Black Holes and Quantum Computation

I will discuss the `holographic complexity conjecture', that seeks to relate the size of the wormhole that lies behind a black hole horizon to quantum computational complexity.

Gufang Zhao - 2018-02-23

Gufang Zhao - 2018-01-26

Axion strings and domain walls

I will discuss the calculation of the axion dark matter relic abundance produced by strings and domain walls in the early universe. These objects appear if the global symmetry that the axion is associated with is unbroken at the end of inflation, and in this scenario there is, in principle, a unique prediction for the axion dark matter mass. I will present results from numerical simulations that indicate that the density of strings may be significantly larger than previously thought, leading to a corresponding change in the required axion dark matter mass.

ETHOS: a framework for structure formation with non-gravitational dark matter interactions

The standard structure formation model is based on the Cold Dark Matter (CDM) hypothesis where non-gravitational dark matter interactions are irrelevant for the formation and evolution of galaxies. Surprisingly, current observations allow for significant departures from the CDM hypothesis,