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We consider scalar Born-Infeld type theories with arbitrary potentials V(T) of a scalar field T. We find that for models with runaway potentials V(T) the generic inhomogeneous solutions after a short transient stage can be very well…

High Energy Physics - Theory · Physics 2009-11-07 Gary Felder , Lev Kofman , Alexei Starobinsky

It is shown that any spatially flat and isotropic universe undergoing accelerated expansion driven by a self-interacting scalar field can be directly related to a contracting, decelerating cosmology. The duality is made manifest by…

General Relativity and Quantum Cosmology · Physics 2009-11-10 James E. Lidsey

We construct a class of CFT's which describe space-dependent closed string tachyon backgrounds, as the IR limit of GLSM's in which the FI-parameter is promoted to a superfield. Whole process of tachyon condensation is described by a single…

High Energy Physics - Theory · Physics 2008-11-26 Takao Suyama

We extend the thermodynamic derivation of gravity in the Jacobson framework by generalizing the Clausius relation through a nontrivial entropy functional. We show that entropy deformations appear as modifications of the effective…

General Relativity and Quantum Cosmology · Physics 2026-04-14 H. R. Fazlollahi

Tachyonic scalar field-driven late universe with dust matter content is considered. The cosmic expansion is modeled with power-law and phantom power-law expansion at late time, i.e. $z \lesssim 0.45$. WMAP7 and its combined data are used to…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-11 Rachan Rangdee , Burin Gumjudpai

In this paper we study the tachyon cosmology in non-interacting and interacting cases in non-flat FRW universe. Then we reconstruct the potential and the dynamics of the tachyon field which describe tachyon cosmology.

General Relativity and Quantum Cosmology · Physics 2010-03-12 M R Setare , J Sadeghi , A R Amani

Guided by previous non-perturbative lattice simulations of a two-step electroweak phase transition, we reformulate the perturbative analysis of equilibrium thermodynamics for generic cosmological phase transitions in terms of effective…

High Energy Physics - Phenomenology · Physics 2023-09-06 Oliver Gould , Tuomas V. I. Tenkanen

A recently investigated tachyonic scalar field dark energy dominated universe exhibits a bivalent future: depending on initial parameters can run either into a de Sitter exponential expansion or into a traversable future soft singularity…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Zoltán Keresztes , László Á. Gergely

We study very generally to what extent the uncertainty with which a phase shift can be estimated in quantum metrology can be reduced by extending the Hamiltonian that generates the phase shift to an ancilla system with a Hilbert space of…

Quantum Physics · Physics 2016-10-20 Julien Mathieu Elias Fraïsse , Daniel Braun

We introduce the method and the implementation of a cosmological simulation of a class of metric-variation f(R) models that accelerate the cosmological expansion without a cosmological constant and evade solar-system bounds of small-field…

Astrophysics · Physics 2008-12-30 Hiroaki Oyaizu

We consider an Anti-de Sitter universe filled by quantum conformal matter with the contribution from the usual tachyon and a perfect fluid. The model represents the combination of a trace-anomaly annihilated and a tachyon driven Anti-de…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Emilio Elizalde , John Quiroga Hurtado

We use dynamical system methods to explore the general behaviour of $f(T)$ cosmology. In contrast to the standard applications of dynamical analysis, we present a way to transform the equations into a one-dimensional autonomous system,…

General Relativity and Quantum Cosmology · Physics 2018-03-14 A. Awad , W. El Hanafy , G. G. L. Nashed , Emmanuel N. Saridakis

We analyze deformations of two-dimensional conformal field theory (CFT) from the perspective of classical bosonic closed string field theory (SFT). The latter can be viewed as a version of Wilsonian renormalization group (RG) improved…

High Energy Physics - Theory · Physics 2024-05-21 Ben Mazel , Joshua Sandor , Charles Wang , Xi Yin

The statistical translation invariance of cosmological random fields is broken by a finite survey boundary, correlating the observable Fourier modes. Standard methods for generating Gaussian fields either neglect these correlations, or are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Julien Carron , Melody Wolk , Istvan Szapudi

In this work we analyze the effects produced by bosonic and fermionic constituents, including quantum corrections, in two-dimensional (2D) cosmological models. We focus on a gravitational theory related to the…

General Relativity and Quantum Cosmology · Physics 2009-08-07 L. L. Samojeden , G. M. Kremer , F. P. Devecchi

We develop the effective field theory (EFT) of perturbations in the context of scalar-tensor theories with a spacelike scalar profile on arbitrary black hole backgrounds. Our construction of the EFT is based on the fact that in the unitary…

General Relativity and Quantum Cosmology · Physics 2025-10-16 Shinji Mukohyama , Emeric Seraille , Kazufumi Takahashi , Vicharit Yingcharoenrat

We investigate a conformal invariant gravitational model which is taken to hold at pre-inflationary era. The conformal invariance allows to make a dynamical distinction between the two unit systems (or conformal frames) usually used in…

High Energy Physics - Theory · Physics 2009-11-10 Yousef Bisabr

In an inhomogeneous universe, an observer associated with a particular matter field does not necessarily measure the same cosmological evolution as an observer in a homogeneous and isotropic universe. Here we consider, in the context of a…

High Energy Physics - Theory · Physics 2015-06-12 Giovanni Marozzi , Gian Paolo Vacca , Robert H. Brandenberger

Intrinsic galaxy alignments yield an important contribution to the observed statistics of galaxy shapes. The general bias expansion for galaxy sizes and shapes in three dimensions has been recently described by Vlah, Chisari \& Schmidt…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-02 Zvonimir Vlah , Nora Elisa Chisari , Fabian Schmidt

The effective field theory (EFT) framework is a precise approximation procedure when the inherent assumptions of a large-scale separation between the Standard Model (SM) and new interactions alongside perturbativity are realised.…

High Energy Physics - Phenomenology · Physics 2024-03-22 Upalaparna Banerjee , Joydeep Chakrabortty , Christoph Englert , Wrishik Naskar , Shakeel Ur Rahaman , Michael Spannowsky