Room-Temperature Supersolid Light Observed in Liquid-Crystal Microcavity

An international team has observed a supersolid quantum phase at room temperature, using a liquid-crystal optical microcavity rather than atoms cooled near absolute zero. The device operated at up to 60°C, roughly 140°F, according to Professor Wiktor Piecek of the Military University of Technology, whose group built the liquid-crystal structures. The finding was published in Science Advances on November 9, 2026.

The consortium behind the work, called TopoLight, spans the University of Warsaw's Faculty of Physics, the Military University of Technology in Poland, IBM Research Zurich, and France's CNRS. Dr. Marcin Muszyński, the paper's first author and now a postdoctoral researcher at The City College of New York, led the experimental effort.

What is a supersolid?

A supersolid combines two properties that classical physics treats as incompatible. It carries the repeating spatial order of a crystal, yet it also flows without viscosity, like a superfluid. Physicists proposed the idea in the 1960s, but experimental confirmation arrived only in 2017, in ultracold atomic Bose-Einstein condensates. Those experiments required sophisticated cryogenic equipment. The new result removes that requirement for one class of system, though it does not transfer directly to atomic platforms.

The Warsaw team worked with exciton polaritons. These quasiparticles form when light couples strongly with matter inside a microcavity. They live for only a few picoseconds — trillionths of a second. Despite that brief lifetime, they can condense into a Bose-Einstein state and behave as a quantum superfluid.

How did the researchers build it?

The device pairs a specially engineered liquid crystal with an organic semiconductor layer. The construction lets light and matter interact strongly enough to produce supersolid behavior without extreme cooling.

• Microcavity: liquid crystal, developed at the Military University of Technology
• Semiconductor: MeLPPP, methyl-substituted ladder-type poly(paraphenylene), deposited at IBM Research Zurich
• Operating range: up to approximately 60°C
• Tunability: first electrically tunable platform for supersolid polariton condensates

Thilo Stöferle of IBM Research noted the material history: "We have studied the organic semiconductor MeLPPP for many years and previously observed Bose-Einstein condensation in this material. This was the first time we combined it with a liquid-crystal microcavity."

What did the measurement show?

The evidence appeared in the emitted light. When the condensate entered the supersolid phase, regularly spaced bright fringes formed. Those fringes signal a spontaneous, repeating density modulation — the crystalline signature of a supersolid.

One detail deserves scrutiny. Each laser pulse produced fringes at a different position. The system repeatedly chose among several equivalent configurations. Professor Guillaume Malpuech of Institut Pascal, CNRS, called it a textbook case: "Theory predicted that the supersolid could choose among several equivalent states, and that is exactly what we observed." That is spontaneous symmetry breaking, made visible in the light pattern.

The condensate also showed a persistent spin helix, a repeating variation in the polarization of the emitted light. Two distinct forms of order — intensity and polarization — coexisted in one system. The full author list and analysis appear in Science Advances, volume 12, issue 42, DOI 10.1126/sciadv.aee4875.

What are the practical constraints?

The experiment came with a hard limitation. The organic semiconductor reacted slowly with the liquid crystal, so each sample remained useful for only a few hours after assembly. "We had to plan the entire sequence of experiments in advance," Muszyński said. "Repeating a measurement meant fabricating an entirely new sample." Sample stability, not physics, set the pace of the work.

The key measurements ran at IBM Research Zurich, where scientists deposited thin semiconductor layers onto photonic structures fabricated at the Military University of Technology.

Why does room temperature matter?

Cryogenic systems impose real cost on any path from laboratory physics to deployable photonics. This result shows that certain exotic quantum states can be studied, and potentially exploited, in devices running at ordinary temperatures.

The researchers point to possible applications in optical computing, neuromorphic accelerators, and polarization-sensitive optical sensors. Those remain research directions, not products. No performance figures exist yet, and the few-hour sample lifetime is an engineering problem any practical device must solve.

The electrical tunability is the strongest near-term claim. Applying an external voltage alters the system's optical properties, something earlier supersolid platforms could not do. That control, combined with room-temperature operation, gives designers a flexible testbed for quantum photonic circuits — provided the materials survive long enough to be useful.