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

Revision 2

Accepted · core change · record

Changes against revision 1:

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 · changed · core
Revision 1: 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.
Revision 2: 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)

Decisions