This work explores how the “island formula” (a way to explain information preservation in black holes) works in “fuzzball” models, where the event horizon is replaced by a reflective boundary. In a two-dimensional model, this boundary leads to a “flickering island,” creating an analog of the information paradox. In higher dimensions, islands strongly depend on the reflective boundary’s position and often vanish. Even in realistic string geometries (superstrata, bubble solutions), islands are not guaranteed: their existence requires a special behavior of the area near the center.
A black hole is usually depicted as an abyss with a point of no return. To save information—which quantum laws forbid from disappearing—physicists replaced that boundary with a fluffy tangle of microscopic strings. Infalling data gets permanently imprinted into its intertwined threads. Recently, the idea emerged of adding entropy islands inside the tangle—tiny regions where hidden information suddenly becomes visible, like a knot momentarily peeking out of tangled wool. But calculations show that depending on the structure of the tangle’s reflective surface, these islands behave capriciously. They flicker—appearing and then promptly falling back, as if someone is tugging the threads.
In more precise models that account for spacetime curvature near the tangle, the islands don’t appear at all. The black hole securely hides its secrets, and the puzzle posed by Stephen Hawking and Jacob Bekenstein only deepens.
🎯 From the outside, this tangle looks exactly like an ordinary black hole. You can tell them apart only by quantum jitters near the horizon—so subtle that detecting them is currently impossible.