Holons, Spinons Demonstrate Quantum Simulators Are To Be Taken Seriously

Divorce in a one-dimensional world

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+  In objects of our everyday world, there is no left without right or front without back. Just as inseparable seem to be the electron’s electric charge and its “spin”. But in a strictly one-dimensional quantum world, both quantum properties are separable from each other. This fifty-year-old prediction has now been confirmed by an experiment conducted by a team from the Munich Center for Quantum Science and Technology (MCQST). Physicists from the Max Planck Institute for Quantum Optics in Garching are playing a leading role. For their successful demonstration, which is now published in the journal “Science”, they used a so-called quantum simulator. Such a specialized quantum computer can precisely estimate the quantum properties of a material, which is impossibly challenging for conventional supercomputers today.

Scientists at the Max-Planck-Institute of Quantum Optics have experimentally confirmed a fifty year old prediction about the (in)separability of an electron’s spin and electric charge using a specialised quantum simulator. The result is now published in “Science”.

+  As soon as the chain of atoms is prepared, the physicists kick an atom out of the middle of the chain with laser light. This disturbance, called “quench”, creates two quasiparticles in the chain. The first quasiparticle is the hole left by the ejected atom. This “holon” contains the quantum property of the electron charge. The second quasiparticle, called the spinon, consists of the two adjacent parallel spins left behind by the holon gap. Compared with the background of alternating spins pointing up and down, this spinon carries an excess spin from the quench.

+  With their quantum simulator, the team was able to follow exactly how the two perturbations travel along the atomic chain. In fact, it turned out that they move at different speeds and not bound together. Charge and spin are thus completely independent of each other and perfectly separated – just like the water and sand buckets in the fire extinguishing chain.

+  On the one hand, this result is exciting from the perspective of basic research in quantum physics. The separability of charge and spin could one day also find fascinating applications in quantum information technology. Above all, however, the Garching experiment successfully demonstrates that quantum simulators are developing into a technology to be taken seriously. Already in the 1980s, the famous Nobel Prize winner Richard Feynman dreamed that it would be possible to understand the behaviour of the materials’ quantum systems, which are hard to access experimentally, by using analogous quantum systems that were perfectly accessible and controllable. Even conventional supercomputers fail to calculate some of such quantum systems exactly. But this elegant possibility is offered by ultracold atoms in light grids. “In the future, this could enable the targeted design of new materials that, for example, become superconducting at room temperature,” says Jayadev Vijayan. Feynman’s dream of a quantum simulator is now becoming reality.

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Source:  MAX PLANCK INSTITUTE .  Dr. Christian Groß,  Divorce in a one-dimensional world…

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