QUASINORMAL MODES OF RN BLACK HOLE SPACETIME WITH COSMIC STRING IN A DIRAC FIELD

We evaluate quasinormal mode frequencies for RN black hole spacetimes with cosmic string perturbed by a massless Dirac field, using Pöschl–Teller potential method. We find that only in the case of RN black hole having small charge, the effect due to cosmic string will dominate when perturbed by a negatively charged Dirac field, but if we are perturbing with positively charged Dirac field decay will be less in the case of black hole having cosmic string compared to the RN black hole without string.

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EFFECT OF COSMIC STRING IN SPHERICALLY SYMMETRIC BLACK HOLE ON THE DIRAC PERTURBATION

Modern Physics Letters A ◽

10.1142/s0217732310031439 ◽

2010 ◽

Vol 25 (02) ◽

pp. 111-124 ◽

Cited By ~ 1

Author(s):

R. SINI ◽

NIJO VARGHESE ◽

V. C. KURIAKOSE

Keyword(s):

Black Hole ◽

Cosmic String ◽

Oscillation Frequency ◽

Quasinormal Modes ◽

Dirac Field ◽

Spherically Symmetric ◽

Black Hole Spacetimes ◽

Quasi Normal Mode ◽

Symmetric Black Hole ◽

Sds Black Hole

The effect of cosmic string on the quasinormal modes (QNMs) of massless Dirac field perturbations were studied in different black hole spacetimes. Quasi-normal mode frequencies of massless Dirac field in Schwarzschild, RN extremal, SdS and near extremal SdS black hole spacetimes with cosmic string are obtained using WKB approximation. Our study shows a clear deviation in QNMs due to presence of cosmic string from those in the absence of string. The influence of cosmic string coded in the form of an increase in the oscillation frequency and damping time of QNMs.

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DECAY OF SPIN-1/2 FIELD AROUND REISSNER–NORDSTROM BLACK HOLE

International Journal of Modern Physics D ◽

10.1142/s0218271804005018 ◽

2004 ◽

Vol 13 (06) ◽

pp. 1105-1118 ◽

Cited By ~ 8

Author(s):

WEI ZHOU ◽

JIAN-YANG ZHU

Keyword(s):

Black Hole ◽

Scalar Field ◽

Quantum Number ◽

Turning Point ◽

Quasinormal Modes ◽

Astronomical Observation ◽

Dirac Field ◽

Neutrino Field ◽

Extremal Limit ◽

Field Decay

To find what influence the charge of the black hole Q will bring to the evolution of the quasinormal modes, we calculate the quasinormal frequencies of the neutrino field (charge e=0) perturbations and those of the massless Dirac field (e≠0) perturbations in the RN metric. The influences of Q, e, the momentum quantum number l, and the mode number n are discussed. Among the conclusions, the most important one is that, at the stage of quasinormal ringing, when the black hole and the field have the same kind of charge (eQ>0), the quasinormal modes of the massless charged Dirac field decay faster than those of the neutral ones, and when eQ<0, the massless charged Dirac field decays slower, which may be helpful in the astronomical observation. In addition, we compare the influence from the charge of the black hole to the spin 1/2 field and scalar field perturbations including the extremal limit (M=Q) and find a turning point of Q exists in both cases. The explanation of this fact is unclear with some suggestions that may be helpful are given.

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