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Now showing items 11-20 of 177
On the equal-mass limit of precessing black-hole binaries
(Institute of PhysicsClassical and Quantum Gravity, 2017-03-23)
We analyze the inspiral dynamics of equal-mass precessing black-hole binaries using multi-timescale techniques. The orbit-averaged post-Newtonian evolutionary equations admit two constants of motion in the equal-mass limit, ...
Parameterization of Frontal Symmetric Instabilities. I: Theory for Resolved Fronts
(ElsevierOcean Modelling, 2017-01-01)
A parameterization is proposed for the effects of symmetric instability (SI) on a resolved front. The parameterization is dependent on external forcing by surface buoyancy loss and/or down-front winds, which reduce potential ...
Using inpainting to construct accurate cut-sky CMB estimators
(American Physical SocietyPhysical Review D - Particles, Fields, Gravitation and Cosmology, 2017-02-23)
The direct evaluation of manifestly optimal, cut-sky cosmic microwave background (CMB) power spectrum and bispectrum estimators is numerically very costly, due to the presence of inverse-covariance filtering operations. ...
The acoustic Green's function for swirling flow in a lined duct
(ElsevierJournal of Sound and Vibration, 2017-05-12)
This paper considers the acoustic field inside an annular duct carrying mean axial and swirling flow and with either acoustically hard or lined walls. The particular aim is to compute the Green's function, which is required ...
The Galilean superstring
(SpringerJournal of High Energy Physics, 2017-02-21)
The action for a Galilean superstring is found from a non-relativistic limit of the closed Green-Schwarz (GS) superstring; it has zero tension and provides an example of a massless super-Galilean system. A Wess-Zumino term ...
Equivariant semidefinite lifts of regular polygons
(Institute for Operations Research and the Management SciencesMathematics of Operations Research, 2017-05-01)
Given a polytope P in $\mathbb{R}^n$, we say that P has a positive
semidefinite lift (psd lift) of size d if one can express P as the linear
projection of an affine slice of the positive semidefinite cone
$\mathbf{S}^d_+$. ...
Lieb's concavity theorem, matrix geometric means, and semidefinite optimization
(Linear Algebra and Its Applications, 2017-01-15)
A famous result of Lieb establishes that the map (A,B)↦tr[K^* A^{1−t}KB^{t}] is jointly concave in the pair (A,B) of positive definite matrices, where K is a fixed matrix and t∈[0,1]. In this paper we show that Lieb's ...
Five vortex equations
(IOP PublishingJournal of Physics A: Mathematical and Theoretical, 2017-02-24)
The Taubes equation for Abelian Higgs vortices is generalised to five distinct U(1) vortex equations. These include the Popov and Jackiw–Pi vortex equations, and two further equations. The Baptista metric, a conformal ...
An experimental study of the spread of buoyant water into a rotating environment
(University of CambridgeDepartment of Applied Maths and Theoretical PhysicsQueens', 2017-05-01)
This thesis examines previously unresolved issues regarding the fluid dynamics of the spread of buoyant water into a rotating environment. We focus in particular on the role that finite potential vorticity and background ...
Probing the Gravitational Dependence of the Fine-Structure Constant from Observations of White Dwarf Stars
(Multidisciplinary Digital Publishing InstituteUniverse, 2017-06-01)
Hot white dwarf stars are the ideal probe for a relationship between the fine-structure constant and strong gravitational fields, providing us with an opportunity for a direct observational test. We study a sample of hot ...