Downfall of the vortex dimple in superfluids

Sonin, É. B.; Manninen, A. J.

doi:10.1103/physrevlett.70.2585

Cited by 14 publications

(5 citation statements)

References 18 publications

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“…This result is indeed confirmed (up to a numerical factor) by the solution of the Euler-Lagrange equation for z when the full surface expression ð1 þðrzÞ 2 Þ 1=2 is taken into account [84]. We can thus conclude that for g !…”

Section: Crater Dimplessupporting

confidence: 68%

“…A vortex in the 4 He film spanning between the two liquid interfaces will then tend to lower the upper 4 He-liquid-vapor interface located at h ¼ h 1 , resulting in a dimple with central depth z d ¼ h 1 À h d . At the same time, the vortex pulls the lower interface at f ¼ f 1 up, producing an upward-oriented dimple of 'height' z u ¼ f u À f 1 (see also [84]). Since the surface tension of the 3 He--4 He interface is much lower than the 4 He liquid-vapor tension (see Table 1), the 'upward-dimple' can be more pronounced than the 'downward-dimple'.…”

Section: Crater Dimplesmentioning

confidence: 99%

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Dimple‐assisted dewetting: heterogeneous nucleation in undercooled wetting films

Blossey

2001

Annalen der Physik

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Undercooled wetting films near a first‐order wetting transition exhibit an unusually long lifetime: the thermal nucleation barrier for formation of a critical hole in a film of thickness F diverges according to Γ ∼ exp (ℰc/kBT) where the excess free energy ℰc ∼ Fζ with ζ ≥ 2. Localized perturbations of the liquid‐vapor interface (‘dimples’) are shown to be a useful tool in reducing Γ in a controlled way: they act as heterogeneous nucleation centers for thermal critical nuclei. For 4He wetting films on weak‐binding alkali substrates (Cs, Rb) dimples can be generated either by vortices in a superfluid film or by surface electrons. The theory of the heterogeneous nucleation process initiated by the presence of surface dimples (‘dimple‐assisted dewetting’) is developed, accompanied by quantitative predictions for experiment.

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Section: Crater Dimplessupporting

confidence: 68%

Section: Crater Dimplesmentioning

confidence: 99%

Dimple‐assisted dewetting: heterogeneous nucleation in undercooled wetting films

Blossey

2001

Annalen der Physik

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“…͑3͒, when the complete surface expression ͓1ϩ(ٌ) 2 ͔ 1/2 is taken into account. 19 For ␥→0, the dimple acquires a craterlike shape and comes to resemble qualitatively closer to a critical hole at h→Ϫ0,TϽT w ͑Ref. 8; the ''partial dewetting'' regime of Ref.…”

Section: Rapid Communicationsmentioning

confidence: 97%

“…Finally, dimple-assisted dewetting is enhanced by several mechanisms which increase the dimple size ͑and hence its free energy͒, as the presence of normal liquid, 19 or gravity. 14 Another interesting possibility for a direct modification of the size of the dimples is by placing charges at the free surface.…”

Section: Rapid Communicationsmentioning

confidence: 99%

Dimple-assisted dewetting in rotating superfluid films

Blossey

1998

Phys. Rev. B

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A superfluid wetting film on a solid substrate responds to rotation above a threshold velocity by formation of vortices which connect the free film surface with the substrate. The vortices cause localized deformations ͑''dimples''͒ at the film surface. It is proposed that surface dimples can support the heterogeneous nucleation of critical holes upon undercooling of the wetting film into a nonwet state, leading to a reduction of the lifetime of the metastable wetting layer. ͓S0163-1829͑98͒52622-7͔It was recently observed in experiment that 4 He undergoes first-order wetting and prewetting transitions on the weak binding substrates Cs and Rb. 1 An even richer wetting behavior is displayed by 3 He-4 He mixtures on Cs. [2][3][4][5] The hysteresis associated with the first-order wetting transitions was found to be unusually asymmetric: while an overheated thin film decays rapidly by nucleation of critical droplets, an undercooled thick film remains on the substrate in a longlived metastable state. 6 This feature, which is also present in interfacial dewetting transitions in binary liquid mixtures, 7 was recently explained on the basis of the topology of the wetting phase diagram. 8 As indicated in Fig. 1 by a doubleheaded arrow, an overheating experiment leads away from the prewetting line h p (T) for TϾT w , while the path of undercooling runs parallel to the bulk coexistence line for T ϽT w . In either direction the path crosses h p (T) so that, in general, the decay of the initial state will occur by homogeneous nucleation of critical nuclei, i.e., critical droplets on the nonwet wall or critical holes in the thick wetting layer. Both the size and the excess free energy E c of the critical nuclei are infinite at the prewetting line h p (T), and at the bulk coexistence line hϵϪ c ϭ0 for TϽT w . 8-10 The latter has been interpreted as a line of first-order surface transitions between a microscopic liquid layer on the wall for h→Ϫ0, and an infinitely thick liquid layer on the wall for h→ϩ0, while at hϭ0 wet and nonwet regions can coexist at the surface. 8 The finite distance of the endpoint of the overheating path from the solid line in Fig. 1 leads to a finite value of E c drop , while E c hole is practically infinite for the endpoint of the undercooling path. Since the nucleation rate behaves as Iϳexp(ϪE c /kT), thermal fluctuations are not sufficient in this situation to bring about the decay of the metastable thick film.In order to facilitate hole formation, energy can be transferred to the system from some external source, e.g., by heating 4 or by laser irradiation. 12 The purpose of the present paper is to point out that when the helium film is superfluid, its rotation can be used to assist hole formation. As Feynman pointed out, 13 a vortex deforms the fluid-fluid interface locally into a surface dimple, i.e., a macroscopic depression of the interface in the vicinity of the vortex. The presence of the dimple affects the nucleation kinetics: the initial state from which a critical hole forms upon undercooling i...

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“…These interfaces include the free surface of the superfluid bath (i.e. the gas -liquid interface) [83], the superfluid -solid 3 He interface [84], the interfaces between 3 He and 4 He superfluids [76,85], and interfaces between the A and B phases in superfluid 3 He [86].…”

Section: Vortex Dynamics Without Pinningmentioning

confidence: 99%

What Can Superconductivity Learn from Quantized Vorticity in 3He Superfluids?

Volovik¹,

Eltsov²,

Krusius³

2002

Springer Series in Solid-State Sciences

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In 3 He superfluids quantized vorticity can take many different forms: It can appear as distributed periodic textures, as sheets, or as lines. In the anisotropic 3 He-A phase in most cases the amplitude of the order parameter remains constant throughout the vortex structure and only its orientation changes in space. In the quasi-isotropic 3 He-B phase vortex lines have a hard core where the order parameter has reduced, but finite amplitude. The different structures have been firmly identified, based on both measurement and calculation. What parallels can be drawn from this information to the new unconventional superconductors or Bose-Einstein condensates?1 Unconventional quantized vorticity Soon after the discovery of the 3 He superfluids in 1972 it was understood that they represented the first example of unconventional Cooper pairing among Fermi systems, a p-wave state with total spin S = 1 and orbital momentum L = 1 [1]. This lead to a wide variety of new phenomena, of which one of the most important is the discovery of new vortex structures [2]. These can be studied with NMR spectroscopy [3], when this is combined with a calculation of the order parameter texture [4].In recent years other unconventional macroscopic quantum systems have been found and have taken the centre stage. Intermetallic alloys such as the heavy fermion metals, the high-temperature superconductors, and the most recent addition, the layered superconductors of Sr 2 RuO 4 type, do not fit in the conventional picture of s-wave pairing. Is it possible that unconventional vortex structures, similar perhaps to some of those in the 3 He superfluids, might also be present in these new systems?Current belief holds that the superconducting state in the tetragonal Sr 2 RuO 4 material is described by an order parameter of the same symmetry class as that in 3 He-A [5,6], an anisotropic superfluid with uniaxial symmetry (where both time reversal symmetry and reflection symmetry are spontaneously broken). Recent advances in optical trapping and cooling of alkali atom clouds to Bose-Einstein condensates have produced Bose systems which also are described by a multi-component order parameter: The spinor

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Downfall of the vortex dimple in superfluids

Cited by 14 publications

References 18 publications

Dimple‐assisted dewetting: heterogeneous nucleation in undercooled wetting films

Dimple‐assisted dewetting: heterogeneous nucleation in undercooled wetting films

Dimple-assisted dewetting in rotating superfluid films

What Can Superconductivity Learn from Quantized Vorticity in 3He Superfluids?

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