Equivalence principle for quantum systems: dephasing and phase shift of free-falling particles

Anastopoulos, Charis; Hu, B. L.

doi:10.1088/1361-6382/aaa0e8

Cited by 52 publications

(65 citation statements)

References 50 publications

(84 reference statements)

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“…Our analysis also highlights the fact that a complete understanding of the mass equivalence in the quantum realm demands the consideration of the internal degrees of freedom. This agrees with other studies showing that the internal variables must be taken into account in order to get a full understanding of the behavior of quantum systems in gravitational fields [13,14,15].…”

Section: Discussionsupporting

confidence: 91%

Atomic stability and the quantum mass equivalence

Sancho

2019

Mod. Phys. Lett. A

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We consider an unexplored aspect of the mass equivalence principle in the quantum realm, its connection with atomic stability. We show that if the gravitational mass were different from the inertial one, a Hydrogen atom placed in a constant gravitational field would become unstable in the long term. In contrast, independently of the relation between the two masses, the atom does not become ionized in an uniformly accelerated frame. This work, in the line of previous analyses studying the properties of quantum systems in gravitational fields, contributes to the extension of that programme to internal variables.

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Section: Discussionsupporting

confidence: 91%

Atomic stability and the quantum mass equivalence

Sancho

2019

Mod. Phys. Lett. A

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“…It thus remains to investigate the effect of other nonclassical features of the clock particles such as shared entanglement among the clocks and spatial superpositions. In regard to the latter, it will be interesting to recover previous relativistic time dilation effects in quantum systems related to particles prepared in spatial superpositions and each branch in the superposition experiencing a different proper time due to gravitational time dilation 18 – 20 , 34 , 50 . We emphasize that the quantum time dilation effect described here differs from these results in that it is a consequence of a momentum superposition rather than gravitational time dilation.…”

Section: Discussionmentioning

confidence: 99%

Quantum clocks observe classical and quantum time dilation

Smith

Ahmadi

2020

Nat Commun

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At the intersection of quantum theory and relativity lies the possibility of a clock experiencing a superposition of proper times. We consider quantum clocks constructed from the internal degrees of relativistic particles that move through curved spacetime. The probability that one clock reads a given proper time conditioned on another clock reading a different proper time is derived. From this conditional probability distribution, it is shown that when the center-of-mass of these clocks move in localized momentum wave packets they observe classical time dilation. We then illustrate a quantum correction to the time dilation observed by a clock moving in a superposition of localized momentum wave packets that has the potential to be observed in experiment. The Helstrom-Holevo lower bound is used to derive a proper time-energy/mass uncertainty relation.

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“…[29] and its connection with the relativistic time dilation for a freely falling particle has been pointed out in Ref. [30]. From Eq.…”

Section: Example: Gravitational Redshift In Atomic-fountain Clocksmentioning

confidence: 99%

Gravitational Redshift in Quantum-Clock Interferometry

Roura

2020

Phys. Rev. X

100

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The creation of delocalized coherent superpositions of quantum systems experiencing different relativistic effects is an important milestone in future research at the interface of gravity and quantum mechanics. This could be achieved by generating a superposition of quantum clocks that follow paths with different gravitational time dilation and investigating the consequences on the interference signal when they are eventually recombined. Light-pulse atom interferometry with elements employed in optical atomic clocks is a promising candidate for that purpose, but suffers from major challenges including its insensitivity to the gravitational redshift in a uniform field. All these difficulties can be overcome with a novel scheme presented here which is based on initializing the clock when the spatially separate superposition has already been generated and performing a doubly differential measurement where the differential phase shift between the two internal states is compared for different initialization times. This can be exploited to test the universality of the gravitational redshift (UGR) with delocalized coherent superpositions of quantum clocks and it is argued that its experimental implementation should be feasible with a new generation of 10-meter atomic fountains that will soon become available. Interestingly, the approach also offers significant advantages for more compact set-ups based on guided interferometry or hybrid configurations. Furthermore, in order to provide a solid foundation for the analysis of the various interferometry schemes and the effects that can be measured with them, a general formalism for a relativistic description of atom interferometry in curved spacetime is developed. It can deal with freely falling atoms, but also include the effects of external forces and guiding potentials, and can be applied to a very wide range of situations. As an important ingredient for quantum-clock interferometry, suitable diffraction mechanisms for atoms in internal-state superpositions are investigated too. Finally, the relation of the proposed doubly-differential measurement scheme to other experimental approaches and to tests of the universality of free fall (UFF) is discussed in detail. arXiv:1810.06744v1 [physics.atom-ph]

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Equivalence principle for quantum systems: dephasing and phase shift of free-falling particles

Cited by 52 publications

References 50 publications

Atomic stability and the quantum mass equivalence

Atomic stability and the quantum mass equivalence

Quantum clocks observe classical and quantum time dilation

Gravitational Redshift in Quantum-Clock Interferometry

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