Spontaneous excitation of an atom in a Kerr spacetime

Abstract

We consider radiative processes of an atom in a rotating black-hole background. We assume the atom, represented by a hypothetical two-level system, is coupled via a monopole interaction with a massless quantum scalar field prepared in each one of the usual physical vacuum states of interest. We constrain ourselves to two different states of motion for the atom, namely a static situation in which the atom is placed at a fixed radial distance, and also the case in which it has a stationary motion but with zero angular momentum. We study the structure of the rate of variation of the atomic energy. The intention is to clarify in a quantitative way the effect of the distinguished contributions of vacuum fluctuations and radiation reaction on spontaneous excitation and on spontaneous emission of atoms. In particular, we are interested in the comprehension of the combined action of the different physical processes underlying the Hawking effect in the scenario of rotating black holes as well as the Unruh-Starobinskii effect. We demonstrate that, in the case of static atoms, spontaneous excitation is also connected with the Unruh-Starobinskii effect, but only in the case of the quantum field prepared in the Frolov-Thorne vacuum state. In addition, we show that, in the ZAMOs perspective, the Boulware vacuum state contains an outward flux of particles as a consequence of the black-hole superradiance. The possible relevance of the findings in the present work is discussed.

Accepted for publication in Physical Review D

References in corpus (7)

• Spontaneous excitation of an accelerated hydrogen atom coupled with electromagnetic vacuum fluctuations
• Position dependent energy level shifts of an accelerated atom in the presence of a boundary
• Do static atoms outside a Schwarzschild black hole spontaneously excite?
• Resonance interaction energy between two accelerated identical atoms in a coaccelerated frame and the Unruh effect
• Spontaneous excitation of a static multilevel atom coupled with electromagnetic vacuum fluctuations in Schwarzschild spacetime
• Relationship between Hawking radiation from black holes and spontaneous excitation of atoms
• Rigidly rotating ZAMO surfaces in the Kerr spacetime

Cited by in corpus (5)

• Quantum optics meets black hole thermodynamics via conformal quantum mechanics: II. Thermodynamics of acceleration radiation
• Entanglement dynamics: Generalized master equation for uniformly accelerated two-level systems
• Atom-field dynamics in curved spacetime
• Hawking effect in an extremal Kerr black hole spacetime
• A dynamic theory of entanglement for uniformly accelerated atoms