Search Talks

It is well known that S-matrix Analyticity, Lorentz invariance and Unitarity place strong constraints on whether Effective Field Theories can be UV completed. A large class of gravitational field theories such as Massive Gravity and DGP inspired braneworld models contain as limits Galileon theories which in the past have been argued to violate the conditions necessary for a UV completion. I will present arguments that imply quite the opposite, although Galileons do not admit a standard Wilsonian UV completion, I will use the recently discovered Galileon duality to argue that these theories can exhibit a non-Wilsonian completion consistent with the `Classicalization’ proposal. These theories have quintessentially gravitational properties such as non-polynomially bounded scattering amplitudes, absence of local off-shell observables and an exponentially soft 2-2 scattering amplitude. These properties show up in a violation of the standard Wightman axioms and are consistent with many of the known properties of UV completions of gravity. I will argue that the superluminal solutions found in the low energy EFT are absent in the UV completion.

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.