Measurement of the Casimir Force between Two Spheres

Garrett, Joseph L.; Somers, David A. T.; Munday, Jeremy N.

doi:10.1103/physrevlett.120.040401

Cited by 83 publications

(103 citation statements)

References 34 publications

(45 reference statements)

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“…In light of their proximity, apart from gravitational interaction, the two masses can also interact via Casimir force. It has been shown that the Casimir energy between two nearby spheres is given by a fraction of the "proximity force approximation" E = −f 0 (π 3 /1440) cR/(L − 2R + x B − x A ) 2 , with the factor 0 ≤ f 0 ≤ 1 [35,36]. As typically x A − x B L − 2R, we expand such expression to find a quadratic term in x A − x B that can produce entanglement between the masses.…”

Section: Calculations Of Entanglement: Released Massesmentioning

confidence: 99%

Observable quantum entanglement due to gravity

et al. 2020

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No experiment to date provided evidence for quantum features of the gravitational interaction. Recently proposed tests suggest looking for the generation of quantum entanglement between massive objects as a possible route towards the observation of such features. Motivated by advances in optical cooling of mirrors, here we provide systematic study of entanglement between two masses that are coupled gravitationally. We first consider the masses trapped at all times in harmonic potentials (optomechanics) and then masses released from the traps. This leads to the estimate of the experimental parameters required for the observation of gravitationally-induced entanglement. The optomechanical setup demands LIGO-like mirrors and squeezing or long coherence times, but the released masses can be light and accumulate detectable entanglement in a timescale shorter than their decoherence times. No macroscopic quantum superposition develops during the evolution. We discuss the implications from such thought experiments regarding the nature of the gravitational coupling.arXiv:1906.08808v1 [quant-ph]

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Section: Calculations Of Entanglement: Released Massesmentioning

confidence: 99%

Observable quantum entanglement due to gravity

et al. 2020

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“…As a result, the error in determination of the sphere radius was decreased as compared to previously reported in the literature (see, e.g., Refs. [12,65,66]). The rms roughness on the sphere surface δ s = 1.13 nm was also measured when the work was completed.…”

Section: Upgraded Setup With a Two-step Surface Cleaningmentioning

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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“…The interaction for such geometry has been probed for a number of different materials over the last decade [6][7][8][9][10][11][12]. The Casimir interaction between two spherical surfaces is also of great interest [13][14][15] given its applications in colloids and surface sciences [16].…”

Section: Introductionmentioning

confidence: 99%

Role of diffraction in the Casimir effect beyond the proximity force approximation

et al. 2019

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We derive the leading-order correction to the proximity force approximation (PFA) result for the electromagnetic Casimir interaction in the plane-sphere geometry by developing the scattering approach in the plane-wave basis. Expressing the Casimir energy as a sum over round trips between plane and sphere, we find two distinct contributions to the correction. The first one results from the variation of the Mie reflection operator, calculated within the geometric optical WKB approximation, over the narrow Fourier interval associated to specular reflection at the vicinity of the point of closest approach on the spherical surface. The second contribution, accounting for roughly 90% of the total correction, results from the modification of the geometric optical WKB Mie scattering amplitude due to diffraction. Our derivation provides a clear physical understanding of the nature of the PFA correction for spherical surfaces.http://dx.

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Measurement of the Casimir Force between Two Spheres

Cited by 83 publications

References 34 publications

Observable quantum entanglement due to gravity

Observable quantum entanglement due to gravity

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

Role of diffraction in the Casimir effect beyond the proximity force approximation

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