MG14 - Talk detail

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Abstract

The author has recently proposed investigating the potential for ground-based detection of gravitational waves by means of nanomechanical parametric amplification involving the Casimir force, that is, on length scales 10-12 orders of magnitude smaller than those of a LIGO-class detector. In the proposed approach, the signal is produced by modulation of the Casimir force between two interacting plates due to the passage of a gravitational wave. Therefore, in the effective-medium-analogy, the gravitational wave corresponds to a modulation in the optical properties of the medium in the gap between the two boundaries. Since, in the Casimir-Lifshitz theory, the dispersion force depends on the optical properties of the gap medium, the pressure between the two plates as well acquires a time-dependency at the same gravitational wave frequency. Instead of making use of mechanical oscillations, the system is pumped by employing the already observed dependence of dispersion forces on illumination in semiconductors. As shown in this paper, this approach simplifies device design, enhances flexibility and performance, and paves the way for nanotube oscillator implementations.

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Session

Accepted

Yes

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Time

Talk

Title

Abstract

Two parallel plane, perfectly conducting mirrors attract each other because of fluctuating electromagnetic field boundary effects – the well-known Casimir force. Does this happen with gravitation? Quite recently, this issue has been explored by Quach, who found that, if the as yet unproven Heisenberg-Coulomb (HC) effect is confirmed, such a hypothetical force might exceed its electromagnetic counterpart by one order of magnitude. Importantly, the additional claim has been made that a positive result "would be the first experimental evidence for the ... existence of gravitons." Here we show that these latter claims are unfounded. In analogy with extensive classical electrodynamics results, even if any gravitational Casimir forces were detected, this would not logically imply field quantization. In fact, adopting a standard radiation pressure approach and postulating gravitational-wave mirrors, it can be proven that classical general relativity straightforwardly accommodates gravitational Casimir forces that, for Lorentz-invariant fluctuation spectral energy densities, are intrinsically indistinguishable from those resulting from quantized gravity.

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