Acoustic Black Holes Get Entangled Differently ⚡ экспресс
A numerical approach has been developed to compute the entanglement entropy of an acoustic black hole model. It is found that for sufficiently large subregions, the entanglement entropy grows linearly with size, i.e., it follows a volume rather than area law. The reason is inseparable long-range correlations caused by the creation of phonon pairs at the event horizon. Additionally, the system is shown to possess local thermality, and the volume part of the entanglement entropy agrees well with the thermal entropy of outgoing 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.