Lawrence M. Widrow

Using the Schroedinger Equation to Simulate Collisionless Matter

A new numerical technique for following the evolution of collisionless matter under the influence of gravity is proposed. Matter is modeled as a Schrodinger field obeying the coupled Schrodinger and Poisson equations. The de Broglie wavelength, λ deB , associated with this field enters as a free parameter and is tuned according to the specifications of the simulation one is doing. In the limit λ deB →0 (a limit which would require infinite computing power) the equations reduce to the coupled Vlasov and Poisson equations as they should. Our method can handle multiple streams in phase space and is competitive in terms of computation time with particle-mesh N-body simulations

Microwave distortions from collapsing domain-wall bubbles

It has been suggested that large-scale structure can be seeded by a postrecombination phase transition that produces soft domain walls. It is found that oscillating domain-wall bubbles produce a distinctive signature on the microwave sky; hot and cold spots with amplitude characterized by G(sigma)/H0 (sigma is the surface tension of the wall). These fluctuations are non-Gaussian and offer a powerful probe of such models. 24 refs.

Coaxing charge from the vacuum

Abstract We examine a U(1)-symmetric field theory for two scalar fields in which thee tree-level potential is ununded from below. We calculate the finite-temperature effective potential and demonstrate that (1) radiative corrections stabilize the theory; (2) Q-balls appear at low temperatures; and (3) the U(1) symmetry is spontaneously broken at high temperatures and restored at low temperatures. We investigate the theorys dynamics in a sector of fixed charge, focusing on the cosmological production of Q-balls as relics of the early era of broken symmetry.

Baryogenesis without baryon number violation

We review a new paradigm for baryogenesis in which the fundamental Lagrangian is baryon conserving [invariant under U(1)B]. At high temperatures, U(1)B is spontaneously broken and an excess of quarks over antiquarks of 10−10s (s≡entropy density) is produced. Today, U(1)B is restored. A fundamental consequence of our assumptions is that the baryon number of the Universe is constant. If initially zero, it will be zero today. The excess baryon number produced in the quark fields is exactly compensated by antibaryon number in a weakly interacting scalar particle. We suggest that this scalar provides the mass density necessary to close the Universe.

Formation of LISA Black Hole Binaries in Merging Dwarf Galaxies: the Imprint of Dark Matter

Theoretical models for the expected merger rates of intermediate-mass black holes (IMBHs) are vital for planned gravitational-wave detection experiments such as the Laser Interferometer Space Antenna (LISA). Using collisionless

General-relativistic domain walls

N

BARYON SYMMETRIC BARYOGENESIS

-body simulations of dwarf galaxy (DG) mergers, we examine how the orbital decay of IMBHs and the efficiency of IMBH binary formation depend on the central dark matter (DM) density profile of the merging DGs. Specifically, we explore various asymptotic inner slopes

Dynamics of thick domain walls

\gamma

Self-Similar Relaxation of Self-Gravitating Collisionless Particles

of the DGs DM density distribution, ranging from steep cusps (

Homogeneous cosmological models and new inflation

\gamma=1