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Nikuni, Tetsuro; Williams, J. E.

doi:10.1023/a:1026206724886

Cited by 79 publications

(58 citation statements)

References 65 publications

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“…(A18) and (A19) in Appendix A. For a dilute Bose gas considered in this paper, one can neglect δU n [31,40].…”

Section: Derivation Of the Spin-1 Kinetic Equationmentioning

confidence: 99%

“…Even though the JILA experiments were done in relatively high-temperature regime T ∼ 2T BEC , where the quantum degeneracy has little effect on the thermodynamic properties, this spin-1/2 system exhibited collective spin dynamics due to the exchange effect, such as spin segregation [25,26,27,28], and spin-wave oscillations [24,29]. There have been many theoretical studies discussing collective spin oscillations in the spin-1/2 system [26,27,28,29,30,31,32,33,34], which showed very good agreement with the experiments [25,35,36].…”

Section: Introductionmentioning

confidence: 99%

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Spin Dynamics of a Trapped Spin-1 Bose Gas above the Bose-Einstein Transition Temperature

Endo

Nikuni

2008

J Low Temp Phys

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We study collective spin oscillations in a spin-1 Bose gas above the Bose-Einstein transition temperature. Starting from the Heisenberg equation of motion, we derive a kinetic equation describing the dynamics of a thermal gas with the spin-1 degree of freedom. Applying the moment method to the kinetic equation, we study spin-wave collective modes with dipole symmetry. The dipole modes in the spin-1 system are classified into the three types of modes. Frequencies and damping rates of the dipole modes are obtained as functions of the peak density. We find that the damping rate is characterized by three relaxation times associated with collisions.

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“…(A18) and (A19) in Appendix A. For a dilute Bose gas considered in this paper, one can neglect δU n [31,40].…”

Section: Derivation Of the Spin-1 Kinetic Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spin Dynamics of a Trapped Spin-1 Bose Gas above the Bose-Einstein Transition Temperature

Endo

Nikuni

2008

J Low Temp Phys

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Section: Introductionmentioning

confidence: 99%

“…In these systems quantum collisional effects can produce spatio-temporal spin oscillations (spin waves) [14][15][16][17]. The observation of collective dynamics of spin waves and spin-state segregation in trapped spinor Bose gases has stimulated a wide range of interest in studying magnetism, topological spin defects and novel quantum phase transitions in spinor Bose gases [18,19]. Two-component spinor Bose gases have been experimentally created in a magnetic trap by rotating two hyperfine states so that the two atomic hyperfine states make up a pseudo-spin doublet [20], e.g., the |F = 2, m F = −1 and |F = 1, m F = 1 hyperfine states of 87 Rb.…”

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confidence: 99%

Ferromagnetic behavior in the strongly interacting two-component Bose gas

2007

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We investigate the low temperature behaviour of the integrable 1D two-component spinor Bose gas using the thermodynamic Bethe ansatz. We find that for strong coupling the characteristics of the thermodynamics at low temperatures are quantitatively affected by the spin ferromagnetic states, which are described by an effective ferromagnetic Heisenberg chain. The free energy, specific heat, susceptibility and local pair correlation function are calculated for various physical regimes in terms of temperature and interaction strength. These thermodynamic properties reveal spin effects which are significantly different than those of the spinless Bose gas. The zero-field susceptibility for finite strong repulsion exceeds that of a free spin paramagnet. The critical exponents of the specific heat cv ∼ T 1/2 and the susceptibility χ ∼ T −2 are indicative of the ferromagnetic signature of the two-component spinor Bose gas. Our analytic results are consistent with general arguments by Eisenberg and Lieb for polarized spinor bosons.PACS numbers: 03.75. Hh, 03.75.Mn, 04.20.Jb, 05.30.Jp I. INTRODUCTIONExperiments with ultracold quantum gases are opening up exciting new possibilities for testing and exploring quantum effects in many-body systems (for recent reviews, see Refs. [1][2][3]). These include experiments on effectively one-dimensional (1D) quantum Bose gases of 87 Rb atoms in which the interaction strength between atoms is tunable [4][5][6][7][8]. The experiments provide a striking example of realizing an integrable quantum many-body problem. They demonstrate the explicit fermionization of bosons and provide a direct test of theoretical results obtained for the integrable 1D interacting (spinless) Bose gas [9,10]. Another frontier of activity involves spinor Bose gases of alkali atoms in which hyperfine states comprise the pseudospins [11][12][13]. In these systems quantum collisional effects can produce spatio-temporal spin oscillations (spin waves) [14][15][16][17]. The observation of collective dynamics of spin waves and spin-state segregation in trapped spinor Bose gases has stimulated a wide range of interest in studying magnetism, topological spin defects and novel quantum phase transitions in spinor Bose gases [18,19]. Two-component spinor Bose gases have been experimentally created in a magnetic trap by rotating two hyperfine states so that the two atomic hyperfine states make up a pseudo-spin doublet [20], e.g., the |F = 2, m F = −1 and |F = 1, m F = 1 hyperfine states of 87 Rb. In general, spin-independent s-wave scattering dominates interactions in alkali atomic gases. In 1D, the two-component Bose gas with spin-independent s-wave scattering can be exactly solved, like the spinless model, by means of the Bethe ansatz [21,22]. In contrast to Fermi gases, ferromagnetic order emerges in spinor Bose gases as long as the interaction is fully spin independent [15,23]. The low-energy excitations of the model split into collective excitations carrying charge and collective excitations carrying spin. The charge...

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“…Shortly afterward, they succeeded in confining 87 Rb atoms with two internal states |F = 2, m F = 1 and |F = 1, m F = −1 , which is called spin-1/2 Bose gas [4]. Spin-1/2 Bose gases are known to exhibit the collective spin dynamics due to the exchange effect even above the Bose-Einstein transition temperature (T BEC ) [5,6,7,8,9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Population Dynamics of a Spin-1 Bose Gas above the Bose–Einstein Transition Temperature

Endo

Nikuni

2009

J. Phys. Soc. Jpn.

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We study population dynamics of a trapped spin-1 Bose gas above the Bose-Einstein transition temperature. Starting from the semiclassical kinetic equation for a spin-1 gas, we derive a coupled rate equations for the populations of internal states. Solving the rate equations, we discuss the dynamical evolution of spin populations. We also estimate the characteristic timescale in which the system reaches equilibrium. Finally, we briefly discuss how the presence of the condensate will affect the population dynamics.

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Untitled

Cited by 79 publications

References 65 publications

Spin Dynamics of a Trapped Spin-1 Bose Gas above the Bose-Einstein Transition Temperature

Spin Dynamics of a Trapped Spin-1 Bose Gas above the Bose-Einstein Transition Temperature

Ferromagnetic behavior in the strongly interacting two-component Bose gas

Population Dynamics of a Spin-1 Bose Gas above the Bose–Einstein Transition Temperature

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