BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Gravitational atom spectroscopy DTSTART:20260226T143000Z DTEND:20260226T160000Z DTSTAMP:20260612T063101Z UID:ef01c437-3847-400c-9b49-6453fe5727eb SEQUENCE:2 CREATED:20260220T154516Z DESCRIPTION:Massive scalar fields can form bound clouds around black holes . Independently of the initial data\, after an initial transient\, these s calar clouds are well described by gravitational atoms\, where the scalar field settles into a superposition of quasi-bound states. In a quasi-bound state\, the scalar field oscillates with a proper complex frequency\, dec ays in time\, has an ingoing wave behaviour at the horizon and exponential ly decays at spatial infinity. Previous results suggest that scalar clouds can be detectable during the inspiral-merger-ringdown. We quantify the ef fect of these scalar clouds on the ringdown by computing the shift of the fundamental quasi-normal mode in the axial sector. We found that for compa ct enough configuration\, these shifts are in principle detectable even wi th current detectors. LAST-MODIFIED:20260220T154527Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/gravitational-atom-spectro scopy/ X-ALT-DESC;FMTTYPE=text/html:

Massive scalar fiel ds can form bound clouds around black holes. Independently of the initial data\, after an initial transient\, these scalar clouds are well described by gravitational atoms\, where the scalar field settles into a superposit ion of quasi-bound states.

In a quasi-bound state\, the scalar f ield oscillates with a proper complex frequency\, decays in time\, has an ingoing wave behaviour at the horizon and exponentially decays at spatial infinity. Previous results suggest that scalar clouds can be detectable du ring the inspiral-merger-ringdown.

We quantify the effect of the se scalar clouds on the ringdown by computing the shift of the fundamental quasi-normal mode in the axial sector. We found that for compact enough c onfiguration\, these shifts are in principle detectable even with current detectors.

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