Collisional losses of ultracold molecules due to intermediate complex formation

Jachymski, Krzysztof; Gronowski, Marcin; Tomza, Michał

doi:10.48550/arxiv.2110.07501

Cited by 4 publications

(5 citation statements)

References 65 publications

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“…This is in qualitative agreement with experimental sticking times that match theory assuming spin conservation [39,40], and consistent with spin-conservation in KRb+KRb collisions [14], although recent results in RbCs collisions suggest the sticking time might be hyperfine state dependent [50]. The approach developed here opens the door to subsequent studies accounting for all hyperfine couplings, their interaction-induced variations [51], and to explore the case of non-zero electronic spin where the finestructure couplings may be orders of magnitude larger.…”

Section: Black Body Spontaneoussupporting

confidence: 87%

Symmetry breaking in sticky collisions between ultracold molecules

Man¹,

Groenenboom²,

Karman³

2022

Preprint

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Ultracold molecules undergo "sticky collisions" that result in loss even for chemically nonreactive molecules. Sticking times can be enhanced by orders of magnitude by interactions that lead to non-conservation of nuclear spin or total angular momentum. We present a quantitative theory of the required strength of such symmetry-breaking interactions based on classical simulation of collision complexes. We find static electric fields as small as 10 V/cm can lead to non-conservation of angular momentum, while we find nuclear spin is conserved during collisions. We also compute loss of collision complexes due to spontaneous emission and absorption of black-body radiation, which are found to be slow.

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Section: Black Body Spontaneoussupporting

confidence: 87%

Symmetry breaking in sticky collisions between ultracold molecules

Man¹,

Groenenboom²,

Karman³

2022

Preprint

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“…The expression of the shielding parameter P S remains identical to equation (21), except that the S matrix has now changed.…”

Section: Theory Of Optical Shieldingmentioning

confidence: 99%

“…It has been proposed that a sticking mechanism generated by the presumably huge density of states of the four-atom complex creates a long-lived complex [17,18], which could then decay by other mechanisms like inelastic collisions or photoassisted processes induced by the trapping laser. However this hypothesis has been reconsidered [19][20][21] while recent experimental results yield to contradictory interpretations in this matter [16,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Engineering long-range interactions between ultracold atoms with light

Xie¹,

Orbán²,

Xing³

et al. 2022

J. Phys. B: At. Mol. Opt. Phys.

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Ultracold temperatures in dilute quantum gases opened the way to an exquisite control of matter at the quantum level. Here we focus on the control of ultracold atomic collisions using a laser to engineer their interactions at large interatomic distances. We show that the entrance channel of two colliding ultracold atoms can be coupled to a repulsive collisional channel by the laser light so that the overall interaction between the two atoms becomes repulsive: this prevents them to come close together and to undergo inelastic processes, thus protecting the atomic gases from unwanted losses. We illustrate such an optical shielding mechanism with 39K and 133Cs atoms colliding at ultracold temperature (<1 microkelvin). The process is described in the framework of the dressed-state picture and we then solve the resulting stationary coupled Schrödinger equations. The role of spontaneous emission and photoinduced inelastic scattering is also investigated as possible limitations of the shielding efficiency. We predict an almost complete suppression of inelastic collisions over a broad range of Rabi frequencies and detunings from the 39K D2 line of the optical shielding laser, both within the [0, 200 MHz] interval. We found that the polarization of the shielding laser has a minor influence on this efficiency. This proposal could easily be formulated for other bialkali-metal pairs as their long-range interaction are all very similar to each other.

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“…It has been initially proposed that a sticking mechanism generated by the presumably huge density of states of the four-atom complex creates a long-lived complex [17,18], which could then decay by other mechanisms like inelastic collisions or photoassisted processes induced by the trapping laser. However this hypothesis has been reconsidered [19][20][21] while recent experimental results yield to contradictory interpretations in this matter [16,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Engineering long-range interactions between ultracold atoms with light

Xie,

Orbán,

Xing

et al. 2021

Preprint

View full text Add to dashboard Cite

Ultracold temperatures in dilute quantum gases opened the way to an exquisite control of matter at the quantum level. Here we focus on the control of ultracold atomic collisions using a laser to engineer their interactions at large interatomic distances. We show that the entrance channel of two colliding ultracold atoms can be coupled to a repulsive collisional channel by the laser light so that the overall interaction between the two atoms becomes repulsive: this prevents them to come close together and to undergo inelastic processes, thus protecting the atomic gases from unwanted losses. We illustrate such an optical shielding mechanism with potassium and cesium atoms colliding at ultracold temperature (<1 microkelvin). The process is described in the framework of the dressedstate picture and we then solve the resulting staionary coupled Schrödinger equations. The role of spontaneous emission and photoinduced inelastic scattering is also investigated as possible limitations of the shielding efficiency. We predict an almost complete suppression of inelastic collisions using a laser-induced coupling characterized by a Rabi frequency of ω = 200 MHz and a frequency detuned from the potassium D2 transition by ∆ = 200 MHz. We found the polarization of the laser has no influence on this efficiency. This proposal could easily be formulated for other bi-alkali-metal pairs as their long-range interaction are all very similar to each other.

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Collisional losses of ultracold molecules due to intermediate complex formation

Cited by 4 publications

References 65 publications

Symmetry breaking in sticky collisions between ultracold molecules

Symmetry breaking in sticky collisions between ultracold molecules

Engineering long-range interactions between ultracold atoms with light

Engineering long-range interactions between ultracold atoms with light

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