Ultracold collisions between metastable bosonic ${}^{88}$ Sr [ $(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}$ ] and fermionic ${}^{87}$ Sr [ $(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}$ $(i=9/2)$ ] atoms are investigated based on an approach of tensorial analysis. The scattering physics of two atoms in fully polarized $s$ -wave entrance channels is studied in detail. In the Born-Oppenheimer approximation, the strong anisotropic interatomic interaction is demonstrated to induce formations of long-range molecular potential wells. However, besides significantly modifying the elastic scattering, the anisotropic interatomic interaction leads to the strong multichannel coupling between different partial waves, which triggers a high rate of inelastic losses. By applying an external static magnetic field ${\mathbf{B}}_{0}={\mathcal{B}}_{0}{\mathbf{e}}_{\mathrm{z}}$ , the inelastic scattering can be suppressed while the elastic scattering is significantly enhanced. Additionally, the energy-dependent complex $s$ -wave scattering lengths at a given relative collision energy strongly depend on the strength of magnetic field. We, moreover, self-consistently investigate ultracold collisions of two atoms at low temperatures in an optical lattice site. In the $\ensuremath{\delta}$-function pseudopotential approximation, we derive the effective $s$ -wave scattering lengths, energy eigenvalues, elastic and inelastic scattering rates, and their dependence on the external magnetic field. We find that (i) the effective scattering lengths of ultracold atoms in entrance channels of interest display resonance behavior at certain values of magnetic field and (ii) the extra Zeeman interaction not only leads to the suppression of inelastic scattering but also enlarges the elastic scattering rates.Ultracold collisions between metastable bosonic ${}^{88}$Sr [$(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}$] and fermionic ${}^{87}$Sr [$(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}$ $(i=9/2)$] atoms are investigated based on an approach of tensorial analysis. The scattering physics of two atoms in fully polarized $s$-wave entrance channels is studied in detail. In the Born-Oppenheimer approximation, the strong anisotropic interatomic interaction is demonstrated to induce formations of long-range molecular potential wells. However, besides significantly modifying the elastic scattering, the anisotropic interatomic interaction leads to the strong multichannel coupling between different partial waves, which triggers a high rate of inelastic losses. By applying an external static magnetic field ${\mathbf{B}}_{0}={\mathcal{B}}_{0}{\mathbf{e}}_{\mathrm{z}}$, the inelastic scattering can be suppressed while the elastic scattering is significantly enhanced. Additionally, the energy-dependent complex $s$-wave scattering lengths at a given relative collision energy strongly depend on the strength of magnetic field. We, moreover, self-consistently investigate ultracold collisions of two atoms at low temperatures in an optical lattice site. In the $\ensuremath{\delta}$-function pseudopotential approximation, we derive the effective $s$-wave scattering lengths, energy eigenvalues, elastic and inelastic scattering rates, and their dependence on the external magnetic field. We find that (i) the effective scattering lengths of ultracold atoms in entrance channels of interest display resonance behavior at certain values of magnetic field and (ii) the extra Zeeman interaction not only leads to the suppression of inelastic scattering but also enlarges the elastic scattering rates.

Physical Review ASep 6, 20122 citations

Universal stereodynamics of cold atom-molecule collisions in electric fields

Timur V. Tscherbul, Jacek A. Kłos

We use numerically exact quantum dynamics calculations to demonstrate universal stereoselectivity of cold collisions of $^{2}\mathrm{\ensuremath{\Pi}}$ molecules with $^{1}\mathrm{S}$ -state atoms in an external electric field. We show that cold collisions of OH molecules in their low-field-seeking $f$ -states, whose dipole moments are oriented against the field direction, are much more likely to lead to inelastic scattering than those of molecules oriented along the field direction, causing nearly perfect steric asymmetry in the inelastic collision cross sections. The universal nature of this effect is due to the threshold suppression of inelastic scattering between the degenerate $\ifmmode\pm\else\textpm\fi{}M$ Stark sublevels of the high-field-seeking $e$ -state, where $M$ is the projection of the total angular momentum of the molecule on the field axis. Above the $\mathrm{\ensuremath{\Lambda}}$-doublet threshold, the stereodynamics of inelastic atom-molecule collisions can be tuned via electric-field-induced resonances, which enable effective control of Ne $+$ OH scattering over the range of collision energies achievable in current merged beam experiments.We use numerically exact quantum dynamics calculations to demonstrate universal stereoselectivity of cold collisions of $^{2}\mathrm{\ensuremath{\Pi}}$ molecules with $^{1}\mathrm{S}$-state atoms in an external electric field. We show that cold collisions of OH molecules in their low-field-seeking $f$-states, whose dipole moments are oriented against the field direction, are much more likely to lead to inelastic scattering than those of molecules oriented along the field direction, causing nearly perfect steric asymmetry in the inelastic collision cross sections. The universal nature of this effect is due to the threshold suppression of inelastic scattering between the degenerate $\ifmmode\pm\else\textpm\fi{}M$ Stark sublevels of the high-field-seeking $e$-state, where $M$ is the projection of the total angular momentum of the molecule on the field axis. Above the $\mathrm{\ensuremath{\Lambda}}$-doublet threshold, the stereodynamics of inelastic atom-molecule collisions can be tuned via electric-field-induced resonances, which enable effective control of Ne $+$ OH scattering over the range of collision energies achievable in current merged beam experiments.

arXiv:2102.12760Physical Review AJun 23, 20213 citations

Atoms in a Magnetic Field: Quantum Mechanical Treatment

Hermann Haken, Hans Christoph Wolf

Springer eBooksJan 1, 19830 citations

Manipulation of p -Wave Scattering of Cold Atoms in Low Dimensions Using the Magnetic Field Vector

Shi-Guo Peng, Shina Tan, Kaijun Jiang

It is well known that the magnetic Feshbach resonances of cold atoms are sensitive to the magnitude of the external magnetic field. Much less attention has been paid to the direction of such a field. In this work we calculate the scattering properties of spin polarized fermionic atoms in reduced dimensions, near a p-wave Feshbach resonance. Because of the spatial anisotropy of the p-wave interaction, the scattering has a nontrivial dependence on both the magnitude and the direction of the magnetic field. In addition, we identify an inelastic scattering process which is impossible in the isotropic-interaction model; the rate of this process depends considerably on the direction of the magnetic field. Significantly, an Einstein-Podolsky-Rosen entangled pair of identical fermions may be produced during this inelastic collision. This work opens a new method to manipulate resonant cold atomic interactions.It is well known that the magnetic Feshbach resonances of cold atoms are sensitive to the magnitude of the external magnetic field. Much less attention has been paid to the direction of such a field. In this work we calculate the scattering properties of spin polarized fermionic atoms in reduced dimensions, near a p-wave Feshbach resonance. Because of the spatial anisotropy of the p-wave interaction, the scattering has a nontrivial dependence on both the magnitude and the direction of the magnetic field. In addition, we identify an inelastic scattering process which is impossible in the isotropic-interaction model; the rate of this process depends considerably on the direction of the magnetic field. Significantly, an Einstein-Podolsky-Rosen entangled pair of identical fermions may be produced during this inelastic collision. This work opens a new method to manipulate resonant cold atomic interactions.

arXiv:1312.3392Physical Review LettersJun 23, 201445 citations

Atoms in a Magnetic Field: Quantum Mechanical Treatment

Springer eBooksMay 23, 20060 citations

Ultracold collisions between metastable bosonic

{}^{88}

Sr [

(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}

] and fermionic

{}^{87}

Sr [

(5s5p){\phantom{\rule{0.16em}{0ex}}}^{3\phantom{\rule{-0.16em}{0ex}}}\phantom{\rule{-0.16em}{0ex}}{P}_{2}

(i=9/2)

] atoms are investigated based on an approach of tensorial analysis. The scattering physics of two atoms in fully polarized

s

-wave entrance channels is studied in detail. In the Born-Oppenheimer approximation, the strong anisotropic interatomic interaction is demonstrated to induce formations of long-range molecular potential wells. However, besides significantly modifying the elastic scattering, the anisotropic interatomic interaction leads to the strong multichannel coupling between different partial waves, which triggers a high rate of inelastic losses. By applying an external static magnetic field

{\mathbf{B}}_{0}={\mathcal{B}}_{0}{\mathbf{e}}_{\mathrm{z}}

, the inelastic scattering can be suppressed while the elastic scattering is significantly enhanced. Additionally, the energy-dependent complex

s

-wave scattering lengths at a given relative collision energy strongly depend on the strength of magnetic field. We, moreover, self-consistently investigate ultracold collisions of two atoms at low temperatures in an optical lattice site. In the $\ensuremath{\delta}$-function pseudopotential approximation, we derive the effective

s

-wave scattering lengths, energy eigenvalues, elastic and inelastic scattering rates, and their dependence on the external magnetic field. We find that (i) the effective scattering lengths of ultracold atoms in entrance channels of interest display resonance behavior at certain values of magnetic field and (ii) the extra Zeeman interaction not only leads to the suppression of inelastic scattering but also enlarges the elastic scattering rates.

We use numerically exact quantum dynamics calculations to demonstrate universal stereoselectivity of cold collisions of $^{2}\mathrm{\ensuremath{\Pi}}$ molecules with

^{1}\mathrm{S}

-state atoms in an external electric field. We show that cold collisions of OH molecules in their low-field-seeking

f

-states, whose dipole moments are oriented against the field direction, are much more likely to lead to inelastic scattering than those of molecules oriented along the field direction, causing nearly perfect steric asymmetry in the inelastic collision cross sections. The universal nature of this effect is due to the threshold suppression of inelastic scattering between the degenerate $\ifmmode\pm\else\textpm\fi{}M$ Stark sublevels of the high-field-seeking

e

-state, where

M

is the projection of the total angular momentum of the molecule on the field axis. Above the $\mathrm{\ensuremath{\Lambda}}$-doublet threshold, the stereodynamics of inelastic atom-molecule collisions can be tuned via electric-field-induced resonances, which enable effective control of Ne

+

OH scattering over the range of collision energies achievable in current merged beam experiments.