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SUMMARY:Axion superradiance in rotating neutron stars - Jamie McDonald (TU
  Munich)
DTSTART:20191017T150000Z
DTEND:20191017T160000Z
UID:TALK126991@talks.cam.ac.uk
CONTACT:Mathieu Pellen
DESCRIPTION:The extreme magnetic fields and high spin of neutron stars mak
 e them an exciting environment in which to probe rotational instabilities 
 driven by the coupling of electromagnetism to new sectors beyond the Stand
 ard Model. In this talk I describe a new class of superradiant instabiliti
 es in which ultralight scalar fields extract rotational energy from neutro
 n stars. The instability arises from the mixing of scalar and photon modes
  in the magnetic field of the neutron star which extract energy from the r
 otating magnetosphere. Unlike for black holes\, where the dissipation requ
 ired for superradiance is provided by an absorptive horizon\, the non-herm
 itian dynamics in this setup comes from the resistivity in the stellar mag
 netosphere. This leads to the exponential growth of the scalar field profi
 le around the star corresponding to complex eigenfrequencies. The instabil
 ity rate can then be compared to the characteristic astrophysical time sca
 les of neutron stars given by their spin-down times.\n\n\nThe slides of th
 e presentation can be found "here":http://www.hep.phy.cam.ac.uk/~conferenc
 e/McDonald_17_10_2019.pdf
LOCATION:MR19 (Potter Room\, Pavilion B)\, CMS
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