In analogue black hole experiments using Bose-Einstein condensates (Steinhauer 2021), a transition of the radiation mode from multi-mode to monochromatic has been observed. This paper proposes the hypothesis that this transition point serves as an operational indicator of the Page time within analogue systems. According to the theory of the Page curve, the Page time represents a critical juncture where the nature of information emission shifts, corresponding to the emergence of the island region predicted by the Island formula. We examine whether the timing of this monochromatic transition aligns with the predictions of the Island formula and provide an operational definition for identifying the Page time in analogue settings.
Takeshi Abe (Sat,) studied this question.