University of Cambridge > Talks.cam > Geometric Analysis and Partial Differential Equations seminar > Dynamics of linearized cosmological perturbations

Dynamics of linearized cosmological perturbations

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Prof. Mihalis Dafermos.

In cosmology an important role is played by homogeneous and isotropic solutions of the Einstein-Euler equations and linearized perturbations of these. In this talk I present results of Paul Allen and myself on the asymptotic behaviour of certain linearized solutions (so-called ‘scalar perturbations’) both in the approach to the initial singularity and at late times. The main equation of interest is a linear hyperbolic equation whose coefficients depend only on time. Expansions for the solutions are obtained in both asymptotic regimes. In both cases it is shown how general solutions can be parametrized by certain functions which are coefficients in the asymptotic expansion. The central technique in the proofs is that of energy estimates. An interesting feature of the results is a bifurcation observed in the late-time asymptotics for an asymptotically polytropic equation of state, occurring for the polytropic index corresponding to a radiation fluid.

This talk is part of the Geometric Analysis and Partial Differential Equations seminar series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

 

© 2006-2019 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity