We discuss in some detail the requirements on an early-Universe model that solves the horizon and flatness problems during the epoch of classical cosmology (t ≥ ti ≫ 10 sec). We show that a dynamical resolution of the horizon problem requires superluminal expansion (or very close to it) and that a truly satisfactory resolution of the flatness problem requires entropy production. This implies th...

We study the functional dependence of the spin-weighted angular moments of the two-point correlation function of the three dimensional cosmic shear on the expansion history of the universe. We first express the redshift dependent total equation of state parameter in terms of the growing mode of the gauge invariant metric perturbation in the conformal-Newtonian gauge for the case of adiabatic pe...

The normal state of the Holstein model is studied at half-filling in infinite dimensions and in the adiabatic regime. The dynamical mean-field equations are solved using perturbation expansions around the extremal paths of the effective action for the atoms. We find that the Migdal-Eliashberg expansion breaks down in the metallic state if the electron-phonon coupling λ exceeds a value of about ...

Abstract We propose a novel method to describe realistically ionization processes with absorbing boundary conditions in basis expansion within the formalism of the so-called Non-Adiabatic Quantum Molecular Dynamics. This theory couples self-consistently a classical description of the nuclei with a quantum mechanical treatment of the electrons in atomic many-body systems. In this paper we extend...

Here we survey the theory and applications of a family of methods (correlated electron-ion dynamics, or CEID) that can be applied to a diverse range of problems involving the non-adiabatic exchange of energy between electrons and nuclei. The simplest method, which is a paradigm for the others, is Ehrenfest Dynamics. This is applied to radiation damage in metals and the evolution of excited stat...

The intersystem crossing rate for the transition between the lowest excited singlet and triplet electronic states of uracil was studied by means of ab initio methods. The rate was evaluated using the time-dependent approach based on the correlation function and its two approximations: the second-order cumulant expansion and the short-time approximation. The normal modes of the singlet and tripl...

We present a linear-response approach for time-dependent density-functional theories using time-adiabatic functionals. The resulting theory can be performed both in the time and in the frequency domain. The derivation considers an impulsive perturbation after which the Kohn-Sham orbitals develop in time autonomously. The equation describing the evolution is not strictly linear in the wave funct...

Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a model in which the transition from decelerated to accelerated expansion of the Universe arises as a pure interaction phenomenon. Various cosmological scenar...

Abstract In this paper, it’s studied that the characteristics and causes of adiabatic shear band produced by expansion deformation barrel muzzle during firing shells. The results show failure property launching process belongs to plastic distortion failure, in is caused abnormal contact collision between its internal components. It easy promote generation band, when material strength (hardness)...

It is shown that non-adiabatic cosmological perturbations cannot appear during the period of reheating following inflation with a single scalar inflaton field. Electronic address: [email protected] According to a widely adopted picture [1], the perturbations to the Robertson– Walker cosmology arose from the quantum fluctuations in a slowly rolling scalar “inflaton” field during a peri...