Year: 2024
Type: article
Abstract: While collision lifetimes are a fundamental property of few-body scattering events, their behavior at ultralow temperatures is not completely understood. Using multichannel quantum-defect theory, we derive a multichannel expression for the Smith lifetime $Q$ matrix that is valid far away from scattering resonances. For collisions mediated by short-range interaction potentials of the form $\ensuremath{-}{C}_{6}/{R}^{6}$, we obtain the average time delay in the incident $s$-wave collision channel in the limit of zero collision energy $E$ as ${Q}_{11}=A/\sqrt{E}+B$, where $A$ and $B$ are constants. We show that the time delay is dominated by elastic scattering and contains an additional multichannel contribution independent of the two-body scattering length. We also obtain the expressions for the collision lifetime using the universal model of Idziaszek and Julienne [Phys. Rev. Lett. 104, 113202 (2010)]. The lifetime acquires an imaginary part in the presence of inelastic loss due to the lack of unitarity of the $S$ matrix and shortens with increasing the short-range loss parameter $y$.
Source: Physical Review A
Authors: Rebekah Hermsmeier, Timur V. Tscherbul
Institution: University of Nevada, Reno
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W4405316638