Rep. James Himes

CVD success: Rep. Himes co-sponsors the Keep STEM Talent Act!

For the APS Congressional Visit Day last month, my team visited the DC office of Representative Jim Himes (D-CT-04) to advocate for a number of issues important to science (see previous post). One of our asks was for Rep. Himes to cosponsor the Keep STEM Talent Act. I just heard that Rep. Himes is now a cosponsor! Thanks so much to my CVD team, to Rep. Himes and to the staffer we met with, Jessica Hagens-Jordan!

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Join the new APS Forum on Diversity and Inclusion!

APS has a new forum dedicated to diversity and inclusion (announcement). This has been in the works for a while, but it’s finally approved and ready to join (for free for APS members). Join now to get in on the ground floor! Below I am copying the email I received with more details and signup instructions (sorry if the formatting is weird).

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NIH is experimenting with ‘cluster hiring’ in an attempt to boost diversity

In this week’s issue of Science they cover a new pilot program by NIH called FIRST that will fund ‘cluster hiring’, where a department hires 10 or more faculty in 1-2 years. The idea is that this will help cast a wider net and yield more junior faculty from underrepresented groups.

I can see how hiring in larger cohorts could make it easier to detect if there are biases, since have a cohort of 10 white men would set of alarm bells. Cluster hiring is unproven, but it’s promising and I’m very much looking forward to seeing what comes out of the pilot program.

Here’s the article (paywall): Science: NIH hopes ‘cluster hiring’ will improve diversity

Just presented at the Annual Meeting of the Physical Society of Taiwan

I just presented a talk “Quenching to field-stabilized magnetization plateaus in the unfrustrated Ising antiferromagnet” based on my preprint that I posted on arXiv last week at the Annual Meeting of the Physical Society of Taiwan at National Pingtung University in Pingtung, Taiwan. I haven’t gotten around to making a post about this paper yet (that is coming soon), but in the meantime I will post my slides from this talk here. My slides included some movies of the process of freezing in to magnetization plateaus. Since PDFs can’t include movies I will post the movies below.

Gif of Ising spin configurations arriving at a frozen plateau state.
The spin configuration over time starting from a random (T=∞) state and doing single spin flip Metropolis updates at T=0 and h=1 until we arrive at a final frozen state. Individual spin states are denoted by the (+) and (-); the background shading shows which of the antiferromagnetic ground states each site is in. In the final frozen state the domain walls are all straight lines or corners with (+) on the inside.

Gif of Ising spin configurations arriving at a frozen plateau state.
The spin configuration over time starting from a random (T=∞) state and doing single spin flip Metropolis updates at T=0 and h=3 until we arrive at a final frozen state. Individual spin states are denoted by the (+) and (-); the background shading shows which of the antiferromagnetic ground states each site is in. In the final frozen state the domain walls are all diagonal or square-wave-like with excess (+) spin.

APS Congressional Visit Day 2020

APS Congressional Visit Day 2020

This week, I am in Washington DC for the APS Congressional Visit Day and Annual Leadership Meeting. We started on Wednesday with the Congressional Visit. APS broke us up into teams by region. I’m a Massachusetts voter, so I joined a team of people from Massachusetts and Connecticut. We had six meetings with the offices of Massachusetts Senators Ed Markey and Elizabeth Warren, Connecticut Senators Chris Murphy and Richard Blumenthal along with House Representatives James Himes and Rosa DeLauro.

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Women are no better or worse than men at doing physics, but they are, however, more persistent.

Myriam P. Sarachik, 2020

Today I attended an awards dinner for several APS awards. Myriam P. Sarachik received the APS Medal for Exceptional Achievement in Research and gave a truly insightful acceptance speech and I just had to share this specific quote. She told a number of stories of the obstacles she faced to building a scientific career and how she overcame them through luck, talent and persistence. A great lesson for us all!

Footnotes and citations should look different

Overall, I think physics is lucky to have its premier journals (Physical Review) be run by our own nonprofit professional society—APS. I think that explains, at least in part, why the arXiv has been so successful in physics and why similar efforts have floundered in other fields.

All that said, I have one bone to pick with the Physical Review journals: they insist that footnotes should be denoted in the same manner as citations [1,2]. Citations and footnotes serve very different purposes, and I both use and consume them in very different ways. When I’m reading a paper, I often read the footnotes, especially if I’m trying to totally understand a passage. I almost never look at the citations on my first reading. As a reader, I love footnotes! They’re a great way to add context, clarifications, parenthetical remarks, or definitions without interrupting the flow of your argument. Citations, on the other hand, are for backing up your claims or giving proper credit. If you mistake a footnote for a citation, you might miss some useful information or you might wrongly assume that the claim is backed up elsewhere in the literature [3]. Finally, I prefer footnotes to endnotes because footnotes keeps the information nearby, rather than forcing readers to flip pages back and forth.

In summary, Physical Review Letters and A, B, C and D: please follow Physical Review E‘s lead and allow separate footnotes!

Just one section called references:

[1] Waldron et al. “The Physical Review Style and Notation Guide” APS 2011 (a citation)
[2] At least for Physical Review B and Physical Review Letters, which are the PR journals I use. Phys Rev E does allow separate footnotes. (a footnote)
[3] For example, if you mistook [2] for a citation, you might not have noticed my caveat about which specific journals exhibit this problem.

Update 2020-03-12

Let the record reflect that after I posted this I heard that PRB does, in fact, allow separate footnotes. I tested this with my most recent paper and I now have experimental proof.

Great resource: Beall’s list of predatory journals

Update 2020-01-24: Beall’s list has a new home:

With your academic email address posted online, you’ll be flooded with sketchy offers inviting you to submit your manuscript to open-access journals with legitimate sounding names like “British Journal of Science” or “Cancer Research Frontiers”. These predatory journals typically do little or no peer review. One pair of scientists was even able to get a paper containing only the repeated text “Get me off your f___ing mailing list” published in the predatory International Journal of Advanced Computer Technology.

The proliferation of these journals is perhaps the chief disadvantage of the move towards open access since, in the digital age, setting up a website is nearly free, and open access journals need not convince any librarians to pay for subscriptions to make money. Instead these ‘journals’ charge huge fees to publish and conduct shoddy peer review or none at all. Some are less directly predatory, but are instead “vanity press” where they get you to pay a fee to publish your thesis with them with little editing or review.

You might also find yourself invited by [person you’ve never met/heard of] to give a talk at [prestigious conference you’ve never heard of] organized by [not a university or professional society]. When you go to register, you’ll find that it’s bizarrely expensive. I think that at least sometimes conferences are real, but like the predatory journals, they are just doing it for a profit.

At least in the case of the predatory journals, Beall’s List of Predatory Journals and Publishers (now located here)provides a great way to check if the journal is a known scam so you can end that email to your spam folder without a tinge of fear that you’re throwing away a legitimate offer. Two notes of caution here: (1) obviously just because it isn’t on the list doesn’t mean everything is above board, so still do your due diligence and (2) on the Beall’s List, you have to click through publishers, standalone journals and vanity press and search each separately.

New paper: Bose-Einstein condensation of deconfined spinons in 2D

My new paper, Bose-Einstein condensation of deconfined spinons in two dimensions, is finally live on arXiv! (arXiv:1909.01594)


Almost all phase transitions are described by a theory known as the Landau-Ginzburg-Wilson (LGW) paradigm, which describes the phase transition in terms of an order parameter that also describes the ordered state (e.g. a transition to a ferromagnet is described by the magnetization). There is therefore great interest in find examples of phase transitions that do not obey this paradigm. Growing numerical evidence suggests that the transition between the Néel antiferromagnet (AFM) and valence-bond solid (VBS) in certain quantum magnets may be such a transition. Since the Néel AFM and VBS break unrelated symmetries (SU(2) and Z4), LGW predicts the transition between them will be first order. Extensive numerical studies, however, strongly suggest that it is continuous. Instead, this transition appears to be described by deconfined quantum criticality (DQC).

In DQC, the critical point is not described by either order parameter, but instead by emergent fractionalized excitations, in this case spinons, which are spin-1/2 bosons (crazy, right?). Away from the critical point spinons are confined inside conventional magnon excitations (like quarks in a proton), but at transition they deconfine. The existence of deconfined quantum criticality remains controversial.

In this paper…

… we add a magnetic field to the DQC point to produce a Bose-Einstein condensate (BEC) of magnetic excitations and use thermodynamics to determine if they are spinons or magnons. My collaborators, Harley Scammell and Oleg Sushkov, developed a quantum field theory approach to predict the low-temperature behavior of a spinons in a magnetic field. We found that the field causes the spinon behavior to differ dramatically from magnons. Using my numerics, we show that the magnetic excitations we observe must indeed be bosonic spinons. This constitutes the first evidence for a BEC of spinons and provides more evidence for DQC theory.


The transition between the Néel antiferromagnet and the valence-bond solid state in two dimensions has become a paradigmatic example of deconfined quantum criticality, a non-Landau transition characterized by fractionalized excitations (spinons). We consider an extension of this scenario whereby the deconfined spinons are subject to a magnetic field. The primary purpose is to identify the exotic scenario of a Bose-Einstein condensate of spinons. We employ quantum Monte Carlo simulations of the JQ model with a magnetic field and perform a quantum field theoretic analysis of the magnetic field and temperature dependence of thermodynamic quantities. The combined analysis provides compelling evidence for the Bose-Einstein condensation of spinons and also demonstrates an extended temperature regime in which the system is best described as gas of spinons interacting with an emergent gauge field.