How does Hawking emission change the analog horizon that produces it? · revision history

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Title
How does Hawking emission change the analog horizon that produces it?
Plain
A real black hole should shrink as it radiates; in a condensate the emitted sound should likewise change the flow that makes the horizon. Theory now predicts how much the flow is changed, but no experiment has measured the change.
Precise
For a quasi-1D BEC sonic black hole, the back-reaction of the Hawking flux on the flow, to first order in the quantum depletion 1/(n_1D $\xi$) (n_1D the linear density, xi the healing length), has been computed as a stationary shift of the density, velocity and Mach-number profiles. Determine whether the surface gravity $\kappa$ also drifts in time (sign and rate of $\mathrm{d}\kappa/\mathrm{d}t$, and whether the evolution follows an evaporation law analogous to $\mathrm{d}M/\mathrm{d}t$ proportional to $-T_H^2$), and measure the predicted stationary or time-dependent profile change. An answer is a measured profile change that agrees with the computed one after three-body loss, heating and stimulated emission are subtracted.
Settled by
A measurement of the density, velocity or Mach-number profile change in a stationary BEC analog that matches the computed back-reaction after atom loss and heating are subtracted.
Kind
well-posed
Answer type
value
References
(empty)
Literature status
partially-resolved
Status note
Back-reaction equations were derived (Liberati, Tricella, Trombettoni 2020; Balbinot, Fabbri, Ciliberto, Pavloff 2025), and Ciliberto et al. (PRA 112, 063323, 2025) computed a stationary Mach-number shift; no measurement has isolated the effect as of 2026.
Posed since
(empty)