Aschenbach effect for spinning particles in Kerr–(A)dS spacetime

Ali Vahedi; Jafar Khodagholizadeh; Arman Tursunov

doi:10.1140/epjc/s10052-021-09081-0

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 280
https://doi.org/10.1140/epjc/s10052-021-09081-0

Regular Article - Theoretical Physics

Aschenbach effect for spinning particles in Kerr–(A)dS spacetime

Ali Vahedi¹, Jafar Khodagholizadeh²^b and Arman Tursunov³^,4

¹ Department of Physics, Kharazmi University, P.O. Box 15614, Mofateh Ave, Tehran, Iran
² Farhangian University, P.O. Box 11876-13311, Tehran, Iran
³ Research Centre for Theoretical Physics and Astrophysics, Institute of Physics, Silesian University in Opava, Bezručovo nám.13, 74601, Opava, Czech Republic
⁴ Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, 050040, Almaty, Kazakhstan

^b gholizadeh@ipm.ir

Received: 21 January 2021
Accepted: 22 March 2021
Published online: 2 April 2021

Abstract

A non-monotonic behavior of the velocity gradient of a test particle revolving around a rapidly rotating black hole in the locally non-rotating frame of reference is known as the Aschenbach effect. This effect can serve as a distinguishing signature of rapidly rotating black holes, being potentially useful for the measurements of the astrophysical black hole spins. This paper is the generalization of our previous research to the motion of spinning particles around a rotating black hole with non-zero cosmological constant. We show that both the particle’s spin s and the cosmological constant $Λ$ $\Lambda$ modify the critical value of the black hole spin $a_{c}$ $$a_c$$ , for which the Aschenbach effect can be observed; $a_{c}$ $$a_c$$ can increase or decrease depending on the signs of s and $Λ$ $\Lambda$ . We also found that the particle’s spin s can mimic the effect of the cosmological constant $Λ$ $\Lambda$ for a given $a_{c}$ $$a_c$$ , causing thus a discrepancy in the measurements of s, $Λ$ $\Lambda$ and $a_{c}$ $$a_c$$ in the Aschenbach effect.

© The Author(s) 2021

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