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We study preheating in the Palatini formalism with a quadratic inflaton potential and an added $\alpha R^2$ term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-29 Alexandros Karam , Eemeli Tomberg , Hardi Veermäe

A quantum statistical model of nuclear multifragmentation is proposed. The recurrence equation method used within the canonical ensemble makes the model solvable and transparent to physical assumptions and allows to get results without…

Nuclear Theory · Physics 2009-10-31 A. S. Parvan , V. D. Toneev , M. Ploszajczak

We study preheating in N-flation, assuming the Mar\v{c}enko-Pastur mass distribution, equal energy initial conditions at the beginning of inflation and equal axion-matter couplings, where matter is taken to be a single, massless bosonic…

Astrophysics · Physics 2008-11-26 Diana Battefeld , Shinsuke Kawai

We extend the formalism to calculate non-Gaussianity of primordial curvature perturbations produced by preheating in the presence of a light scalar field. The calculation is carried out in the separate universe approximation using the…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-31 Pulkit S. Ghoderao , Arttu Rajantie

Within an early Universe scenario, nonextensive thermostatistics (NET) is investigated on the basis of data concerning primordial Helium abundance. We obtain first order corrections to the energy densities and weak interactions rates, and…

Astrophysics · Physics 2009-10-30 Diego F. Torres , Héctor Vucetich , A. Plastino

The solution to large-scale power deficit in the cosmic microwave background fluctuations may be relevant with the physics in the preinflationry period, and significantly depends on whether the initial conditions are set as Bunch-Davies…

General Relativity and Quantum Cosmology · Physics 2019-03-15 Zucheng Li , Yanbin Deng , Yong-chang Huang

Long-range quantum systems, in which the interactions decay as $1/r^{\alpha}$, are of increasing interest due to the variety of experimental set-ups in which they naturally appear. Motivated by this, we study fundamental properties of…

Quantum Physics · Physics 2026-01-08 Jorge Sánchez-Segovia , Jan T. Schneider , Álvaro M. Alhambra

We derive the first systematic observational constraints on reheating in models of inflation where an additional light scalar field contributes to primordial density perturbations and affects the expansion history during reheating. This…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-19 Robert J. Hardwick , Vincent Vennin , Kazuya Koyama , David Wands

Early dark energy solutions to the Hubble tension introduce an additional scalar field which is frozen at early times but becomes dynamical around matter-radiation equality. In order to alleviate the tension, the scalar's share of the total…

High Energy Physics - Phenomenology · Physics 2025-04-01 Marc Kamionkowski , Anubhav Mathur

We present a macroscopic model of the decay of a coherent classical scalar field into statistical fluctuations through the process of parametric amplification. We solve the field theory (henceforth,"microscopic") model to leading order in a…

High Energy Physics - Phenomenology · Physics 2007-05-23 Esteban Calzetta , Marc Thibeault

Ultracold fermionic atoms in optical lattices offer pristine realizations of Hubbard models, which are fundamental to modern condensed matter physics. Despite significant advancements, the accessible temperatures in these optical lattice…

The microscopic quantum field theory origins of warm inflation dynamics are reviewed. The warm inflation scenario is first described along with its results, predictions and comparison with the standard cold inflation scenario. The basics of…

High Energy Physics - Phenomenology · Physics 2009-02-25 Arjun Berera , Ian G. Moss , Rudnei O. Ramos

We solve the mean-field-like $p$-spin Ising model under a spatio-temporal inhomogeneous transverse field to study the effects of inhomogeneity on the performance of quantum annealing. We find that the problematic first-order quantum phase…

Quantum Physics · Physics 2018-10-23 Yuki Susa , Yu Yamashiro , Masayuki Yamamoto , Itay Hen , Daniel A. Lidar , Hidetoshi Nishimori

The Variation After Projection approach is applied for the first time to the pairing hamiltonian to describe the thermodynamics of small systems with fixed particle number. The minimization of the free energy is made by a direct…

Nuclear Theory · Physics 2015-06-04 Danilo Gambacurta , Denis Lacroix

Analytic results are presented for preheating in both flat and open models of chaotic inflation, for the case of massless inflaton decay into further inflaton quanta. It is demonstrated that preheating in both these cases closely resembles…

High Energy Physics - Phenomenology · Physics 2009-10-30 David I. Kaiser

We compute the leading and next--to--leading corrections to the finite temperature scalar potential for a 3+1 dimensional $\phi^4$ theory using a systematic $1/N$ expansion. Our approach automatically avoids problems associated with…

High Energy Physics - Phenomenology · Physics 2009-10-22 Vidyut Jain

Motivated by the recent experiment on kagome-lattice antiferromagnets, we study the zero-field ordering behavior of the antiferromagnetic classical Heisenberg model on a uniaxially distorted kagome lattice by Monte Carlo simulations. A…

Statistical Mechanics · Physics 2012-08-27 Hiroshi Masuda , Tsuyoshi Okubo , Hikaru Kawamura

The behavior of several nuclear properties with temperature is analyzed within the framework of the Finite Temperature Hartree-Fock-Bogoliubov (FTHFB) theory with the Gogny force and large configuration spaces. Thermal shape fluctuations in…

Nuclear Theory · Physics 2014-11-18 V. Martin , J. L. Egido , L. M. Robledo

Cosmic inflation is arguably the most favoured paradigm of the very early Universe. It postulates an early phase of fast, nearly exponential, and accelerated expansion. Inflationary models are capable of explaining the overall flatness and…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-08 Cristian Joana

A quantum system at equilibrium is represented by a corresponding classical system, chosen to reproduce the thermodynamic and structural properties. The objective is to develop a means for exploiting strong coupling classical methods (e.g.,…

Statistical Mechanics · Physics 2015-05-30 James W. Dufty , Sandipan Dutta