Bulletin of the American Physical Society
43rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 57, Number 5
Monday–Friday, June 4–8, 2012; Orange County, California
Session B2: Atomic Spin Dynamics |
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Chair: Chandra Raman, Georgia Tech Room: Grand Ballroom GF |
Tuesday, June 5, 2012 10:30AM - 10:42AM |
B2.00001: Spin instabilities in an ultra-cold gas Jeffrey McGuirk, Dorna Niroomand, Lydia Zajiczek We study spin dynamics and instabilities in an out-of-equilibrium quantum gas. Using an optical technique, we imprint arbitrary one-dimensional spin structures in a trapped gas of $^{87}$Rb atoms near quantum degeneracy. These spin structures can exhibit instabilities, such as the Castaing instability, in which a strong longitudinal spin gradient is unstable to transverse perturbations. This instability can lead to large-amplitude spontaneous transverse magnetization oscillations. We report on progress towards driving and observing these instabilities. [Preview Abstract] |
Tuesday, June 5, 2012 10:42AM - 10:54AM |
B2.00002: Spatial modulation of immiscible $^{87}$Rb hyperfine states Daniel Campbell, Ryan Price, Subhadeep De, Ian Spielman Using adiabatic rapid passage in the presence of RF dressing, atoms are transferred to an eigenstate with equal $m_f=-1$ and $m_f=+1$ components in the $F=1$ ground state manifold of $^{87}$Rb. There exists a critical coupling where the spin mixing term of the RF dressing competes with the energy gain of spin ordering due to the spin dependent interaction term. We investigate the relationship between the number of spin domains and the quench of RF dressing. [Preview Abstract] |
Tuesday, June 5, 2012 10:54AM - 11:06AM |
B2.00003: Non-equilibrium Spin Domains in Quenched Sodium Spinor Bose-Einstein condensates Anshuman Vinit, Eva Bookjans, Chandra Raman We report spontaneous spin domain formation in sodium Bose-Einstein condensates that are quenched, i.e. rapidly tuned, through a quantum phase transition from polar to antiferromagnetic phases. A microwave ``dressing'' field globally shifts the energy of the $m_F = 0$ level below the average of the $m_F = \pm 1$ energy levels, inducing a dynamical instability recently uncovered by our group [1]. We use local spin measurements to quantify the spatial ordering kinetics in the vicinity of the phase transition. For an elongated BEC, the instability nucleates small antiferromagnetic domains near the center of the polar condensate that grow in time along one spatial dimension. After a rapid nucleation and coarsening phase, the system exhibits long timescale non-equilibrium dynamics without relaxing to a uniform antiferromagnetic phase. \\[4pt] [1] E. M. Bookjans, A. Vinit, and C. Raman, Phys. Rev. Lett. 107, 195306 (2011). [Preview Abstract] |
Tuesday, June 5, 2012 11:06AM - 11:18AM |
B2.00004: Dynamics of multi-component fermions in optical lattices Christoph Becker, Jasper Simon Krauser, Jannes Heinze, Nick Fl\"aschner, S\"oren G\"otze, Klaus Sengstock Quantum gases in optical lattices offer intriguing possibilities for quantum simulation due to the full control over lattice and interaction parameters as well as the internal atomic degrees of freedom. In our setup, we produce different interacting spin-mixtures of fermionic K atoms and load them into an optical lattice. The atoms behave similar to electrons in a crystal. However, in contrast to spin-1/2 electrons, potassium possesses high spin, which has important effects on the properties of the system. We induce dynamics by quenching the system from a polarized to a non-polarized regime and compare our experimental data to theoretical calculations. In the latter, we assume a simplified two-particle model which is in very good agreement with our observations. Extending the calculations to larger many-body system may guide the experiment to study complex fermionic lattice-systems beyond conventional spin-1/2 systems. [Preview Abstract] |
Tuesday, June 5, 2012 11:18AM - 11:30AM |
B2.00005: Properties of excited states of a one-dimensional gas of spin-1 Bose atoms in a magnetic field Vladimir Yurovsky Zeeman shifts of atom energies in an inhomogeneous magnetic field depend on the spin and coordinate states of the atoms. This dependence lifts the integrability of a Yang --- Gaudin one-dimensional spinor gas with zero-range interactions. Eigenstates of such a gas of Bose atoms with two spin states are analyzed here using symmetric group representations. The system has three integrable points: the ideal and Tonks-Gerardeau gases at zero and infinitely-strong interatomic interactions, respectively, and the Yang solution at the zero magnetic field (see, e.g., [1]). Approximate eigenenergies and eigenfunctions are evaluated in the vicinity of each of the integrable points. Applicability ranges of corresponding approximations are estimated in dependence of the number of atoms.\\[4pt] [1] V. A. Yurovsky, M. Olshanii, and D. S. Weiss, Adv. At. Mol. Opt. Phys. {\bf 55}, 61 (2008). [Preview Abstract] |
Tuesday, June 5, 2012 11:30AM - 11:42AM |
B2.00006: Matter-wave amplification in a seeded $^{23}$Na spinor Bose-Einstein condensate Jonathan Wrubel, Hyewon Pechkis, Paul Griffin, Ryan Barnett, Eite Tiesinga, Paul Lett In an $F=1$ spinor condensate, spin-changing interactions of atoms in the $|m_{F_A},m_{F_B}\rangle = |0,0\rangle$ state can only produce the $|0,0\rangle$ (unchanged) or $|1,-1\rangle$ states. Because of the ideally perfect correlation in the production of $m_F=-1$ and $m_F=+1$ atoms, the magnetization $m=n_{m_F=+1}-n_{m_F=-1}$ is a squeezed quadrature of the system. Here we use a microwave-dressed $^{23}$Na Bose-Einstein condensate to create a nonlinear matter-wave amplifier which can produce spin-squeezed states. We then use microwaves to transfer a fraction of the $m_F=0$ condensate into a coherent seed of $m_{F}=+1$ atoms. After some evolution time, we show that $n_{m_F=+1}$ can be used as a large amplitude measurement of only a few atoms initially in the $m_F=-1$ state. This kind of measurement may be important in achieving high phase sensitivity in Heisenberg-limited matter-wave interferometers. [Preview Abstract] |
Tuesday, June 5, 2012 11:42AM - 11:54AM |
B2.00007: Manipulating dipolar and spin-exchange interactions in spin-1 Bose-Einstein condensates Bo-Yuan Ning, S. Yi, Jun Zhuang, J.Q. You, Wenxian Zhang For a spin-1 Bose-Einstein condensate (BEC), it has been a challenge to experimentally single out the effects of the magnetic dipolar and the spin-exchange interactions, which are usually entangled together and cooperatively determine the spin dynamics. In this work, we develop a generalized WAHUHA rf pulse sequence to suppress dipolar interaction and employ the periodic dynamical decoupling optical pulse sequence to suppress the spin-exchange interaction through Freshbach resonance, respectively. Our results demonstrate that the two sequences are independent of each other and suppress substantially the spin interaction. With this scheme, it is possible to make one spin interaction overwhelm the other and dominate the spin dynamics, so that one can investigate unambiguously the effects of the corresponding spin interaction. Moreover, the two sequences can be applied together to freeze the spin dynamics, which provides an opportunity to manufacture more sensitive magnetometers based on spin-1 BECs. Our method is easy to implement in experiments and is useful to investigate individually the effects of each spin interaction in spinor BECs. [Preview Abstract] |
Tuesday, June 5, 2012 11:54AM - 12:06PM |
B2.00008: Quantum Spin Dynamics in Spin-1 BEC Corey Gerving, Thai Hoang, Ben Land, Martin Anquez, Chris Hamley, Michael Chapman Current study in quantum dynamical evolution of complex systems investigates quantum many-body systems characterized by fluctuations and quantum correlations. Advances in cold atom physics have provided new tools for exploring important topics in this area including atomic squeezed states and non-equilibrium dynamics of many-body quantum systems. Here, we study quantum spin dynamics of a spin-1 condensate. [Preview Abstract] |
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