Casimir effect in quadratic theories of gravity

Buoninfante, Luca; Lambiase, Gaetano; Stabile, An.

doi:10.1140/epjc/s10052-019-6574-1

Cited by 43 publications

(39 citation statements)

References 91 publications

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“…From Eqs. (56,57) it is clear that nonlocality in IDT becomes important only when the interaction is switched on, while at the level of free theory it does not play any role and the only solutions are given by the local ones [82], i.e. φ = 0.…”

Section: Comparison With Infinite Derivative Field Theory (Idt)mentioning

confidence: 99%

“…for energies beyond the scale of nonlocality, p 2 > M 2 s . Infinite derivative Lagrangians were also studied in the context of thermal field theory [50][51][52], inflationary cosmology [53], supersymmetry [54,55] and applied to the study of the Casimir effect in curved background [56]. Recently, it has also been pointed out that in presence of multi particle interactions, such as mutiparticle scattering, the nonlocal scale can be transmuted from the UV to the IR depending on the number of particles involved in the scattering process.…”

Section: Introductionmentioning

confidence: 99%

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Nonlocal generalization of Galilean theories and gravity

2019

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In this paper we propose a wider class of symmetries including the Galilean shift symmetry as a subclass. We will show how to construct ghost-free nonlocal actions, consisting of infinite derivative operators, which are invariant under such symmetries, but whose functional form is not simply given by exponentials of entire functions. Motivated by this, we will consider the case of a scalar field and discuss the pole structure of the propagator which has infinitely many complex conjugate poles, but satisfies the tree-level unitarity. We will also consider the possibility to construct UV complete Galilean theories by showing how the ultraviolet behavior of loop integrals can be ameliorated. Moreover, we will consider kinetic operators respecting the same symmetries in the context of linearized gravity. In such a scenario, the graviton propagator turns out to be ghost-free and the spacetime metric generated by a point-like source is nonsingular. These new nonlocal models can be seen as an infinite derivative generalization of Lee-Wick theories and open a new branch of nonlocal theories.

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Section: Comparison With Infinite Derivative Field Theory (Idt)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nonlocal generalization of Galilean theories and gravity

2019

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“…Computations of scattering amplitudes were performed in [48][49][50], while a detailed study of spontaneous breaking of symmetry with nonlocal interactions in [51,52]. Applications also appeared in the context of astrophysical compact objects [53,54], cosmological inflation [55], thermal field theory [56][57][58][59], supersymmetry [60,61], Hawking radiation [62], Galilean theories [63], quantum mechanics [64][65][66][67], curved Casimir effect [68] and neutrino oscillations [69].…”

Section: Introductionmentioning

confidence: 99%

Generalized ghost-free propagators in nonlocal field theories

et al. 2020

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In this paper we present an iterative method to generate an infinite class of new nonlocal field theories whose propagators are ghost-free. We first examine the scalar field case and show that the pole structure of such generalized propagators possesses the standard two derivative pole and in addition can contain complex conjugate poles which, however, do not spoil at least tree level unitarity as the optical theorem is still satisfied. Subsequently, we define analogous propagators for the fermionic sector which is also devoid of unhealthy degrees of freedom. As a third case, we apply the same construction to gravity and define a new set of theories whose graviton propagators around the Minkowski background are ghost-free. Such a wider class also includes nonlocal theories previously studied, and Einstein's general relativity as a peculiar limit. Moreover, we compute the linearized gravitational potential generated by a static point-like source for several gravitational theories belonging to this new class and show that the nonlocal nature of gravity regularizes the singularity at the origin.

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“…This phenomenon can still be associated to a quantum field with arbitrary spin describing baryonic or even exotic matter [31]. The progressive increment in the precision of the Casimir effect measurements show that they tend to be a relevant source of tests for both high energy physics and modified theories of gravity [32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Casimir effect in an axially symmetric spacetime with unparticles

2019

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We investigate the Casimir effect of the massless scalar field in a cavity formed by ideal parallel plates in the spacetime generated by a rotating axially symmetric distribution of vector or scalar (tensor) unparticles, around which the plates orbit. The presence of the unparticles is incorporated to the background by means of a correction to the Kerr solution of the Einstein equations, in which the characteristic length and the scale dimension associated to the unparticle theory are taken into account. We show that the Casimir energy density depends also on these parameters. The analysis of the "ungravity" limit for the Casimir energy density, in which the characteristic length is very large in comparison to the horizon radius, is made, too. At zero temperature, we show that such a limit implies the instability of the system, since the Casimir energy density becomes an imaginary quantity. The general result is compared to the current terrestrial experiments of the Casimir effect. Thermal corrections also are investigated and the ungravity limit again examined, with the aforementioned instability disappearing at high temperatures.

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Casimir effect in quadratic theories of gravity

Cited by 43 publications

References 91 publications

Nonlocal generalization of Galilean theories and gravity

Nonlocal generalization of Galilean theories and gravity

Generalized ghost-free propagators in nonlocal field theories

Casimir effect in an axially symmetric spacetime with unparticles

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