radiazioni qn e buchi neri

Department of Physics, Dniepropetrovsk National University, St. Naukova 13, Dniepropetrovsk 49050, Ukraine

Received 14 April 2004; published 18 August 2004

We consider the BTZ black hole surrounded by the conformal scalar field. Within general relativity, the resonant quasinormal (QN) modes dominate in the response of a black hole to external perturbations. At the same time, the metric of an evaporating black hole is affected by the Hawking radiation. We estimate the shift in the quasinormal spectrum of the BTZ black hole stipulated by the back reaction of the Hawking radiation.
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The dominant contribution to the corrections to the QNMs is simply a shift of ω2 proportional to -(Λ/M)3/2(4L2+M)ħ.
It is negligible for large black holes but essential for small ones, giving rise to considerable increasing of the quality factor. Thus, the small evaporating black hole is expected to be a much better oscillator than a large one.