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By measuring energy spectra of the electron emission from a sharp tungsten tip induced by few-cycle laser pulses, the laser-field dependence of the emission mechanism was investigated. In strong laser fields, we confirm the appearance of…

The paper describes the production of thin, focused microjets with velocities up to 850 m/s by the rapid vaporization of a small mass of liquid in an open liquid-filled capillary. The vaporization is caused by the absorption of a low-energy…

We investigate the emergence of superfluid p=p_x+ip_y phases in an ultracold gas of dipolar Fermi molecules lying in two parallel square lattices in 2D. As shown by a two body study, dipole moments oriented in opposite directions in each…

Quantum Gases · Physics 2019-03-27 G. A. Dominguez-Castro , R. Paredes

The onset mechanism of superfluidity is examined by taking the case of the capillary flow of liquid helium 4. In the capillary flow, a substantial fall of the shear viscosity has been observed in the normal phase (lambda point<T<3.7K). In…

Superconductivity · Physics 2008-09-01 Shun-ichiro Koh

We investigate the evaporation of trace amounts of helium solvated in liquid water using molecular dynamics simulations and theory. Consistent with experimental observations, we find a super-Maxwellian distribution of kinetic energies of…

Chemical Physics · Physics 2024-08-21 Kritanjan Polley , Kevin R. Wilson , David T. Limmer

Evidence for a new type of superfluid phase in second-layer $^4$He on graphite has been obtained from simultaneous measurements of torsional-oscillator response and heat-capacity on exactly the same sample down to 30 mK, which resolve…

Other Condensed Matter · Physics 2026-01-12 Jun Usami , Hiroshi Fukuyama

Measurements of superfluid $^3$He in 98% aerogel demonstrate the existence of a metastable \emph{A}-like phase and a stable \emph{B}-like phase. It has been suggested that the relative stability of these two phases is controlled by…

Other Condensed Matter · Physics 2009-04-24 J. Pollanen , J. P. Davis , B. Reddy , K. R. Shirer , H. Choi , W. P. Halperin

The ionization rate of interstellar material by cosmic rays has been a major source of controversy, with different estimates varying by three orders of magnitude. Observational constraints of this rate have all depended on analyzing the…

Solar and Stellar Astrophysics · Physics 2015-05-14 Nick Indriolo , L. M. Hobbs , K. H. Hinkle , Benjamin J. McCall

The properties of hot dense helium at megabar pressures were studied with two first-principles computer simulation techniques, path integral Monte Carlo and density functional molecular dynamics. The simulations predicted that the…

Materials Science · Physics 2009-11-11 B. Militzer

Based on a first principles treatment of the excitation states we show that superfluidity of superfluid $^4$He (He II) results from a reduction in the number of phonon wavevector $K$ states $\N2(K)$ to a level that is negligibly low when…

Condensed Matter · Physics 2007-05-23 J. X. Zheng-Johansson , B. Johansson , P-I. Johansson

We propose a method to measure the superfluid fraction of an atomic gas. The method involves the use of a vector potential generated by optical beams with non-zero angular momentum to simulate uniform rotation. The induced change in angular…

Quantum Gases · Physics 2010-01-19 Nigel R. Cooper , Zoran Hadzibabic

This paper demonstrates particle tracking velocimetry performed for a model system wherein particle-laden liquid metal flow about a cylindrical obstacle was studied. We present the image processing methodology developed for particle…

The laser-induced fragmentation dynamics of this most fundamental polar molecule HeH$^+$ are measured using an ion beam of helium hydride and an isotopologue at various wavelengths and intensities. In contrast to the prevailing…

Chemical Physics · Physics 2018-08-21 P. Wustelt , F. Oppermann , Lun Yue , M. Möller , T. Stöhlker , S. Gräfe , M. Lein , G. G. Paulus , A. M. Sayler

Visualization of thermal counterflow in He II using PIV (particle image velocimetry) and PTV (particle tracking velocimetry) is difficult because tracer particle motion can be influenced by both the normal fluid and superfluid components of…

Other Condensed Matter · Physics 2018-06-27 Brian Mastracci , Wei Guo

A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a $\Pi-$shaped Dusty Plasma Experimental…

Plasma Physics · Physics 2016-11-23 S. Jaiswal , P. Bandyopadhyay , A. Sen

We report hot-wire measurements performed in two very different, co- and counter-rotating flows, in normal and superfluid helium at 1.6 K, 2 K, and 2.3 K. As recently reported, the power spectrum of the hot-wire signal in superfluid flows…

We use an extended laser Doppler technique to track optically the velocity of individual particles in a high Reynolds number turbulent flow. The particle sizes are of the order of the Kolmogorov scale and the time resolution, 30…

Fluid Dynamics · Physics 2009-11-13 Romain Volk , Nicolas Mordant , Gautier Verhille , Jean-François Pinton

The guiding and control of ultrahigh flux, femtosecond relativistic electron pulses through solid density matter is of great importance for many areas of high energy density science. Efforts so far include the use of magnetic fields…

We review fundamental problems involved in liquid theory including both classical and quantum liquids. Understanding classical liquids involves exploring details of their microscopic dynamics and its consequences. Here, we apply the same…

Statistical Mechanics · Physics 2025-01-28 K. Trachenko

The reciprocal energy and enstrophy transfers between normal fluid and superfluid components dictate the overall dynamics of superfluid $^4$He including the generation, evolution and coupling of coherent structures, the distribution of…