Quantum Soup of Atoms: A New View on Spin Liquid ⚡ экспресс
In a quantum simulator based on N = 114 dipolar Rydberg atoms in a kagome geometry, a frustrated spin-exchange antiferromagnet was experimentally studied. Using local addressing, low-energy states were adiabatically prepared in search of a gapless U(1) Dirac spin liquid, predicted by recent theories. Measurements of local polarization and spin-spin correlations according to the protocol revealed a transition from a checkerboard product state through an intermediate magnetic crystal to a disordered correlated liquid. The entropy density of the atomic liquid is comparable to that in frustrated magnetic insulators at liquid nitrogen temperatures. The correlations are in good agreement with a simple parameter-free ansatz for the Dirac spin liquid in terms of alternating sign structure and spatial decay. The static susceptibility of the system to local field perturbations and geometric distortion was measured. The results show that Rydberg atom arrays are a promising platform for the preparation and microscopic study of candidates for quantum spin liquids.
Physicists took 114 rubidium atoms, cooled them to near absolute zero (as in experiments with liquid helium), and neatly arranged them in a honeycomb pattern. They then smoothly adjusted the interaction strength, as if slowly turning up the heat under a pot. On low 'flame,' the atoms stayed in orderly magnetic rows, like a crystal. But as disorder increased, the rigid order melted away, giving way to a liquid state where each atomic magnet spun incessantly, together resembling whirlpools in a boiling water.
This magnetic broth, known to theorists as a spin liquid, behaves astonishingly: the excitations that arise in it race without resistance, like light—mass is no obstacle for them. This is exactly the behavior predicted by Richard Feynman when he contemplated quantum simulators. Tests showed that this soup is not mere chaos, but a long-sought state that could hold the key to building quantum computers. It turns out that even from atomic disorder, you can cook up an ideal medium for computation.
🎯 Excitations in this magnetic liquid move without resistance, as if they have no mass—just like light. That's why it's called an 'ideal quantum medium.'