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Quantum Simulation: A Better ­Understanding of Magnetism

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quantum simulation, illustration

Atoms (shown in green and blue) are held in a trap of laser light (red) in which they can move in one dimension only.

Credit: Heidelberg University

Heidelberg University physicists have devised a new way to study magnetism via quantum simulation, using four ultracold atoms at near absolute zero to build a model simulating the behavior of electrons in a solid. "Precisely preparing such a small number of atoms . . . allows us . . . to control the state of the atoms with extreme precision," says Heidelberg doctoral student Simon Murmann. The atoms are corralled in a laser light trap permitting movement in only one dimension. "Initially, there is no interaction between the atoms," Murmann notes. "In this state, they can move freely inside the trap without any fixed arrangement. But when we introduce increasing repulsion between the atoms, they can no longer pass one another and end up forming a chain. Each atom in the chain points in the opposite direction of its neighbor, one up and one down. This brings about an antiferromagnetic state."

This activity is interesting because antiferromagnetism is linked to physical phenomena that could lead to far-reaching applications. "Superconductivity . . . was observed in antiferromagnetic materials at relatively high temperatures of only minus 135 degrees Celsius," says Heidelberg professor Selim Jochim. "We hope that our experiments will contribute to the understanding of the fundamental processes in solids. One vision is to develop new materials that will remain superconductive even at room temperature."

From Heidelberg University 
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