Microscopic Superfluidity in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>He</mml:mi></mml:mrow><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>Clusters Stirred by a Rotating Impurity Molecule

Wairegi, Angeline; Gamboa, Antonio; Burbanks, Andrew; Lee, Ernestine A.; Farrelly, David

doi:10.1103/physrevlett.112.143401

Cited by 8 publications

(9 citation statements)

References 33 publications

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“…[8,[28][29][30] for a discussion). In this work, we utilize the moment of inertia based definition, which has its origin in the two-fluid model [31][32][33][34]:…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

Yan

Blume

2014

Phys. Rev. A

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While the zero-temperature properties of harmonically trapped cold few-atom systems have been discussed fairly extensively over the past decade, much less is known about the finite-temperature properties. Working in the canonical ensemble, we characterize small harmonically trapped atomic systems as a function of the temperature using analytical and numerical techniques. We present results for the energetics, structural properties, condensate fraction, superfluid fraction, and superfluid density. Our calculations for the two-body system underline that the condensate and superfluid fractions are distinctly different quantities. Our work demonstrates that the path-integral Monte Carlo method yields reliable results for bosonic and fermionic systems over a wide temperature range, including the regime where the de Broglie wavelength is large, i.e., where the statistics plays an important role. The regime where the Fermi sign problem leads to reasonably large signal-to-noise ratios is mapped out for selected parameter combinations. Our calculations for bosons focus on the unitary regime, where the physics is expected to be governed by the three-body parameter. If the three-body parameter is large compared to the inverse of the harmonic oscillator length, we find that the bosons form a droplet at low temperature and behave approximately like a noninteracting Bose and eventually Boltzmann gas at high temperature. The change of the behavior occurs over a fairly narrow temperature range. A simple model that reproduces the key aspects of the phase-transition-like feature, which can potentially be observed in cold atom Bose gas experiments, is presented.

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“…[8,[28][29][30] for a discussion). In this work, we utilize the moment of inertia based definition, which has its origin in the two-fluid model [31][32][33][34]:…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

Yan

Blume

2014

Phys. Rev. A

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“…The BOAS model has consistently been shown to provide a reasonably accurate description of the nodal surfaces of weakly bound van der Waals complexes containing several He atoms. The advantage is that considerably less computational effort is requited to solve the BOAS problem than the full-dimensionality problem because of difficulties including the radial degrees of freedom [36][37][38]. Here we demonstrate how GA-DMC can be used to compute nodal surfaces on the fly for these systems.…”

Section: Excited States Of He-c 2 Hmentioning

confidence: 96%

“…As in a previous study of the He-CO complex [38] the He atom is confined to a sphere (in this case of radius R 0 = 9.55 bohr). The BOAS model has consistently been shown to provide a reasonably accurate description of the nodal surfaces of weakly bound van der Waals complexes containing several He atoms.…”

Section: Excited States Of He-c 2 Hmentioning

confidence: 97%

“…In practice, it is often the case that only certain states are being sought (e.g., see Ref. [38]) and, in this case, system-specific information can be used to guide the GA. 3. One of the clusters is selected for further investigation and a new GA-DMC calculation is done.…”

Section: Within the Energy Region Of Interest A Scatter Plot Is Made mentioning

confidence: 99%

“…We have recently developed an automated version of this procedure in which the search for nodes is treated as an optimization problem that is solved using a genetic algorithm (GA), on the fly, i.e., http within the DMC computation itself [36][37][38]. Essentially the nodal surface is optimized such that the normalized local flux of DMC walkers crossing the surface in opposite directions are equal, as are the pocket energies.…”

Section: Introductionmentioning

confidence: 99%

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On the fly nodal searches in importance sampled fixed-node diffusion Monte Carlo using a parallel, fine-grained, genetic algorithm

Wairegi

Farrelly

2015

Chemical Physics Letters

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Rotational Spectroscopic Study of Quantum Solvation in Isotopologic (pH₂)_N–CO Clusters

Jäger

2017

J. Phys. Chem. A

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We report the Fourier transform microwave spectra of (pH)-CO, (pH)-CO, and (pH)-CO (N ≤ 8) clusters. We find that the frequencies of the a-type J = 1-0 transitions decrease to a minimum at N = 6 and then rapidly increase up to at least N = 8; this is similar to what was previously reported for (pH)-CO, for which the turnaround was found to correlate with an increase in the superfluid fraction of the pH component of the clusters [ Raston Phys. Rev. Lett. 2012 , 108 , 253402 ]. The data suggest that the turnaround in the transition frequency marks an abrupt decrease in the anisotropy of the potential (i.e., in going from N = 6 → 7 → 8), as evidenced from the isotopologic differences rapidly evolving from end-over-end to free-rotor character. Structurally, a more quantitative analysis of the anisotropy was hindered by the lack of accurate frequencies in the b-type series, and a simple Kraitchman analysis yielded unphysical results. In addition to comparing the transition frequencies of the different isotopologic clusters, we provide here more comprehensive details and further discussion of the initial measurements made on (pH)-CO.

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Microscopic Superfluidity inHe4Clusters Stirred by a Rotating Impurity Molecule

Cited by 8 publications

References 33 publications

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

On the fly nodal searches in importance sampled fixed-node diffusion Monte Carlo using a parallel, fine-grained, genetic algorithm

Rotational Spectroscopic Study of Quantum Solvation in Isotopologic (pH₂)_N–CO Clusters

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Microscopic Superfluidity inHe4Clusters Stirred by a Rotating Impurity Molecule

Cited by 8 publications

References 33 publications

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

Temperature dependence of small harmonically trapped atom systems with Bose, Fermi, and Boltzmann statistics

On the fly nodal searches in importance sampled fixed-node diffusion Monte Carlo using a parallel, fine-grained, genetic algorithm

Rotational Spectroscopic Study of Quantum Solvation in Isotopologic (pH2)N–CO Clusters

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Rotational Spectroscopic Study of Quantum Solvation in Isotopologic (pH₂)_N–CO Clusters