Search Talks

In this talk I will assess various proposals for the source of the intuition that there is something problematic about contextuality, and argue that contextuality is best thought of in terms of fine-tuning. I will suggest that as with other fine-tuning problems in quantum mechanics, this behaviour can be understood as a manifestation of teleological features of physics. I will also introduce several formal mathematical frameworks that have been used to analyse contextuality and discuss how their results should be interpreted. 

Let K be a knot or link in the 3-sphere. I will explain how one can count minimal surfaces in hyperbolic 4-space which have ideal boundary equal to K, and in this way obtain a link invariant. In other words the number of minimal surfaces doesn’t depend on the isotopy class of the link. These counts of minimal surfaces can be organised into a two-variable polynomial which is perhaps a known polynomial invariant of the link, such as HOMFLYPT. “Counting minimal surfaces” needs to be interpreted carefully here, similar to how Gromov-Witten invariants “count” J-holomorphic curves. Indeed I will explain how these minimal surface invariants can be seen as Gromov-Witten invariants for the twistor space of hyperbolic 4-space. Whilst Gromov-Witten theory suggests the overall strategy for defining the minimal surface link-invariant, there are significant differences in how to actually implement it. This is because the geometry of both hyperbolic space and its twistor space become singular at infinity. As a consequence, the PDEs involved (both the minimal surface equation and J-holomorphic curve equation) are degenerate rather than elliptic at the boundary. I will try and explain how to overcome these complications. 

Zoom link:  https://pitp.zoom.us/j/95847819111?pwd=MVg5dWFsNUpiZWVPL1l4Uk9PV2tZZz09

In this talk, I will explain the construction of a (1+1) spacetime with a wormhole and its conversion into a time-machine spacetime. Then, I will describe a massless scalar quantum field theory in such spacetime. I focus in comparing this quantization of the field in the time-machine spacetime with the quantization on the two-dimensional Einstein cylinder, the emergence of a zero mode and its regularization.

Zoom link:  https://pitp.zoom.us/j/94856731951?pwd=MnFNZjlkUHVVWkRRQTIxR0o0TDFnUT09

Zoom link:  https://pitp.zoom.us/j/96132106700?pwd=L3ZMOXltZks4Y25abUl5TTdhZTVKUT09

Solar neutrinos are an inevitable background to any dark matter direct detection experiment as they closely mimic the signature of dark matter. In this talk, I will discuss the effects of solar neutrinos on the reach of dark matter-electron scattering experiments, with a focus on semiconductor and xenon-based detectors. In addition, I will present the prospects of measuring and understanding the various solar neutrino components using the same detectors, as well as the effects of non-standard neutrino interactions, thus turning solar neutrinos from a background to an interesting signal in their own right.