Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δ a ( S · I ) of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δ a ( S · I ) of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δ a ( S · I ) of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δ a ( S · I ) of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.

Chinese PhysicsMar 20, 20073 citations

Zeeman relaxation of cold atomic iron and nickel in collisions with He3

Cort Johnson, Bonna K. Newman, Nathan Brahms +3 more

We have measured the ratio $\ensuremath{\gamma}$ of the diffusion cross section to the angular momentum reorientation cross section in the colliding Fe- $^{3}\mathrm{He}$ and Ni- $^{3}\mathrm{He}$ systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold ( $<1$ K) $^{3}\mathrm{He}$ buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the $^{3}\mathrm{He}$ temperature. $\ensuremath{\gamma}$ is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine $\ensuremath{\gamma}$ accurately, we introduce a model of Zeeman-state dynamics that includes thermal excitations. We find ${\ensuremath{\gamma}}_{\mathrm{Ni}{\ensuremath{-}}^{3}\mathrm{He}}=5\ifmmode\times\else\texttimes\fi{}{10}^{3}$ and ${\ensuremath{\gamma}}_{\mathrm{Fe}{\ensuremath{-}}^{3}\mathrm{He}}\ensuremath{\leqslant}3\ifmmode\times\else\texttimes\fi{}{10}^{3}$ at 0.75 K in a 0.8-T magnetic field. These measurements are interpreted in the context of submerged shell suppression of spin relaxation, as studied previously in transition metals and rare-earth-metal atoms [C. I. Hancox, S. C. Doret, M. T. Hummon, R. V. Krems, and J. M. Doyle, Phys. Rev. Lett. 94, 013201 (2005); C. I. Hancox, S. C. Doret, M. T. Hummon, L. Luo, and J. M. Doyle, Nature (London) 431, 281 (2004); A. Buchachenko, G. Chaasiski, and M. Szczniak, Eur. Phys. J. D 45, 147 (2007)].We have measured the ratio $\ensuremath{\gamma}$ of the diffusion cross section to the angular momentum reorientation cross section in the colliding Fe-$^{3}\mathrm{He}$ and Ni-$^{3}\mathrm{He}$ systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold ($<1$ K) $^{3}\mathrm{He}$ buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the $^{3}\mathrm{He}$ temperature. $\ensuremath{\gamma}$ is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine $\ensuremath{\gamma}$ accurately, we introduce a model of Zeeman-state dynamics that includes thermal excitations. We find ${\ensuremath{\gamma}}_{\mathrm{Ni}{\ensuremath{-}}^{3}\mathrm{He}}=5\ifmmode\times\else\texttimes\fi{}{10}^{3}$ and ${\ensuremath{\gamma}}_{\mathrm{Fe}{\ensuremath{-}}^{3}\mathrm{He}}\ensuremath{\leqslant}3\ifmmode\times\else\texttimes\fi{}{10}^{3}$ at 0.75 K in a 0.8-T magnetic field. These measurements are interpreted in the context of submerged shell suppression of spin relaxation, as studied previously in transition metals and rare-earth-metal atoms [C. I. Hancox, S. C. Doret, M. T. Hummon, R. V. Krems, and J. M. Doyle, Phys. Rev. Lett. 94, 013201 (2005); C. I. Hancox, S. C. Doret, M. T. Hummon, L. Luo, and J. M. Doyle, Nature (London) 431, 281 (2004); A. Buchachenko, G. Chaasiski, and M. Szczniak, Eur. Phys. J. D 45, 147 (2007)].

arXiv:1003.1106Physical Review AJun 21, 20107 citations

Transitions in Two-Level Systems in Atomic Collisions

E. Duman

peacJan 1, 19750 citations

We have measured the ratio $\ensuremath{\gamma}$ of the diffusion cross section to the angular momentum reorientation cross section in the colliding Fe-

^{3}\mathrm{He}

and Ni-

^{3}\mathrm{He}

systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold (

<1

^{3}\mathrm{He}

buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the

^{3}\mathrm{He}

temperature. $\ensuremath{\gamma}$ is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine $\ensuremath{\gamma}$ accurately, we introduce a model of Zeeman-state dynamics that includes thermal excitations. We find ${\ensuremath{\gamma}}_{\mathrm{Ni}{\ensuremath{-}}^{3}\mathrm{He}}=5\ifmmode\times\else\texttimes\fi{}{10}^{3}$ and ${\ensuremath{\gamma}}_{\mathrm{Fe}{\ensuremath{-}}^{3}\mathrm{He}}\ensuremath{\leqslant}3\ifmmode\times\else\texttimes\fi{}{10}^{3}$ at 0.75 K in a 0.8-T magnetic field. These measurements are interpreted in the context of submerged shell suppression of spin relaxation, as studied previously in transition metals and rare-earth-metal atoms [C. I. Hancox, S. C. Doret, M. T. Hummon, R. V. Krems, and J. M. Doyle, Phys. Rev. Lett. 94, 013201 (2005); C. I. Hancox, S. C. Doret, M. T. Hummon, L. Luo, and J. M. Doyle, Nature (London) 431, 281 (2004); A. Buchachenko, G. Chaasiski, and M. Szczniak, Eur. Phys. J. D 45, 147 (2007)].