Search results for "Quantum fluids"

showing 3 items of 3 documents

Density functional study of two-dimensionalHe4clusters

2005

Binding energies and density profiles of two-dimensional systems of liquid He-4 with different geometries are studied by means of a zero-range density functional adjusted to reproduce the line tension obtained in a previous diffusion Monte Carlo calculation (lambda_{DMC}=0.121 K/A). It is shown that this density functional provides accurate results for the binding energy of large clusters with a reasonable computational effort.

Quantum fluidOrbital-free density functional theoryBinding energyMonte Carlo methodFOS: Physical sciencesLambdaHeli líquidMolecular physicsQuantum fluidsMètode de MontecarloLiquid heliumPhysicsLíquids quànticsFísicaTeoria del funcional de densitatCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsCondensed Matter - Other Condensed MatterMonte Carlo methodDensity functional theoryPhysical chemistryDiffusion Monte CarloDensity functional theoryEnergy (signal processing)Other Condensed Matter (cond-mat.other)Physical Review B
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Classical and quantum vortex leapfrogging in two-dimensional channels

2020

The leapfrogging of coaxial vortex rings is a famous effect which has been noticed since the times of Helmholtz. Recent advances in ultra-cold atomic gases show that the effect can now be studied in quantum fluids. The strong confinement which characterizes these systems motivates the study of leapfrogging of vortices within narrow channels. Using the two-dimensional point vortex model, we show that in the constrained geometry of a two-dimensional channel the dynamics is richer than in an unbounded domain: alongsize the known regimes of standard leapfrogging and the absence of it, we identify new regimes of backward leapfrogging and periodic orbits. Moreover, by solving the Gross-Pitaevskii…

Quantum fluidFOS: Physical sciences01 natural sciences010305 fluids & plasmassymbols.namesakeQuantum fluids0103 physical sciencesVortex dynamics010306 general physicsLeapfroggingSettore MAT/07 - Fisica MatematicaQuantumPhysicsPhysics::Computational PhysicsCondensed Matter::Quantum GasesMechanical EngineeringQuantum vortexFluid Dynamics (physics.flu-dyn)Physics - Fluid DynamicsVorticityCondensed Matter PhysicsVortexVortex ringClassical mechanicsMechanics of MaterialsQuantum Gases (cond-mat.quant-gas)Helmholtz free energysymbolsVortex interactionsCondensed Matter - Quantum Gases
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Ca impurity in small mixed He-4-He-3 clusters

2009

The structure of small mixed helium clusters doped with one calcium atom has been determined within the diffusion Monte Carlo framework. The results show that the calcium atom sits at the He-4-He-3 interface. This is in agreement with previous studies, both experimental and theoretical, performed for large clusters. A comparison between the results obtained for the largest cluster we have considered for each isotope shows a clear tendency of the Ca atom to reside in a deep dimple at the surface of the cluster for He-4 clusters, and to become fully solvated for He-3 clusters. We have calculated the absorption spectrum of Ca around the 4s4p <- 4s(2) transition and have found that it is bluesh…

Atomic clustersFísicaCalciumMonte Carlo methodsPhysics::Atomic Physicsheliumimpurity absorption spectraquantum fluidsimpurities
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