A supersolid made of light observed at room temperature
· BehindLines newsroom
Physicists at the University of Warsaw and their partners say they have observed a supersolid at room temperature, whereas earlier observations relied on atomic gases cooled to within a hair of absolute zero. The results, published in the journal Science Advances (article eaee4875, 2026), were relayed on 9 November by ScienceDaily from a release by Warsaw's physics faculty.
What is a supersolid?
A supersolid combines two properties that seem to exclude each other: a periodic structure, like that of a crystal, and frictionless flow, typical of superfluids. Predicted in the 1960s, it was first observed in 2017 in Bose-Einstein condensates of ultracold atoms.
The set-up
The team worked with exciton polaritons, hybrid quasi-particles of light and matter that exist for only a few picoseconds. It produced them in an optical microcavity containing a liquid crystal designed for the experiment, coated with an organic semiconductor called MeLPPP. Professor Wiktor Piecek's group at the Military University of Technology developed these structures, which can operate at up to nearly 60 °C.
The supersolid shows up as regularly spaced bright fringes in the emitted light. From one laser pulse to the next the fringes shift position, a sign that the system picks among several equivalent states. Professor Guillaume Malpuech of CNRS sees in this a classic example of spontaneous symmetry breaking. The condensate also shows a persistent spin helix, that is, a periodic variation in the polarisation of the light.
Limits and next steps
The semiconductor reacts with the liquid crystal, so samples are usable for only a few hours after assembly: repeating a measurement means building a new sample, stresses first author Marcin Muszyński, now at the City College of New York. The researchers, who also include IBM Research Zurich, describe these microcavities as the first platform whose optical properties can be tuned with an electric voltage to study condensates of this kind.
They mention possible applications, such as ultrafast photonic devices, neuromorphic computing accelerators or optical sensors. These are leads rather than products: no such device is announced. For research, the immediate interest is a platform that needs neither cryogenics nor extreme equipment to explore this quantum state.