Quantum gravitational effects in the near-horizon region of a black hole may drastically change the classical description of the black hole by removing or modifying the event horizon. Echoes in the postmerger ringdown of the gravitational waves spectrum can be understood as a definitive observational signature of such modifications. In this talk, I will discuss about horizonless Kerr-like exotic compact objects (ECO) within the context of Kerr/CFT correspondence. The near horizon modifications of the black hole (or ECO) can be understood as finite size and/or finite N effects in the dual CFT. The quasi normal modes and the absorption cross-section of these ECOs will be obtained from the dual CFT living on a finite circle. I will further discuss how the echo time-delay is related to the length of the circle on which the CFT lives. The reflectivity of the ECO membrane will be obtained in terms of the CFT modular parameter, showing that it takes the Boltzmann form.
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Zoom Meeting ID: 852 8915 0495
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