Area Spectrum of BTZ Black Holes from the Periodicity in Euclidean Time
  The recent proposal of Maggiore that the periodicity of a black hole may be the origin of area quantization law is analyzed in the context of three dimensional black holes. We use the period of motion of an outgoing wave which is shown to be related to the vibrational frequency of the perturbed black hole, to quantize the horizon area of rotating and non-rotating BTZ black holes. It is shown that the equally spaced area spectrum takes the same form as the obtained in the literature using the quasinormal mode analysis for both metrics. Using this method, we do not need to use the small angular momentum assumption which is necessary in the quasinormal mode approach for the rotating black hole. 
Alexis Larranaga
gr-qc hep-th