17 research outputs found
Gravitational Radiation from Pulsating White Dwarfs
Rotating white dwarfs undergoing quasi-radial oscillations can emit
gravitational radiation in a frequency range from 0.1 - 0.3 Hz. Assuming that
the energy source for the gravitational radiation comes from the oblateness of
the white dwarf induced by the rotation, the strain amplitude is found to be
\sim 10^{-27} for a white dwarf at \sim 50 pc. The galactic population of these
sources is estimated to be \sim 10^7, and may produce a confusion limited
foreground for proposed advanced detectors in the frequency band between
space-based and ground-based interferometers. Nearby oscillating white dwarfs
may provide a clear enough signal to investigate white dwarf interiors through
gravitational wave asteroseismology.Comment: Accepted for Astrophysical Journal Letters. Changed value of
branching ratio resulting in an order of magnitude drop in gravitational wave
amplitude
Towards a Holographic Model of Color-Flavor Locking Phase
We demonstrate a holographic realization of color-flavor locking phase, using
N=4 SU(Nc) SYM coupled to N=2 Nf fundamental hypermultiplets as an example. The
gravity dual consists of Nc D3-branes and Nf D7-branes with world volume gauge
field representing the baryon density. Treating a small number \tilde{N}c << Nc
of D3-branes as Yang-Mills instantons on the D7-branes, we consider possible
potential(s) on their moduli space or equivalently the Higgs branch. We show
that a non-trivial potential can be generated by including the backreaction of
the baryonic density on the D7-branes, this dynamically drives the instantons
(= D3-branes) into dissolution. We interpret this as a color-flavor locking
since the size of the instanton is the squark vev, and study the symmetry
breaking patterns. Extending to finite temperature setup, we demonstrate that
color-flavor locking persists, and the thermal effect provides additional
structures in the phase diagram.Comment: 1+38 pages, 6 eps figures; typos corrected, acknowledgment and
references added, discussions in sections 3.1 and 4.3 improve