Single-atom billiards in an ultracold bath with energy-tunable collisions and threshold-sensitive detection
Abstract
Transport processes at the microscopic scale can differ strongly from their macroscopic counterparts, particularly when the environment is not a well-defined surface but an unordered thermal medium. Ultracold quantum gases offer a high degree of controllability and directly observable dynamics, thereby providing a versatile platform to study such transport processes under precisely controllable conditions. Here, we realize an energy-tunable single-atom collider by transporting individual cesium atoms at controlled velocity through an ultracold rubidium bath. The constant lattice velocity sets the directed contribution to the collision-energy distribution, while the lattice depth provides a tunable energy threshold for collision-induced transport disruption. By independently varying these parameters together with bath density and temperature, we separate the number of collision events from their probability to disrupt transport. Across a regime with only a few expected collisions per passage, the inferred single-collision ejection probability rises from small values to near unity as the collision energy exceeds the lattice confinement scale. The experiment thus converts microscopic collisional energy transfer into a binary single-atom observable and provides a controlled link between individual scattering events and emergent dissipative transport.
Related
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BibTeX
@misc{hiebel2026singleatom,
title = {{Single-atom billiards in an ultracold bath with energy-tunable collisions and threshold-sensitive detection}},
author = {Silvia Hiebel and Sabrina Burgardt and Julian Feß and Artur Widera},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40098},
eprint = {2610.40098},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40098},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Single-atom billiards in an ultracold bath with energy-tunable collisions and threshold-sensitive detection
AU - Silvia Hiebel
AU - Sabrina Burgardt
AU - Julian Feß
AU - Artur Widera
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40098
UR - https://arxiv.org/abs/2610.40098
AB - Transport processes at the microscopic scale can differ strongly from their macroscopic counterparts, particularly when the environment is not a well-defined surface but an unordered thermal medium. Ultracold quantum gases offer a high degree of controllability and directly observable dynamics, thereby providing a versatile platform to study such transport processes under precisely controllable conditions. Here, we realize an energy-tunable single-atom collider by transporting individual cesium atoms at controlled velocity through an ultracold rubidium bath. The constant lattice velocity sets the directed contribution to the collision-energy distribution, while the lattice depth provides a tunable energy threshold for collision-induced transport disruption. By independently varying these parameters together with bath density and temperature, we separate the number of collision events from their probability to disrupt transport. Across a regime with only a few expected collisions per passage, the inferred single-collision ejection probability rises from small values to near unity as the collision energy exceeds the lattice confinement scale. The experiment thus converts microscopic collisional energy transfer into a binary single-atom observable and provides a controlled link between individual scattering events and emergent dissipative transport.
ER -