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Giuseppe Gaetano Luciano

Publications and source records attributed to Giuseppe Gaetano Luciano.

71 records · Page 4Linked to original sources
arXiv2020

Phenomenology of GUP stars

We study quantum corrections at the horizon scale of a black hole induced by a Generalized Uncertainty Principle (GUP) with a quadratic term in the momentum. The interplay between quantum mechanics and gravity manifests itself into a non-zero uncertainty in the location of the black hole radius, which turns out to be larger than the usual Schwarzschild radius. We interpret such an effect as a correction which makes the horizon disappear, as it happens in other models of quantum black holes already considered in literature. We name this kind of horizonless compact objects $GUP stars$. We also investigate some phenomenological aspects in the astrophysical context of binary systems and gravitational wave emission by discussing Love numbers, quasi-normal modes and echoes, and studying their behavior as functions of the GUP deformation parameter. Finally, we preliminarily explore the possibility to constrain such a parameter with future astrophysical experiments.

gr-qc↗
arXiv2020

Testing gravity with neutrinos: from classical to quantum regime

In this manuscript, we survey the main characteristics that provide neutrinos with the capability of being the perfect candidate to test gravity. A number of potentially resourceful scenarios is analyzed, with particular emphasis on how the versatility of neutrinos lends itself to understand the multifaceted nature of the gravitational interaction, both at classical and quantum scales. As a common thread running through the two different regimes, we consider the fundamental principles underpinning General Relativity and its possible quantum extensions. Finally, we discuss some open problems and future perspectives.

gr-qc↗
arXiv2020

On the beta-decay of the accelerated proton and neutrino oscillations: a three-flavor description with CP violation

The (inverse) beta-decay of uniformly accelerated protons (p -> n + e+ + ne) has been recently analyzed in the context of two-flavor neutrino mixing and oscillations. It has been shown that the decay rates as measured by an inertial and comoving observer are in agreement, provided that: i) the thermal nature of the accelerated vacuum (Unruh effect) is taken into account; ii) the asymptotic behavior of neutrinos is described through flavor (rather than mass) eigenstates; iii) the Unruh radiation is made up of oscillating neutrinos. Here we extend the above considerations to a more realistic scenario including three generations of Dirac neutrinos. By following the outlined recipe, we find that the equality between the two rates still holds true, confirming that mixing is perfectly consistent with the General Covariance of Quantum Field Theory. Notably, we prove that the analysis of CP violation in neutrino oscillations provides a further solid argument for flavor states as fundamental representation of asymptotic neutrino states. Our approach is finally discussed in comparison with the other treatments appeared in literature.

hep-ph↗
arXiv2020

Neutrino oscillations in extended theories of gravity

We study neutrino oscillations within the framework of extended theories of gravity. Based on the covariant reformulation of Pontecorvo formalism, we evaluate the oscillation probability of neutrinos propagating in static spacetimes described by gravitational actions quadratic in the curvature invariants. Calculations are carried out in the two-flavor approximation, for oscillations both in vacuum and matter. It is shown that the neutrino phase is sensitive to the violation of the strong equivalence principle. By way of illustration, we specialize our analysis to various extended models of gravity in order both to quantify such a violation and to understand how the characteristic free parameters of these models affect the neutrino phase. The possibility to fix new bounds on these parameters and to constrain extended theories of gravity is finally discussed.

gr-qc↗
arXiv2019

Heuristic derivation of Casimir effect in minimal length theories

We propose a heuristic derivation of Casimir effect in the context of minimal length theories based on a Generalized Uncertainty Principle (GUP). By considering a GUP with only a quadratic term in the momentum, we compute corrections to the standard formula of Casimir energy for the parallel-plate geometry, the sphere and the cylindrical shell. For the first configuration, we show that our result is consistent with the one obtained via more rigorous calculations in Quantum Field Theory. Experimental developments are finally discussed.

hep-th↗
arXiv2019

Non-thermal aspects of Unruh effect

The search for a relation among GR, QFT and TFT is the toughest challenge of theoretical physics since Hawking's discovery. The emergence of a temperature in spacetimes with an event horizon has unveiled the existence of a fertile territory, where gravity, thermal and quantum effects are non-trivially connected. Although black holes are the best arena to explore this interplay, evidences for their existence are lacking, suggesting to address less exotic contexts. In this sense, a promising stage is the QFT in curved space: specifically, the Unruh effect (UE) provides the first step toward unifying the quantum and gravity worlds via the EP. Waiting for a successful theory of quantum gravity, a careful investigation of UE, and, in particular, of any deviations of Unruh spectrum from its thermal behavior, may thus offer a window to new physics in the limbo between GR and QFT. Here we study the connection between geometric features of spacetime and ensuing thermal quantum phenomena from a non-traditional perspective, based on the analysis of perturbative effects that affect the standard scenarios. As a test bench, we consider the UE. After a discussion on the origin of UE, we examine to what extent its distinctive profile is spoilt i) for mixed neutrinos; ii) in presence of a minimal length arising from gravity at Planck scale. On one side, we show that the UE loses its thermality. Implications of this are analyzed in the context of the inverse beta-decay, also in view of the debate on a possible violation of the General Covariance of QFT. On the other, we focus on the effects induced by deformations of HUP, exploring the possibility to constrain the GUP-parameter via UE. The question is addressed of whether these unrelated frameworks have common roots. Along this line, we provide a unifying perspective of these effects, which still relies on a geometric interpretation of their origin.

hep-th↗
arXiv2019

AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space

We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. This paper is based on a submission (v1) in response to the Call for White Papers for the Voyage 2050 long-term plan in the ESA Science Programme. ESA limited the number of White Paper authors to 30. However, in this version (v2) we have welcomed as supporting authors participants in the Workshop on Atomic Experiments for Dark Matter and Gravity Exploration held at CERN: ({\tt https://indico.cern.ch/event/830432/}), as well as other interested scientists, and have incorporated additional material.

gr-qc↗
arXiv2019

Time-energy uncertainty relation for neutrino oscillations in curved spacetime

We derive the Mandelstam-Tamm time-energy uncertainty relation for neutrino oscillations in a generic stationary curved spacetime. In particular, by resorting to Stodolsky covariant formula of the quantum mechanical phase, we estimate gravity effects on the neutrino energy uncertainty. Deviations from the standard Minkowski result are explicitly evaluated in Schwarzschild, Lense-Thirring and Rindler (uniformly accelerated) geometries. Finally, we discuss how spacetime could affect the characteristic neutrino oscillation length in connection with the recent view of flavor neutrinos as unstable particles.

hep-th↗
arXiv2019

Neutrino oscillations in the Unruh radiation

The study of the decay of an accelerated proton recently provided a theoretical proof of the Unruh effect. On the basis of general covariance of Quantum Field Theory, indeed, it was found that the decay rates in the inertial and comoving frames do coincide only when the thermal nature of the accelerated vacuum is taken into account. Such an analysis was then extended to the case with neutrino mixing. In this Letter, we show that, by further embedding neutrino oscillations in the above framework, general covariance necessarily entails the use of flavor neutrinos as asymptotic states, as well as the occurrence of neutrino oscillations in the Unruh thermal bath.

hep-th↗
arXiv2019

Generalized Uncertainty Principle and Corpuscular Gravity

We show that the implications of the generalized uncertainty principle (GUP) in the black hole physics are consistent with the predictions of the corpuscular theory of gravity, in which a black hole is conceived as a Bose-Einstein condensate of weakly interacting gravitons stuck at the critical point of a quantum phase transition. In particular, we prove that the GUP-induced shift of the Hawking temperature can be reinterpreted in terms of non-thermal corrections to the spectrum of the black hole radiation, in accordance with the corpuscular gravity picture. By comparing the two scenarios, we are able to estimate the GUP deformation parameter $β$, which turns out to be of the order of unity, in agreement with the expectations of some models of string theory. We also comment on the sign of $β$, exploring the possibility of having a negative deformation parameter when a corpuscular quantum description of the gravitational interaction is assumed to be valid.

gr-qc↗
arXiv2019

GUP parameter from Maximal Acceleration

We exhibit a theoretical calculation of the parameter βappearing in the generalized uncertainty principle (GUP) with only a quadratic term in the momentum. A specific numerical value is obtained by comparing the GUP-deformed Unruh temperature with the one predicted within the framework of Caianiello's theory of maximal acceleration. The physical meaning of this result is discussed in connection with constraints on βpreviously fixed via both theoretical and experimental approaches.

hep-th↗
arXiv2018

Neutrino oscillations in accelerated frames

We discuss neutrino oscillations in vacuum from the point of view of a uniformly accelerated observer. A covariant definition of quantum phase is introduced with the aim of generalizing the standard expression of the oscillation amplitude to the accelerating frame. By way of illustration, we address a simplified two-flavor model with relativistic neutrinos, showing that inertial effects on the usual Pontecorvo formula are intimately related to the energy redshift. Phenomenological aspects are preliminarily analyzed in the context of atmospheric neutrinos. Finally, we discuss a gedanken experiment in order to investigate our formalism in regime of extreme acceleration.

hep-ph↗
arXiv2018

Casimir effect for mixed fields

We analyze the Casimir effect for a flavor doublet of mixed scalar fields con- fined inside a one-dimensional finite region. In the framework of the unitary inequivalence between mass and flavor representations in quantum field theory, we employ two alternative approaches to derive the Casimir force: in the first case, the zero-point energy is evaluated for the vacuum of fields with definite mass, then similar calculations are performed for the vacuum of fields with defi- nite flavor. We find that signatures of mixing only appear in the latter context, showing the result to be independent of the mixing parameters in the former.

hep-th↗
arXiv2018

Unified formalism for Thermal Quantum Field Theories: a geometric viewpoint

In this paper we study a unified formalism for Thermal Quantum Field Theories, i.e., for the Matsubara approach, Thermo Field Dynamics and the Path Ordered Method. To do so, we employ a mechanism akin to the Hawking effect which explores a relationship between the concept of temperature and spacetimes endowed with event-horizons. In particular, we consider an eight dimensional static spacetime, the so-called eta-xi spacetime, which we show to form an appropriate geometric background for generic Thermal Quantum Field Theories. Within this framework, the different formalisms of Thermal Field Theory are unified in a very natural way via various analytical continuations and the set of time-paths used in the Path Ordered Method is interpreted in geometric terms. We also explain reported inconsistencies inherent in the Thermo Field Dynamics through the appearance of horizons (and ensuing loss of information) in the eta-xi spacetime.

hep-th↗
arXiv2018

Role of neutrino mixing in accelerated proton decay

The inverse beta decay of accelerated protons has been analyzed both in the laboratory frame (where the proton is accelerated) and in the comoving frame (where the proton is at rest and interacts with the Fulling-Davies-Unruh thermal bath of electrons and neutrinos). The equality between the two rates has been exhibited as an evidence of the necessity of Fulling-Davies-Unruh effect for the consistency of Quantum Field Theory formalism. Recently, it has been argued that neutrino mixing can spoil such a result, potentially opening new scenarios in neutrino physics. In the present paper, we analyze in detail this problem and we find that, assuming flavor neutrinos to be fundamental and working within a certain approximation, the agreement can be restored.

hep-ph↗
arXiv2017

Non-thermal signature of the Unruh effect in field mixing

Mixing transformations for a uniformly accelerated observer (Rindler observer) are analyzed within the quantum field theory framework as a basis for investigating gravitational effects on flavor oscillations. In particular, the case of two charged boson fields with different masses is discussed. In spite of such a minimal setting, the standard Unruh radiation is found to loose its characteristic thermal interpretation due to the interplay between the Bogolubov transformation hiding in field mixing and the one arising from the Rindler spacetime structure. The modified spectrum detected by the Rindler observer is explicitly calculated in the limit of small mass difference.

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