We present a rapid binary-evolution algorithm that enables modelling of even the most complex binary systems. In addition to all aspects of single-star evolution, features such as mass transfer, mass accretion, common-envelope evolution, collisions, supernova kicks and angular momentum loss mechanisms are included. In particular, circularization and synchronization of the orbit by tidal interactions are calculated for convective, radiative and degenerate damping mechanisms. We use this algorithm to study the formation and evolution of various binary systems. We also investigate the effect that tidal friction has on the outcome of binary evolution. Using the rapid binary code, we generate a series of large binary populations and evaluate the formation rate of interesting individual species and events. By comparing the results for populations with and without tidal friction, we quantify the hitherto ignored systematic effect of tides and show that modelling of tidal evolution in binary systems is necessary in order to draw accurate conclusions from population synthesis work. Tidal synchronism is important but, because orbits generally circularize before Roche lobe overflow, the outcome of the interactions of systems with the same semilatus rectum is almost independent of eccentricity. It is not necessary to include a distribution of eccentricities in population synthesis of interacting binaries; however, the initial separations should be distributed according to the observed distribution of semilatera recta rather than periods or semimajor axes.

https://researchbank.swinburne.edu.au/file/ab4c7d3f-f3a0-4cb3-bb4f-9790d3f33b19/1/PDF (Accepted manuscript).pdf

Evolution of binary stars and the effect of tides on binary populations

Light-induced rotation of absorbing microscopic particles by transfer of angular momentum from light to the material raises the possibility of optically driven micromachines. The phenomenon has been observed using elliptically polarized laser beams1 or beams with helical phase structure2,3. But it is difficult to develop high power in such experiments because of overheating and unwanted axial forces, limiting the achievable rotation rates to a few hertz. This problem can in principle be overcome by using transparent particles, transferring angular momentum by a mechanism first observed by Beth in 19364, when he reported a tiny torque developed in a quartz ‘wave-plate’ owing to the change in polarization of transmitted light. Here we show that an optical torque can be induced on microscopic birefringent particles of calcite held by optical tweezers5. Depending on the polarization of the incident beam, the particles either become aligned with the plane of polarization (and thus can be rotated through specified angles) or spin with constant rotation frequency. Because these microscopic particles are transparent, they can be held in three-dimensional optical traps at very high power without heating, leading to rotation rates of over 350 Hz.

/pdf/optical-alignment-and-spinning-of-laser-trapped-microscopic-1tu8bhvzbg.pdf

Optical Alignment and Spinning of Laser-Trapped Microscopic Particles

Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.

https://link.springer.com/content/pdf/10.12942%2Flrr-2009-2.pdf

Physics, Astrophysics and Cosmology with Gravitational Waves

There is accumulating evidence that (fundamental) scalar fields may exist in nature. The gravitational collapse of such a boson cloud would lead to a boson star (BS) as a new type of a compact object. As with white dwarfs and neutron stars, a limiting mass exists similarly, below which a BS is stable against complete gravitational collapse to a black hole. According to the form of the self-interaction of the basic constituents and spacetime symmetry, we can distinguish mini-, axidilaton, soliton, charged, oscillating and rotating BSs. Their compactness prevents a Newtonian approximation; however, modifications of general relativity, as in the case of Jordan?Brans?Dicke theory as a low-energy limit of strings, would provide them with gravitational memory. In general, a BS is a compact, completely regular configuration with structured layers due to the anisotropy of scalar matter, an exponentially decreasing 'halo', a critical mass inversely proportional to the constituent mass, an effective radius and a large particle number. Due to the Heisenberg principle, a completely stable branch exists, and as a coherent state, it allows for rotating solutions with quantized angular momentum. In this review, we concentrate on the fascinating possibilities of detecting the various subtypes of (excited) BSs: possible signals include gravitational redshift and (micro-)lensing, emission of gravitational waves, or, in the case of a giant BS, its dark matter contribution to the rotation curves of galactic halos.

https://iopscience.iop.org/article/10.1088/0264-9381/20/20/201/pdf

General relativistic boson stars

Astrophysical methods to constrain axions and other novel particle phenomena

Ultrashort-Period Binaries, Gravitational Radiation, and Mass Transfer. I. The Standard Model, with Applications to WZ Sagittae and Z Camelopardalis

Ultrashort-Period Binaries. II. HZ 29 (=AM CVn): a Double-White Semidetached Postcataclysmic Nova?

If the Sun contained even a small mass fraction of weakly interacting massive particles, there could be significant effects on central solar structure. The long mean free paths associated with such particles make them very efficient energy conductors. Consequently, an essentially isothermal core can be produced, which removes the central temperature peak responsible for the bulk of the predicted solar neutrinos in Davis's /sup 37/Cl neutrino capture experiment. We explore the solar evolutionary consequences of both imposed isothermal core models and models including energy transport by a specific class of weakly interacting particles. In particular, a relative mass fraction, 10/sup -8/, of 4GeV particles reduces predicted neutrino count rates by more than a factor of 3.

Weakly interacting, massive particles and the solar neutrino flux

Horizontal branch characteristics correlation with observed metal abundance, reexamining stellar survival in helium flash without mixing

John Faulkner

Papers

Ultrashort-Period Binaries, Gravitational Radiation, and Mass Transfer. I. The Standard Model, with Applications to WZ Sagittae and Z Camelopardalis

Ultrashort-Period Binaries. II. HZ 29 (=AM CVn): a Double-White Semidetached Postcataclysmic Nova?

Weakly interacting, massive particles and the solar neutrino flux

On the nature of the horizontal branch. i

Quasi-homology relations and the eggen--sandage residue.