Giant Coupling Effects in Confined 4He Near T λ

Perron, Justin K.; Gasparini, Francis M.

doi:10.1007/s10909-010-0306-0

Cited by 7 publications

(9 citation statements)

References 17 publications

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“…1 But our detailed examination of finite-size effects is, as far as we know, new. 2 In this section M denotes the length of the horizontal edge and N the strip width, this notation is due to historical reasons. The final results are obviously covariant under the mutual exchange of K 1 with K 2 .…”

Section: Domain Wall Free Energymentioning

confidence: 99%

Action at a distance in classical uniaxial ferromagnetic arrays

et al. 2017

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We examine in detail the theoretical foundations of striking long-range couplings emerging in arrays of fluid cells connected by narrow channels by using a lattice gas (Ising model) description of a system. We present a reexamination of the well known exact determination of the two-point correlation function along the edge of a channel using the transfer matrix technique and a new interpretation is provided. The explicit form of the correlation length is found to grow exponentially with the cross section of the channels at the bulk two-phase coexistence. The aforementioned result is recaptured by a refined version of the Fisher-Privman theory of first order phase transitions in which the Boltzmann factor for a domain wall is decorated with a contribution stemming from the point tension originated at its endpoints. The Boltzmann factor for a domain wall together with the point tension is then identified exactly thanks to two independent analytical techniques, providing a critical test of the Fisher-Privman theory. We then illustrate how to build up the network model from its elementary constituents, the cells and the channels. Moreover, we are able to extract the strength of the coupling between cells and express them in terms of the length and width and coarse grained quantities such as surface and point tensions. We then support our theoretical investigation with a series of corroborating results based on Monte Carlo simulations. We illustrate how the long range ordering occurs and how the latter is signaled by the thermodynamic quantities corresponding to both planar and three-dimensional Ising arrays.

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Section: Domain Wall Free Energymentioning

confidence: 99%

Action at a distance in classical uniaxial ferromagnetic arrays

et al. 2017

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“…This is the approach taken some time ago by Mamaladze and Cheishvili [38,39] in considering the possibility of what would constitute a weak link to couple two region of helium and display Josephson effects [40]. This mean field approach does not work for the effects discussed here as has been calculated explicitly [10]. Josephson effects have been seen in both 3 He and 4 He [41][42][43].…”

Section: Dmentioning

confidence: 94%

“…This lateral dimension, as well as the height h are kept constant while W is varied for different cells. This design, with 1/3 of the ring area being bonded, insures uniformity for the opening of small height h. The magnitude of h is chosen to match as closely as possible the film thickness used in the measurements with (2 µm) 3 boxes of helium, and in a separate experiment where the full cell consisted of a 33.6 ± 0.9 nm planar film [3,10]. These data will form a basis for comparison with the present results.…”

Section: Methodsmentioning

confidence: 99%

“…4 on a log-log plot. Also shown in this figure are data for a cell with a uniform 33.6 nm film [3,10]. The solid line is the dependence of the superfluid fraction for bulk, unconfined helium [21].…”

Section: Figmentioning

confidence: 99%

“…However, recent work has been reported by Del Maestro [9]. Mean field calculations do not describe the effects seen [10].…”

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

Long-distance correlation-length effects and hydrodynamics ofHe4films in a Corbino geometry

2016

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Previous measurements of the superfluid density ρs and specific heat for 4 He have identified effects that are manifest at distances much larger than the correlation length ξ3D [1-3]. We report here new measurements of the superfluid density which are designed to explore this phenomenon further. We determine the superfluid fraction ρs/ρ from the resonance of 34 nm films of varying widths 4 ≤ W ≤ 100 µm. The films are formed across a Corbino ring separating two chambers where a thicker 268 nm film is formed. This arrangement is realized using lithography and direct Si-wafer bonding. We identify two effects in the behavior of ρs/ρ : one is hydrodynamic, for which we present an analysis; and the other, a correlation-length effect which manifests as a shift in the transition temperature Tc relative to that of a uniform 34 nm film uninfluenced by proximity effects. We find that one can collapse both ρs/ρ and the quality factor of the resonance onto universal curves by shifting Tc as ∆Tc ∼ W −ν. This new scaling is a surprising result on two counts: it involves a very large length scale W relative to the magnitude of ξ3D; and, the dependence on W is not what is expected from correlation-length finite-size scaling which would predict ∆Tc ∼ W −1/ν .

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Theory of Adiabatic Fountain Resonance

Williams

2017

J Low Temp Phys

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The theory of "Adiabatic Fountain Resonance" with superfluid 4 He is clarified. In this geometry a film region between two silicon wafers bonded at their outer edge opens up to a central region with a free surface. We find that the resonance in this system is not a Helmholtz resonance as claimed by Gasparini and co-workers, but in fact is a fourth sound resonance. We postulate that it occurs at relatively low frequency because the thin silicon wafers flex appreciably from the pressure oscillations of the sound wave.

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Giant Coupling Effects in Confined 4He Near T λ

Cited by 7 publications

References 17 publications

Action at a distance in classical uniaxial ferromagnetic arrays

Action at a distance in classical uniaxial ferromagnetic arrays

Long-distance correlation-length effects and hydrodynamics ofHe4films in a Corbino geometry

Theory of Adiabatic Fountain Resonance

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