Impact-parameter selective Rydberg atom collision by optical tweezers

TL;DR

This study demonstrates control over impact-parameter specific collisions between Rydberg atoms using optical tweezers, combining experimental and simulation methods to analyze collision probabilities and cross sections.

Contribution

It introduces a novel experimental technique to control and measure impact-parameter dependent collisions between Rydberg atoms, supported by quantum and classical simulations.

Findings

Collision probability depends on impact parameter.

Good agreement between experiment and simulations.

Quantum effects are significant in certain regimes.

Abstract

Cold collisions between two Rydberg rubidium atoms ($^{87}$Rb) are investigated by controlling the impact parameter and collision energy. Optical tweezers are employed to hold one atom stationary while propelling the other to a constant velocity. After the tweezers are deactivated, both atoms are excited to a Rydberg state by a $\pi$-pulse. After a collision, a second $\pi$-pulse is applied. If the stationary atom does not experience a significant momentum transfer and is de-excited to its ground state, it can be recaptured when reactivating the tweezer. The impact parameter dependent collision probability is extracted from the atom loss from the tweezer and used to evaluate the collisional cross section between Rydberg atoms. Quantum and classical simulations of elastic two-body collisions show good agreement with the present experimental data and provide insights into the critical parameter regime where quantum effects become important.