Evidence for a Common Physical Origin of the Landau and BEC Theories of Superfluidity

Diallo, Souleymane; Azuah, R. T.; Abernathy, D. L.; Taniguchi, Jun; Suzuki, Masaru; Bossy, J.; Mulders, N.; Glyde, H. R.

doi:10.1103/physrevlett.113.215302

Cited by 17 publications

(45 citation statements)

References 45 publications

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“…This behavior has also been observed in semi-classical liquids. The collective excitations in confined D 2 35 strongly couple to the pore walls, leading to a frictional effect that reduces molecular diffusive mobility and shortens the lifetime of the collective modes. The rotational and translational dynamics of H 2 are also damped by confinement 36 due to the pore walls.…”

Section: Fig 3 Reported Linewidths (Full Width-half Max) Formentioning

confidence: 99%

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Bulklike excitations in nanoconfined liquid helium

et al. 2017

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The effects of confinement, disorder, and reduced dimensionality upon quantum fluids have been studied by the adsorption of liquid helium in porous media. The effects of extreme, nanoscale confinement upon its microscopic excitations are not presently understood. Several previous experiments have suggested that, at sufficiently low temperature, the roton mean free path is set by the restricted geometry. Here we show that the lifetime of the roton excitation is unaffected when superfluid helium is confined within cylindrical pores only a few nanometers in diameter. The temperature-dependence of its lifetime are found to be identical to the bulk fluid, implying that the lifetime is not set by the scale of the confinement. Our results demonstrate that the rotons in the pore center propagate without being modified by the confining media, unlike the collective excitations of classical fluids.

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Section: Fig 3 Reported Linewidths (Full Width-half Max) Formentioning

confidence: 99%

“…Liquid helium confined in porous media provides a model system for the study of the effects of confinement, quenched disorder, and reduced dimensionality on strongly interacting Bose fluids [1][2][3][4][5][6][7][8] . Studies of the effects of confinement on the elementary quasiparticle excitations has been particularly illuminating.…”

Section: Introductionmentioning

confidence: 99%

Bulklike excitations in nanoconfined liquid helium

et al. 2017

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“…Atoms interact through the dispersion force, and as a result only about 7% of helium condenses into the Bose–Einstein ground state11. Consequence of helium being a non-ideal system on the nature of BEC has been the subject of active studies up to today121314151617. In ideal gas atoms have no spatial correlations.…”

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confidence: 99%

Observation of dynamic atom-atom correlation in liquid helium in real space

et al. 2017

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Liquid 4He becomes superfluid and flows without resistance below temperature 2.17 K. Superfluidity has been a subject of intense studies and notable advances were made in elucidating the phenomenon by experiment and theory. Nevertheless, details of the microscopic state, including dynamic atom–atom correlations in the superfluid state, are not fully understood. Here using a technique of neutron dynamic pair-density function (DPDF) analysis we show that 4He atoms in the Bose–Einstein condensate have environment significantly different from uncondensed atoms, with the interatomic distance larger than the average by about 10%, whereas the average structure changes little through the superfluid transition. DPDF peak not seen in the snap-shot pair-density function is found at 2.3 Å, and is interpreted in terms of atomic tunnelling. The real space picture of dynamic atom–atom correlations presented here reveal characteristics of atomic dynamics not recognized so far, compelling yet another look at the phenomenon.

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“…(2) is also consistent with the view that the insulating Bose glass close to the transition is a collection of locally condensed puddles with finite mean density [Eq. (3)], which fail to connect phase-coherently over the full system size [19][20][21][22]. However, Eq.…”

Section: Inhomogeneous Josephson Relationmentioning

confidence: 93%

“…Only within mean-field theory, neglecting quantum and thermal fluctuations, one finds that ps = m\i//\2 [see Eq. (22) below], and there is no need for subtle distinctions between condensate and superfluid. But especially under critical conditions, the Josephson relation is precious because it connects the scaling properties of condensate and superfluid order parameters through the Josephson (hyper-)scaling law [1,4,5], Because of its conceptual and practical importance, the Josephson relation has been rederived over the years using various methods [2,3,[5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Josephson relation for disordered superfluids

Müller

2015

Phys. Rev. A

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The Josephson sum rule relates the superfluid density to the condensate order parameter, via the infrared residue of the single-particle Green's function. We establish an effective Josephson relation for disordered condensates valid upon ensemble averaging. This relation has the merit to show explicitly how superfluidity links to the coherent density, i.e., the density of particles with zero momentum. Detailed agreement is reached with perturbation theory for weak disorder.Comment: 4 pages; v2: minor corrections, published versio

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Evidence for a Common Physical Origin of the Landau and BEC Theories of Superfluidity

Cited by 17 publications

References 45 publications

Bulklike excitations in nanoconfined liquid helium

Bulklike excitations in nanoconfined liquid helium

Observation of dynamic atom-atom correlation in liquid helium in real space

Josephson relation for disordered superfluids

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