August 1, 2016
Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of ...
January 22, 2003
Calculations of the electron-phonon interaction in the alkali metals, Potassium and Rubidium, using the results of band theory and BCS theory-based techniques suggest that at high pressures K and Rb would be superconductors with transition temperatures approaching 10 K.
April 10, 2008
This paper has been withdrawn by the author, since now all four parts of the review are available as a single file 0804.1639. I also made some revision of the text in order to avoid misprints and some inaccurate expressions.
December 24, 2003
A comment on ``Metallization of Fluid Nitrogen and the Mott Transition in Highly Compressed Low-Z Fluids'' by Chau et al, Phys. Rev. Lett. 90, 245501 (2003).
February 11, 2016
The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures, which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the conditions in the cores of giant planets of the solar system such as Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all its electrons are collectivized. Perturbation theory in the electron and proton interaction is appli...
April 11, 2008
Bose-Einstein condensate of rarified atomic gases is considered as the state formed by exchange of virtual photons, resonant to the lowest levels of atoms; such representation corresponds to the Einstein opinion about an inter-influence of condensable particles. Considered interactions directly lead to the QED structure of nonlinear potential in the Gross-Pitaevskii equation. Linear momenta that correspond to the thermal energy of condensable atoms are connected to near field...
February 23, 2015
The aim of this introductory article is two-fold. First, we aim to offer a general introduction to the theme of Bose-Einstein condensates, and briefly discuss the evolution of a number of relevant research directions during the last two decades. Second, we introduce and present the articles that appear in this Special Volume of Romanian Reports in Physics celebrating the conclusion of the second decade since the experimental creation of Bose-Einstein condensation in ultracold...
December 16, 2004
We propose a simple approach for studying systems of compressed matter based on the Thomas-Fermi statistical model of single atom. The central point of our work is the development of the concept of ``statistical ionization'' by compression; in simple terms, we calculate the fraction of electrons within the atom whose positive energy, due to the compression, exceeds the negative binding energy electron-nucleus. Next we extend this concept from a single atom to macroscopic syst...
March 14, 2016
Ab-initio electron - liquid phase xenon fully differential cross-sections for electrons scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework [1] which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential cross-section is us...
August 16, 2024
In this study, we analyzed the pressure-volume ($P-V$) relationship of elements using the equation of state at an ambient temperature within the multi-megabar pressure range of 200-300 GPa. We investigated the compressibility of elements under ultra-high pressures based on their positions in the periodic table. For the elemental materials in this region, pressure ($P$) can be approximated as an $N$-order function of volume ($V$): $P$ $\propto$ $1/V^N$. By determining the $N$ ...