arXiv subjects

Giuseppe Gaetano Luciano

Publications and source records attributed to Giuseppe Gaetano Luciano.

At least 19 recordsLinked to original sources

arXiv2026

Entropy applications in cosmology: spacetime thermodynamics, holographic dark energy, entropic gravity and beyond - a review

Entropy has emerged as a key concept at the intersection of gravity, quantum theory, and cosmology, revealing deep connections between geometry, information, and thermodynamics. The realization that black holes are thermodynamic systems, characterized by an entropy proportional to their horizon area, has provided evidence that spacetime itself may possess a microscopic structure. Since then, entropy has acquired a central role across quantum field theory, holography, quantum gravity, and cosmology. In this review, we present a unified account of entropy in gravitational and cosmological contexts. We first survey entropy in gravitational systems, focusing on black-hole thermodynamics, entropy bounds, the holographic principle, entanglement entropy, and the area law, together with the main corrections and generalizations arising from quantum field theory, generalized uncertainty principles, modified statistics, and extended theories of gravity. We then discuss three conceptually distinct ways in which entropy is employed in cosmology. The first is through the spacetime-thermodynamics conjecture, in which gravitational dynamics emerge from thermodynamic relations applied to cosmological horizons, and generalized entropy forms consequently lead to modified cosmological evolution. The second is the holographic approach, in which entropy bounds constrain the vacuum energy of the Universe, giving rise to the holographic dark energy scenario and its various extensions. The third is entropic gravity, where gravity is interpreted as an emergent phenomenon of entropic origin, leading to interesting cosmological phenomenology. By reviewing the theoretical foundations and cosmological implications of these entropic frameworks, we aim to clarify the role of entropy, discuss open issues and outline directions toward a deeper thermodynamic and informational understanding of gravity and cosmology.

astro-ph.CO↗

arXiv2026

Cosmological consequences of scale-dependent Barrow-Tsallis entropy

We investigate an extended cosmological scenario based on the Barrow-Tsallis entropy, incorporating a varying (i.e., energy-scale-dependent) anomalous dimension. This behavior is reminiscent of quantum gravity and effective field theory settings, where the relevant couplings acquire a nontrivial scale dependence. By applying the gravity-thermodynamic conjecture on the apparent horizon of a flat Friedmann-Robertson-Walker Universe, we derive the corresponding modified cosmological equations. The standard dynamics is recovered as a limiting case when the Barrow-Tsallis entropy reduces to the conventional Bekenstein-Hawking form. The proposed model is tested against a combination of early- and late-time datasets, including observational Hubble parameter measurements, the Pantheon+ catalog of Type~Ia supernovae, the second data release of DESI baryon acoustic oscillations and cosmic microwave background constraints. Using the Bayesian Information Criterion, we finally compare the fitting performance of our framework with that of the $Λ$CDM paradigm. While the latter remains mildly favored, our model is shown to be fully compatible with current observations within suitable regions of the parameter space, unveiling a richer phenomenology that points towards a possible alleviation of the Hubble tension.

gr-qc↗

arXiv2026

Observational constraints on Luciano-Saridakis holographic dark energy

Holographic dark energy (HDE) models provide a natural framework for linking gravitational thermodynamics to the late-time accelerated expansion of the Universe. In this work, we investigate the observational viability of an extended HDE scenario arising from a recently proposed generalized entropy. For bounded systems, this entropy exhibits a generalized holographic scaling with two independent area contributions, giving rise to a modified HDE density that encompasses both standard HDE and $Λ$CDM as limiting cases. Focusing on the Hubble-horizon infrared cutoff, we constrain the model using Cosmic Chronometers, the Pantheon$^+$+SH0ES Type Ia supernova compilation, DESI DR2 baryon acoustic oscillations, and compressed Planck 2018 CMB shift parameters. We find that the model provides an excellent fit to the combined dataset and admits regions of parameter space in which the Pantheon$^+$+SH0ES and CMB constraints can be simultaneously accommodated. The preferred solutions lie close to the $Λ$CDM regime, although non-standard entropic contributions remain compatible with current observations. We further compare the complete realization of the model, containing both independent area contributions, with its reduced single-contribution limit, finding that both provide essentially equivalent descriptions of the data, with a mild preference for the latter. Our results establish generalized entropic HDE as a viable and theoretically motivated extension of the standard cosmological scenario and provide the first observational assessment of this cosmological framework.

physics.gen-ph↗

arXiv2026

Thermodynamic formulation of Cotton gravity in the Codazzi parametrization

We develop a thermodynamic formulation of Cotton gravity in the Codazzi parametrization, providing a general framework in which the gravitational dynamics can be interpreted in terms of horizon thermodynamics. As paradigmatic examples, we apply the formalism to FriedmannRobertson-Walker (FRW) and static spherically symmetric spacetimes. By implementing the first law of thermodynamics on the apparent cosmological and event horizons, we derive a modified holographic entropy consisting of the standard Bekenstein-Hawking term supplemented by a correction induced by the Codazzi tensor. In the cosmological setting, this correction is governed by the temporal component of the Codazzi tensor, while in static configurations it is controlled by its anisotropic sector. Remarkably, the sign of this contribution provides a potential diagnostic of the underlying matter content, allowing one to distinguish between ordinary matter, a cosmological constant and phantom-like components. These results establish horizon thermodynamics as a sensitive probe of Cotton gravity, offering a complementary perspective beyond background kinematics and enabling a characterization of the statistical and thermodynamic properties of spacetime within the Codazzi formulation.

gr-qc↗

arXiv2026

Coherent states in minimal-length Quantum Mechanics: inequivalent characterizations and emergent squeezing

Several approaches to quantum gravity suggest the emergence of a fundamental minimal length at the Planck scale. In quantum mechanics, this feature is naturally encoded through deformations of the Heisenberg algebra, leading to the Generalized Uncertainty Principle (GUP). While the phenomenological implications of GUP have been extensively explored, a consistent characterization of coherent states in minimal-length quantum mechanics remains elusive. In this work, we present a systematic analysis of coherent states for the one-dimensional harmonic oscillator. We show that the canonical equivalence among their standard characterizations - as eigenstates of the annihilation operator, displaced vacuum states and minimum-uncertainty wave packets - is generically lost in the presence of a minimal length. We then investigate the dynamical and semiclassical consequences of this inequivalence by comparing the evolution of generalized coherent states with that of states saturating the GUP. In particular, we demonstrate that minimal-length effects induce nontrivial deformations of phase-space trajectories and give rise to an intrinsic squeezing mechanism with no counterpart in ordinary quantum mechanics. These results establish a unified framework for coherence in GUP-based quantum theories and identify distinctive semiclassical signatures of minimal-length physics, opening a new avenue for probing quantum-gravitational effects.

quant-ph↗

arXiv2026

From information bounds to infrared gravity: implications of Sharma-Mittal entropy

The Sharma--Mittal (SM) entropy provides a two-parameter generalization encompassing both the Rényi and Tsallis statistical frameworks. In this work, we investigate its thermodynamic and gravitational implications in the context of black hole physics and emergent gravity. Specifically, we examine the compatibility of the gravitational realization of the SM entropy with the Bekenstein bound and show that the corresponding framework consistently interpolates between the Rényi and Bekenstein--Hawking entropies in the appropriate limits. By incorporating Landauer's principle into black hole thermodynamics, we obtain a modified mass-loss relation associated with one-bit information erasure, exhibiting nontrivial parameter-dependent asymptotic behavior in both the small- and large-mass regimes. Furthermore, within Verlinde's entropic gravity framework, we derive modified gravitational force and acceleration laws induced by the SM entropy. We show that the resulting acceleration deviates from the Newtonian prediction at large distances and naturally reproduces a MOND-like regime for the specific parameter relation $R/δ= 3/2$. This condition establishes a direct connection between the SM entropy parameters and the MOND acceleration scale $a_0$. Our findings highlight the potential of the SM framework to provide a unified link between black hole thermodynamics, information theory, and infrared modifications of gravity, while offering new insights into phenomena traditionally attributed to the dark matter paradigm.

gr-qc↗

arXiv2026

Constraints on Kaniadakis Cosmology from Starobinsky Inflation and Primordial Tensor Perturbations

We investigate a generalized entropic cosmology obtained by applying the gravity-thermodynamics conjecture to the Universe horizon using Kaniadakis statistics, namely a relativistic extension of the standard Boltzmann--Gibbs formalism. The resulting deformation of the horizon entropy naturally modifies the Friedmann dynamics and provides a phenomenologically consistent extension of the $Λ$CDM paradigm. Within this framework, we explore the implications of the modified cosmological dynamics for the physics of the early Universe, focusing in particular on primordial gravitational waves (PGWs) and slow-roll inflation in a Starobinsky-like scenario. We show that the generalized entropic corrections simultaneously affect the evolution of tensor perturbations and the inflationary slow-roll dynamics, inducing characteristic deviations in the PGW spectrum as well as nontrivial corrections to the main inflationary observables. By confronting the theoretical predictions with the latest Planck and BICEP/Keck observations, we derive stringent constraints on the Kaniadakis parameter and assess the observational viability of the model. Our results establish a direct connection between generalized horizon thermodynamics and inflationary cosmology, showing that quantum-statistical modifications of the entropy-area law can propagate into potentially observable signatures in the physics of the early Universe.

gr-qc↗

arXiv2026

Observational constraints on Luciano-Saridakis entropic cosmology

A recently proposed generalized entropy by Luciano and Saridakis extends the standard Boltzmann-Gibbs and Bekenstein-Hawking framework through a microscopically motivated construction involving two independent entropic exponents. When applied within the gravity-thermodynamics correspondence, this entropy leads to a modified cosmological dynamics that can be interpreted as an effective dark energy sector of entropic origin, while recovering $Λ$CDM in appropriate limits. In this work, we perform the first observational confrontation of the resulting entropic cosmology at the background level. Focusing on the case $α_δ=0$, we constrain the model using Cosmic Chronometers, Pantheon$^+$ Type Ia supernovae calibrated with SH0ES, BAO measurements from DESI DR2 and compressed Planck 2018 CMB information. We find that the model yields a statistically robust fit to the combined data sets and can simultaneously satisfy Pantheon$^+$, SH0ES and CMB shift-parameter constraints, unlike $Λ$CDM. Although the entropic parameters remain close to their standard values, the $Λ$CDM limit is excluded at the $2σ$ level within the restricted parameter space considered. These results indicate that the Luciano-Saridakis entropic cosmology offers a viable extension of the standard model with the potential to alleviate the Hubble tension at the background level.

astro-ph.CO↗

arXiv2026

From minimal-length quantum theory to modified gravity

In this work, we consider generalized uncertainty principles (GUPs) that incorporate a minimal length through generic momentum-dependent deformation functions. We thus develop a systematic approach connecting such a framework to effective gravitational actions extending general relativity. By examining quantum gravity-motivated corrections to black hole entropy induced by the GUP and employing Wald's formalism, we reconstruct modifications to Einstein's gravity within the contexts of $f(R)$ and $f(R, R_{μν} R^{μν})$ theories. In this way, we establish a direct mapping between the GUP parameters and the higher-order curvature coefficients in the gravitational Lagrangian. As an illustrative application, we compute corrections to the general relativistic prediction for light deflection, which in turn allows us to infer a stringent upper bound on the minimal measurable length. Our results show that GUP-induced effects can be consistently embedded into extended gravity theories, offering a promising framework for testing quantum gravity phenomenology through astrophysical and cosmological observations.

gr-qc↗

arXiv2026

$κ$-entropic statistical paradigm for relativistic corrections to the Heisenberg principle

The Heisenberg position-momentum uncertainty relation is a cornerstone of quantum mechanics. However, its standard formulation is not fully consistent with special relativity. While partial understanding has been achieved in the ultra-relativistic regime, a comprehensive description is still lacking, particularly in the intermediate velocity domain, where particle speeds remain well below the speed of light yet relativistic corrections are expected to become appreciable. This regime constitutes the most promising arena for experimentally probing relativistic modifications of quantum uncertainty. By adopting a variational approach, in this work we derive a relativistic extension of the Heisenberg algebra within the framework of $κ$-deformed Kaniadakis statistics. The latter emerges from the application of the Maximum Entropy Principle to Kaniadakis entropy, a one-parameter generalization of the Boltzmann-Gibbs-Shannon entropy naturally induced by Lorentz transformations. We investigate the physical implications of the resulting uncertainty relation, deriving constraints on the Kaniadakis parameter from precision measurements of the fine-structure constant and confronting our construction with other extensions discussed in the recent literature.

quant-ph↗

arXiv2026

Testing gravitational wave polarizations with LISA

In this paper we quantify the ability of the Laser Interferometer Space Antenna (LISA) to test the presence of non-tensorial polarizations as well as modifications to the tensor ones in gravitational waves emitted from massive black hole binaries. We employ the Parametrized Post-Einsteinian (PPE) formalism to model deviations from General Relativity (GR) for tensor, vector, and scalar polarizations. Our PPE parametrization is inspired by post-Newtonian waveforms from four modified gravity theories: Horndeski, Einstein-aether, Rosen's bimetric, and Lightman-Lee. We consistently implement these modifications across the inspiral, merger, and ringdown phases, ensuring proper waveform alignment and tapering. Subsequently, we perform Fisher forecasts to derive expected constraints on deviations from General Relativity and map these constraints to the parameter spaces of the four gravity theories. For tensor polarizations, LISA achieves constraints on amplitude modifications ranging between $\sim 10^{-4}-10^{-2}$ precision level, depending on the frequency evolution of the modifications, for systems with $10^5-10^7 {\, \rm M}_\odot$ at $z = 1$. We find that LISA can distinguish breathing and longitudinal scalar polarizations only for relatively light binaries with $M \lesssim 10^4 {\, \rm M}_\odot$, beyond which these modes become degenerate in the detector response. Importantly, constraints on vector polarizations are approximately 2-3 times more precise than for scalar polarizations. For both vector and scalar modes, amplitude measurements reach precisions ranging between $\sim 10^{-8}-10^{-2}$, depending on the frequency evolution of the modifications, for systems with $10^5-10^7 {\, \rm M}_\odot$ at $z = 1$. These results demonstrate LISA's potential to probe gravity in the strong-field regime via gravitational wave polarizations.

astro-ph.CO↗

arXiv2026

Statistical physics on Euclidean Snyder space: connections with the GUP and cosmological implications

We develop a systematic formulation of statistical mechanics on Euclidean Snyder space, where noncommutativity is geometrically encoded in the curvature of momentum space. Adopting a realization independent approach based on momentum-space invariants, we derive modified partition functions and thermodynamic quantities for systems obeying Maxwell-Boltzmann, Bose-Einstein and Fermi-Dirac statistics in both non-relativistic and ultrarelativistic regimes. We show that momentum-space curvature induces temperature-dependent corrections that suppress the energy, entropy and energy density with respect to their standard counterparts. We apply these results to early-Universe cosmology, deriving the corresponding corrections to the Friedmann equations driven by the modified energy density of radiation. Using Big Bang Nucleosynthesis as a precision probe, we derive bounds on the Snyder deformation parameter and, via a phenomenological mapping, on the Generalized Uncerainty Principle (GUP) parameter, providing one of the most stringent cosmological and astrophysical constraints currently available. Our analysis demonstrates that high-energy cosmological processes provide a predictive arena for testing momentum-space curvature and noncommutative geometry effects.

physics.gen-ph↗

arXiv2025

Challenging $Λ$CDM with Higher-Order GUP Corrections

We study quantum corrections to the $Λ$CDM model model arising from a minimum measurable length in Heisenberg's uncertainty principle. We focus on a higher-order Generalized Uncertainty Principle, beyond the quadratic form. This generalized GUP introduces two free parameters, and we determine the modified Friedmann equation. This framework leads to a perturbative cosmological model that naturally reduces to $Λ$CDM in an appropriate limiting case of the deformation parameters. We construct the modified cosmological scenario, analyze its deviations from the standard case, and examine it as a mechanism for the description of dynamical dark energy. To constrain the model, we employ Cosmic Chronometers, the latest Baryon Acoustic Oscillations from the DESI DR2 release, and Supernova data from the PantheonPlus and Union3 catalogues. Our analysis indicates that the modified GUP model is statistically competitive with the $Λ$CDM scenario, providing comparable or even improved fits to some of the combined datasets. Moreover, the data constrain the deformation parameter of the GUP model, with the preferred value found to be negative, which corresponds to a phantom regime in the effective dynamical dark energy description.

gr-qc↗

arXiv2025

Baryogenesis constraints on generalized mass-to-horizon entropy

We investigate the generation of the baryon asymmetry within the cosmological framework based on a generalized mass-to-horizon entropy. This entropy, recently proposed as a power-law extension of the Bekenstein-Hawking area law, arises from a modified mass-horizon relation constructed to ensure consistency with the Clausius relation. By applying the gravity-thermodynamics conjecture, the resulting corrections to the Friedmann equations modify the evolution of the Hubble parameter. Consequently, even the standard supergravity coupling between the Ricci scalar and the baryon current can generate a non-vanishing matter-antimatter asymmetry. Comparison with observational data yields a stringent constraint on the entropic exponent, namely $0 < 1 - n \lesssim \mathcal{O}(10^{-2})$, at the decoupling temperature $T_D \simeq 10^{16}\,\text{GeV}$, corresponding to the current upper limit on tensor-mode fluctuations at the inflationary scale. These findings indicate that minor, subtle, yet physically significant departures, from the standard Bekenstein-Hawking entropy ($n = 1$) may be required to achieve full consistency with present cosmological observations.

gr-qc↗

arXiv2025

Modified cosmology through generalized mass-to-horizon entropy: implications for structure growth and primordial gravitational waves

In the framework of entropic cosmology, entropic forces arising at the cosmological horizon have been proposed as an alternative mechanism to explain the Universe's current accelerated phase. However, recent studies have shown that, under the Clausius relation and assuming a linear mass-to-horizon (MHR) relation, all entropic force models reduce to the original Bekenstein-Hawking formulation, regardless of the specific form of the horizon entropy. As a result, they inherit the same observational limitations in accounting for cosmic dynamics. To address this issue, a generalized MHR has been introduced, providing the foundation for a modified cosmological scenario rooted in the gravity-thermodynamics conjecture. In this work, we explore the implications of this generalized framework for early-Universe dynamics. Specifically, we analyze the growth of matter perturbations within the spherical Top-Hat formalism in the linear regime, showing that the density contrast profile is significantly influenced by the modified background dynamics predicted by the model. Moreover, considering the sensitivity of upcoming gravitational wave detectors in the sub-$10^3\,\mathrm{Hz}$ range, we examine the impact on the relic abundance of Primordial Gravitational Waves (PGWs), identifying parameter regions where deviations from standard cosmology may arise through an enhanced PGW spectrum.

gr-qc↗

arXiv2025

Late-Time Cosmological Constraints on Kaniadakis Holographic Dark Energy

Kaniadakis Holographic Dark Energy is a one-parameter extension of the standard HDE framework, in which the horizon entropy is reformulated using Kaniadakis entropy. At the cosmological level, it has been shown to give rise to modified Friedmann equations, leading to a richer phenomenology compared to $Λ$CDM. In this work we test the Kanadiakis holography model against multiple late-time observational probes, including Type Ia supernovae from PantheonPlus and Union3, Cosmic Chronometer measurements of the Hubble parameter and Baryon Acoustic Oscillation from the Dark Energy Spectroscopic Instrument Data Release 2 (DESI DR2). Using a Bayesian inference approach with MCMC methods, we constrain the cosmological parameters of the model and evaluate its performance against $Λ$CDM through the Akaike Information Criterion. We find that Kaniadakis holography can provide a better fit for some data combinations, although $Λ$CDM remains slightly statistically favored overall. These results highlight Kaniadakis holography as a competitive alternative to the standard cosmological model, offering valuable insights into the role of generalized entropy in dark energy dynamics.

astro-ph.CO↗

arXiv2025

Barrow and Tsallis entropies after the DESI DR2 BAO data

Modified cosmology based on Barrow entropy arises from the gravity-thermodynamics conjecture, in which the standard Bekenstein-Hawking entropy is replaced by the Barrow entropy of quantum-gravitational origin, characterized by the Barrow parameter $Δ$. Interestingly, this framework exhibits similarities with cosmology based on Tsallis $δ$-entropy, which, although rooted in a non-extensive generalization of Boltzmann-Gibbs statistics, features the same power-law deformation of the holographic scaling present in the Barrow case. We use observational data from Supernova Type Ia (SNIa), Cosmic Chronometers (CC), and Baryonic acoustic oscillations (BAO), including the recently released DESI DR2 data, in order to extract constraints on such scenarios. As we show, the best-fit value for the Barrow exponent $Δ$ is found to be negative, while the zero value, which corresponds to $Λ$CDM paradigm, is allowed only in the range of $2σ$ for three out of four datasets. Additionally, for the case of the SN$_{0}$+OHD+BAO dataset, for the current Hubble function we obtain a value of $H_0= 72.2_{-0.9}^{+0.9}$, which may potentially alleviate the $H_0$ tension. Moreover, we compare our results with the Gaussian Process reconstruction of the dark-energy equation of state for the DESI + Cosmic Microwave Background (CMB) + Union3 datasets. Finally, by applying information criteria such as the Akaike Information Criterion and the Bayes evidence, we compare the fitting efficiency of the scenario at hand with $Λ$CDM cosmology, showing that the latter is slightly favoured.

gr-qc↗

arXiv2025

Modified cosmology through generalized mass-to-horizon entropy: observational constraints from DESI DR2 BAO data

A generalized mass-to-horizon entropy has recently been proposed as an extension of the Bekenstein-Hawking area law, derived from a modified mass-horizon relation constructed to ensure consistency with the Clausius equation. Within the gravity-thermodynamics conjecture, this entropy formulation yields modified Friedmann equations, which recover the standard $Λ$CDM cosmology in the appropriate limit of the model's two free parameters. In the present study, we constrain this framework using observations from TypeIa supernovae (SNIa), cosmic chronometers (CC) and baryon acoustic oscillations (BAO, including DESI~DR2), together with the SH0ES distance-ladder prior on $H_0$, across four combinations of data sets. Although the extended entropic scenario yields a slightly better, or statistically comparable, fit to the data, model selection via the Akaike Information Criterion (AIC) mildly favors the cosmological constant as the dark energy candidate. Moreover, the $Λ$CDM limit lies within $\sim 1σ$ of our constraints, indicating no significant deviation from standard cosmology with current data.

gr-qc↗