My research interests are relativistic astrophysics, general relativity, cosmology, and extragalactic astronomy.  Early on in my studies, as an undergraduate, I fell in love with the gravitational theories and laws of motion of Albert Einstein and Sir Isaac Newton, thence came my love for gravity and magnetic fields.

 

My main focus has been the physics of energy extraction from rotating black holes of all sizes: from supermassive black holes that power quasars and found at the center of most galaxies, to stellar black holes (or microquasars) located throughout the galaxy.  Analytical expressions for the energy-momentum four vectors of the extracted (i.e., escaping) particles are determined for particles that have undergone scattering events in the ergosphere.  Monte Carlo computer simulations of these expressions in four-dimensions show that high energy particles escape in the form of relativistic bi-polar jets, consistent with astronomical observations (R. K. Williams 1995, Phys. Rev., 51, No. 10, 5387-5427; R. K. Williams 1999, https://arxiv.org/abs/astro-ph/0306135; R. K. Williams 2004, Astrophysical Journal, 611, 952-963).

 

Equally, and more recently, in the area of cosmology, my focus has been the physics of “dark energy,” investigating what is causing the late accelerated cosmic expansion, whereas we expected the expansion to be slowing down (see R. K. Williams, https://arxiv.org/abs/1109.5652).  In this investigation, the spacetime metric of a rotating and expanding universe is used to derive and evaluate the “gravitomagnetic” field (gravitational analog of a magnetic field).  The gravitomagnetic (GM) force field results from the rotating cosmic matter, frame dragging the expanding inertial spacetime frame into rotation.  This pseudo (or fictitious) force field is the general relativistic version of Newtonian Coriolis force. 

 

In this investigation, a cosmic time evolution of the derived GM force field reveals a repulsive nature, arising in the late or present Universe.  The manifestation of this repulsive GM (gravitational) force could possible give an explanation for dark energy.  In addition, and importantly, this dynamical cosmological model yields  (1) a primordial magnetic (PB) field, consistent with theory and observations; (2) that the spin density of the global cosmic matter appears to couple the PB field to the GM field and also appears to couple the PB field to cosmic mass density, rho, of the familiar attractive gravitational field; and (3) that frame dragging of the spacetime continuum (as in the Lense-Thirring effect when rotation of the gravitating source is included in Einstein’s general relativistic field equations) might be a macroscopic description of torsion coupling to spin, in a general sense, theorized by quantum-gravity-particle physicists: to exist when the intrinsic quantum mechanical spin density of fermionic particles interacts microscopically with the continuum in an Einstein-Cartan spacetime.  Item 3 is to say that torsion of spacetime, in a general sense, and frame dragging of spacetime might be one in the same, brought on by intrinsic spin or intrinsic rotation.