Seção de choque de absorção de buracos negros de Schwarzschild e de buracos acústicos canônicos / Section of shock of absorption of black holes of Schwarzschild and of canonical acoustic holes
AUTOR(ES)
Ednilton Santos de Oliveira
DATA DE PUBLICAÇÃO
2008
RESUMO
In this dissertation we compute the absorption cross section of Schwarzschild black holes for the massless scalar and electromagnetic fields. We also compute the absorption cross section of canonical acoustic holes for sound waves. We use a numerical method to obtain the results in arbitrary frequencies. We also obtain analytic expressions for the low- and high-frequency absorption cross sections. The numerical results are in excellent agreement with the low- and high-frequency absorption cross section values obtained analytically. In the zero-frequency limit the absorption cross section tends to the event horizon area value for both the massless scalar field in Schwarzschild spacetime and the canonical acoustic hole cases. However, as the frequency increases, these two results become very different. This shows that, although the spacetime geometry does not influence the absorption cross section in the zero-frequency limit, it is important for arbitrary frequencies. We also see that massless scalar and electromagnetic absorption cross section values for the Schwarzschild black hole coincide for high enough frequencies and angular momenta. The spin of the scattered particle, in this case, although being very important for low frequencies, becomes less relevant to the absorption cross section value as the frequency and the angular momentum of the incident particle increase.
ASSUNTO(S)
absorption cross section buracos negros de schwarzschild field theory in curved spaces schwarzschild black holes seção de choque de absorção teoria de campos em espaços curvos buracos acústicos canônicos canonical acoustic holes fisica
