Talks

Gravitational waves (GW) imprint apparent Doppler shifts on the frequency of photons propagating between an emitter and detector of light. This forms the basis of a method to detect mHz GW using Doppler velocimetry between pairs of satellites [1]. The crucial component in such GW detectors is the frequency standard on board the emitting and receiving satellites. I will discuss how recent developments in atomic clock technology have led to devices that could be sufficiently sensitive to probe astrophysically interesting sources. I will present a design for a robust, space-capable optical frequency standard [2], that is being developed at York.

References

[1] JW Armstrong, Living Rev. Relativity 9, (2006), 1 [2] AC Vutha, arXiv:1501.01733 (2015)

In this talk I will outline the process of institutional change begun at the University of Michigan in 2001 and continuing today. This will include discussion of a range of institutional efforts to improve hiring, recruitment, climate and leadership that was focused on creating a more diverse and inclusive faculty.  I will close with brief discussion of two studies: one assessing changes in the workplace climate for faculty in 2001, 2006 and 2012; and one examining the characteristics of departments that made the most change in contrast to those that made the least.  I will conclude with some observations about the change process.

The last years have seen a renewed interest in theories of massive gravity. They represent an infra-red modification of gravity where the gravitational force weakens at very large scales. Heuristically, they provide the playground to understand a possible modification of GR which could potentially provide a dynamical solution to the cosmological constant problem. In this talk I will discuss a number of theoretical aspects of massive gravity theories, focusing on the relevance of the so-called Vainstein mechanism, both at the classical and the quantum level. I will also discuss how we can use cosmology from the early and late universe to constrain these theories. For example, what does the Cosmic Microwave Background Radiation know about the graviton mass?