A pump is a device that uses a constant motion to move cargo. Air flow can be created by the repeated up and down strokes of a piston. The water is moved between the reservoirs by turning a crank. The concept of transporting electrons one by one through solid-state materials has been explored in quantum systems.
A surprising twist to the story has been added by a team led by Dr. Tobias Donner, a senior scientist in the group of Prof. Tilman Esslinger. A quantum pump that doesn't require any periodic driving from the outside is reported in Nature.
New puzzles are being searched for.
The team of Esslinger and Donner work with atoms in complex structures created by intersecting laser beams. Synthetic crystals have the advantage of being able to control both the atoms and the crystal lattice with ease. The platform can be used to gain a better understanding of known effects or to create scenarios in which quantum systems behave in unforeseen ways. This is exactly what the team achieved.
The synthetic crystal is formed in the optical cavity. The light fields and the atoms are involved in a process called acoupling. The experimenters have good control over the photons leaking out of the Cavity. An open quantum system is a system that has no boundaries. When dissipation is controlled, it can be an asset rather than a nuisance. Members of the Esslinger group found that the dynamics of a synthetic crystal can be changed by the leaking of a photon. The work was published in the journal Science.
Going in circles makes advancement possible.
The observation that the atoms trapped in the synthetic crystal structure started to move was the big surprise that led to the now- published work. The mechanism behind the atomic motion is explained by the fact that the center of mass of the atoms is shifted by a fixed amount in each cycle. The light field leaking from the cavity was analyzed by the physicists at ETH.
The person who turns the crank is not known.
Compared to previous realizations of quantum pumps, what is unique in these experiments is that a particle current is not driven. The current comes from the cavity and leads to self-oscillating It's important that the atom configurations between which the system is oscillated are different on a fundamental level. The demonstrated transport mechanism should be stable against external perturbations and robust against the detailed form of the pumping protocol.
These findings are very interesting. Modern physics has both topology and open quantum systems. A practical tool for realizing exotic states of quantum matter will be provided by the connection between the two.
More information: Davide Dreon et al, Self-oscillating pump in a topological dissipative atom–cavity system, Nature (2022). DOI: 10.1038/s41586-022-04970-0Dissipation causes structural instability in a quantum gas. There is a science.aaw4465.
Journal information: Science , Nature Citation: A quantum pump without a crank (2022, August 22) retrieved 22 August 2022 from https://phys.org/news/2022-08-quantum-crank.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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