Related papers: Dynamics of molecular rotors in bulk superfluid he…
Buffer gas cooling, one of the most relevant direct cooling techniques for cooling molecules, relies on dissipating the energy of the molecule via collisions with a buffer gas. The cooling efficiency hinges on the molecule-atom scattering…
The motion of helium crystals has been experimentally studied when the crystals fall in the superfluid liquid owing to gravity at temperatures above the roughening transitions where the whole crystal surface is in the atomically rough…
Single molecules trapped in the solid state at liquid helium temperatures are promising quantum emitters for the development of quantum technologies owing to their remarkable photostability and their lifetime-limited optical coherence time…
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…
We consider a diatomic molecule driven by a linearly polarized laser pulse with a polarization axis rotating with a constant acceleration. This setup is referred to as optical centrifuge, and it is known to lead to high-angular momenta for…
Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the…
We design models for helium in matrices like aerogel, Vycor or Geltech from a manifestly microscopic point of view. For that purpose, we calculate the dynamic structure function of 4He on Si substrates and between two Si walls as a function…
A theory accounting for the dynamical aspects of the superfluid response of one dimensional (1D) quantum fluids is reported. In long 1D systems the onset of superfluidity is related to the dynamical suppression of quantum phase slips at low…
Understanding the behavior of molecules interacting with superfluid helium represents a formidable challenge and, in general, requires approaches relying on large-scale numerical simulations. Here we demonstrate that experimental data…
We focus on an in-depth study of the forced dynamics of a ferromagnetic single-domain uniaxial nanoparticle placed in a viscous fluid and driven by an external rotating magnetic field. The process of conversion of magnetic and mechanical…
Helium is recognized as a model system for the study of phase transitions. Of particular interest is the superfluid phase in two dimensions. We report measurements on superfluid helium films adsorbed on the surface of a suspended carbon…
Vortex dynamics in 3He-B is divided by the temperature dependent damping into a high-temperature regime, where the number of vortices is conserved, and a low-temperature regime, where rapid vortex multiplication takes place in a turbulent…
We investigate in detail, using both analytical and numerical tools, the decoherence of electron spins in quantum dots (QDs) coupled to a bath of nuclear spins in magnetic fields or with various initial bath polarizations, focusing on the…
The solvation process of an alkali ion (Na$^+$, K$^+$, Rb$^+$, Cs$^+$) inside a superfluid $^4$He$_{2000}$ nanodroplet is investigated theoretically using liquid $^4$He time-dependent density functional theory at zero temperature. We…
Metastable helium molecules generated in a discharge near a sharp tungsten tip operated in either pulsed mode or continuous field-emission mode in superfluid liquid $^{4}$He are imaged using a laser-induced-fluorescence technique. By…
We investigate the thermodynamics of a hybrid quantum device consisting of two qubits collectively interacting with a quantum rotor and coupled dissipatively to two equilibrium reservoirs at different temperatures. By modelling the dynamics…
An ab initio molecular dynamics study of femtosecond laser processing of germanium is presented in this paper. The method based on the finite temperature density functional theory is adopted to probe the structural change, thermal motion of…
Matter at low temperatures exhibits unusual properties such as superfluidity, superconductivity, Bose-Einstein condensation, and supersolidity. These states display quantum mechanical behaviours at scales much larger than atomic dimensions.…
The behavior of quantum fluids (4He and H2) within nanopores is explored in various regimes, using several different methods. A focus is the evolution of each fluid's behavior as pore radius R is increased. Results are derived with the path…
Generation, statistically steady state, and temporal decay of axially rotating thermal counterflow of superfluid $^4$He (He~II) in a square channel is probed using the second sound attenuation technique, measuring the density of quantized…