相关论文: The Question Whether an Energy Gap Does Exist in H…
Energy gap, the difference between the energy of the ground state of a given Hamiltonian and the energy of its first excited state, is a parameter of a critical importance in analysis of phase transitions and adiabatic quantum computation.…
Possibility for coexistence of a phonon and one-particle spectra in ${}^4He$ at all temperatures including temperatures below the $\lambda$ - point is shown. An approach developed to consider the problem of the weakly imperfect Bose gas…
It is shown that atoms in the system can be treated as quantum particles localized in potential wells, created by atomic potentials of neighboring atoms. As a result, the state of atoms in the liquid is characterized by wave functions and…
There is presently disagreement between theory and experiment as well as between different theoretical calculations concerning the fine-structure splitting of the lowest P state of the neutral helium atom. We believe that we have found a…
The differential cross section for scattering of the astrophysically important X-ray emission lines by a helium atom is calculated with an accuracy sufficient for astrophysical applications. For a helium atom an energy ``gap'' (due to the…
We report an experimental investigation of the electric response of superfluid helium. Our results confirm the presence of electric potential that appears at the relative oscillatory motion of normal fluid and superfluid components in…
Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable…
Correlation theory of hydrodynamic fluctuations of a liquid helium II inside a spherical volume is developed.
Equilibrium properties of hydrogen-helium mixtures under conditions similar to the interior of giant gas planets are studied by means of first principle density functional molecular dynamics simulations. We investigate the molecular and…
The $m \alpha^6$ correction to energy is expressed in terms of an effective Hamiltonian $H^{(6)}$ for an arbitrary state of helium. Numerical calculations are performed for $n=2$ levels, and the previous result for the $2^3P$ centroid is…
Adiabatic quantum computation, based on the adiabatic theorem, is a promising alternative to conventional quantum computation. The validity of an adiabatic algorithm depends on the existence of a nonzero energy gap between the ground and…
A macroscopic quantum state that is characterized by an energy gap in the electronic spectrum and occurs in organic structural components of the cell is hypothesized to provide a basis for the phenomenon of life. The width of the band gap…
I present a brief review on the determination of the primordial helium abundance by unit mass, Yp. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c)…
Recent advances on the quest to determine the primordial or pregalactic helium abundance, Yp, are reviewed. There are seven problems affecting the He/H abundance determinations of H II regions that are briefly discussed: the underlying…
An experimental proposal to test the existence of a liquid-liquid critical point in water, based on high pressure calorimetric measurements, is presented on this paper. Considering the existence of an intramolecular correlation in the water…
The different point defects formed by two hydrogen atoms or two helium atoms in tungsten were investigated through first-principles calculation. The energetically favorable site for a hydrogen atom is tetrahedral interstitial site while…
Helium is the second most common chemical species in the Universe. The study of helium abundance has the potential to unravel the chemical evolution of and within galaxies. In this study, we provide an empirical calibration for the singly…
The potential energy problem in an electrostatically bound two-body system is studied in the framework of a recently proposed impact model of the electrostatic force and in analogy to the potential energy in a gravitationally bound system.…
We propose a possible microscopic explanation of the exhaustion of \rho_s of helium-II on the wall at T>T_{c} = 0.5 - 1 K and predict a possibility of the existence in He-II of the "dry" friction at T < T_{c}. Both of the effects connect…
In this paper we study two electrons on a line on the same side of the nucleus which interact with each other by their mean value. We prove that there exists a unique periodic orbit and examine for which charges the two orbits of the…