Experimental Observation of a Superfluid Gyroscope in a Dilute Bose-Einstein Condensate

Hodby, E.; Hopkins, S. A.; Hechenblaikner, Gerald; Smith, Natasha; Foot, C. J.

doi:10.1103/physrevlett.91.090403

Cited by 33 publications

(34 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is proposed that the observed vortices with large core densities are in vibrating modes corresponding to excited rotational states of BEC's with an angular momentum higher than the stationary GP states. This proposal is based on my results that the core density increases rapidly as the angular momentum increases and is supported by the experimental findings that the angular momentum per particle, averaged over an ensemble of one-vortex systems, is larger than ប [15,16]. The calculated density profiles for the excited vortices are in good agreement with experimental measurements of a single vortex in the center of the trap.…”

supporting

confidence: 67%

Structure of excited vortices with higher angular momentum in Bose-Einstein condensates

Tang

2004

Phys. Rev. A

View full text Add to dashboard Cite

The structure of vortices in Bose-Einstein condensed atomic gases is studied taking into account many-body correlation effects. It is shown that for excited vortices the particle density in the vortex core increases as the angular momentum of the system increases. The core density can increase by several times with only a few percent change in the angular momentum. This result provides an explanation for the observations in which the measured angular momentum is higher than the estimation based on counting the number of vortices and the visibility of the vortex cores is simultaneously reduced. The calculated density profiles for the excited vortices are in good agreement with experimental measurements of a single vortex.

show abstract

supporting

confidence: 67%

Structure of excited vortices with higher angular momentum in Bose-Einstein condensates

Tang

2004

Phys. Rev. A

View full text Add to dashboard Cite

show abstract

“…While the OAM has been measured in SFs [56][57][58], we also expect signatures of unpaired fermions-which create a current localized around the vortex core that flows counter to the superflow-in local supercurrent density measurements in MQV states [17].…”

mentioning

confidence: 84%

Multiply Quantized Vortices in Fermionic Superfluids: Angular Momentum, Unpaired Fermions, and Spectral Asymmetry

et al. 2017

View full text Add to dashboard Cite

We compute the orbital angular momentum Lz of an s-wave paired superfluid in the presence of an axisymmetric multiply quantized vortex. For vortices with winding number |k| > 1, we find that in the weak-pairing BCS regime Lz is significantly reduced from its value N k/2 in the Bose-Einstein condensation (BEC) regime, where N is the total number of fermions. This deviation results from the presence of unpaired fermions in the BCS ground state, which arise as a consequence of spectral flow along the vortex sub-gap states. We support our results analytically and numerically by solving the Bogoliubov-de-Gennes equations within the weak-pairing BCS regime.Quantized vortices are a hallmark of superfluids (SFs) and superconductors. These topological defects form in response to external rotation or magnetic field and play a key role in understanding a broad spectrum of phenomena, such as the Berezinskii-Kosterlitz-Thouless transition in two-dimensional (2D) SFs [1,2], superconductor/insulator transitions [3][4][5], turbulence [6], and dissipation [7,8]. In fermionic s-wave paired states, the structure of the ground state and low lying excitations of an axisymmetric singly quantized vortex has been established through analytical and numerical studies in both the strong-pairing regime (where the SF phase is understood as a Bose-Einstein condensate (BEC) of bosonic molecules) and in the weak-pairing Bardeen Cooper Schrieffer (BCS) regime. In the BEC regime, the microscopic Gross-Pitaevskii equation provides a reliable framework [9,10], while in the BCS regime the (selfconsistent) Bogoliubov-deGennes (BdG) theory is key in identifying the structure of the ground state [11,12] and the spectrum of sub-gap fermionic excitations [13].Multiply quantized vortices (MQVs) have however not received much attention. Generically in a homogeneous bulk system, the logarithmic repulsion between vortices, which scales as the square of the vortex winding number k, energetically favors an instability of a multiply quantized vortex into separated elementary unit vortices [14]. However, MQVs are of interest since under certain circumstances, the interaction between vortices is not purely repulsive and can support multi-vortex bound states, at least as metastable defects. This can happen, for instance, in type-II mesoscopic superconductors, where MQVs have been predicted [15] and experimentally observed [16][17][18][19]. In addition, it has been argued that MQVs are expected to be energetically stable in multicomponent superconductors [20,21] and in chiral p-wave superconductors [22,23]. In fermionic SFs, a doubly quantized vortex was predicted [24] and observed in 3 He-A [25]. It has further been argued that fast rotating Fermi gases trapped in an anharmonic potential will support an MQV state [26][27][28]. Similar vortex states have been created in rotating BEC experiments [29][30][31][32].Surprisingly, as we demonstrate in this Letter, there is a fundamental difference between a singly quantized vortex (|k| = 1) and an MQV (|k| > 1) in a wea...

show abstract

“…This bending is a symmetry breaking effect, and it can be understood by noticing that a radially centered vortex is favored at the axial center of the cigar, where the density is large, whereas it costs less energy to radially off-center the vortex line at the ends of the cigar, where the density is low [44,45,46,47,48,49]. Some specific normal modes of the vortex line have also been observed, such as the precession of a single vortex when it is not aligned with the trap axes [50,51,52,53], and the Kelvin mode of the vortex line (see Fig. 2) [54,55,56,57,58].…”

Section: Single Vortex Physicsmentioning

confidence: 99%

Bose-Einstein condensates in fast rotation

et al. 2005

View full text Add to dashboard Cite

In this short review we present our recent results concerning the rotation of atomic Bose-Einstein condensates confined in quadratic or quartic potentials, and give an overview of the field. We first describe the procedure used to set an atomic gas in rotation and briefly discuss the physics of condensates containing a single vortex line. We then address the regime of fast rotation in harmonic traps, where the rotation frequency is close to the trapping frequency. In this limit the Landau Level formalism is well suited to describe the system. The problem of the condensation temperature of a fast rotating gas is discussed, as well as the equilibrium shape of the cloud and the structure of the vortex lattice. Finally we review results obtained with a quadratic + quartic potential, which allows to study a regime where the rotation frequency is equal to or larger than the harmonic trapping frequency.

show abstract

Experimental Observation of a Superfluid Gyroscope in a Dilute Bose-Einstein Condensate

Cited by 33 publications

References 18 publications

Structure of excited vortices with higher angular momentum in Bose-Einstein condensates

Structure of excited vortices with higher angular momentum in Bose-Einstein condensates

Multiply Quantized Vortices in Fermionic Superfluids: Angular Momentum, Unpaired Fermions, and Spectral Asymmetry

Bose-Einstein condensates in fast rotation

Contact Info

Product

Resources

About