Bethe strings predicted in 1931 created and observed in ultracold gas

· Science

Nearly a century after physicist Hans Bethe predicted them, scientists have created and directly observed unusual quantum states known as Bethe strings in an ultracold gas. The team cooled cesium atoms to near absolute zero and trapped them in thousands of tiny one-dimensional tubes, allowing groups of atoms to form the predicted string-like configurations. The result is a rare experimental confirmation of a long-standing theoretical prediction in quantum many-body physics, a field that seeks to understand how large numbers of interacting particles behave. Such cold-atom platforms are increasingly used to simulate phenomena that are difficult or impossible to compute directly, including aspects of quantum magnetism and exotic states of matter.

Why it matters：Direct observation of Bethe strings validates decades of quantum many-body theory and strengthens cold-atom simulators as tools for probing otherwise intractable physics.

Key points

  • Cesium atoms were cooled to near absolute zero and held in thousands of one-dimensional tubes.
  • The states were first predicted by Hans Bethe in 1931.
  • Bethe strings were both created and directly observed.

Sources (original reporting)

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