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๐Ÿ” roberto navigli ๐Ÿ“‚ Physics
Showing 4131 results for "roberto navigli" in Physics
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Fractional Cosmic String Loops In Expanding Universe

Pankaj Chaturvedi, Bikram Nath ยท 2026

We study the dynamics of circular cosmic string loops in a spatially flat Friedmann Lema\^itre Robertson Walker universe within a fractional Polyakov framework that incorporates nonlocal memory effectโ€ฆ

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Integrability of Conformal Killing Vectors in the Eisenhart Lift of Scalar-Field FLRW Cosmology

Takeshi Chiba, Tsuyoshi Houri ยท 2026

We study the integrability conditions of the conformal Killing equations for the Eisenhart lift of a scalar field in a flat Friedmann-Lema\^\i tre-Robertson-Walker universe. We show that the potentialโ€ฆ

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Cosmological discrete self-similarity in primordial black hole formation

Luis E. Padilla, Tomohiro Harada, Ethan Milligan, David Mulryne ยท 2026

We demonstrate that discrete self-similarity (DSS), originally discovered in the collapse of a massless scalar field in an asymptotically flat system, survives in primordial black hole (PBH) formationโ€ฆ

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Thermodynamic behavior of cosmological models with fractional entropy

Miguel Cruz, Diego da Silva, Simon Gonzalez, Samuel Lepe, Joel Saavedra, Manuel Gonzalez-Espinoza ยท 2026

We investigate the thermodynamic and phenomenological implications of a cosmological model governed by fractional entropy applied to the apparent horizon of a flat Friedmann-Lema\^{i}tre-Robertson-Walโ€ฆ

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Viable Cosmological Solutions from Hybrid Potentials

Koralia Tzanni, John Miritzis ยท 2026

We study flat Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) models with a perfect fluid matter source and a scalar field minimally coupled to matter with power-law-exponential \textquotedblleft hybrโ€ฆ

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Cosmological dynamics and structure formation in a generalized mass-to-horizon entropy-inspired modified gravity

Subhra Mondal, Amitava Choudhuri ยท 2026

In this article, our goal is to investigate the cosmological dynamics and structure formation in a modified cosmological framework inspired by a generalized mass-to-horizon entropy relation and consisโ€ฆ

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Notes on some inequalities, resulting uncertainty relations and correlations. 1. General mathematical formalism

Krzysztof Urbanowski ยท 2026

We analyze the Schwarz inequality and its generalizations, as well as inequalities resulting from the Jensen inequality. They are used in quantum theory to derive the Heisenberg-Robertson (HR) and Schโ€ฆ

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Oppenheimer-Snyder Collapse in f(R) Gravity : Stalemate or Resolution?

Soumya Chakrabarti, Apratim Ganguly, Radouane Gannouji, Chiranjeeb Singha ยท 2026

We study the Oppenheimer--Snyder (OS) collapse problem in metric $f(R)$ gravity by matching a homogeneous dust Friedmann--Lema\^itre--Robertson--Walker (FLRW) interior to a generalized Vaidya exteriorโ€ฆ

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The Roberge-Weiss transition as a probe for conformality in many-flavor QCD

Massimo D'Elia, Marco Nacci, Kevin Zambello ยท 2026

We consider the problem of identifying the onset of the conformal window for QCD with $N_f$ massless flavors in the fundamental representation, and propose a new effective method to determine it from โ€ฆ

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Observational Tests for Distinguishing Classes of Cosmological Models

Asta Heinesen, Timothy Clifton ยท 2026

We investigate observational tests that can be used to distinguish between broad classes of cosmological models. This is achieved using curvature-consistency tests of the Friedmann-Lema\^{i}tre-Robertโ€ฆ

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Post-Inflationary Quenched Production of Axion SU(2) Dark Matter

Imtiaz Khan, Pirzada, G. Mustafa ยท 2026

The relic abundance of vector dark matter originating from an inherited axion-$SU(2)$ condensate is typically determined by implementing an adiabatic matching procedure across the symmetry-breaking trโ€ฆ

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A Survey through Conformal Time

Tahereh Aeenehvand, Ahmad Shariati ยท 2026

We revisit conformal time $\eta$ in a spatially flat Friedmann--Robertson--Walker universe and use a $1+1$-dimensional setting as a technically transparent pedagogical arena. Our purpose is to clarifyโ€ฆ

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Diagnostic Consistency Tests of the Concordance Cosmology

S. M. Koksbang, A. Heinesen ยท 2026

The $\Lambda$CDM cosmological model faces increasingly significant and robust tensions among independent cosmological probes, prompting renewed scrutiny of its foundational assumptions. While General โ€ฆ

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Persistence and Transition Varieties in Scalar Field Cosmology

Spiros Cotsakis ยท 2026

We develop a bifurcation-theoretic description of Friedmann--Robertson--Walker cosmologies with a scalar field $\phi$, a barotropic fluid of index $\gamma$, and spatial curvature. For the strict exponโ€ฆ

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Friedmann cosmology with fluids and hyperfluids

Ilaria Andrei, Damianos Iosifidis, Laur Jarv, Margus Saal ยท 2026

We discuss flat Friedmann-Lemaitre-Robertson-Walker (FLRW) metric-affine cosmology where the metric and connection as well as the matter energy-momentum and hypermomentum all obey the symmetry of spatโ€ฆ

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Nonlinear Lattice Framework for Inflation: Bridging stochastic inflation and the $\delta{N}$ formalism

Pankaj Saha, Yuichiro Tada, Yuko Urakawa ยท 2026

Understanding when inflationary perturbations become genuinely nonlinear near the horizon crossing requires methods that go beyond both linear perturbation theory and the gradient expansion. In this wโ€ฆ

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Big bang stability and isotropisation for the Einstein-scalar field equations in the ekpyrotic regime

Florian Beyer, David Garfinkle, James Isenberg, Todd A. Oliynyk ยท 2026

It has been shown that, in spacetime dimensions $n\geq 3$, that the Kasner-scalar field solutions to the Einstein-scalar fields equations with potential $V_0 e^{-s \phi}$, where $s<s_c=\sqrt{\frac{8(nโ€ฆ

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Sterile Neutrinos as a Dynamical Cosmological Fluid: Implications for the Expansion History and Matter-Radiation Equality

Poulastya Kar, Bipin Singh Koranga ยท 2026

Sterile neutrinos arise naturally in extensions of the Standard Model and can affect cosmological evolution even with subdominant abundance. Their impact is often described by a constant shift in the โ€ฆ

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A Graphical Coaction for FRW Wavefunction Coefficients

Andrew McLeod, Andrzej Pokraka, Lecheng Ren ยท 2026

We show that the wavefunction of the universe in theories of conformally coupled scalars in power-law Friedmann-Robertson-Walker (FRW) cosmologies satisfies a graphical coaction, by means of which we โ€ฆ

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A Slit Mask Integral Field Unit for the Robert Stobie Spectrograph on the Southern African Large Telescope: I. Instrument Development

Sabyasachi Chattopadhyay, Matthew A. Bershady, Michael P. Smith, Antoine Mahoro, Marsha J. Wolf ยท 2026

Integral field spectroscopy (IFS) has been added as a new observation mode to the Robert Stobie Spectrograph (RSS), the workhorse multi-mode instrument on the Southern African Large Telescope. RSS opeโ€ฆ

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