Physicists at UC Santa Barbara have become the first to observe a quirky behavior of the quantum world: aquantum boomerang, which occurs when particles in a disordered system are kicked out of their locations. They turn around and come back to where they started and stopped.
The effect is a fundamentally quantum mechanical effect, according to atomic physicist David Weld, whose lab produced the effect and documented it in a paper published in Physical Review X.
Philip Anderson predicted roughly 60 years ago that a disorder called Anderson localization would affect transport of electrons. According to the paper, the disorder can be caused by flaws in a material's atomic lattice.
Sajjad said that this type of disorder will keep them from being dispersed. The electrons localize instead of zipping along the lattice, turning what would otherwise be a conducting material into an insulator. The quantum boomerang effect was predicted a few years ago.
The Weld Lab had a few tricks up its sleeve, but it is very difficult to launch electrons away from their location. The researchers used a gas of 100,000 ultracold lithium atoms suspended in a standing wave of light and kicked them. They used a method that avoids some experimental difficulties without changing the underlying physics of the boomerang effect.
If you were looking for the boomerang effect, you would give your electron some finite velocity and then look for whether it came back to the same spot.
The lattice was pulsed a few dozen times, noting an initial shift in average momentum. Despite repeated kicks, average momentum returned to zero.
It is a fundamentally different behavior, Weld said. He explained that in a classical system, a rotor kicked in this way would respond by constantly absorbing energy from the kicks. It becomes what is called a dynamically localized state.
He said that the behavior is due to the wave-like nature of quantum systems.
Weld explained that the chunk of stuff that you push away is a wave, and that is a central concept of quantum mechanics.
If individual boomerang effects are cool, how much more of a party would it be to have several interacting boomerang effects?
There are a lot of theories and questions about what should happen. The system can be used to study the boomerang in higher dimensions.
The research was done by Jeremy L. Tanlimco, Hector Mas, Eber Nolasco-Martinez, Tommaso Macr, and Patrizia Vignolo.
More information: Roshan Sajjad et al, Observation of the Quantum Boomerang Effect, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.011035 Journal information: Physical Review X Citation: Physicists report on 'quantum boomerang' effect in disordered systems (2022, February 28) retrieved 28 February 2022 from https://phys.org/news/2022-02-physicists-quantum-boomerang-effect-disordered.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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