Related papers: He-4 spectrum shift caused by He-3 admixture
The lambda point in liquid He4 is a well established phenomenon acknowledged as an example of Bose-Einstain condensation. This is generally accepted, but there are serious discrepancies between the theory and experimental results, namely…
We investigate the behavior of the collective excitations of adsorbed $^4$He in an ordered hexagonal mesopore, examining the crossover from a thin film to a confined fluid. Here we present the inelastic scattering results as a function of…
We compute the the Bogoliubov-de-Gennes excitation spectrum in a trapped two-component spin-orbit-coupled (SOC) Bose-Einstein condensate (BEC) in quasi-two-dimensions as a function of linear and angular momentum and analyse them. The…
We propose a new theoretical approach to the excitation spectrum of superfluid ${^4}He$. It is based on the assumption that, in addition to the usual Feynman density fluctuations, there exist localized modes which describe the short range…
We consider the dynamics of a large quantum system of $N$ identical bosons in 3D interacting via a two-body potential of the form $N^{3\beta-1} w(N^\beta(x-y))$. For fixed $0\leq \beta <1/3$ and large $N$, we obtain a norm approximation to…
The vibrational frequency of hydrogen molecules has been observed to increase strongly with He concentration in helium hydrogen fluid mixtures. This has been associated with He-H interactions, either directly through chemical bonding, or…
We present a dynamical study of $e^+e^-$ and $\mu^+ \mu^-$ production in proton-nucleus and nucleus-nucleus collisions at CERN-SPS energies on the basis of the covariant transport approach HSD employing a momentum-dependent $\rho$-meson…
We formulate the time-dependent Bogoliubov dynamics of colliding Bose-Einstein condensates in terms of a positive-P representation of the Bogoliubov field. We obtain stochastic evolution equations for the field which converge to the full…
We investigate the low energy excitation spectrum of a Bose gas with weak, long range repulsive interactions. In particular, we prove that the Bogoliubov spectrum of elementary excitations with linear dispersion relation for small momentum…
Bogoliubov Theory provides important predictions for the low energy properties of the weakly interacting Bose gas. Recently, Bogoliubov's predictions could be justified rigorously in \cite{BBCS3} for translation invariant systems in the…
We investigate the collective excitations of Bose atoms in the condensate phase with finite-range interactions, modeled using the P\"oschl-Teller (PT) potential to explicitly account for the finite interaction range. Utilizing Bogoliubov…
We investigate the low-energy excitation spectrum of a Bose gas confined in a trap, with weak long-range repulsive interactions. In particular, we prove that the spectrum can be described in terms of the eigenvalues of an effective…
Rotational absorption spectra of acetylene in superfluid $^4$He are calculated using a combined correlated basis function-diffusion Monte Carlo method (CBF/DMC) as well as a numerically exact path integral correlation function approach…
The recent experimental observation of step-like structure in the superfluid density of $^{4}$He films on graphite is interpreted in terms of passage close to Mott insulating lobes in the Bose--Hubbard model. Plateaus develop in the…
We present a detailed study of the low-lying collective excitations of a spherically trapped Bose-Fermi mixture at finite temperature in the collisionless regime. The excitation frequencies of the condensate are calculated self-consistently…
An interacting boson model Hamiltonian determined from Hartree-Fock-Bogoliubov calculations with the new microscopic Gogny energy density functional D1M, is applied to the spectroscopic analysis of neutron-rich Yb, Hf, W, Os and Pt isotopes…
Single-particle spectral properties near the Mott transition in the one-dimensional Hubbard model are investigated by using the dynamical density-matrix renormalization group method and the Bethe ansatz. The pseudogap, hole-pocket behavior,…
Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean field calculations with the Gogny energy…
Recently, the monopole transition form factor of the electron-scattering excitation of the 0^+_2 state (E_x=20.21 MeV) of the 4He nucleus was observed over a broad momentum transfer range (0.5 < q^2 < 5.0 fm^-2) with dramatically improved…
We analyze the Bogoliubov spectrum of the 3-sites Bose-Hubbard model with finite number of Bose particles by using a semiclassical approach. The Bogoliubov spectrum is shown to be associated with the low-energy regular component of the…