Black hole superradiance has proven being very valuable in several realms of gravitational physics, and holds a promising discovery potential. In this paper, we show how it can sheed light on a long standing problem in physics, the quest for magnetic monopoles in the Universe. Placing them in the interior of primordial rotating black holes, which act as natural amplifiers, we show that massive charged bosonic fields in their vicinity exhibit a superradiant instability which surpasses significantly that of neutral Kerr black holes. Strikingly, this is true for black holes containing an order-one number of magnetic monopoles, or merely a single one, and possessing either low, moderate or large values of angular momentum. In particular, the instability is drastically faster than the radiative decay time of charged pions, thus making it physically relevant. Furthermore, our analysis identifies the most unstable modes as a class of monopole spheroidal harmonics, that we dub north and south monopole modes, whose morphology is markedly different from the usual superradiantly unstable modes since they extend along the rotational axis. We conclude by discussing implications of our results for primordial magnetic black holes, and their observational signatures as sources of cosmic rays and high-frequency gravitational waves.
Black hole superradiance has been proven to be valuable in various areas of gravitational physics and offers significant potential for discovery. In this paper, we focus on its application to the long-standing challenge of finding magnetic monopoles in the Universe.
We propose that primordial rotating black holes could serve as natural amplifiers for magnetic monopoles placed within their interiors. This amplification leads to a superradiant instability in the vicinity of these black holes, which is even more pronounced than that observed in neutral Kerr black holes. This instability is relevant for black holes containing just one or a small number of magnetic monopoles, regardless of their level of angular momentum.
An interesting finding is that the superradiant instability occurs at a much faster rate than the radiative decay time of charged pions, making it physically relevant. Additionally, our analysis reveals the existence of a specific class of monopole spheroidal harmonics known as north and south monopole modes. These modes differ from the usual superradiantly unstable modes as they extend along the rotational axis of the black hole.
In conclusion, our research has significant implications for understanding primordial magnetic black holes and their potential role as sources of cosmic rays and high-frequency gravitational waves. By exploring the phenomenon of black hole superradiance and its application to magnetic monopoles, we have opened up new avenues for investigation and future discoveries in gravitational physics.
Roadmap for Readers
- Introduction to black hole superradiance and its relevance in gravitational physics
- Discussion of the long-standing problem of finding magnetic monopoles in the Universe
- Explanation of the proposed use of primordial rotating black holes as amplifiers for magnetic monopoles
- Presentation of the superradiant instability observed in the vicinity of these black holes
- Comparison of the instability in black holes with different numbers of magnetic monopoles and levels of angular momentum
- Analysis of the faster rate of the superradiant instability compared to the decay time of charged pions
- Description of the unique monopole spheroidal harmonics known as north and south monopole modes
- Discussion of the implications for primordial magnetic black holes and their potential observational signatures as sources of cosmic rays and high-frequency gravitational waves
- Summary of the key findings and their significance in advancing our understanding of gravitational physics
Potential Challenges and Opportunities
While our research opens up exciting possibilities for further exploration, there are several challenges that need to be addressed:
- Experimental verification: The proposed phenomenon needs to be empirically tested in order to validate its existence.
- Data collection: Gathering observational data on primordial magnetic black holes and their characteristics poses technological and logistical challenges.
- Theoretical refinement: Further theoretical analysis is required to fully understand the underlying mechanisms and implications of the observed superradiant instability.
- Interdisciplinary collaboration: Collaboration between researchers from diverse fields such as astrophysics, particle physics, and gravitational wave astronomy is crucial for comprehensive investigations.
Despite these challenges, the opportunities presented by this research are immense:
- Potential discovery of magnetic monopoles: This research offers a new avenue for detecting elusive magnetic monopoles in the Universe.
- Advancement of gravitational physics: The study of black hole superradiance and its application to magnetic monopoles can significantly contribute to our understanding of gravitational phenomena.
- Expanded knowledge of primordial black holes: Investigating the role of primordial rotating black holes in amplifying magnetic monopoles can shed light on the formation and evolution of these mysterious objects.
- New observational tools: The identification of primordial magnetic black holes as potential sources of cosmic rays and high-frequency gravitational waves opens up new possibilities for detecting and studying these phenomena.