Topological Physics at Room Temperature Using Light ✛

Original: "Realizing the Haldane Model in Thermal Atoms"

· Jiefei Wang, Jianhao Dai, Ruosong Mao, Yunzhou Lu, Xiao Liu, Huizhu Hu, Shi-Yao Zhu, Xingqi Xu, Han Cai, Da-Wei Wang

arXiv:2509.08411 · 2025-09-10 · CC BY 4.0 · 1 min

Physicists have realized the Haldane model without ultra-low temperatures for the first time, thanks to a laser lattice.

Thermal noise is the eternal nemesis of quantum experiments. Atoms jitter randomly, like musicians trying to play in a bustling market. Until now, only extreme cold could help — fridge-sized setups filled with liquid helium.

In this new experiment, physicists gave the atoms an orchestra with no conductor. A laser created a periodic lattice where particles emit light in harmony — thermal noise literally drowns in the collective chorus. A simple brightness measurement captured the shift between stable quantum phases. The approach is as straightforward as comparing the volume of two notes.

But the biggest surprise? The system isn't just noise-proof: it's far more intricate. With stronger modulation, multilayered structures emerged (phases with high Chern numbers) that are normally out of reach. Each layer plays its own part without interfering with the rest. The platform works at room temperature on an ordinary table, promising quantum devices outside the lab.

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The most complex states observed, with high Chern numbers, are like a multi-layered musical score, each part playing independently.

\theta_j(t) = f \sin(\delta t + \phi_j)

Phase modulation of the three laser fields, which makes the Dirac points move along a circle and accumulate a Berry phase of π per period, opening a topological gap.

\eta = \frac{|c_{k+}|^2 - |c_{k-}|^2}{|c_{k+}|^2 + |c_{k-}|^2}

Superradiance contrast of two directional modes; its sign directly indicates the sign of the Chern number, allowing detection of the topological transition.

Scientists

Christian Doppler D. B. McLaughlin Didier Queloz Michel Mayor R. A. Rossiter James Clerk Maxwell

Concepts

high temperature superconductor cryogenic temperature cryostat quantum thermal stability quantum thermometer thermoelectric device thermal equilibrium liquid helium cryogenic sensing aluminum nitride topological superconductivity heat dissipation ultracold atoms rydberg atom simulator helium thermocline superconductivity dome heat engine cooling topological insulator

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Topological Physics at Room Temperature Using Light ✛