Emission of Discrete Vortex Rings by a Vibrating Grid In Superfluid<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts><mml:mtext mathvariant="normal">−</mml:mtext><mml:mi>B</mml:mi></mml:math>: A Precursor to Quantum Turbulence

Bradley, D. I.; Clubb, D. O.; Fisher, S. N.; Guénault, A. M.; Haley, R. P.; Matthews, Craig J.; Pickett, G. R.; Tsepelin, V.; Zaki, K.

doi:10.1103/physrevlett.95.035302

Cited by 91 publications

(36 citation statements)

References 12 publications

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“…4, where wire 4 detects a fast vortex ring signal at the same time as the nearer wires detect turbulence. Coexistence of quantum turbulence and primary vortex rings was observed in measurements with the earlier grid, but only very close to the transition region (54).…”

Section: Decay Of the Vortex Signalmentioning

confidence: 93%

“…These have a greater chance of further recombinations resulting in the production of a vortex tangle (quantum turbulence). The above scenario was first inferred from measurements of the decay of the vortex signal (54) and was confirmed by numerical simulations (56). We can obtain more detailed information from the steady-state regime by studying fluctuations, as discussed below.…”

Section: Spatial Correlations Of Vortex Ringsmentioning

confidence: 99%

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Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Fisher

Jackson

Sergeev

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Andreev reflection of quasiparticle excitations provides a sensitive and passive probe of flow in superfluid 3 He-B. It is particularly useful for studying complex flows generated by vortex rings and vortex tangles (quantum turbulence). We describe the reflection process and discuss the results of numerical simulations of Andreev reflection from vortex rings and from quantum turbulence. We present measurements of vortices generated by a vibrating grid resonator at very low temperatures. The Andreev reflection is measured using an array of vibrating wire sensors. At low grid velocities, ballistic vortex rings are produced. At higher grid velocities, the rings collide and reconnect to produce quantum turbulence. We discuss spatial correlations of the fluctuating vortex signals measured by the different sensor wires. These reveal detailed information about the formation of quantum turbulence and about the underlying vortex dynamics. Quantum turbulence in superfluid 4 He has been studied for many decades (3-5). There has been a great deal of renewed interest in quantum turbulence in recent years owing to several factors: quantum turbulence was discovered in superfluid 3 He (6-8), techniques were developed to extend the study of quantum turbulence in superfluid 4 He to very low temperatures (9, 10), imaging techniques were developed to visualize superfluid turbulence at higher temperatures (11-13) (see the review in ref. 14), mechanical resonator techniques were developed for quantum turbulence (15-18), and quantum turbulence was studied in dilute gases (19,20); there were many important theoretical developments, for example refs. 21-26, and numerical methods were enormously improved (27-29) to complement and better interpret experimental results.In this article, we discuss quantum turbulence generated by vibrating grids in superfluid 3 He-B at low temperatures, where the normal fluid component is very small. The primary thermal excitations in 3 He are quasiparticle and quasihole excitations (30). At low temperatures, the excitation mean free path between collisions vastly exceeds the experimental dimensions. In this ballistic regime, excitations move independently and normally scatter only with the container walls. The normal fluid concept no longer applies because there is no collective motion of excitations.In addition to normal scattering, excitations can also undergo Andreev reflection. Andreev scattering produces nearly perfect retroreflection of excitations with very little momentum transfer: Quasiparticles become quasiholes, and vice versa. This provides an ideal probe for vortices and quantum turbulence at low temperatures. Andreev Scattering from Superfluid FlowThe dispersion curve for excitations is shown in Fig. 1A. The excitation group velocity v g = dE=dp is parallel to the momentum for quasiparticles that have p > p F , where p F is the Fermi momentum and is antiparallel to the momentum for quasiholes that have p < p F . The dispersion curve is tied to the reference frame of the superfluid. So, accordi...

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Section: Decay Of the Vortex Signalmentioning

confidence: 93%

Section: Spatial Correlations Of Vortex Ringsmentioning

confidence: 99%

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Fisher

Jackson

Sergeev

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Here it is worth mentioning that the investigation of evolving vortex string networks has a tradition in different areas of physics from topological defects in solids to cosmic strings (Vilenkin and Shellard, 1994). Many aspects of the associated dynamical rules and the generation of entangled string networks have also been extensively studied for superfluid turbulence [for surveys see Schwarz (1982); Martins et al (2004);Bradley et al (2005)]. The predicted richness of possible behaviors has not yet been fully identified in cyclically dominated three-state games.…”

Section: Rotating Spiral Armsmentioning

confidence: 99%

Evolutionary games on graphs

2007

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Game theory is one of the key paradigms behind many scientific disciplines from biology to behavioral sciences to economics. In its evolutionary form and especially when the interacting agents are linked in a specific social network the underlying solution concepts and methods are very similar to those applied in non-equilibrium statistical physics. This review gives a tutorial-type overview of the field for physicists. The first four sections introduce the necessary background in classical and evolutionary game theory from the basic definitions to the most important results. The fifth section surveys the topological complications implied by non-mean-field-type social network structures in general. The next three sections discuss in detail the dynamic behavior of three prominent classes of models: the Prisoner's Dilemma, the Rock-Scissors-Paper game, and Competing Associations. The major theme of the review is in what sense and how the graph structure of interactions can modify and enrich the picture of long term behavioral patterns emerging in evolutionary games.

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“…The important role that vortex rings occupy in the study of quantum turbulence has prompted detailed experimental studies of these excitations in both 4 He and 3 He 2,17 . This has revealed that the number density of vortex rings strongly determines the likelihood of neighbouring vortex rings to reconnect.…”

Section: Introductionmentioning

confidence: 99%

Scattering of Line-Ring Vortices in a Superfluid

Villois¹,

Salman²,

Proment³

2015

J Low Temp Phys

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We study the scattering of vortex rings by a superfluid line vortex using the Gross-Pitaevskii equation in a parameter regime where a hydrodynamic description based on a vortex filament approximation is applicable. By using a vortex extraction algorithm, we are able to track the location of the vortex ring as a function of time. Using this, we show that the scattering of the vortex ring in our Gross-Pitaevskii simulations is well captured by the local induction approximation of a vortex filament model for a wide range of impact parameters. The scattering of a vortex ring by a line vortex is characterised by the initial offset of the centre of the ring from the axis of the vortex. We find that a strong asymmetry exists in the scattering of a ring as a function of this initial scattering parameter.

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Emission of Discrete Vortex Rings by a Vibrating Grid In SuperfluidHe3−B: A Precursor to Quantum Turbulence

Abstract: We report a transition in the vorticity generated by a grid moving in the B phase of superfluid 3He at T< Show more

Cited by 91 publications

References 12 publications

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Evolutionary games on graphs

Scattering of Line-Ring Vortices in a Superfluid

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Emission of Discrete Vortex Rings by a Vibrating Grid In SuperfluidHe3−B: A Precursor to Quantum Turbulence

Abstract: We report a transition in the vorticity generated by a grid moving in the B phase of superfluid 3He at T< Show more

Cited by 91 publications

References 12 publications

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in 3 He-B

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in 3 He-B

Evolutionary games on graphs

Scattering of Line-Ring Vortices in a Superfluid

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Product

Resources

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Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in ³ He-B