Related papers: Rotons and Quantum Evaporation from Superfluid 4He
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…
A new method of obtaining the interaction Hamiltonian of phonons at superfluid helium-solid interface is proposed in the work. Equations of hydrodynamic variables are obtained in terms of second quantization if helium occupies a half-space.…
A detailed study of the dispersion law of surface excitations in liquid \hef at zero temperature is presented, with special emphasis to the short wave length region. The hybridization mechanism between surface and bulk modes is discussed on…
Fundamental considerations predict that macroscopic quantum systems such as superfluids and the electrons in superconductors will exhibit oscillatory motion when pushed through a small constriction. Here we report the observation of these…
We proceed from the premise that the spectrum of elementary excitations in the normal component in Landau's theory of superfluidity should depend on the superfluid helium temperature. This leads to generalization of the Landau superfluidity…
Parametric excitation of rotons by oscillating electric field exhibits a narrow resonance at the roton minimum frequency. The resonance width is in good agreement with experimental results on the microwave absorption in superfluid helium.
The elementary excitations in superfluid liquid He-4 named rotons have an unusual dispersion curve. The energy is an approximately quadratic function of (p-p_0), the difference between the magnitude of the momentum p and a characteristic…
Excitations in the form of quantized vortex rings are known to exist in superfluid $^{4}He$ at energies and momenta exceeding those of the Landau phonon-roton spectrum. They form a vortex branch of elementary excitations spectrum which is…
The dynamics of superfluid 4He at and above the Landau quasiparticle regime is investigated by high precision inelastic neutron scattering measurements of the dynamic structure factor. A highly structured response is observed above the…
Continuing previous work, we have measured the projectile scattering-angle dependency for transfer excitation of fast protons (300-1200 keV/u) colliding with helium (p+He $\rightarrow$ H + He$^{+ *}$). Our high-resolution fully differential…
We present neutron scattering measurements of the phonon-roton (P-R) mode of superfluid 4He confined in 47 \AA MCM-41 at T = 0.5 K at wave vectors, Q, beyond the roton wave vector (Q_R =1.92 \AA$^{-1}$). Measurements beyond the roton…
We consider the evaporation of rotating micro black holes produced in highly energetic particle collisions, taking into account the polarization due to the coupling between the spin of the emitted particles and the angular momentum of the…
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…
We examine the energetics of bulk and layer-roton excitations of 4He in various porous medial such as aerogel, Geltech, or Vycor, in order to find out what conclusions can be drawn from experiments on the energetics about the physisorption…
Optically generated excitons dictate the absorption and emission spectrum of doped semiconductor transition metal dichalcogenide monolayers. We show that upon increasing the electron density, the elementary optical excitations develop a…
Formation of vortex rings around moving spherical objects in superfluid He-4 at 0 K is modeled by time-dependent density functional theory. The simulations provide detailed information of the microscopic events that lead to vortex ring…
We investigate the interaction of ultracold antihydrogen with a conducting surface. Our discussion focuses on the physical regime where the phenomenon of quantum reflection manifests. We calculate the reflection probability as function of…
A superfluid having atomic scale superflow of a hexagonal lattice of vortex and antivortex filaments, described by a single macroscopic wave function is presented as a supersolid. As superfluid \he4 is pressurized, at a first order…
We compute the graybody factor and evaporation rate of a rotating black hole in the presence of a hypothetical reflective surface slightly outside the outer horizon radius, assuming that it spontaneously emits thermal radiation due to…
Liquid helium and spin-1/2 cold-atom Fermi gases both exhibit in their superfluid phase two distinct types of excitations, gapless phonons and gapped rotons or fermionic pair-breaking excitations. In the long wavelength limit, revising and…