Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics Conference Series

Modeling ultracold lithium ion-atom collision

Amrendra Pandey, M Niranjan, N Joshi, S. A. Rangwala, Olivier Dulieu

Published Jan 1, 2020• 1 citation
Publisher

Abstract

Synopsis Accurate estimation of the scattering properties at the ultracold temperatures is challenging due to the demand for the precise knowledge of interactions between the colliding partners. We identify the aspects of interactions that play the defining roles in the scattering calculations. We compute potential energy curves for the 7Li+-7Li, X2∑g + and A2∑u +, and determine their collisional properties.

DOI
10.1088/1742-6596/1412/12/122010

Related papers

Collisional dynamics of ultra-cold atomic gases

Jean Dalibard, Jean Dalibard

Collision physics plays a key role in understanding the properties of ultracold gases. First, collisions ensure thermalization in trapped atomic samples, which is essential for the success of evaporative cooling. Second, interactions between atoms determine the equilibrium shape and the dynamics of the condensate once it is formed. Finally collisions limit the achievable spatial densities via inelastic processes, which ultimately determine whether a given atomic species may lead to Bose-Einstein condensation. The purpose of the following lectures is to give a basic introduction to collision physics with a special emphasis on the low temperature aspect of these interactions. We will consider here only binary interactions between atoms since one of the remarkable prop-erties of the physics of ultra-cold dilute gases is that all the macroscopic properties of the system can be directly deduced from the two-body interaction potential. In particular the essential concept of scattering length will be introduced and developped for some simple potentials, using as practical examples experimental results obtained on atomic cesium and rubidium. The present lectures are complementary to the ones given by D. Heinzen where a detailed comparison between the collisional properties of the various alkali atoms will be found, together with explanations of the spectroscopic approaches used in the precise determination of interatomic potentials. 1. – Scattering theory: a brief reminder 1.1. Collision between two particles. – We consider here an elementary collision process between two particles 1 and 2 with the same mass M, interacting through the potential

•Jan 1, 1998•13 citations

Interaction potentials and ultracold scattering cross sections for the Li+7–Li7 ion-atom system

Amrendra Pandey, M. Niranjan, N. Joshi +3 more

We calculate the isotope-independent ${\mathrm{Li}}^{+}$-Li potential energy curves for the electronic ground and first excited states. The scattering phase shifts and total scattering cross section for the $^{7}\mathrm{Li}^{+}\text{\ensuremath{-}}^{7}\mathrm{Li}$ collision are calculated, with an emphasis on the ultralow-energy domain down to the $s$-wave regime. The effect of physically motivated alterations on the calculated potential energy curves is used to determine the bound of accuracy of the low-energy scattering parameters for the ion-atom system. It is found that the scattering length for the $A{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ state, ${a}_{u}=1325{a}_{0}$, is positive and has well-constrained bounds. For the $X{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ state, the scattering length, ${a}_{g}=20\phantom{\rule{0.16em}{0ex}}465{a}_{0}$, has a large magnitude, as it is sensitive to the restrained change of the potential, due to the presence of a vibrational state in the vicinity of the dissociation limit.

arXiv:2005.09102•Physical Review A•May 11, 2020•10 citations

Rydberg Molecules for Ion-Atom Scattering in the Ultracold Regime

T. Schmid, C. Veit, N. Zuber +4 more

We propose a novel experimental method to extend the investigation of ion-atom collisions from the so far studied cold, essentially classical regime to the ultracold, quantum regime. The key aspect of this method is the use of Rydberg molecules to initialize the ultracold ion-atom scattering event. We exemplify the proposed method with the lithium ion-atom system, for which we present simulations of how the initial Rydberg molecule wave function, freed by photoionization, evolves in the presence of the ion-atom scattering potential. We predict bounds for the ion-atom scattering length from ab initio calculations of the interaction potential. We demonstrate that, in the predicted bounds, the scattering length can be experimentally determined from the velocity of the scattered wave packet in the case of ^{6}Li^{+}-^{6}Li and from the molecular ion fraction in the case of ^{7}Li^{+}-^{7}Li. The proposed method to utilize Rydberg molecules for ultracold ion-atom scattering, here particularized for the lithium ion-atom system, is readily applicable to other ion-atom systems as well.

arXiv:1709.10488•Physical Review Letters•Apr 12, 2018•47 citations

Coupled-channels analysis of Feshbach resonances in a Mott insulator

T. Secker, S. J. J. M. F. Kokkelmans

Ultracold atomic gas experiments have proven to be a versatile ground for studying quantum mechanics, quantum many-body physics, quantum simulation and computation. A precise model for two-body collisions in those systems is essential. Coupled-channels models can accurately describe the two-atom system at ultracold temperatures by detailed interaction potentials that are finetuned by just a few parameters, determined from experiment. We extend such a coupled-channels model to include the situation in a Mott insulator phase of ultracold bosonic atoms, where two atoms are confined to one lattice site. Of particular importance is the specific conversion between the on-site interaction energy, which remains finite in the lattice, and the scattering length around a Feshbach resonance that diverges. Recently spectroscopic techniques allowed for a precise experimental determination of the on-site interaction energy in a system of 7Li atoms, we analyze this data with our model to improve the precision of current lithium interaction potentials.

•May 1, 2019•0 citations

Calculation of scattering parameters for ultracold 6 Li— 7 Li elastic collisions

Jicai Zhang, Jinfeng Sun, Yufang Liu

This paper theoretically studies the elastic scattering properties in a mixture of 6Li and 7Li atoms at cold and ultracold temperatures. Based on the constructed accurate interatomic potential of the triplet state for 6Li7Li mixture by the mass scaling method, it calculates the interspecies s-wave scattering lengths and the p-wave scattering lengths by the variable phase method and the semiclassical method, respectively. The scattering length is in good agreement with the experiment. The partial-wave and total cross sections are also calculated and a rich resonance structure is found.

Chinese Physics B•Feb 1, 2011•5 citations

Accurate calculation of the elastic scattering properties of 7 Li atoms at ultralow temperatures

Sun Jin-Feng, Zhang Ji-Cai, Jiemin Wang

The elastic scattering properties for collisions between two 7 Li atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybrid potentials for the singlet X 1 ∑ g + and triplet a 3 ∑ u + ground states of the Li 2 . Our calculated values for the scattering lengths a and the effective ranges r e are compared with previous ones and found them to be in good agreement. The scattering lengths are 34.6 a 0 for the singlet state and −27.6 a 0 for the triplet state. Shape resonances occur in the collisions at low energies. We also calculate the total cross sections and the energy positions of shape resonances for both X 1 ∑ g + and a 3 ∑ u + states.

Chinese Physics•Mar 1, 2006•19 citations
Synopsis Accurate estimation of the scattering properties at the ultracold temperatures is challenging due to the demand for the precise knowledge of interactions between the colliding partners. We identify the aspects of interactions that play the defining roles in the scattering calculations. We compute potential energy curves for the 7Li+-7Li, X2∑g + and A2∑u +, and determine their collisional properties.
Collision physics plays a key role in understanding the properties of ultracold gases. First, collisions ensure thermalization in trapped atomic samples, which is essential for the success of evaporative cooling. Second, interactions between atoms determine the equilibrium shape and the dynamics of the condensate once it is formed. Finally collisions limit the achievable spatial densities via inelastic processes, which ultimately determine whether a given atomic species may lead to Bose-Einstein condensation. The purpose of the following lectures is to give a basic introduction to collision physics with a special emphasis on the low temperature aspect of these interactions. We will consider here only binary interactions between atoms since one of the remarkable prop-erties of the physics of ultra-cold dilute gases is that all the macroscopic properties of the system can be directly deduced from the two-body interaction potential. In particular the essential concept of scattering length will be introduced and developped for some simple potentials, using as practical examples experimental results obtained on atomic cesium and rubidium. The present lectures are complementary to the ones given by D. Heinzen where a detailed comparison between the collisional properties of the various alkali atoms will be found, together with explanations of the spectroscopic approaches used in the precise determination of interatomic potentials. 1. – Scattering theory: a brief reminder 1.1. Collision between two particles. – We consider here an elementary collision process between two particles 1 and 2 with the same mass M, interacting through the potential
We calculate the isotope-independent Li+{\mathrm{Li}}^{+}Li+-Li potential energy curves for the electronic ground and first excited states. The scattering phase shifts and total scattering cross section for the $^{7}\mathrm{Li}^{+}\text{\ensuremath{-}}^{7}\mathrm{Li}$ collision are calculated, with an emphasis on the ultralow-energy domain down to the sss-wave regime. The effect of physically motivated alterations on the calculated potential energy curves is used to determine the bound of accuracy of the low-energy scattering parameters for the ion-atom system. It is found that the scattering length for the $A{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ state, au=1325a0{a}_{u}=1325{a}_{0}au​=1325a0​, is positive and has well-constrained bounds. For the $X{\phantom{\rule{0.16em}{0ex}}}^{2}{\mathrm{\ensuremath{\Sigma}}}_{g}^{+}$ state, the scattering length, ag=20465a0{a}_{g}=20\phantom{\rule{0.16em}{0ex}}465{a}_{0}ag​=20465a0​, has a large magnitude, as it is sensitive to the restrained change of the potential, due to the presence of a vibrational state in the vicinity of the dissociation limit.
We propose a novel experimental method to extend the investigation of ion-atom collisions from the so far studied cold, essentially classical regime to the ultracold, quantum regime. The key aspect of this method is the use of Rydberg molecules to initialize the ultracold ion-atom scattering event. We exemplify the proposed method with the lithium ion-atom system, for which we present simulations of how the initial Rydberg molecule wave function, freed by photoionization, evolves in the presence of the ion-atom scattering potential. We predict bounds for the ion-atom scattering length from ab initio calculations of the interaction potential. We demonstrate that, in the predicted bounds, the scattering length can be experimentally determined from the velocity of the scattered wave packet in the case of ^{6}Li^{+}-^{6}Li and from the molecular ion fraction in the case of ^{7}Li^{+}-^{7}Li. The proposed method to utilize Rydberg molecules for ultracold ion-atom scattering, here particularized for the lithium ion-atom system, is readily applicable to other ion-atom systems as well.
Ultracold atomic gas experiments have proven to be a versatile ground for studying quantum mechanics, quantum many-body physics, quantum simulation and computation. A precise model for two-body collisions in those systems is essential. Coupled-channels models can accurately describe the two-atom system at ultracold temperatures by detailed interaction potentials that are finetuned by just a few parameters, determined from experiment. We extend such a coupled-channels model to include the situation in a Mott insulator phase of ultracold bosonic atoms, where two atoms are confined to one lattice site. Of particular importance is the specific conversion between the on-site interaction energy, which remains finite in the lattice, and the scattering length around a Feshbach resonance that diverges. Recently spectroscopic techniques allowed for a precise experimental determination of the on-site interaction energy in a system of 7Li atoms, we analyze this data with our model to improve the precision of current lithium interaction potentials.
This paper theoretically studies the elastic scattering properties in a mixture of 6Li and 7Li atoms at cold and ultracold temperatures. Based on the constructed accurate interatomic potential of the triplet state for 6Li7Li mixture by the mass scaling method, it calculates the interspecies s-wave scattering lengths and the p-wave scattering lengths by the variable phase method and the semiclassical method, respectively. The scattering length is in good agreement with the experiment. The partial-wave and total cross sections are also calculated and a rich resonance structure is found.
The elastic scattering properties for collisions between two 7 Li atoms are investigated in the cold and ultracold regimes separately. Based on recent theoretical and experimental results, we present the improved hybrid potentials for the singlet X 1 ∑ g + and triplet a 3 ∑ u + ground states of the Li 2 . Our calculated values for the scattering lengths a and the effective ranges r e are compared with previous ones and found them to be in good agreement. The scattering lengths are 34.6 a 0 for the singlet state and −27.6 a 0 for the triplet state. Shape resonances occur in the collisions at low energies. We also calculate the total cross sections and the energy positions of shape resonances for both X 1 ∑ g + and a 3 ∑ u + states.