Heat from the void: how to catch the Unruh effect ⚡ экспресс
The Unruh effect predicts that an accelerating observer sees thermal radiation where a stationary observer sees only cold vacuum. The main obstacle is the exponential suppression of particle creation when their mass is large compared to the acceleration energy. The authors calculated this suppression for the first time: for an electron at accelerations of ~10²⁰ m/s², it amounts to over 10^9 orders of magnitude, making direct observation impossible. But there is a way out: create not a massless field, but a field with a very small effective mass in a superconducting circuit. The proposed scheme with a Josephson qubit and a microwave resonator mimics an Unruh detector, paving the way for laboratory verification of the effect.
The void is deceptive. William Unruh showed that an accelerating observer perceives the vacuum as hot. The effect resembles the particle birth near black holes, predicted by Stephen Hawking, but instead of spacetime curvature, acceleration is at work. Yet for massive particles — electrons, for example — the heat is suppressed: it's like trying to hear the ring of a ship's hawser. Even at accelerations close to light speed, the signal is weakened by an unimaginable 10⁹ orders.
The solution: replace the detector with a super-light double. In a superconducting circuit, an 'effective mass' is created — an almost weightless ghost of a particle. It's like taking the thinnest guitar string: it responds to the slightest touch. Just so, the ghost particle under acceleration chisels thermal glow out of the vacuum, detectable by lab instruments.
An unexpected twist: the Unruh effect is the mathematical twin of Hawking radiation, but while the radiation of black holes is almost impossible to observe, this experiment turns quantum heat into something tangible. For the first time, we will be able to see how acceleration births entropy where previously there was only curvature.
🎯 The Unruh effect is mathematically almost identical to Hawking radiation, though one requires acceleration and the other a black hole's event horizon.
🎬 In Greg Egan's novel 'Incandescence', a civilization living in an accretion disk uses the Unruh effect to understand thermodynamics.