An international team of physicists has engineered an exotic quantum state of matter, a supersolid in an exciton-polariton Bose-Einstein condensate, at room temperature, using a tiny light-trapping microcavity that avoids the extreme cooling typically required. Published in Science Advances, the results point the way to more practical uses of quantum technology in advanced computing systems and sensors.
The researchers combined a liquid crystal, controllable by voltage, and an organic semiconductor, which interacts strongly with light, in a microcavity. Laser pulses supplied energy for the quantum reaction. The technical term for the resulting state is a supersolid in an exciton-polariton Bose-Einstein condensate (BEC).
Part liquid and part solid, the quantum state exhibited both superfluidity (flow without resistance) and a repeating crystal arrangement, without the extreme cooling that quantum states usually require. “Our liquid-crystal microcavities can operate even at temperatures approaching 60 °C (140 °F),” said physicist Wiktor Piecek from the Military University of Technology in Poland.
The behavior was short-lived: the materials degraded over time as the semiconductor reacted with the liquid crystal. “We had to plan the entire sequence of experiments in advance,” said physicist Marcin Muszyński, from the City College of New York. “Repeating a measurement meant fabricating an entirely new sample.” Each laser pulse reformed the condensate, with its crystal stripes appearing in slightly different positions each time, evidence that the quantum state was intrinsic, not influenced by the microcavity. “This is a textbook example of spontaneous symmetry breaking,” said physicist Guillaume Malpuech, from the French National Centre for Scientific Research (CNRS). “Theory predicted that the supersolid could choose among several equivalent states, and that is exactly what we observed.”
Multiple samples were tested with the same results, backed by computer simulations. Future work may focus on extending the reaction lifetime and studying quantum vortices that appeared as flaws in the stripe patterns, indicating superfluid behavior. Almost any quantum effect involving light, including those relevant to computer chips and advanced sensors, could benefit. “Our work opens new perspectives for quantum fluids of light physics in the presence of spin-orbit coupling and beyond,” they write in their paper.
Analysis
Why This Matters
- Room-temperature quantum states could lead to practical quantum computers and sensors without expensive cryogenic cooling.
- The microcavity platform is relatively inexpensive and voltage-controlled, making quantum research more accessible.
- Advances in spin-orbit coupling and quantum vortices observed here may enable new types of quantum devices.
Background
Quantum states of matter such as superfluids and supersolids normally require temperatures near absolute zero to form. This team used a microcavity combining a liquid crystal and an organic semiconductor to create a supersolid Bose-Einstein condensate at room temperature. The experiments were conducted by researchers from institutions in Poland, the United States, and France.
What to Watch
- Efforts to extend the lifetime of the quantum state, currently limited by material degradation after each laser pulse.
- Further exploration of spin-orbit coupling in this platform for quantum computing applications.
- Integration of the microcavity design into existing semiconductor chip technology for practical devices.
Checked
12 claims in this story checked against 1 source: 12 supported.
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- SupportedAn exotic quantum state of matter was engineered at room temperature by an international team.ScienceAlert: “What's more, it was engineered at room temperature, without the extreme cooling that quantum states usually require. The results of the experiments, carried out by an international team of researchers”
- SupportedThe state was a supersolid in an exciton-polariton Bose-Einstein condensate, observed without extreme cooling, with potential uses in computing and sensors.ScienceAlert: “The technical term for this quantum state is a supersolid in an exciton-polariton Bose-Einstein condensate”
- SupportedThe results were published in Science Advances and point toward practical uses of quantum technology in advanced computing systems and sensors.ScienceAlert: “The results of the experiments, carried out by an international team of researchers, have been published in Science Advances . They point the way to more practical uses of quantum technology in advanced computing systems and sensors.”
- SupportedThe researchers combined a voltage-controllable liquid crystal with an organic semiconductor that interacts strongly with light, using laser pulses to supply energy.ScienceAlert: “the researchers combined a liquid crystal (which can be controlled by voltage) and an organic semiconductor (which interacts strongly with light). Laser pulses were then used to supply energy for the quantum reaction.”
- SupportedWiktor Piecek said the liquid-crystal microcavities can operate at temperatures approaching 60 °C (140 °F).ScienceAlert: “"Our liquid-crystal microcavities can operate even at temperatures approaching 60 °C (140 °F)," says physicist Wiktor Piecek from the Military University of Technology in Poland.”
- SupportedThe materials degraded over time as the semiconductor reacted with the liquid crystal.ScienceAlert: “the materials degraded over time, as the semiconductor reacted with the liquid crystal.”
- SupportedMarcin Muszyński said the team had to plan the experiments in advance and make a new sample to repeat a measurement.ScienceAlert: “"We had to plan the entire sequence of experiments in advance," says physicist Marcin Muszyński, from the City College of New York. "Repeating a measurement meant fabricating an entirely new sample."”
- SupportedEach successive laser pulse reformed the condensate, with its stripes appearing in different places, indicating the state was inherent rather than imposed by the microcavity.ScienceAlert: “The condensate reformed each time, with its stripes – the solid, crystal-like part of the supersolid – lining up in slightly different places with every refresh. That might not sound like much, but it's evidence of the inherent nature of this quantum state, rather than anything influenced by the external microcavity.”
- SupportedGuillaume Malpuech called the result a textbook example of spontaneous symmetry breaking and said it matched the theory’s prediction.ScienceAlert: “"This is a textbook example of spontaneous symmetry breaking," says physicist Guillaume Malpuech, from the French National Centre for Scientific Research (CNRS). "Theory predicted that the supersolid could choose among several equivalent states, and that is exactly what we observed."”
- SupportedMultiple samples produced the same results, which were also supported by computer simulations.ScienceAlert: “Multiple samples were tested with the same results, which were also backed up by computer simulation models.”
- SupportedFuture work may seek to extend the reaction lifetime and study quantum vortices that appeared as flaws in the stripe patterns, indicating superfluid behavior.ScienceAlert: “Routes for developing the experiments further might involve working on ways to get the core reactions to last for longer, and interrogating in more detail the quantum vortices that appeared – flaws in the stripe patterns that indicated superfluid behavior.”
- SupportedThe researchers wrote that their work opens new perspectives for quantum fluids of light physics with spin-orbit coupling and beyond.ScienceAlert: “"Our work opens new perspectives for quantum fluids of light physics in the presence of spin-orbit coupling and beyond," write the researchers in their published paper.”
