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An ordinary kettle: you heat it up — temperature rises, molecular chaos grows, and steam shoots out. But in the lab, they've created a peculiar "kettle"—an analog black hole made from superconducting circuits cooled to the extreme. The idea of William Unruh allowed them to mimic the key traits of real black holes: trapping waves and the temperature predicted by Hawking.

The main oddity: here, the link between heating and entropy (a measure of disorder) can be severed. In a real black hole, temperature is rigidly tied to mass — the heavier it is, the colder it gets. But in the lab version, you can change it without touching the internal state: as if the kettle heats up, but no steam comes out. The system's behavior splits into two independent halves — thermal and "disorderly."

Yet a surprise: no known model of gravity describes these samples. The scientists took an inverse approach — instead of tweaking theory, they engineered superconducting circuits with desired properties. Thus, the quest for quantum rules for curved spacetime turns into a precise engineering task.

Original abstract

as written by the authors arXiv:2605.11046

We investigate which dilaton gravity models can reproduce the typical two dimensional analogue black holes realized in platforms such as superconducting quantum circuits. We identify the most reasonable assumptions these models must satisfy, and determine the dilaton models for which the state-dependence of the Hawking temperature, T, can be switched on and off, a feature that is absent in four dimensional black holes. When the analogue black hole exhibits state-independent temperature, as in the cases considered here, the kinematics governing T decouples from the dynamics underlying S. Our numerical analysis reveals that the given analogue black holes do not correspond to known dilaton gravity models, limiting their usefulness for extracting theoretical insights. We then show that the logic can be easily reversed: starting from established well known dilaton models, one can derive the conditions that laboratory implementations must satisfy. This shifts the challenge from the theoretical perspective to the experimental realization.