Fluffy Black Holes: The Flickering Tangle and the Paradox ⚡ экспресс
We investigate the application of the island recipe in black hole models inspired by fuzzballs. In a simplified setup, the event horizon is replaced by a reflective boundary (stretched horizon). In a two-dimensional model, we analyze entanglement entropy dynamics: the boundary modifies the island saddle point, and in a certain parameter region a “flickering island” effect arises, inevitably leading to an analogue of the information paradox. The analysis is generalized to higher dimensions, incorporating bulk and boundary contributions to generalized entropy. The existence of island solutions is sensitive to boundary conditions and the stretched horizon’s location, resulting in the absence of entanglement islands over a wide parameter range. We examine more realistic stringy fuzzball geometries, including superstrata and bubble solutions, and assess the likelihood of island formation. Our findings show that the presence of islands hinges on the geometric area’s behavior near the “cap” and is generally not guaranteed.
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.