Examining the Casimir puzzle with an upgraded AFM-based technique and advanced surface cleaning

Liu, Mingyue; Xu, Jun; Klimchitskaya, G. L.; Mostepanenko, V. M.; Mohideen, U.

doi:10.1103/physrevb.100.081406

Cited by 55 publications

(116 citation statements)

References 42 publications

(66 reference statements)

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“…Taking into account the significance of the above problems in Casimir physics, which remain unsolved for almost twenty years, in Ref. [61] an upgraded atomic force microscope (AFM)-based technique was developed and an advanced surface cleaning procedure was used in order to eliminate the role of patch potentials and make progress towards a precision measurement of the Casimir interaction at larger separations. For this purpose both interior surfaces of the vacuum chamber and Au-coated test bodies (the sphere and the plate) were successively cleaned by means of UV light and Ar ions.…”

Section: Introductionmentioning

confidence: 99%

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

et al. 2019

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We report precision measurements of the Casimir interaction at larger separation distances between the Au-coated surfaces of a sphere and a plate in ultrahigh vacuum using a much softer cantilever of the dynamic atomic force microscope-based setup and two-step cleaning procedure of the vacuum chamber and test body surfaces by means of UV light and Ar-ion bombardment.Compared to the previously performed experiment, two more measurement sets for the gradient of the Casimir force are provided which confirmed and slightly improved the results. Next, additional measurements have been performed with a factor of two larger oscillation amplitude of the cantilever. This allowed obtaining meaningful results at much larger separation distances. The comparison of the measurement data with theoretical predictions of the Lifshitz theory using the dissipative Drude model to describe the response of Au to the low-frequency electromagnetic field fluctuations shows that this theoretical approach is experimentally excluded over the distances from 250 to 1100 nm (i.e., a major step forward has been made as compared to the previous work where it was excluded up to only 820 nm). The theoretical approach using the dissipationless plasma model at low frequencies is shown to be consistent with the data over the entire measurement range from 250 to 1300 nm. The possibilities to explain these puzzling results are discussed. * Umar.Mohideen@ucr.edu arXiv:1911.00703v2 [quant-ph]

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Section: Introductionmentioning

confidence: 99%

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

et al. 2019

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“…The relative corrections to an approximate expression (20), which are less than a/R [24,25], are negligibly small in this experiment. Small corrections due to the surface roughness have been taken into account perturbatively [1,8,50] in the Casimir pressure P theor (note that the surface roughness plays a more important role at very short separations between the test bodies [51]).…”

Section: Proaches and Comparison With Experimentsmentioning

confidence: 54%

“…[25]. The corrections due to the surface roughness were also included in the theoretical gradients of the Casimir force [20].…”

Section: Proaches and Comparison With Experimentsmentioning

confidence: 99%

Casimir force, causality, and the Gurzhi model

Mostepanenko

Woods

2020

Phys. Rev. B

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An extended Drude model, termed as the Gurzhi model, which takes into account the electronphonon and electron-electron interactions, is applied to calculate the Casimir force between two metallic plates. It is shown that although the dielectric permittivity of the Gurzhi model has a first order pole in the upper half-plane of complex frequencies and, thus, violates the causality principle, it can be used in a restricted frequency interval in combination with the experimental permittivity determined by the optical data for the complex index of refraction. The imaginary part of the Gurzhi dielectric permittivity of Au at low frequencies demonstrates better agreement with the permittivity given by the optical data than the simple Drude model. The Casimir pressure between two Au plates is computed using the Gurzhi, Drude and plasma model approaches, taking into account the optical data, as well as with the simple Drude and plasma models. The contribution of the electron-electron scattering to the Casimir pressure is estimated. Although a comparison with the measurement data of two precise experiments show that the Gurzhi model does not resolve the Casimir puzzle, the obtained results suggest further clarification of this fundamental problem.

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“…Another approach to compute the temperature dependent part of the free energy is to work on the real line. In order to compute T F we start from (18) where we have to sum up the Boltzmann factors over the spectrum, or equivalent, to sum over the zeroes of the secular equation f θ (ω) = 0, which gives us the band energy structure of the comb:…”

Section: A Free Energy: Real Frequenciesmentioning

confidence: 99%

“…However, not much attention was paid to [16] since there only the separation dependent part of the entropy was considered and the focus was on another, possibly related, effect; namely a violation of the Nernst's heat theorem while using the Drude model for the dielectric slab. This problem remains still unresolved and it is related to the choice of plasma or Drude model in Casimir force calculations, see [18] for the actual status.…”

Section: Introductionmentioning

confidence: 99%

Free energy and entropy for finite temperature quantum field theory under the influence of periodic backgrounds

2020

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The basic thermodynamic quantities for a non-interacting scalar field in a periodic potential composed of either a one-dimensional chain of Dirac δ-δ functions or a specific potential with extended support are calculated. First, we consider the representation in terms of real frequencies (or one-particle energies). Then we turn the axis of frequency integration towards the imaginary axis by a finite angle, which allows for easy numerical evaluation, and finally turn completely to the imaginary frequencies and derive the corresponding Matsubara representation, which this way appears also for systems with band structure. In the limit case T → 0 we confirm earlier results on the vacuum energy. We calculate for the mentioned examples the free energy and the entropy and generalize earlier results on negative entropy.

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Examining the Casimir puzzle with an upgraded AFM-based technique and advanced surface cleaning

Cited by 55 publications

References 42 publications

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

Precision measurements of the gradient of the Casimir force between ultraclean metallic surfaces at larger separations

Casimir force, causality, and the Gurzhi model

Free energy and entropy for finite temperature quantum field theory under the influence of periodic backgrounds

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