Nobel Prize in Physiology or Medicine Awarded for Work on the Circadian Rhythm

The 2017 Nobel Prize in Physiology or Medicine was awarded for discovering molecular mechanisms that control the circadian rhythm!

What Happens in Exeter Stays in Exeter

I am syncing in Exeter.

This is Improbable Too

I didn't realize this before last night's Ig Nobel show (in which I performed), but our work on cow synchrony made not only the new Improbable Research book but also its cover.

Now all I need is an actual Ig Nobel Prize to go with it...

Additionally, here is a video of an Ig Nobel show in which I performed in 2012. I am introduced and start discussing cow synchronization at about 39:00 in the video.

"Noise-Induced Synchronization, Desynchronization, and Clustering in Globally Coupled Nonidentical Oscillators"

One of my papers came out in final form today. Here are the details.

Title: Noise-Induced Synchronization, Desynchronization, and Clustering in Globally Coupled Nonidentical Oscillators

Authors: Yi Ming Lai and Mason A. Porter


Abstract: We study ensembles of globally coupled, nonidentical phase oscillators subject to correlated noise, and we identify several important factors that cause noise and coupling to synchronize or desynchronize a system. By introducing noise in various ways, we find an estimate for the onset of synchrony of a system in terms of the coupling strength, noise strength, and width of the frequency distribution of its natural oscillations. We also demonstrate that noise alone can be sufficient to synchronize nonidentical oscillators. However, this synchrony depends on the first Fourier mode of a phase sensitivity function, through which we introduce common noise into the system. We show that higher Fourier modes can cause desynchronization due to clustering effects, and that this can reinforce clustering caused by different forms of coupling. Finally, we discuss the effects of noise on an ensemble in which antiferromagnetic coupling causes oscillators to form two clusters in the absence of noise.

My "Performance" at the Imperial College Ig Nobel Show (3/9/12)

Here is the video for the show that includes my 5-minute "performance" on cow synchronization as part of the Ig Nobel show at Imperial College on 9 March. My 5 minutes of fame occurred right after Marc's long introduction.

(Tip of the cap to the Annals of Improbable Research's very own Marc Abrahams --- the head honcho there --- with whom I just finished having coffee.)

Cows are apparently sexier than tensors.

As you know, I am the coauthor on a new paper on community structure in multislice networks, which has just appeared in Science and which I genuinely believe makes a very big advance.

I am also the coauthor of a recently submitted paper entitled A Mathematical Model for the Dynamics and Synchronization of Cows that has been posted on the arXiv, as is normal procedure in mathematics and physics (and, increasingly, other fields). Nevertheless, this paper has not yet been peer-reviewed, and I can't stress this enough.

Guess which paper is getting more attention?

I will readily admit that I have some fun when I get media attention, and that it's pretty damned cool to be see articles in places like Technology Review, Boing Boing, and Marginal Revolution about my work. I'm flattered, and some of what is written is entertaining (and some of the accompanying pictures are entertaining). This has been a fun project with some interesting scientific results (on which I believe we can build with a lot of additional hard work), and we included a couple of jokes in the paper because frankly it makes it nicer to read. Also, I am happy to see a lighthearted tone in some of the places that have discussed our work, but I am a bit disturbed by a couple of things:

(1) Some of the venues that have discussed our work used figures without asking for our permission. That's just not cool. I would gladly give permission, but you really ought to ask.

(2) I'm not surprised by the media attention on something that hasn't been peer-reviewed and indeed have experienced this before, but can we please make a distinction between something that is published and something that is on a preprint server and has not yet undergone peer review? Some (but not all) of the articles that I have seen are ignoring this crucial distinction, and it's a bit annoying to see increasingly inaccurate statements from people who are playing a sort of "whispering game" and making incorrect approximations of what other people wrote (and writing unsubstantiated things as if they were facts). I know that's the nature of things, but it's frustrating, and when I see a post that is not lighthearted but instead tries to use our work to advocate some cause that has absolutely nothing to do with what we studied (which is a biologically-inspired mathematical model, and I feel a very interesting one), I feel just a little bit worse about the world than I did before.


If you are reading this and are a journalist, please note that my coauthors and I wish to wait until after the peer review process runs its course (and the paper is accepted to a scientific journal---ideally the one to which we have already submitted it) before we grant any interviews. We are very excited about our work, but please let's not be premature about things! Now if you want to talk to me about multislice networks, then I would be extremely pleased to talk to you now.

Thank you.

Online Steve Strogatz Lecture on Synchronization

Courtesy the website of the Society for Industrual and Applied Mathematics, here is a online lecture on synchronization by Steve Strogatz that has been posted on the Exchange Morning Post website. I haven't watched the lecture yet, but it is intended for public audiences, and Steve is one of the most inspiring speakers I've ever watched. (By the way, as some of you know, he was on my Ph.D. thesis committee.)

Anyway, enjoy!

Vortex Lattice Locking in Two-Component Bose-Einstein Condensates

This is the title of my new paper that just came out. You can find a link here.

Unlike most of my papers, this one is very condensed-mattery (to invent a new word... think of it the way you would use the word "buttery") and doesn't have much mathematics at all. I do spend a lot of time working on condensed matter physics problems, but the style of my papers ordinarily reveals my nonlinear heart (or, rather, my nonlinear science/applied math heart). This particular paper was written jointly with my fellow scientists in Caltech's theoretical condensed matter group, and the flavor of the paper is correspondingly different---it's most definitely a physics paper rather than an applied math paper.

The first author is Caltech postdoc Ryan Barnett. Also on the list are Caltech faculty member Gil Refael and non-Caltech condensed matter theorist Hanspeter buchler (who goes by Hans Peter in publications).

Here is the abstract:

The vortex density of a rotating superfluid, divided by its particle
mass, dictates the superfluid’s angular velocity through the Feynman relation. To
find how the Feynman relation applies to superfluid mixtures, we investigate a
rotating two-component Bose–Einstein condensate, composed of bosons with
different masses. We find that in the case of sufficiently strong interspecies
attraction, the vortex lattices of the two condensates lock and rotate at the drive
frequency, while the superfluids themselves rotate at two different velocities,
whose ratio equals the ratio between the particle masses of the two species.
In this paper, we characterize the vortex-locked state, establish its regime of
stability, and find that it survives within a disk smaller than a critical radius,
beyond which vortices become unbound and the two Bose-gas rings rotate
together at the frequency of the external drive.


I view this as a form of synchronization, but instead of the better-studied frequency-locking, one actually needs to take the different masses of the species into account (it's a momentum-locking). One of the very important points we make is that if you look at a lot of papers, you'll see that they assume that two different masses are the same "without loss of generality" (and the literature on multiple-component Bose-Einstein condensates is absolutely riddled with that assumption). Of course, as we show in this paper, that's just not true, as there are very interesting phenomena that you'll simply miss if you always make that assumption.