Spinor condensate of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Rb</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>87</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>as a dipolar gas

Świsłocki, Tomasz; Brewczyk, Mirosław; Gajda, Mariusz; Rza̧żewski, Kazimierz

doi:10.1103/physreva.81.033604

Cited by 24 publications

(16 citation statements)

References 27 publications

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“…The dynamics of this quantum phase transition has been investigated in Refs. [5,[24][25][26][27][28]. When q < 0, the fully polarized state with m = 1 or −1 can minimize both the ferromagnetic interaction and the quadratic Zeeman energy.…”

Section: Ground-state Phase Diagram In the Absence Of Mddimentioning

confidence: 99%

Spontaneous magnetic ordering in a ferromagnetic spinor dipolar Bose-Einstein condensate

et al. 2010

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We study the spin dynamics of a spin-1 ferromagnetic Bose-Einstein condensate with magnetic dipole-dipole interaction (MDDI) based on the Gross-Pitaevskii and Bogoliubov theories. We find that various magnetic structures such as checkerboards and stripes emerge in the course of the dynamics due to the combined effects of spin-exchange interaction, MDDI, quadratic Zeeman and finite-size effects, and nonstationary initial conditions. However, the short-range magnetic order observed by the Berkeley group [Phys. Rev. Lett. 100, 170403 (2008)] is not fully reproduced in our calculations; the periodicity of the order differs by a factor of 3 and the checkerboard pattern eventually dissolves in the course of time. Possible reasons for the discrepancy are discussed.

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Section: Ground-state Phase Diagram In the Absence Of Mddimentioning

confidence: 99%

Spontaneous magnetic ordering in a ferromagnetic spinor dipolar Bose-Einstein condensate

et al. 2010

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“…It is certainly less obvious that alkali atoms (whose magnetic dipole moment is an order of magnitude lower than that of chromium atoms) might be a good candidate to observe how spin is transmitted into orbital motion. However, some authors suggested that the magnetic dipolar interactions could already lead to observable effects in condensates of alkali atoms [9,[11][12][13][14][15][16][17]. Also a first experiment showed that a spin-1 87 Rb spinor condensate can exhibit dipolar properties [18].In this Letter we demonstrate that controlling the dipolar interactions by using an oscillating magnetic field is a perfect way to observe the Eintein-de Haas effect in alkali condensates provided it is done under a resonance condition.…”

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confidence: 99%

How to Observe Dipolar Effects in Spinor Bose-Einstein Condensates

2011

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We propose an experiment which proves the possibility of spinning gaseous media via dipolar interactions in the spirit of the famous Einstein-de Haas effect for ferromagnets. The main idea is to utilize resonances we find in spinor condensates of alkali atoms while these systems are placed in an oscillating magnetic field. A significant transfer of angular momentum from spin to motional degrees of freedom observed on resonance is a spectacular manifestation of dipolar effects in spinor condensates.Historically, first attempts at proving the relationship between magnetism and angular momentum (i.e., the Ampère's hypothesis on "molecular currents") were already performed in the 19th century [1]. They were all unsuccessful because of difficulties in measuring the tiny forces involved in the process. The efforts continued in the beginning of 20th century resulted in the emergence of a new class of effects named as magnetomechanical. The most known is certainly the Einstein-de Haas effect [2] in which a magnetized ferromagnetic rod is forced to rotate when its magnetization is reversed. In the experiment the magnetomechanical ratio is measured and its value can be directly related to the motion of electrons in the rod. It tells us how large a portion of magnetization comes from the spin of electrons and how large from the orbital motion of electrons.Experiments with neutral "molecular currents" would be of particular interest in proving the direct and sole relation between the spin and the magnetization of the system. The recent realization of chromium condensates [3] has launched huge interest in ultracold dipolar systems [4,5] which would be an ideal candidate for such studies. Although spectacular features due to dipolar forces related to expansion [6] and collapse [7] were already observed, the Einstein-de Haas effect so far remains elusive. A route towards observing the Einstein-de Haas effect in chromium condensates via controlling the magnetic field was recently suggested [8,9] and first experiments demonstrated the possibility to control the dipolar relaxation rate in this way [10].It is tempting to test these concepts also in alkali systems which represent the majority of experiments. It is certainly less obvious that alkali atoms (whose magnetic dipole moment is an order of magnitude lower than that of chromium atoms) might be a good candidate to observe how spin is transmitted into orbital motion. However, some authors suggested that the magnetic dipolar interactions could already lead to observable effects in condensates of alkali atoms [9,[11][12][13][14][15][16][17]. Also a first experiment showed that a spin-1 87 Rb spinor condensate can exhibit dipolar properties [18].In this Letter we demonstrate that controlling the dipolar interactions by using an oscillating magnetic field is a perfect way to observe the Eintein-de Haas effect in alkali condensates provided it is done under a resonance condition. In the following we explain our reasoning in detail.The equation of motion for a spinor condensate in t...

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“…In the system composed of 52 Cr atoms [25][26][27][28] Feshbach resonances can enhance the effect of dipole-dipole forces. It was suggested in [29][30][31][32][33], and confirmed in [34], that dipolar effects may be observed also in the spinor F = 1 87 Rb BEC. The existence of long-range interactions is a motivating factor for studing systematically the effect of dipolar interactions on the level of squeezing in the simplest F = 1 spinor BECs.…”

Section: Introductionmentioning

confidence: 98%

Spin squeezing in dipolar spinor condensates

Kajtoch

Witkowska

2016

Phys. Rev. A

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We study the effect of dipolar interactions on the level of squeezing in spin-1 Bose-Einstein condensates by using the single mode approximation. We limit our consideration to the su(2) Lie subalgebra spanned by spin operators. The biaxial nature of dipolar interactions allows for dynamical generation of spin-squeezed states in the system. We analyze the phase portraits in the reduced mean-filed space in order to determine positions of unstable fixed points. We calculate numerically spin squeezing parameter showing that it is possible to reach the strongest squeezing set by the two-axis countertwisting model. We partially explain scaling with the system size by using the Gaussian approach and the frozen spin approximation.

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Spinor condensate ofRb87as a dipolar gas

Cited by 24 publications

References 27 publications

Spontaneous magnetic ordering in a ferromagnetic spinor dipolar Bose-Einstein condensate

Spontaneous magnetic ordering in a ferromagnetic spinor dipolar Bose-Einstein condensate

How to Observe Dipolar Effects in Spinor Bose-Einstein Condensates

Spin squeezing in dipolar spinor condensates

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