A5008341555- Cosmology and Gravitation Theories
- Noncommutative and Quantum Gravity Theories
- Black Holes and Theoretical Physics
- Quantum Electrodynamics and Casimir Effect
- Relativity and Gravitational Theory
- Quantum Mechanics and Applications
- Advanced Thermodynamics and Statistical Mechanics
- Pulsars and Gravitational Waves Research
- Experimental and Theoretical Physics Studies
- Geophysics and Gravity Measurements
- Advanced Differential Geometry Research
- Biofield Effects and Biophysics
- Geometric Analysis and Curvature Flows
- Computational Physics and Python Applications
- Earth Systems and Cosmic Evolution
- Particle physics theoretical and experimental studies
- History and Developments in Astronomy
- Galaxies: Formation, Evolution, Phenomena
- Advanced Mathematical Theories and Applications
- Astrophysical Phenomena and Observations
- Mechanical and Optical Resonators
- Mathematics and Applications
- High-Energy Particle Collisions Research
- Meromorphic and Entire Functions
- Statistical Mechanics and Entropy
University of Bergamo
2016-2025
Istituto Nazionale di Fisica Nucleare, Sezione di Milano
2014-2025
Walailak University
2023
Aix-Marseille Université
2016
Istituto Nazionale di Fisica Nucleare
1996-2014
University of Mons
1998-2002
University of Milan
1993
General Relativity and the $\Lambda$CDM framework are currently standard lore constitute concordance paradigm. Nevertheless, long-standing open theoretical issues, as well possible new observational ones arising from explosive development of cosmology last two decades, offer motivation lead a large amount research to be devoted in constructing various extensions modifications. All extended theories scenarios first examined under light consistency, then applied geometrical backgrounds, such...
Abstract Casimir energy is always indicated as a potential source to generate traversable wormhole. It also used prove the existence of negative which can be built in laboratory. However, scientific literature there no trace consequences on wormhole itself. In this work, we would like consider such see if and kind produced. further analysis, examine quantum weak conditions traversability We find agreement with original Nevertheless, despite result, one finds once again that only principle...
We investigate the connection between Gravity's Rainbow and Hořava–Lifshitz gravity, since both theories incorporate a modification in ultraviolet regime which improves their quantum behavior at cost of Lorentz invariance loss. In particular, extracting Wheeler–De Witt equations two case Friedmann–Lemaître–Robertson–Walker spherically symmetric geometries, we establish correspondence that bridges them.
In this work, we consider time-dependent dark-energy star models, with an evolving parameter $\ensuremath{\omega}$ crossing the phantom divide $\ensuremath{\omega}=\ensuremath{-}1$. Once in regime, null energy condition is violated, which physically implies that negative radial pressure exceeds density. Therefore, enormous center may, principle, imply a topology change, consequently opening up tunnel and converting into wormhole. The criteria for change are discussed and, particular, Casimir...
In this work, we find exact wormhole solutions in the context of noncommutative geometry, and further explore their physical properties characteristics. The energy density these geometries is a smeared particle-like gravitational source, where mass diffused throughout region linear dimension α due to intrinsic uncertainty encoded coordinate commutator. Furthermore, also analyze considering that equation governing quantum fluctuations behaves as backreaction equation. particular, graviton one...
We compute the Zero Point Energy in a spherically symmetric background distorted at high energy as predicted by \textit{Gravity's Rainbow}. In this context we setup Sturm-Liouville problem with cosmological constant considered associated eigenvalue. The eigenvalue equation is reformulation of Wheeler-DeWitt equation. With help canonical decomposition, find that relevant contribution to one loop given graviton quantum fluctuations around background. By means variational approach based on...
Based on the results obtained in our previous study gravity's rainbow, we determine quantum corrections to space-time metric for Schwarzschild and de Sitter background, respectively. We analyze how fluctuations alter these metrics, inducing modifications propagation of test particles. Significantly enough, find that can become relevant not only particles approaching Planck energy but, due one-loop contribution, even low-energy as far Planckian length scales are considered. briefly compare...
We compute the Zero Point Energy in a spherically symmetric background combining high energy distortion of Gravity's Rainbow with modification induced by f(R) theory. Here is generic analytic function Ricci curvature scalar R 4D and 3D. The explicit calculation performed for Schwarzschild metric. Due to property metric we can compare effects theory find that final effect combined have finite quantities shift Energy. In this context setup Sturm-Liouville problem cosmological constant...
In this paper, we study the cosmological constant emerging from Wheeler-DeWitt equation as an eigenvalue of related Sturm-Liouville problem. We employ Gaussian trial functionals and perform a mode decomposition to extract transverse-traceless component, namely, graviton contribution, at one loop. implement noncommutative-geometry--induced minimal length calculate number modes. As result, find regular fluctuation energies for Schwarzschild, de Sitter, anti-de Sitter backgrounds. No...
In this paper, we consider the Wheeler–DeWitt equation modified by a deformation of second quantized canonical commutation relations. Such relations are induced Generalized Uncertainty Principle. Since can be related to Sturm–Liouville problem where associated eigenvalue interpreted as cosmological constant, it is possible explicitly relate such an parameter corresponding equation. The analysis performed in Mini-Superspace approach scale factor appears only degree freedom. gives rise...
In this paper we continue the investigation about connection between Casimir energy and traversability of a wormhole. addition to negative density obtained by device, include effect an electromagnetic field generated electric charge. This combination defines electrovacuum source which has extra parameter related size throat. Even if is positive Null Energy Condition still violated. The main reason that satisfies property $\rho=-p_{r}$. As consequence Traversable Wormhole throat can be...
Inspired by holographic dark energy models, we explore various density profiles as potential sources for creating traversable wormholes. Because these densities are all positive, introduce an equation of state in the form pr(r)=ωr(r)ρ(r). We find that achieving Zero Tidal Forces requires ωr(r) to become infinite r approaches infinity. To solve this issue, appropriate modifications on function such a way obtain finite result everywhere. These do not affect behavior near wormhole's throat....
A possible candidate for the late time accelerated expanding universe is phantom energy, which possesses rather bizarre properties, such as prediction of a Big Rip singularity and violation null energy condition. The latter fundamental ingredient traversable wormholes, it has been shown that may indeed sustain these exotic geometries. Inspired by evolving dark parameter crossing divide, we consider in this work varying equation state dependent on radial coordinate, i.e., ω(r) = p(r)/ρ(r). We...
In the framework of ADM formalism, it is possible to find out eigenvalues WDW equation with meaning vacuum states, i.e. cosmological constants, for f(R) theories gravity, where a generic analytic function Ricci curvature scalar R. The explicit calculation performed Schwarzschild metric one-loop energy derived by zeta regularization method and renormalized running Λ0 constant obtained.
In this work, we consider the possibility that wormhole geometries are sustained by their own quantum fluctuations, in context of modified dispersion relations. More specifically, energy density graviton one-loop contribution to a classical background is considered as self-consistent source for wormholes. semiclassical context, specific choices rainbow's functions and find solutions cis-Planckian trans-Planckian regimes. former regime, spacetimes not asymptotically flat need be matched an...
We compute the Zero Point Energy (ZPE) induced by a naked singularity with help of reformulation Wheeler-DeWitt equation. A variational approach is used for calculation Gaussian Trial Wave Functionals. The one loop contribution graviton to ZPE extracted keeping under control UltraViolet divergences means distorted gravitational field. Two examples distortion are taken consideration: Gravity's Rainbow and Noncommutative Geometry. Surprisingly we find that no more singular when singularity.
In this work, we consider a Yukawa modification of the Casimir wormhole. With help an Equation State, impose Zero Tidal Forces. We will examine two different approaches: in first approach, fix form shape function wormholes modified by term three ways and finally superposition profiles. second original source deduce both approaches reference energy density be that source. Connection with Absurdly Benign Traversable Wormhole are also discussed.
Abstract In this paper, we have for the first time considered consequences of finite temperature contributions to a traversable wormhole. This was done by using generalization Casimir effect as source hot To include effects, plates positioned either parametrically fixed or radially varying. Such results been obtained in both high and low-temperature regimes. We explicitly investigate such corrections on size
Generalizing the result of H. Ellis who embedded a warp bubble in background black hole, we introduce de Sitter universe. We show that under certain conditions (namely, is moving radial direction at velocity equal to speed expansion universe), it possible for have strictly non--negative Eulerian energy density and satisfy averaged weak null (though they are violated locally). also prove more generic theorem if perturbations vacuum produce least some underdense regions all reference frames,...
In this work, we explore the possibility that quantum fluctuations induce an electric or magnetic charge both, in context of Gravity's Rainbow. A semi-classical approach is adopted, where graviton one-loop contribution to a classical energy background spacetime computed through variational with Gaussian trial wave functionals. The density contribution, context, acts as source for electric/magnetic charge. ultraviolet (UV) divergences, which arise analyzing procedure, are kept under control...
Abstract A Casimir wormhole is a traversable powered by energy source within static reference frame. natural extension of this system the inclusion rotation. We will explore two basic configurations: one with radially varying plates and another parametrically fixed plates. In both cases, we show that rotations do not alter structure wormhole, behavior observed in frame reaffirmed. Since case predicts constant angular velocity as solution, must introduce an exponential cutoff additional scale...
We study aspects of quantum cosmology in the presence modified space-time geometry. In particular, within context gravity's rainbow geometry, motivated from gravity corrections at Planck energy scale, we show that distortion metric leads to a Wheeler-DeWitt equation whose solution admits outgoing plane waves. Hence, period cosmological inflation may arise without need introducing an inflaton field.
A simple model of spacetime foam, made by N wormholes in a semiclassical approximation, is taken under examination. The Casimir-like energy the quantum fluctuation such and its probability being realized are computed. Implications on Bekenstein–Hawking entropy cosmological constant considered.