Quantum Physics and Interacting Particles

One of the primary objectives of quantum physics studies is to measure the quantum states of large systems composed of many interacting particles. This could be particularly useful for the development of quantum computers and other quantum information processing devices.

Researchers at the University of Cambridge's Cavendish Laboratory have recently introduced a new approach for measuring the spin states of a nuclear ensemble, a system comprised of many interacting particles with long-lived quantum properties. This method, presented in a paper published in Nature Physics, works by exploiting the response of this system to collective spin excitations.

"For a dense ensemble of quantum objects, such as spins, it isn't possible to measure each individually, to learn how they interacted with each other," Claire Le Gall and Mete Atatüre, two of the researchers who carried out the study, told Phys.org. "Instead, one can look for tell-tale signals in the collective response of the ensemble; a bit like the behavior of a flock of birds might say something about how the birds engage with each other. Our system of interest is a large flock, or ensemble, of nuclear spins in a semiconductor quantum dot."

In 2002, three Harvard University physicists figured out that large ensembles of nuclear spins in a semiconductor quantum dot could be potential hosts for solid-state quantum memories, then published their work a year later. 19 years later, Le Gall, Atatüre, and their colleagues probed this type of nuclear ensemble using a 'proxy' quantum bit, an electron spin that simultaneously couples to all nuclear spins, as reported in their latest paper.  READ MORE...