Seminar of Department of Theoretical Physics - Surajit Das (13.10.2026)
Tuesday 13.10.2026 at 14:00, Lecture room F2/125
Surajit Das (Department of Astronomy, School of Physical Sciences, University of Science and Technology of China):
Spin-Environment Induced Chaos around Astrophysical Black Holes at Realistic Astrophysical Spin
Abstract:
Extreme-mass-ratio inspirals (EMRIs) are promising sources for future space-based gravitational-wave detectors such as LISA, TianQin, and Taiji. While the motion of a small compact object around a black hole is usually described by integrable geodesic dynamics, the spin of the compact object introduces spin–curvature coupling and can lead to resonances and chaos. I will discuss the onset of chaos for a spinning compact orbiting a non-spinning supermassive black hole surrounded by a dark-matter halo. In particular, it will be shown that the presence of the halo can trigger chaotic behaviour at much lower astrophysically realistic spin values. Interestingly, these effects are not limited to the immediate vicinity of the black hole but can also appear at much larger orbital distances. The possible implications of such chaotic dynamics for gravitational-wave signals, and for probing dark-matter environments around astrophysical black holes, will also be discussed.