Zobrazeno 1 - 10
of 30
pro vyhledávání: '"McDonald, J"'
Autor:
McDonald, J. I.
It is well-known that gravitational waves can induce electromagnetic perturbations in magnetised plasmas, with production occurring via the direct coupling of gravitational waves to the background magnetic field: this is the so-called Gertsenshtein e
Externí odkaz:
http://arxiv.org/abs/2408.02553
Neutron stars provide a powerful probe of axion dark matter, especially in higher frequency ranges where there remain fewer laboratory constraints. Populations of neutron stars near the Galactic Centre have been proposed as a means to place strong co
Externí odkaz:
http://arxiv.org/abs/2407.19028
Autor:
McDonald, J. I., Millington, P.
Light particle-photon mixing in magnetised plasmas plays a vital role in constraining the existence of new physics, especially axions, dark photons, and ultra-high-frequency gravitational waves. Recently, we derived an expression for the resonant con
Externí odkaz:
http://arxiv.org/abs/2407.11192
Autor:
McDonald, J. I., Witte, S. J.
Ray tracing plays a vital role in black hole imaging, modeling the emission mechanisms of pulsars, and deriving signatures from physics beyond the Standard Model. In this work we focus on one specific application of ray tracing, namely, predicting ra
Externí odkaz:
http://arxiv.org/abs/2309.08655
Publikováno v:
JCAP12(2023)031
With axions now a primary candidate for dark matter, understanding their indirect astrophysical signatures is of paramount importance. Key to this is the production of photons from axions in magnetised astrophysical plasmas. While simple formulae for
Externí odkaz:
http://arxiv.org/abs/2307.11812
Autor:
McDonald, J.
Higgs Inflation via the unmodified metastable Standard Model Higgs Potential is possible if the effective Planck mass in the Jordan frame increases after inflation ends. Here we consider the predictions of this model independently of the dynamics res
Externí odkaz:
http://arxiv.org/abs/2305.16208
Autor:
Battye, R. A., Keith, M. J., McDonald, J. I., Srinivasan, S., Stappers, B. W., Weltevrede, P.
Axion dark matter can be converted into photons in the magnetospheres of neutron stars leading to a spectral line centred on the Compton wavelength of the axion. Due to the rotation of the star and the plasma effects in the magnetosphere the signal i
Externí odkaz:
http://arxiv.org/abs/2303.11792
Autor:
Lloyd-Stubbs, A. K., McDonald, J.
Publikováno v:
Phys.Rev.D 105 (2022), 103532
We demonstrate the existence of Q-balls in non-minimally coupled inflation models with a complex inflaton in the Palatini formulation of gravity. We show that there exist Q-ball solutions which are compatible with inflation and we derive a window in
Externí odkaz:
http://arxiv.org/abs/2112.09121
Autor:
McDonald, J. I.
The hunt for dark matter remains one of the principal objectives of modern physics and cosmology. Searches for dark matter in the form of axions are proposed or underway across a range of experimental collaborations. As we look to the next generation
Externí odkaz:
http://arxiv.org/abs/2108.13894
We apply novel, recently developed plasma ray-tracing techniques to model the propagation of radio photons produced by axion dark matter in neutron star magnetospheres and combine this with both archival and new data for the galactic centre magnetar
Externí odkaz:
http://arxiv.org/abs/2107.01225