Acoustic Black Holes Get Entangled Differently ⚡ экспресс
For the first time, scientists have numerically calculated the entanglement entropy (a measure of quantum correlations) for an acoustic black hole—a region in a fluid where sound can't escape. They found that for large areas, it scales with volume, not surface area. That's a volume law, unusual for gravitational systems. The culprit? Inseparable long-range correlations triggered by the birth of phonon pairs (sound quanta) at the horizon. The system acts locally thermal, and the volumetric part of the entanglement matches the thermal entropy of Hawking radiation.
An acoustic black hole is a fluid flow faster than sound, so sound waves can't escape. The boundary—the surface where the flow speed reaches the speed of sound—spawns pairs of phonons: sound quanta, one flying away, the other plunging inward.
Calculations show that the entropy of entanglement here depends on volume, not horizon area. Phonons throughout the interior are connected to each other—as if invisible strings weave through a waterfall, linking every drop to the others. Paradoxically, particles born at the boundary and forever separated by it retain a shared memory at any distance inside the flow.
🎯 If interstellar gas flowed around a massive object at supersonic speed, an acoustic black hole would form—and even the roar of a supernova couldn't escape.
🎬 In Fred Hoyle's novel 'The Black Cloud,' an intelligent gas cloud manipulates matter flows, resembling an acoustic analogue but without quantum effects.