My multiverse review has been published. The link is here:

http://arjournals.annualreviews.org/eprint/ab2zHiQJeieXvBsjuxC4/full/10.1146/annurev-nucl-102115-044644

Since the link did not work, here is the article itself :Multiverse Annual Reviews

My multiverse review has been published. The link is here:

http://arjournals.annualreviews.org/eprint/ab2zHiQJeieXvBsjuxC4/full/10.1146/annurev-nucl-102115-044644

Since the link did not work, here is the article itself :Multiverse Annual Reviews

This fall I am spending a month at the University of Vienna as the Schrodinger Visiting Professor.

Here is some info, and one of the lectures.

Edit: I am posting the lectures here.

Here is the man himself in the grand arcade of the University’s main building.

In August, I participated in a very nice conference on quantum gravity

This was nicely curated, and had many interesting folks there. Good physics!

Also earlier in the summer was a conference on Relativistic Quantum Information

I was a bit of a “fish out of water” there, as it was more quantum information, but it also was intellectually stimulating and quite nice.

Today I gave my talk at the KITP workshop on Quantum Gravity Foundations; UV to IR. It was on Nonlocality in the Effective Field Theory of Gravity, reviewing many of our past results but centered on the theme that low energy quantum effects are nonlocal. This is a change from classical GR where we have a spacetime manifold, a local equation governing it, geodesics and crisp events. The workshop here is quite interesting and the setting is great. Today is also the start of my long sabbatical.

It is nice that our recent paper on quantum effects on light bending got highlighted in Physical Review Letters. This paper calculates the quantum correction to the interaction of light. The effect is small but conceptually there are interesting consequences. For example massless particles no longer follow null geodesics, and massless particles with different spin bend at different angles.

After a lot of work and a long wait, the second edition of our book has appeared.

We have our own copies and it looks very good. The eBook edition is available everywhere at the moment. The hardcover is available in Europe, and will be so in the US in a few weeks once the slow boat delivers the shipment.

With the help of Grigory Ovanesyan and Basem El-Menoufi, we have made a nice step of progress in understanding Regge behavior in Soft Collinear Effective Theory (SCET). The paper is here. The issue turns out to be a very subtle one for effective field theory, involving the overlap of different field modes, and it may be important for understanding the limits of factorization theorems.

Basem and I have a paper exploring the nonlocal effects that come from loops of light fields in gravity. I think that this is an important new area. Already, it seems to have major effects, such as the avoidance of singularities in general relativity, providing a quantum exception to the classical Hawking-Penrose theorems. There seems to be much to do in this area of nonlocal properties of field theory.

I participated in a workshop on this topic at the Perimeter Institute. I am a bit of an outsider as I have used the effective field theory treatment to criticize naive applications of running gravitational couplings. The connection of a field like that of Asymptotic Safety to real Loretzian effective field theory is something that needs a better understanding, and I now have a collaboration working on some progress in this area.

The talks at the workshop can be found here.

Besides the science, they produced the best conference photo ever.

After a long-running project, Emil Bjerrum-Bohr, Pierre Vanhove and I submitted our paper on using on-shell techniques in the gravitational interaction. This started several years ago when I was on sabbatical at the IHES and NBI. Pierre gave some nice lectures on the topic and this project was the result.