On the Dipole Moment of Quantized Vortices in the Presence of Flows

Shevchenko, S. I.; Konstantinov, A. M.

doi:10.1007/s10909-016-1529-5

Cited by 15 publications

(13 citation statements)

References 10 publications

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“…A variety of experimental and theoretical studies of dislocations in solid helium have revealed a number of their properties. One of the first theoretical predictions of the possibility of superfluidity along the cores of edge dislocations was that proposed by Shevchenko [52]. Recent experimental thermodynamic studies of solid helium (precise pressure measurements) [53] observed an additional pressure P ∼ T 2 contribution, which at T < 0.35 K exceeds the phonon contribution.…”

Section: Discussionmentioning

confidence: 97%

Dissipative superfluid mass flux through solidHe4

Vekhov¹,

Hallock²

2014

Phys. Rev. B

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The thermo-mechanical effect in superfluid helium is used to create an initial chemical potential difference, ∆µ0, across a solid 4 He sample. This ∆µ0 causes a flow of helium atoms from one reservoir filled with superfluid helium, through a sample cell filled with solid helium, to another superfluidfilled reservoir until chemical potential equilibrium is restored. The solid helium sample is separated from each of the reservoirs by Vycor rods that allow only the superfluid component to flow. With an improved technique, measurements of the flow, F , at several fixed solid helium temperatures, T , have been made as function of ∆µ in the pressure range 25.5 -26.1 bar. And, measurements of F have been made as a function of temperature in the range 180 < T < 545 mK for several fixed values of ∆µ. The temperature dependence of the flow above 100 mK shows a reduction of the flux with an increase in temperature that is well described by F = F * 0 [1 − a exp(−E/T )]. The non-linear functional dependence F ∼ (∆µ) b , with b < 0.5 independent of temperature but dependent on pressure, documents in some detail the dissipative nature of the flow and suggests that this system demonstrates Luttinger liquid-like one-dimensional behavior. The mechanism that causes this flow behavior is not certain, but is consistent with superflow on the cores of edge dislocations.

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Section: Discussionmentioning

confidence: 97%

Dissipative superfluid mass flux through solidHe4

Vekhov¹,

Hallock²

2014

Phys. Rev. B

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“…In solid 4 He, dislocations are extremely mobile and can reduce the solid's shear modulus by as much as 90%-an effect referred to as "giant plasticity" [10]. It has been proposed that some dislocations in 4 He have superfluid cores [11,12] which would allow new phenomena like "giant isochoric compressibility" [12], "superclimb" [13], and superflow in the dislocation network [11,14]. However, the most important open question involves mass flow.…”

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confidence: 99%

Helium Mass Flow Through a Solid-Superfluid-Solid Junction

et al. 2015

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We report the results of flow experiments in which two chambers containing solid ^{4}He are connected by a superfluid Vycor channel. At low temperatures and pressures, mechanically squeezing the solid in one chamber produced a pressure increase in the second chamber, a measure of mass transport through our solid-superfluid-solid junction. This pressure response is very similar to the flow seen in recent experiments at the University of Massachusetts: it began around 600 mK, increased as the temperature was reduced, then decreased dramatically at a temperature, T_{d}, which depended on the ^{3}He impurity concentration. Our experiments indicate that the flow is limited by mass transfer across the solid-liquid interface near the Vycor ends, where the ^{3}He collects at low temperature, rather than by flow paths within the solid ^{4}He.

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“…The superfluid contribution would dominate because, experimentally, it is seen that limitation of dislocation motion in conventional crystals due to Peierls barrier is absent in solid 4 He. The onset temperature of this unusual elastic behavior in solid 4 He is in the same temperature range as the onset of superfluid behavior in [50,18] dislocation networks. As noted above, the superfluid contribution to dislocation mobility scales with the superfluid fraction i.e.…”

Section: Discussionmentioning

confidence: 71%

“…According to Refs. [50,18] dislocation network superfluidity is characterized by two temperature scales -T 0 ∼ 1K (comparable to the bulk λ temperature for liquid 4 He) and T c ∼ T 0 a/L f , where a is the interatomic distance along a dislocation core and L f is the free segment length of dislocation line. Within such a model for superfluidity associated with dislocation lines, the onset temperatures are roughly consistent with the experimentally [11,51,52] found range 0.1K to 0.075K where the onset of anomalous behavior is observed.…”

Section: Results -Modeling Of Experimental Shear Modulus Datamentioning

confidence: 99%

Dislocation Mobility and Anomalous Shear Modulus Effect in $$^4$$ 4 He Crystals

2016

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We calculate the dislocation glide mobility in solid 4 He within a model that assumes the existence of a superfluid field associated with dislocation lines. Prompted by the results of this mobility calculation, we study within this model the role that such a superfluid field may play in the motion of the dislocation line when a stress is applied to the crystal. To do this, we relate the damping of dislocation motion, calculated in the presence of the assumed superfluid field, to the shear modulus of the crystal. As the temperature increases, we find that a sharp drop in the shear modulus will occur at the temperature where the superfluid field disappears. We compare the drop in shear modulus of the crystal arising from the temperature dependence of the damping contribution due to the superfluid field, to the experimental observation of the same phenomena in solid 4 He and find quantitative agreement. Our results indicate that such a superfluid field plays an important role in dislocation pinning in a clean solid 4 He at low temperatures and in this regime may provide an alternative source for the unusual elastic phenomena observed in solid 4 He.

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On the Dipole Moment of Quantized Vortices in the Presence of Flows

Cited by 15 publications

References 10 publications

Dissipative superfluid mass flux through solidHe4

Dissipative superfluid mass flux through solidHe4

Helium Mass Flow Through a Solid-Superfluid-Solid Junction

Dislocation Mobility and Anomalous Shear Modulus Effect in $$^4$$ 4 He Crystals

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