Spinning black holes as cosmic string factories

We study the formation and evolution of vortices in U(1) dark photon dark matter and dark photon clouds that arise through black hole superradiance. We show how the production of both longitudinal mode and transverse mode dark photon dark matter can lead to the formation of vortices. After vortex formation, the energy stored in the dark photon dark matter will be transformed into a large number of vortex strings, eradicating the coherent dark photon dark matter field. In the case where a dark photon magnetic field is produced, bundles of vortex strings are formed in a superheated phase transition, and evolve towards a configuration consisting of many string loops that are uncorrelated on large scales, analogous to a melting phase transition in condensed matter. In the process, they dissipate via dark photon and gravitational wave emission, offering a target for experimental searches. Vortex strings were also recently shown to form in dark photon superradiance clouds around black holes, and we discuss the dynamics and observational consequences of this phenomenon with phenomenologically motivated parameters. In that case, the string loops ejected from the superradiance cloud, apart from producing gravitational waves, are also quantised magnetic flux lines and can be looked for with magnetometers. We discuss the connection between the dynamics in these scenarios and similar vortex dynamics found in type II superconductors.

Section: Jhep12(2022)089mentioning

confidence: 99%

Section: Jhep12(2022)089mentioning

confidence: 99%

Section: Dark Magnetic Flux Tubementioning

confidence: 99%

Section: Dark Magnetic Flux Tubementioning

confidence: 99%

See 2 more Smart Citations

Dark photon vortex formation and dynamics

East

Huang

2022

“…Under certain conditions cosmic strings, such as the ones just reviewed, can pierce black holes in our universe (see e.g. [42,[68][69][70][71][72][73][74] for several possible formation mechanisms). Black holes pierced by cosmic strings can for example be formed in the early universe as primoridial black holes [42]: 9 When primordial overdensities become order one (as predicted to happen by some inflationary models), the entire corresponding Hubble volume collapses to a (primordial) black hole of mass l H G N , where l H is the size of the horizon at formation time [75][76][77].…”

Section: Black Hole Piercingmentioning

confidence: 99%

Polarimetric signatures of the photon ring of a black hole that is pierced by a cosmic axion string

Gußmann

2021

A black hole image contains a bright ring of photons that have closely circled the black hole on their way from the source to the detector. Here, we study the photon ring of a rotating black hole which is pierced by a global hyper-light axion-type cosmic string. We show that the coupling 𝜙F$$ \overset{\sim }{F} $$ F ~ between the axion 𝜙 and the photon can give rise to a unique polarimetric structure of the photon ring. The structure emerges due to an Aharonov-Bohm type effect that leads to a change of the polarization directions of linear polarized photons when they circle the black hole. For several parameter choices, we determine concrete polarization patterns in the ring. Measuring these patterns can provide us with a way of determining the value of the coefficient of the mixed anomaly between electromagnetism and the symmetry that gave rise to the cosmic string. Finally, we briefly review a possible formation mechanism of black holes that are pierced by cosmic strings and discuss under which conditions we can expect such objects to be present as supermassive black holes in the center of galaxies.

Mass and spin for classical strings in dS3

Parmentier

2021

We demonstrate that all rigidly rotating strings with center of mass at the origin of the dS3 static patch satisfy the Higuchi bound. This extends the observation of Noumi et al. for the open GKP-like string to all solutions of the Larsen-Sanchez class. We argue that strings violating the bound end up expanding towards the horizon and provide a numerical example. Adding point masses to the open string only increases the mass/spin ratio. For segmented strings, we write the conserved quantities, invariant under Gubser’s algebraic evolution equation, in terms of discrete lightcone coordinates describing kink collisions. Randomly generated strings are found to have a tendency to escape through the horizon that is mostly determined by their energy. For rapidly rotating segmented strings with mass/spin < 1, the kink collisions eventually become causally disconnected. Finally we consider the scenario of cosmic strings captured by a black hole in dS and find that horizon friction can make the strings longer.