Black Holes and Matter: Atomic Condensates, Information, Magnetospheres, and Axions

University Of Maryland, College Park, College Park MD

Investigators

Abstract

The proposed work involves theoretical studies, aiming to shed light on questions related to 1) laboratory analogs of Hawking radiation from black holes, 2) quantum mechanics applied to gravity and black holes, 3) magnetic fields and charged particles around astrophysical black holes and in other systems, 4) a possible source of dark matter from spinning, magnetized neutron stars. Each of these four topics represents a critical area that probes into the fundamental nature of the formation and structure of the universe. The results of the proposed research will be disseminated through written articles, as well as seminars, conference talks, and colloquia. The PI will provide instruction and mentoring to a postdoctoral scholar, as well as to graduate and undergraduate students, regarding scientific research, writing, and verbal communication. The PI will also continue to teach physics courses at all levels, and the graduate students will gain teaching experience as assistants. The PI will seek out opportunities to speak to the general public on topics in physics. All these activities will contribute to training, scientific literacy, and appreciation of the insights of physics. On a more technical level, research under item 1) will use the Gross-Pitaevskii equation to model the atomic condensate, and will study the density-density correlation function while averaging over variations in the number of atoms, in addition to averaging over realizations of the quantum noise using the truncated Wigner approximation. Item 2) will focus on the possibility that the black hole information paradox can be resolved by a proper accounting of the structure of the state space of quantum gravity, specifically, the redundant encoding of information into the wave function satisfying the quantum Einstein equation, i.e.\ the Wheeler-de Witt equation. A related study will investigate whether the notion of the turnover time of the thermal vacuum atmosphere of a black hole has a Lorentz invariant meaning, and whether it is related to the much discussed scrambling time for black hole information processing. Item 3) includes work aimed at a sharp formulation of magnetic helicity in a general relativistic setting, and in the presence of boundaries such as the surface of a neutron star or the horizon of a black hole. A key mathematical tool for this work will be the use of differential forms. Also, an effective field sheet theory will be developed, and applied to characterize the impact of cyclotron motion on the stagnation surface around black holes and neutron stars. This surface defines the boundary between the charges that are gravitationally pulled to the body and those that are flung outward by magnetocentrifugal force. The work under item 4) will investigate the axion field sourced by electric fields parallel to magnetic fields, in static and in time dependent settings, first without, and then with, gravitation taken into account. The findings will then be used to constrain axion mass and coupling strength, and to determine whether observable effects could be produced.