition, which means that the Casimir force show whether the dimensionality of additional compactified space is integer or fraction. 相似文献
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We consider the Casimir force acting on a d-dimensional rectangular piston due to a massless scalar field with periodic, Dirichlet and Neumann boundary conditions and
an electromagnetic field with perfect electric-conductor and perfect magnetic-conductor boundary conditions. The Casimir energy
in a rectangular cavity is derived using the cut-off method. It is shown that the divergent part of the Casimir energy does
not contribute to the Casimir force acting on the piston, thus renders an unambiguously defined Casimir force acting on the
piston. At any temperature, it is found that the Casimir force acting on the piston increases from −∞ to 0 when the separation
a between the piston and the opposite wall increases from 0 to ∞. This implies that the Casimir force is always an attractive
force pulling the piston towards the closer wall, and the magnitude of the force gets larger as the separation a gets smaller. Explicit exact expressions for the Casimir force for small and large plate separations and for low and high
temperatures are computed. The limits of the Casimir force acting on the piston when some pairs of transversal plates are
large are also derived. An interesting result regarding the influence of temperature is that in contrast to the conventional
result that the leading term of the Casimir force acting on a wall of a rectangular cavity at high temperature is the Stefan–Boltzmann
(or black-body radiation) term which is of order T
d+1, it is found that the contributions of this term from the two regions separating the piston cancel with each other in the
case of piston. The high-temperature leading-order term of the Casimir force acting on the piston is of order T, which shows that the Casimir force has a nontrivial classical ℏ→0 limit. Explicit formulas for the classical limit are computed. 相似文献
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Within a microscopic approach we show that in the case of an ideal quantum gas enclosed in a slit the Casimir force can be simply expressed in terms of the bulk one-particle density matrix. The corresponding formula, which holds both for bosons and fermions, allows to relate the range of the Casimir force to the bulk correlation length. The low-temperature behavior of the Casimir forces is derived. 相似文献
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We report the optical detection of mechanical deformation of a macroscopic object induced by the Casimir force. An adaptive holographic interferometer based on a photorefractive BaTiO3:Co crystal was used to measure periodical nonlinear deformations of a thin pellicle caused by an oscillating Casimir force. A reasonable agreement between the experimental and calculated values of the first and second harmonics of the Casimir force oscillations has been obtained. 相似文献
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The role of the “Casimir force analogue” at the microscopic processes of crystallization and melting
Melting (crystallization), a phase transition from a crystalline solid to a liquid state, is a common phenomenon in nature. We suggest a new factor, “the Casimir force analogue”, to describe mechanisms of melting and crystallization. The Casimir force analogue is a force occurring between the surfaces of solid and liquid phases of metals caused by different energy density of phonons of these phases. It explains abrupt changes in geometry and thermodynamic parameters at a melting point. “The Casimir force analogue” helps to estimate latent melting heat and to gain an insight into a solid–liquid transition problem. 相似文献
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Bruno P 《Physical review letters》2002,88(24):240401
The zero-point quantum fluctuations of the electromagnetic field in vacuum are known to give rise to a long-range attractive force between metal plates (Casimir effect). For ferromagnetic layers separated by vacuum, it is shown that the interplay of the Casimir effect and of the magneto-optical Kerr effect gives rise to a long-range magnetic interaction. The Casimir magnetic force is found to decay as D-1 in the limit of short distances, and as D-5 in the limit of long distances. Explicit expressions for realistic systems are given in the large- and small-distance limits. An experimental test of the Casimir magnetic interaction is proposed. 相似文献
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J. C. Losada R. M. Benito F. Borondo 《The European physical journal. Special topics》2008,165(1):183-193
The Casimir effect is a force arising in the macroscopic world as a result of
radiation pressure of vacuum fluctuations. It thus plays a key role in the
emerging domain of nano-electro-mechanical systems (NEMS).
This role is reviewed in the present paper, with discussions of the influence
of the material properties of the mirrors, as well as the geometry dependence
of the Casimir effect between corrugated mirrors.
In particular, the lateral component of the Casimir force and restoring torque
between metal plates with misaligned corrugations are evaluated. 相似文献