In a first, US scientists turn exciton superfluids into supersolids

Scientists at Columbia University and the University of Texas have, for the first time, transformed exciton superfluids into a supersolid state without external instrumentation. Superfluids, known for their frictionless flow and quantum vortices at temperatures near absolute zero, were converted into supersolids—states that maintain zero viscosity but exhibit an orderly, crystal-like particle structure while still supporting quantum vortices. Previously, creating supersolids required external energy fields to enforce particle order, but this research demonstrated a natural phase transition between superfluid and supersolid states using only excitons. The experiment involved two graphene sheets subjected to a strong magnetic field and cooled to temperatures between 1.5 and 4 degrees Celsius above absolute zero. Excitons—neutral quasiparticles formed by electron-hole pairs excited by light—first formed a superfluid and then transitioned into a supersolid upon further cooling. This discovery challenges the conventional view of superfluidity as the lowest temperature ground state and suggests the existence of an unusual