Constraining the swift memory burden effect with GW250114-like events

A bstract Black hole spectroscopy allows to infer the properties of the remnant of a binary black hole coalescence. Motivated by the recent proposal that a black hole’s information load can alter its classical response to small perturbations, an effect known as the swift memory burden (SMB), we develop a minimal phenomenological framework to analyze the ringdown of a binary black hole merger and confront it with the data from the GW250114 event. In particular, we model the SMB imprint through a suppression factor derived as an upper bound and adopt the least-suppressive form. We perform a Bayesian analysis combining the frequencies of the (220) and (440) quasi-normal modes and obtain a lower bound log 10 p ≳ 2, where p controls how the gaps reopen when the black hole’s master mode occupation departs from the critical value. Moreover, using a Fisher information matrix (high signal-to-noise ratio) approximation, we forecast the lower bound log 10 p ≳ 3 for a GW250114-like event observed with Cosmic Explorer or Einstein Telescope. Within this minimal, weak-effect framework, our results disfavour rapid gap reopening, shedding light on how the swift memory burden effect can be probed with current and next-generation detectors.