Coherent states for generalized uncertainty relations as Tsallis probability amplitudes: new route to non-extensive thermostatistics

We study coherent states associated to a generalized uncertainty principle (GUP). We separately analyze the cases of positive and negative deformation parameter $\beta$, showing that the ensuing probability distribution is a Tsallis distribution whose non-extensivity parameter $q$ is monotonically related to $\beta$. Moreover, for $\beta <0$ (corresponding to $q<1$), we reformulate the GUP in terms of a one-parameter class of Tsallis entropy-power based uncertainty relations, which are again saturated by the GUP coherent states. We argue that this combination of coherent states with Tsallis entropy offers a natural conceptual framework allowing to study quasi-classical regime of GUP in terms of non-extensive thermodynamics. We substantiate our claim by discussing generalization of Verlinde's entropic force and ensuing implications in the late-inflation epoch. Corresponding dependence of the $\beta$ parameter on cosmological time is derived for the reheating epoch. The obtained $\beta$ is consistent with values predicted by both string-theory models and the naturalness principle. Further salient issues, including derivation of new $\beta$-dependent expressions for the lowest possible value of the spin and Immirzi parameter in Loop Quantum Gravity, and connection of our proposal with the Magueijo--Smolin doubly special relativity are also discussed. This article provides a more extended and comprehensive treatment of our recent letter [Phys. Rev. D 105, L121501 (2022)].Comment: 25 pages, 4 figures, accepted to Physical Review

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.Comment: 8 pages. V2: minor changes, results unchanged, version accepted for publication in EPJ

Decoherence limit of quantum systems obeying generalized uncertainty principle: New paradigm for Tsallis thermostatistics

The generalized uncertainty principle (GUP) is a phenomenological model whose purpose is to account for a minimal length scale (e.g., Planck scale or characteristic inverse-mass scale in effective quantum description) in quantum systems. In this paper, we study possible observational effects of GUP systems in their decoherence domain. We first derive coherent states associated to GUP and unveil that in the momentum representation they coincide with Tsallis probability amplitudes, whose nonextensivity parameter q monotonically increases with the GUP deformation parameter β. Second, for β<0 (i.e., q<1), we show that, due to Bekner-Babenko inequality, the GUP is fully equivalent to information-theoretic uncertainty relations based on Tsallis-entropy-power. Finally, we invoke the maximal entropy principle known from estimation theory to reveal connection between the quasiclassical (decoherence) limit of GUP-related quantum theory and nonextensive thermostatistics of Tsallis. This might provide an exciting paradigm in a range of fields from quantum theory to analog gravity. For instance, in some quantum gravity theories, such as conformal gravity, aforementioned quasiclassical regime has relevant observational consequences. We discuss some of the implications

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

From the emergence of cosmic space to horizon thermodynamics in Barrow entropy-based Cosmology

Padmanabhan’s paradigm states that the spatial expansion of our Universe can be understood as the consequence of the emergence of space with the progress of cosmic time. Based on this argument, here we extract the first Friedmann equation for a curved (n + 1)-dimensional Friedmann-Robertson-Walker Universe and analyze the consistency of Padmanabhan’s proposal with horizon entropy maximization in the framework of Barrow entropy. The latter is a one-parameter deformation of Bekenstein-Hawking entropy induced by quantum-gravitational effects. We show that the viability of Padmanabhan’s paradigm and its relationship with horizon thermodynamics are well supported in Barrow model, providing preliminary indications on how the emergent gravity perspective should appear in a quantum gravity-like scenario.The author acknowledges the Spanish “Ministerio de Universidades” for the awarded Maria Zambrano fellowship and funding received from the European Union - NextGenerationEU. He is also grateful for participation in the COST Association Action CA18108 “Quantum Gravity Phenomenology in the Multimessenger Approach” and LISA Cosmology Working grou

Slow-roll inflation and growth of perturbations in Kaniadakis Cosmology

Kaniadakis entropy is a one-parameter deformation of the classical Boltzmann-Gibbs-Shannon entropy, arising from a self-consistent relativistic statistical theory. Assuming a Kaniadakis-type generalization of the entropy associated with the apparent horizon of Friedmann-Robertson-Walker (FRW) Universe and using the gravity-thermodynamics conjecture, a new cosmological scenario is obtained based on the modified Friedmann equations. By employing such modified equations, we analyze the slow-roll inflation, driven by a scalar field with power-law potential, at the early stages of the Universe. We explore the phenomenological consistency of this model by computation of the scalar spectral index and tensor-to-scalar ratio. Comparison with the latest Planck data allows us to constrain Kaniadakis parameter to $\kappa\lesssim\mathcal{O}(10^{-13}\div10^{-12})$, which is discussed in relation to other observational bounds in the past literature. We also disclose the effects of Kaniadakis correction term on the growth of perturbations at the early stages of the Universe by employing the spherically symmetric collapse formalism in the linear regime of density perturbations. We find out that the profile of density contrast is non-trivially affected in this scenario. Interestingly enough, we observe that increasing Kaniadakis parameter $\kappa$ corresponds to a faster growth of perturbations in a Universe governed by the corrected Friedmann equations.Comment: 10 pages, 3 labeled figures, 1 Tabl

Is arrhythmogenic right ventricular cardiomyopathy a paediatric problem too?

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disease that is often familial, characterized by arrhythmias of right ventricular origin, due to transmural fatty or fibrofatty replacement of atrophic myocardium. ARVC is usually diagnosed in the clinical setting between 20 and 40 years of age. The disease is seldom recognised in infancy or under the age of 10, probably because the clinical expression of the disease is normally postponed to youth and adulthood. This review focuses its attention to the pediatric age, defined as the period of life raging from birth to 18 years. During this span of life, ARVC is not so rare as previously supposed and can be identified by applying the same diagnostic criteria proposed for the adult. Ventricular arrhythmias range from isolated ventricular arrhythmias to sustained ventricular tachycardia and fibrillation. Children and adolescents with ARVC must be carefully evaluated and followed-up especially when a family positive history is present, taking into account the high probability during this life-period that asymptomatic affected patients become symptomatic or that arrhythmias worsen during follow-up. The recent identification of the first defective gene opens new avenues for the early identification of affected subjects even when asymptomatic.peer-reviewe