How to create an Alice string (half-quantum vortex) in a vector Bose-Einstein condensate

Leónhardt, Ulf; Volovik, G. E.

doi:10.1134/1.1312008

Cited by 145 publications

(128 citation statements)

References 20 publications

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“…The vortex strings in this kind of phase are called "Alice strings" and are known to have very unusual properties [42][43][44][45][46]. As one travels around the vortex the direction of the condensate changes by π (not 2π), since the reversed orientation can be made up by a shift in the phase by π.…”

Section: Topological Defectsmentioning

confidence: 99%

The phases of deuterium at extreme densities

Bedaque

Buchoff

Cherman

2011

J. High Energ. Phys.

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We consider deuterium compressed to higher than atomic, but lower than nuclear densities. At such densities deuterium is a superconducting quantum liquid. Generically, two superconducting phases compete, a "ferromagnetic" and a "nematic" one. We provide a power counting argument suggesting that the dominant interactions in the deuteron liquid are perturbative (but screened) Coulomb interactions. At very high densities the ground state is determined by very small nuclear interaction effects that probably favor the ferromagnetic phase. At lower densities the symmetry of the theory is effectively enhanced to SU (3), and the quantum liquid enters a novel phase, neither ferromagnetic nor nematic. Our results can serve as a starting point for investigations of the phase dynamics of deuteron liquids, as well as exploration of the stability and dynamics of the rich variety of topological objects that may occur in phases of the deuteron quantum liquid, which range from Alice strings to spin skyrmions to Z2 vortices.

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Section: Topological Defectsmentioning

confidence: 99%

The phases of deuterium at extreme densities

Bedaque

Buchoff

Cherman

2011

J. High Energ. Phys.

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“…In the particular case of Bose degenerate gases with spin degree of freedom, commonly known as spinor condensates, the fundamental topological excitations are more exotic vortical entities, called half-quantum vortices (HQVs) [18][19][20][21][22][23] . They can be conceived as the primary structural components of singly charged vortices (namely vortices with winding number ± 1).…”

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confidence: 99%

Dissociation dynamics of singly charged vortices into half-quantum vortex pairs

et al. 2012

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The quest for identification and understanding of fractional vorticity is a major subject of research in the quantum fluids domain, ranging from superconductors, superfluid Helium-3 to cold atoms. In a two-dimensional Bose degenerate gas with a spin degree of freedom, the fundamental topological excitations are fractional vortical entities, called half-quantum vortices. Convincing evidence for the existence of half-quantum vortices was recently provided in spinor polariton condensates. The half-quantum vortices can be regarded as the fundamental structural components of singly charged vortices but, so far, no experimental evidence of this relation has been provided. Here we report on the direct and time-resolved observation of the dynamical process of the dissociation of a singly charged vortex into its primary components, a pair of half-quantum vortices. The physical origin of the observed phenomenology is found in a spatially inhomogeneous static potential that couples the two spin components of the condensate.

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“…There is a rich variety of topological defect structures, which are already predicted in the earlier studies [6,7] on the spinor BEC. These are followed by others [8,9,10,11,12,13,14,15,16] who examine these topological structures more closely, such as skyrmion, monopole, meron or axis-symmetric or non axis-symmetric vortices both for antiferromagnetic and ferromagnetic cases.Superfluid 3 He is analogous to the spinor BEC where the neutral Cooper pair possesses the orbital and spin degrees of freedom, thus the order parameter is a multi-component [17]. Among various topological structures, the Mermin-Ho (MH) [18] and Anderson-Toulouse (AT) [19] vortices of a coreless and non-singular l-vector texture are proposed in 3 He-A phase.…”

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confidence: 99%

mentioning

confidence: 99%

Mermin-Ho Vortex in Ferromagnetic Spinor Bose-Einstein Condensates

2002

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The Mermin-Ho and Anderson-Toulouse coreless non-singular vortices are demonstrated to be thermodynamically stable in ferromagnetic spinor Bose-Einstein condensates with the hyperfine state F = 1. The phase diagram is established in a plane of the rotation drive vs the total magnetization by comparing the energies for other competing non-axis-symmetric or singular vortices. Their stability is also checked by evaluating collective modes.PACS numbers: 03.75. Fi, 67.57.Fg, 05.30.Jp Topological structure plays an important and decisive role in various research fields, ranging from condensed matter physics to high energy physics. They provide a common framework to connect diverse fields, enhancing mutual understanding [1].Recent advance of experimental techniques on BoseEinstein condensation (BEC) prompts us to closely and seriously look into theoretical possibilities which were mere imagination for theoreticians in this field. This is particularly true for spinor BEC where all hyperfine states of an atom Bose-condensed simultaneously, keeping these "spin" states degenerate and active. Recently, Barrett at al [3] have succeeded in cooling 87 Rb with the hyperfine state F = 1 by all optical methods without resorting to a usual magnetic trap in which the internal degrees of freedom is frozen. Since the spin interaction of the 87 Rb atomic system is ferromagnetic, based on the refined calculation of the atomic interaction parameters by Klausen at al[4], we now obtain concrete examples of the three component spinor BEC (F = 1, m F = 1, 0, −1) for both antiferromagnetic ( 23 Na) [5] and ferromagnetic interaction cases. In the present spinor BEC the degenerate internal degrees of freedom play an essential role to determine the fundamental physical properties. There is a rich variety of topological defect structures, which are already predicted in the earlier studies [6,7] on the spinor BEC. These are followed by others [8,9,10,11,12,13,14,15,16] who examine these topological structures more closely, such as skyrmion, monopole, meron or axis-symmetric or non axis-symmetric vortices both for antiferromagnetic and ferromagnetic cases.Superfluid 3 He is analogous to the spinor BEC where the neutral Cooper pair possesses the orbital and spin degrees of freedom, thus the order parameter is a multi-component [17]. Among various topological structures, the Mermin-Ho (MH) [18] and Anderson-Toulouse (AT) [19] vortices of a coreless and non-singular l-vector texture are proposed in 3 He-A phase. These are an extremely interesting object to study if they exist. The MH vortex is expected to spontaneously appear in a cylindrical vessel without any external rotation as an equilibrium state because the rigid wall boundary imposes the l-vector perpendicular to the vessel wall. The MH vortex is stable also under slow rotation because of their non-singular coreless structures [20].A similar topological structure, called skyrmion in general is proposed in the spinor BEC. Khawaja and Stoof[10] study a skyrmion in the ferromagnetic BEC with ...

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How to create an Alice string (half-quantum vortex) in a vector Bose-Einstein condensate

Cited by 145 publications

References 20 publications

The phases of deuterium at extreme densities

The phases of deuterium at extreme densities

Dissociation dynamics of singly charged vortices into half-quantum vortex pairs

Mermin-Ho Vortex in Ferromagnetic Spinor Bose-Einstein Condensates

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