Primordial standing waves

Primordial gravitational waves and cosmology.

The observation of primordial gravitational waves could provide a new and unique window on the earliest moments in the history of the universe and on possible new physics at energies many orders of magnitude beyond those accessible at particle accelerators. Such waves might be detectable soon, in current or planned satellite experiments that will probe for characteristic imprints in the polariz...

Standing Waves: the Equilateral Triangle

It is well known that symmetry considerations can often be a powerful tool for simplifying physical systems. We consider a wave which satisfies the Helmholtz equation in a region with some given symmetry, and note that any solution can be transformed by that symmetry to give another solution. Using this simple observation we describe a number of necessary conditions for wave solutions. For boun...

Bifurcation behavior of standing waves

Two different types of standing waves (SW0 and SWπ) can appear instead of spiral vortices from a supercritical Hopf bifurcation in counter-rotating Taylor-Couette flow for sufficiently small aspect ratios [1,2]. The bifurcation sequence from basic flow to spiral vortices via SW0 can include modulated waves, homoclinic bifurcations, and hysteresis as a consequence of broken translational invaria...

Primordial Gravitational Waves From Open Inflation

We calculate the spectrum of gravitational waves generated during inflation in open (Ω0 < 1) inflationary models. In such models an initial epoch of old inflation solves the horizon and flatness problems, and during this first epoch of inflation the quantum state of the graviton field rapidly approaches the Bunch-Davies vacuum. Then old inflation ends by the nucleation of a single bubble, insid...

Large scale instability of nonlinear standing waves