Testing the equivalence principle and discreteness of spacetime through the t3 gravitational phase with quantum information technology

Abstract

We propose a new thought experiment, based on present-day Quantum Information Technologies, to measure quantum gravitational effects through the Bose-Marletto-Vedral (BMV) effect [1][2][3][4] by revealing the gravitational t 3 phase term, its expected relationships with low-energy quantum gravity phenomena and test the equivalence principle of general relativity. The technique here proposed promise to reveal gravitational field fluctuations from the analysis of the stochastic noise associated to an ideal output of a measurement process of a quantum system. To improve the sensitivity we propose to cumulate the effects of the gravitational field fluctuations in time on the outputs of a series of independent measurements acted on entangled states of particles, like in the building of a quantum cryptographic key, and extract from the associated time series the effect of the expected gravitational field fluctuations. In fact, an ideal quantum cryptographic key, built with the sharing of maximally entangled states of particles, is represented by a random sequence of uncorrelated symbols mathematically described by a perfect white noise, a stochastic process with zero mean and without correlation between its values taken at different times. Gravitational field perturbations, including quantum gravity fluctuations and gravitational waves, introduce additional phase terms that decohere the entangled pairs used to build the quantum cryptographic key, with the result of coloring the white noise [5,6]. We find that this setup, built with massive mesoscopic particles, can potentially reveal the t 3 gravitational phase term and thus, the BMV effect.

Stern-Gerlach Interferometry for Tests of Quantum Gravity and General Applications

“…The proposal in [5] can in effect, be extended beyond what it intends to achieve and/or demonstrate. The authors in [24] for instance, propose a novel thought experiment based on presentday quantum cryptographic concepts to potentially detect lowenergy perturbative quantum gravity fluctuations in a setup that closely resembles the setup proposed in [5] (also see [96]) by experimentally revealing the notorious gravitational T 3 phase term, which they then argue would allow one to test the Einstein equivalence principle. The hope is to detect gravitational field fluctuations from a rigorous analysis of the stochastic noise associated with an otherwise ideal output (one with a very high state-readout fidelity) of a measurement process of a quantum system (for more details regarding the operational principle of the proposed setup, see [24]).…”

“…The authors in [24] for instance, propose a novel thought experiment based on presentday quantum cryptographic concepts to potentially detect lowenergy perturbative quantum gravity fluctuations in a setup that closely resembles the setup proposed in [5] (also see [96]) by experimentally revealing the notorious gravitational T 3 phase term, which they then argue would allow one to test the Einstein equivalence principle. The hope is to detect gravitational field fluctuations from a rigorous analysis of the stochastic noise associated with an otherwise ideal output (one with a very high state-readout fidelity) of a measurement process of a quantum system (for more details regarding the operational principle of the proposed setup, see [24]). Future experimental works in this direction can turn out to be a promising venture, primarily because currently existing quantum technologies can in principle, as the authors in [24] point out, detect quantum gravitational effects through the direct measure of the gravitational T 3 phase term.…”

“…The hope is to detect gravitational field fluctuations from a rigorous analysis of the stochastic noise associated with an otherwise ideal output (one with a very high state-readout fidelity) of a measurement process of a quantum system (for more details regarding the operational principle of the proposed setup, see [24]). Future experimental works in this direction can turn out to be a promising venture, primarily because currently existing quantum technologies can in principle, as the authors in [24] point out, detect quantum gravitational effects through the direct measure of the gravitational T 3 phase term.…”

Spin‐Spacetime Censorship

“…Recent advances in theories of gravitational decoherence offer intriguing thought and laboratory experiments that may resolve the conflict created by our gedanken experiment or be contradicted by it. [86][87][88][89] The Bose-Marletto-Vedral (BMV) thought experiment [18,21] and applications thereof [90][91][92][93] could also be discussed in the context of our gedanken experiment. Their basic observation is that the mediator of quantum entanglement must be quantum in itself (provided that spontaneous collapse mechanisms like the aforementioned ones do not impede such gravitationally mediated entanglement).…”