2,746 research outputs found
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 , showing that the ensuing probability distribution is a
Tsallis distribution whose non-extensivity parameter is monotonically
related to . Moreover, for (corresponding to ), 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 parameter
on cosmological time is derived for the reheating epoch. The obtained
is consistent with values predicted by both string-theory models and the
naturalness principle. Further salient issues, including derivation of new
-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 . 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
, 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
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
- …