Interferometric measurement of interhyperfine scattering lengths in Rb87

Abstract

We present interferometeric measurements of the f = 1 to f = 2 inter-hyperfine scattering lengths in a single-domain spinor Bose-Einstein condensate of 87 Rb. The inter-hyperfine interaction leads to a strong and state-dependent modification of the spin-mixing dynamics with respect to a non-interacting description. We employ hyperfine-specific Faraday-rotation probing to reveal the evolution of the transverse magnetization in each hyperfine manifold for different state preparations, and a comagnetometer strategy to cancel laboratory magnetic noise. The method allows precise determination of inter-hyperfine scattering length differences, calibrated to intra-hyperfine scattering length differences. We report (a (12) 3 −a (12) 2 )/(a (1) 2 −a (1) 0 ) = −1.27(15) and (a (12) 1 −a (12) 2 )/(a (1) 2 −a (1) 0 ) = −1.31(13), limited by atom number uncertainty. With achievable control of atom number, we estimate precisions of ≈0.3 % should be possible with this technique.

Intrinsic Decoherence and Recurrences in a Large Ferromagnetic F = 1 Spinor Bose–Einstein Condensate

“…It is of interest for our purposes that the experiments in ultracold gases showing Bose-Einstein condensation [19][20][21][22] are the closest to dealing with true isolated systems. Yet, these gases, due to atomic collisions, relax to equilibrium and, when in the presence of external magnetic fields, show decoherence phenomena [23,24]. The study of the magnetization of the latter case is the subject of the present article.…”

“…The diagonal terms g jj (θ) are all equal, shown in Figure 9. The initial condition is given again by the matrix in Equation (23). show the density matrix ρ jk (t) and the expectation value of the operatorf x for a single example in the limit N|η|/q 1 (η = −10 −5 and q = 7, for N = 300).…”

“…To be precise, within a full quantum scheme, we study here the phenomenon of intrinsic decoherence, as well as the appearance of recurrences, in the time dynamics of an F = 1 Spinor Bose-Einstein Condensate (SBEC) composed of a mixture of three different hyperfine spin components, in the presence of a uniform magnetic field, starting in a well-defined coherent state. Depending on the sign of the spin-mixing interaction strength, the atomic cloud can be polar if positive, such as a gas of 23 Na atoms, or ferromagnetic if negative, as in a gas of 87 Rb atoms [32,33]. We shall study here the ferromagnetic case only since the condensate acquires a macroscopic spin texture that makes it behave as a "giant" spin.…”

Bose-Einstein Condensate Comagnetometer

“…Other potential applications include precision measurements of cold collision physics in ultracold quantum gases [30], and angle-resolved spin amplification. Spin amplifiers use coherent collision processes in a BEC to achieve high-gain, quantum-noise limited amplification of small spin perturbations [44].…”

“…and effective volume V eff are defined in [30]. When η (f ) 1 the orientationto-alignment oscillations are suppressed, which prevents hyperfine-relaxing collisions in initially stretched f = 2 states.…”