Hyperfine Interactions of Interacting Atoms.

Collisions with chemically inert atoms or molecules change the hyperfine coupling $A\phantom{\rule{0.16em}{0ex}}\mathbf{I}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{S}$ of an alkali-metal atom through the hyperfine-shift interaction $\ensuremath{\delta}A\phantom{\rule{0.16em}{0ex}}\mathbf{I}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{S}$. This interaction is responsible for the pressure shifts of the microwave resonances of alkali-metal atoms in buffer gases, is an important spin interaction in alkali-metal--noble-gas van der Waals molecules, and is anticipated to enable the magnetoassociation of ultracold molecules such as RbSr. An improved estimate is presented for the long-range asymptote of this interaction for Na, K, Rb, and Cs. To test the results, the change in hyperfine coupling due to a static electric field is estimated and reasonable agreement is found.Collisions with chemically inert atoms or molecules change the hyperfine coupling $A\phantom{\rule{0.16em}{0ex}}\mathbf{I}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{S}$ of an alkali-metal atom through the hyperfine-shift interaction $\ensuremath{\delta}A\phantom{\rule{0.16em}{0ex}}\mathbf{I}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{S}$. This interaction is responsible for the pressure shifts of the microwave resonances of alkali-metal atoms in buffer gases, is an important spin interaction in alkali-metal--noble-gas van der Waals molecules, and is anticipated to enable the magnetoassociation of ultracold molecules such as RbSr. An improved estimate is presented for the long-range asymptote of this interaction for Na, K, Rb, and Cs. To test the results, the change in hyperfine coupling due to a static electric field is estimated and reasonable agreement is found.

arXiv:1306.0048Physical Review AMay 31, 20136 citations

Theory of Hyperfine Effects in Interacting Atoms.

Bijan Kumar Rao

Jan 1, 19710 citations

The effects of hyperfine interactions on collisions between optically trapped atoms

Thad G Walker, P.Y. Feng, Dominikus Hoffmann

The authors report measurements of excited state collision rates of optically trapped {sup 85}Rb and {sup 87}Rb. The collision rates have been measured in the vicinity of the P{sub 3/2} and P{sub 1/2} states of both isotopes. By studying the collision rates as a function of the frequency of light used to cause the collisions, they obtain collision spectra that reveal the importance of hyperfine interactions on the collision dynamics. In certain frequency ranges the collision rates for the two isotopes are nearly identical, while in others they find substantially reduced rates for {sup 87}Rb (large hyperfine interaction) as compared to {sup 85}Rb (small hyperfine interaction). For the P{sub 1/2} states, where hyperfine splittings are large compared to the characteristic frequency scales for these collisions, the shapes of the spectra more closely correspond to those expected from simple models that neglect hyperfine interactions.The authors report measurements of excited state collision rates of optically trapped {sup 85}Rb and {sup 87}Rb. The collision rates have been measured in the vicinity of the P{sub 3/2} and P{sub 1/2} states of both isotopes. By studying the collision rates as a function of the frequency of light used to cause the collisions, they obtain collision spectra that reveal the importance of hyperfine interactions on the collision dynamics. In certain frequency ranges the collision rates for the two isotopes are nearly identical, while in others they find substantially reduced rates for {sup 87}Rb (large hyperfine interaction) as compared to {sup 85}Rb (small hyperfine interaction). For the P{sub 1/2} states, where hyperfine splittings are large compared to the characteristic frequency scales for these collisions, the shapes of the spectra more closely correspond to those expected from simple models that neglect hyperfine interactions.

Bulletin of the American Physical SocietyDec 1, 19930 citations

On the role of hyperfine-interactions-mediated Zeeman effect in the condensation temperature shift of trapped atomic Bose-Einstein condensates

Fabio Briscese, S. Sergeenkov, M. Grether +1 more

We discuss the effect of interatomic interactions on the condensation temperature $T_c$ of a laboratory atomic Bose-Einstein condensate under the influence of an external trapping magnetic field. We predict that accounting for hyperfine interactions mediated Zeeman term in the mean-field approximation produces, in the case of the $403 \, G$ Feshbach resonance in the $|F,m_F> = |1,1>$ hyperfine state of a $^{39}K$ condensate, with $F$ the total spin of the atom, an experimentally observed (and not yet explained) shift in the condensation temperature $ΔT_{c}/T_{c}^{0}=b^{*}_0+b^{*}_1 (a/λ_{T}) + b^{*}_2 (a/λ_{T})^2$ with $b^{*}_0 \simeq 0.0002$ , $b^{*}_1 \simeq -3.4$ and $b^{*}_2 \simeq 47$ , where $a$ is the s-wave scattering length, and $λ_T$ is the thermal wavelength at $T_{c}^{0}$ . Generic expressions for the coefficients $b^*_0$ , $b^*_1$ and $b^*_2$ are also obtained, which can be used to predict the temperature shift for other Feshbach resonances of $^{39}K$ or other atomic condensates.We discuss the effect of interatomic interactions on the condensation temperature $T_c$ of a laboratory atomic Bose-Einstein condensate under the influence of an external trapping magnetic field. We predict that accounting for hyperfine interactions mediated Zeeman term in the mean-field approximation produces, in the case of the $403 \, G$ Feshbach resonance in the $|F,m_F> = |1,1>$ hyperfine state of a $^{39}K$ condensate, with $F$ the total spin of the atom, an experimentally observed (and not yet explained) shift in the condensation temperature $ΔT_{c}/T_{c}^{0}=b^{*}_0+b^{*}_1 (a/λ_{T}) + b^{*}_2 (a/λ_{T})^2$ with $b^{*}_0 \simeq 0.0002$, $b^{*}_1 \simeq -3.4$ and $b^{*}_2 \simeq 47$, where $a$ is the s-wave scattering length, and $λ_T$ is the thermal wavelength at $T_{c}^{0}$. Generic expressions for the coefficients $b^*_0$, $b^*_1$ and $b^*_2$ are also obtained, which can be used to predict the temperature shift for other Feshbach resonances of $^{39}K$ or other atomic condensates.

arXiv:1409.4231Sep 15, 20140 citations

We discuss the effect of interatomic interactions on the condensation temperature

T_c

of a laboratory atomic Bose-Einstein condensate under the influence of an external trapping magnetic field. We predict that accounting for hyperfine interactions mediated Zeeman term in the mean-field approximation produces, in the case of the

403 \, G

Feshbach resonance in the

|F,m_F> = |1,1>

hyperfine state of a

^{39}K

condensate, with

F

the total spin of the atom, an experimentally observed (and not yet explained) shift in the condensation temperature

ΔT_{c}/T_{c}^{0}=b^{*}_0+b^{*}_1 (a/λ_{T}) + b^{*}_2 (a/λ_{T})^2

with

b^{*}_0 \simeq 0.0002

b^{*}_1 \simeq -3.4

and

b^{*}_2 \simeq 47

, where

a

is the s-wave scattering length, and

λ_T

is the thermal wavelength at

T_{c}^{0}

. Generic expressions for the coefficients

b^*_0

b^*_1

and

b^*_2

are also obtained, which can be used to predict the temperature shift for other Feshbach resonances of

^{39}K

or other atomic condensates.