- Physicists created a polariton fluid that mimics a black hole's event horizon.
- Polaritons are light-matter hybrids with mass 100,000 times lighter than an electron.
- The experiment demonstrates conditions for Hawking-like radiation without needing a real black hole.
Maxime Jacquet has spent a decade trying to trap light the way black holes do. In July, the physicist at Paris's Kastler Brossel Laboratory and his colleagues finally succeeded.
They created a quantum fluid of light that mimics the event horizon of a black hole, the boundary beyond which nothing escapes.
The achievement, published in Physical Review Letters, offers physicists something remarkable: a way to study quantum effects near black holes without needing an actual black hole.
Key figure
10-5
Times lighter than an electron: the effective mass of polaritons in this experiment
Trapping Sound the Way Black Holes Trap Light
The technique relies on particles called polaritons, hybrids of light and matter that form when laser photons couple with electrons in semiconductors.
Jacquet's team directed laser beams at layered semiconductors sandwiched between mirrors. The polaritons that emerged collectively behaved like a flowing fluid of light.
By carefully shaping the laser's spatial profile, they engineered an artificial horizon. At this boundary, the fluid's flow speed transitions from slower than sound to faster than sound.
Sound waves forming in the fluid cannot escape from beyond this horizon. The physics mirrors how light cannot escape a black hole's event horizon.
What is analogue gravity?
Analogue gravity uses laboratory systems to mimic gravitational effects. When a fluid flows faster than its own sound waves can travel, those waves become trapped, just as light becomes trapped by a black hole's gravity. The mathematics describing both situations is remarkably similar.
Testing Hawking's 50-Year-Old Prediction
In 1974, Stephen Hawking proposed that black holes aren't entirely black. Quantum fluctuations at the event horizon should produce faint radiation, now called Hawking radiation.
The effect has never been observed from an actual black hole. The radiation is too faint, orders of magnitude below what any telescope could detect.
Laboratory analogues offer a different path. If the mathematics holds, similar quantum effects should appear at artificial horizons.
The polariton fluid demonstrated the necessary ingredients for an equivalent effect, with sound waves playing the role of particles. Quantum fluctuations of the acoustic field should yield entangled emission across the horizon, just as Hawking predicted for black holes.
Why Light Makes a Better Laboratory
Other researchers have built black hole analogues from ultracold atoms, water waves, and optical fibres. Each has limitations.
Polariton fluids offer three advantages. First, direct optical access: the emission angle reveals the particles' momentum, enabling precise measurements. Second, programmable flows: spatial light modulators let researchers sculpt the fluid's velocity and density. Third, tuneable frequency: adjusting the laser changes the temperature window where Hawking-like effects should appear.
The team's recent lecture notes describe the system as "a rare combination in condensed matter physics: a quantum fluid of light whose macroscopic phase and flow are directly set by the driving field."
The Next Challenge: Spontaneous Emission
The current experiment demonstrates that polariton fluids can create the conditions for Hawking-like radiation. Observing that radiation spontaneously emerging from the quantum vacuum remains the next goal.
In Israel, Jeff Steinhauer at Technion has pursued similar questions using ultracold atoms, collecting 97,000 repetitions over 124 days to confirm that his analogue's radiation was stationary, as Hawking predicted.
Jacquet's team now has a platform where the horizon can be programmed at will. The hunt for laboratory Hawking radiation continues, one photon at a time.
Sources
- Primary Research: K. Falque et al., "Polariton fluids as quantum field theory simulators on tailored curved spacetimes," Phys. Rev. Lett. 135, 023401 (2025). DOI link
- Additional Context:
- Quantum Fluid Mimics Black Hole's Horizon (Physics Magazine)
- Polariton fluids of light as programmable simulators (arXiv lecture notes)
- Polariton fluids for analogue gravity physics (Royal Society, 2020)
Fact Check: Claim-by-Claim Verification Verified
The recap accurately summarizes the primary research paper and Physics synopsis, with all key claims, names, methods, and context matching the sources.
Commentary
- Lead researcher named Kévin Falque in paper (likely "Maxime Jacquet and colleagues" in synopsis), but article's emphasis on Jacquet aligns with his senior role.
- Hawking radiation not yet observed in this setup; article correctly frames it as a future goal with necessary ingredients present.
- arXiv lecture notes (2512.14194) from Dec 2025 post-date July PRL but describe the same system accurately.
Sources used for verification
Academic/Peer-reviewed:
- Polariton Fluids as Quantum Field Theory Simulators on Tailored Curved Spacetimes - journals.aps.org
- Acoustic horizons and the Hawking effect in polariton fluids of light - arxiv.org
- Polariton fluids for analogue gravity physics - pmc.ncbi.nlm.nih.gov
Other reliable sources:
- Quantum Fluid Mimics Black Hole’s Horizon - physics.aps.org
- Simulating the Hawking effect and other quantum field theory predictions - phys.org
Fact-checked by Perplexity Sonar Pro on 2026-01-16
