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We investigate the evolution of localized initial value profiles when propagated in integrable versions of higher time-derivative theories. In contrast to the standard cases in nonlinear integrable systems, where these profiles evolve into…

Exactly Solvable and Integrable Systems · Physics 2024-10-01 Andreas Fring , Takano Taira , Bethan Turner

We study the phenomenon of bounces, as predicted by Belinski, Khalatnikov and Lifshitz (BKL) in the study of singularities arising from Einstein's equations, as an instability mechanism within the setting of the (inhomogeneous)…

General Relativity and Quantum Cosmology · Physics 2024-08-23 Warren Li

We construct quantum field theory in an analogue curved spacetime in Bose-Einstein condensates based on the Bogoliubov-de Gennes equations, by exactly relating quantum particles in curved spacetime with Bogoliubov quasiparticle excitations…

Other Condensed Matter · Physics 2010-11-02 Yasunari Kurita , Michikazu Kobayashi , Takao Morinari , Makoto Tsubota , Hideki Ishihara

Our formalism described recently in (Dolby et al, hep-th/0103228) is applied to the study of particle creation in spatially uniform electric fields, concentrating on the cases of a time-invariant electric field and a so-called `adiabatic'…

High Energy Physics - Theory · Physics 2015-06-26 Carl E. Dolby , Stephen F. Gull

We derive the effective equations for the out of equilibrium time evolution of the order parameter and the fluctuations of a scalar field theory in spatially flat FRW cosmologies. After setting the problem in general we propose a…

High Energy Physics - Phenomenology · Physics 2007-05-23 H. J. de Vega

We study the classical dynamics of the universe undergoing a transition from contraction to expansion through a big bang singularity. The dynamics is described by a system of differential equations for a set of physical quantities, such as…

General Relativity and Quantum Cosmology · Physics 2015-04-14 BingKan Xue , Edward Belbruno

We present a field-theoretical method to obtain consistently the equations of motion for small amplitude condensate perturbations in a homogeneous Bose-condensed gas directly in real time. It is based on linear response, and combines the…

Condensed Matter · Physics 2009-11-07 D. Boyanovsky , S. -Y. Wang , D. -S. Lee , H. -L. Yu , S. M. Alamoudi

A non-perturbative canonical quantization of Gowdy $T^3$ polarized models carried out recently is considered. This approach profits from the equivalence between the symmetry reduced model and 2+1 gravity coupled to a massless real scalar…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Alejandro Corichi , Jeronimo Cortez , Hernando Quevedo

The field theoretic wavefunction in cosmological spacetimes has received much attention as a fundamental object underlying the generation of primordial perturbations in our universe. Assuming an initial Bunch-Davies state, unitary time…

High Energy Physics - Theory · Physics 2025-01-09 Diptimoy Ghosh , Enrico Pajer , Farman Ullah

Relativistic quantum field theories for complex scalar and Dirac fields are investigated in non-equilibrium thermo field dynamics. The thermal vacuum is defined by the Bogoliubov transformed creation and annihilation operators. Two…

High Energy Physics - Theory · Physics 2015-06-03 Yuichi Mizutani , Tomohiro Inagaki

The real-time broadening of density profiles starting from non-equilibrium states is at the center of transport in condensed-matter systems and dynamics in ultracold atomic gases. Initial profiles close to equilibrium are expected to evolve…

Strongly Correlated Electrons · Physics 2017-02-01 R. Steinigeweg , F. Jin , D. Schmidtke , H. De Raedt , K. Michielsen , J. Gemmer

The particle distribution in a Bose condensate under the trapping potential and its time evolution after switching off the trapping potential suddenly are calculated. We investigate the problem from the viewpoint of quantum field…

Condensed Matter · Physics 2007-05-23 Koichi Nakamura , Yoshiya Yamanaka

We analyze the convergence of a perturbed circular interface for the two-phase Mullins-Sekerka evolution in flat two-dimensional space. Our method is based on the gradient flow structure of the evolution and captures two distinct regimes of…

Analysis of PDEs · Mathematics 2025-07-29 Saša Lukić

To take initial correlations into account, a method, based on the time-independent projection operator technique, that allows converting the conventional linear inhomogeneous (containing a source caused by initial correlations)…

Statistical Mechanics · Physics 2015-12-15 Victor F. Los

Relativistic hydrodynamics provides a solid framework for evolving matter and energy in a wide variety of phenomena. Nevertheless, the inclusion of dissipative effects in realistic scenarios through causal, stable, and well-posed theories…

General Relativity and Quantum Cosmology · Physics 2025-09-10 Delfina Fantini , Marcelo E. Rubio

A time dependent variational approach is considered to derive the equations of movement for the $\lambda \phi^4$ model. The temporal evolution of the model is performed numerically in the frame of the Gaussian approximation in a lattice of…

High Energy Physics - Phenomenology · Physics 2009-11-07 Fabio L. Braghin

We study how to set the initial evolution of general cosmological fluctuations at second order, after neutrino decoupling. We compute approximate initial solutions for the transfer functions of all the relevant cosmological variables…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-22 Pedro Carrilho , Karim A. Malik

In this paper, we consider the initial value problem for the Einstein-Vlasov-Scalar field equations in temporal gauge, where the initial data are prescribed on two characteristic smooth intersecting hypersurfaces. From a suitable choice of…

Mathematical Physics · Physics 2016-08-04 Marcel Dossa , Jean Baptiste Patenou

We study the detailed out of equilibrium time evolution of a homogeneous Bose-Einstein condensate.We consider a nonrelativistic quantum theory for a self-interacting complex scalar field, immersed in a thermal bath, as an effective…

Soft Condensed Matter · Physics 2009-10-31 Daniel G. Barci , E. S. Fraga , Rudnei O. Ramos

We study the evolution of bubble spacetimes in vacuum and electrovac scenarios by numerical means. We find strong evidence against the formation of naked singularities in (i) scenarios with negative masses displaying initially collapsing…

High Energy Physics - Theory · Physics 2009-11-10 Olivier Sarbach , Luis Lehner