Category Archives: Life as a Physicist

No Unmoved Movers

Economists must find academics confusing.

When investors put money in a company, they have some control over what that company does. They vote to decide a board, and the board votes to hire a CEO. If the company isn’t doing what the investors want, the board can fire the CEO, or the investors can vote in a new board. Everybody is incentivized to do what the people who gave the money want to happen. And usually, those people want the company to increase its profits, since most of them people are companies with their own investors).

Academics are paid by universities and research centers, funded in the aggregate by governments and student tuition and endowments from donors. But individually, they’re also often funded by grants.

What grant-givers want is more ambiguous. The money comes in big lumps from governments and private foundations, which generally want something vague like “scientific progress”. The actual decision of who gets the money are made by committees made up of senior scientists. These people aren’t experts in every topic, so they have to extrapolate, much as investors have to guess whether a new company will be profitable based on past experience. At their best, they use their deep familiarity with scientific research to judge which projects are most likely to work, and which have the most interesting payoffs. At their weakest, though, they stick with ideas they’ve heard of, things they know work because they’ve seen them work before. That, in a nutshell, is why mainstream research prevails: not because the mainstream wants to suppress alternatives, but because sometimes the only way to guess if something will work is raw familiarity.

(What “works” means is another question. The cynical answers are “publishes papers” or “gets citations”, but that’s a bit unfair: in Europe and the US, most funders know that these numbers don’t tell the whole story. The trivial answer is “achieves what you said it would”, but that can’t be the whole story, because some goals are more pointless than others. You might want the answer to be “benefits humanity”, but that’s almost impossible to judge. So in the end the answer is “sounds like good science”, which is vulnerable to all the fads you can imagine…but is pretty much our only option, regardless.)

So are academics incentivized to do what the grant committees want? Sort of.

Science never goes according to plan. Grant committees are made up of scientists, so they know that. So while many grants have a review process afterwards to see whether you achieved what you planned, they aren’t all that picky about it. If you can tell a good story, you can explain why you moved away from your original proposal. You can say the original idea inspired a new direction, or that it became clear that a new approach was necessary. I’ve done this with an EU grant, and they were fine with it.

Looking at this, you might imagine that an academic who’s a half-capable storyteller could get away with anything they wanted. Propose a fashionable project, work on what you actually care about, and tell a good story afterwards to avoid getting in trouble. As long as you’re not literally embezzling the money (the guy who was paying himself rent out of his visitor funding, for instance), what could go wrong? You get the money without the incentives, you move the scientific world and nobody gets to move you.

It’s not quite that easy, though.

Sabine Hossenfelder told herself she could do something like this. She got grants for fashionable topics she thought were pointless, and told herself she’d spend time on the side on the things she felt were actually important. Eventually, she realized she wasn’t actually doing the important things: the faddish research ended up taking all her time. Not able to get grants doing what she actually cared about (and, in one of those weird temporary European positions that only lasts until you run out of grants), she now has to make a living from her science popularization work.

I can’t speak for Hossenfelder, but I’ve also put some thought into how to choose what to research, about whether I could actually be an unmoved mover. A few things get in the way:

First, applying for grants doesn’t just take storytelling skills, it takes scientific knowledge. Grant committees aren’t experts in everything, but they usually send grants to be reviewed by much more appropriate experts. These experts will check if your grant makes sense. In order to make the grant make sense, you have to know enough about the faddish topic to propose something reasonable. You have to keep up with the fad. You have to spend time reading papers, and talking to people in the faddish subfield. This takes work, but also changes your motivation. If you spend time around people excited by an idea, you’ll either get excited too, or be too drained by the dissonance to get any work done.

Second, you can’t change things that much. You still need a plausible story as to how you got from where you are to where you are going.

Third, you need to be a plausible person to do the work. If the committee looks at your CV and sees that you’ve never actually worked on the faddish topic, they’re more likely to give a grant to someone who’s actually worked on it.

Fourth, you have to choose what to do when you hire people. If you never hire any postdocs or students working on the faddish topic, then it will be very obvious that you aren’t trying to research it. If you do hire them, then you’ll be surrounded by people who actually care about the fad, and want your help to understand how to work with it.

Ultimately, to avoid the grant committee’s incentives, you need a golden tongue and a heart of stone, and even then you’ll need to spend some time working on something you think is pointless.

Even if you don’t apply for grants, even if you have a real permanent position or even tenure, you still feel some of these pressures. You’re still surrounded by people who care about particular things, by students and postdocs who need grants and jobs and fellow professors who are confident the mainstream is the right path forward. It takes a lot of strength, and sometimes cruelty, to avoid bowing to that.

So despite the ambiguous rules and lack of oversight, academics still respond to incentives: they can’t just do whatever they feel like. They aren’t bound by shareholders, they aren’t expected to make a profit. But ultimately, the things that do constrain them, expertise and cognitive load, social pressure and compassion for those they mentor, those can be even stronger.

I suspect that those pressures dominate the private sector as well. My guess is that for all that companies think of themselves as trying to maximize profits, the all-too-human motivations we share are more powerful than any corporate governance structure or org chart. But I don’t know yet. Likely, I’ll find out soon.

Making More Nails

They say when all you have is a hammer, everything looks like a nail.

Academics are a bit smarter than that. Confidently predict a world of nails, and you fall to the first paper that shows evidence of a screw. There are limits to how long you can delude yourself when your job is supposed to be all about finding the truth.

You can make your own nails, though.

Suppose there’s something you’re really good at. Maybe, like many of my past colleagues, you can do particle physics calculations faster than anyone else, even when the particles are super-complicated hypothetical gravitons. Maybe you know more than anyone else about how to make a quantum computer, or maybe you just know how to build a “quantum computer“. Maybe you’re an expert in esoteric mathematics, who can re-phrase anything in terms of the arcane language of category theory.

That’s your hammer. Get good enough with it, and anyone with a nail-based problem will come to you to solve it. If nails are trendy, then you’ll impress grant committees and hiring committees, and your students will too.

When nails aren’t trendy, though, you need to try something else. If your job is secure, and you don’t have students with their own insecure jobs banging down your door, then you could spend a while retraining. You could form a reading group, pick up a textbook or two about screwdrivers and wrenches, and learn how to use different tools. Eventually, you might find a screwdriving task you have an advantage with, something you can once again do better than everyone else, and you’ll start getting all those rewards again.

Or, maybe you won’t. You’ll get less funding to hire people, so you’ll do less research, so your work will get less impressive and you’ll get less funding, and so on and so forth.

Instead of risking that, most academics take another path. They take what they’re good at, and invent new problems in the new trendy area to use that expertise.

If everyone is excited about gravitational waves, you turn a black hole calculation into a graviton calculation. If companies are investing in computation in the here-and-now, then you find ways those companies can use insights from your quantum research. If everyone wants to know how AI works, you build a mathematical picture that sort of looks like one part of how AI works, and do category theory to it.

At first, you won’t be competitive. Your hammer isn’t going to work nearly as well as the screwdrivers people have been using forever for these problems, and there will be all sorts of new issues you have to solve just to get your hammer in position in the first place. But that doesn’t matter so much, as long as you’re honest. Academic research is expected to take time, applications aren’t supposed to be obvious. Grant committees care about what you’re trying to do, as long as you have a reasonably plausible story about how you’ll get there.

(Investors are also not immune to a nice story. Customers are also not immune to a nice story. You can take this farther than you might think.)

So, unlike the re-trainers, you survive. And some of the time, you make it work. Your hammer-based screwdriving ends up morphing into something that, some of the time, actually does something the screwdrivers can’t. Instead of delusionally imagining nails, you’ve added a real ersatz nail to the world, where previously there was just a screw.

Making nails is a better path for you. Is it a better path for the world? I’m not sure.

If all those grants you won, all those jobs you and your students got, all that money from investors or customers drawn in by a good story, if that all went to the people who had the screwdrivers in the first place, could they have done a better job?

Sometimes, no. Sometimes you happen upon some real irreproducible magic. Your hammer is Thor’s hammer, and when hefted by the worthy it can do great things.

Sometimes, though, your hammer was just the hammer that got the funding. Now every screwdriver kit has to have a space for a little hammer, when it could have had another specialized screwdriver that fit better in the box.

In the end, the world is build out of these kinds of ill-fitting toolkits. We all try to survive, both as human beings and by our sub-culture’s concept of the good life. We each have our hammers, and regardless of whether the world is full of screws, we have to convince people they want a hammer anyway. Everything we do is built on a vast rickety pile of consequences, the end-results of billions of people desperate to be wanted. For those of us who love clean solutions and ideal paths, this is maddening and frustrating and terrifying. But it’s life, and in a world where we never know the ideal path, screw-nails and nail-screws are the best way we’ve found to get things done.

How Subfields Grow

A commenter recently asked me about the different “tribes” in my sub-field. I’ve been working in an area called “amplitudeology”, where we try to find more efficient ways to make predictions (calculate “scattering amplitudes”) for particle physics and gravitational waves. I plan to do a longer post on the “tribes” of amplitudeology…but not this week.

This week, I’ve got a simpler goal. I want to talk about where these kinds of “tribes” come from, in general. A sub-field is a group of researchers focused on a particular idea, or a particular goal. How do those groups change over time? How do new sub-groups form? For the amplitudes fans in the audience, I’ll use amplitudeology examples to illustrate.

The first way subfields gain new tribes is by differentiation. Do a PhD or a Postdoc with someone in a subfield, and you’ll learn that subfield’s techniques. That’s valuable, but probably not enough to get you hired: if you’re just a copy of your advisor, then the field just needs your advisor: research doesn’t need to be done twice. You need to differentiate yourself, finding a variant of what your advisor does where you can excel. The most distinct such variants go on to form distinct tribes of their own. This can also happen for researchers at the same level who collaborate as Postdocs. Each has to show something new, beyond what they did as a team. In my sub-field, it’s the source of some of the bigger tribes. Lance Dixon, Zvi Bern, and David Kosower made their names working together, but when they found long-term positions they made new tribes of their own. Zvi Bern focused on supergravity, and later on gravitational waves, while Lance Dixon was a central figure in the symbology bootstrap.

(Of course, if you differentiate too far you end up in a different sub-field, or a different field altogether. Jared Kaplan was an amplitudeologist, but I wouldn’t call Anthropic an amplitudeology project, although it would help my job prospects if it was!)

The second way subfields gain new tribes is by bridges. Sometimes, a researcher in a sub-field needs to collaborate with someone outside of that sub-field. These collaborations can just be one-and-done, but sometimes they strike up a spark, and people in each sub-field start realizing they have a lot more in common than they realized. They start showing up to each other’s conferences, and eventually identifying as two tribes in a single sub-field. An example from amplitudeology is the group founded by Dirk Kreimer, with a long track record of interesting work on the boundary between math and physics. They didn’t start out interacting with the “amplitudeology” community itself, but over time they collaborated with them more and more, and now I think it’s fair to say they’re a central part of the sub-field.

A third way subfields gain new tribes is through newcomers. Sometimes, someone outside of a subfield will decide they have something to contribute. They’ll read up on the latest papers, learn the subfield’s techniques, and do something new with them: applying them to a new problem of their own interest, or applying their own methods to a problem in the subfield. Because these people bring something new, either in what they work on or how they do it, they often spin off new tribes. Many new tribes in amplitudeology have come from this process, from Edward Witten’s work on the twistor string bringing in twistor approaches to Nima Arkani-Hamed’s idiosyncratic goals and methods.

There are probably other ways subfields gain new tribes, but these are the ones I came up with. If you think of more, let me know in the comments!

An “Open-Source” Grant Proposal

Back in the Fall, I spent most of my time writing a grant proposal.

In Europe, getting a European Research Council (ERC) grant is how you know you’ve made it as a researcher. Covering both science and the humanities, ERC grants give a lump of funding big enough to hire a research group, turning you from a lone expert into a local big-shot. The grants last five years, and are organized by “academic age”, the number of years since your PhD. ERC Starting Grants give 1.5 million euros for those with academic age 2-7. At academic age 7-12, you need to apply for the Consolidator Grant. The competition is fiercer, but if you make it through you get 2 million euros. Finally, Advanced Grants give 2.5 million to more advanced researchers.

I’m old, at least in terms of academic age. I applied to the ERC Starting Grant in 2021, but this last year I was too academically old to qualify, so I applied to the Consolidator Grant instead.

I won’t know if they invite me for an interview until June…but since I’m leaving the field, there wouldn’t be much point in going anyway. So I figured, why not share the grant application with you guys?

That’s what I’m doing in this post. I think there are good ideas in here, a few research directions that fellow amplitudeologists might want to consider. (I’ve removed details on one of them, the second work package, because some friends of mine are already working on it.)

The format could also be helpful. My wife is more than a bit of a LaTeX wiz, she coded up Gantt charts and helped with the format of the headers and the color scheme. If you want an ERC proposal that doesn’t look like the default thing you could do with LaTeX or Word, then take a look.

Finally, I suspect some laymen in the audience are just curious what a scientific grant proposal looks like. While I’ve cut a few things (and a few of these were shorter than they ought to have been to begin with), this might satisfy your curiosity.

You can find the proposal in a zip file here: https://drive.proton.me/urls/WTVN0F16HG#mYaz0edaOGha . I’ve included pdfs of the two required parts, B1 and B2, as well as the LaTeX files used to generate them.

For those of you still in the game, good luck with your ERCs!


Update from November 2024:

I wanted to include a bit more information for those who want to build off some of the ideas in the proposal.

I did end up getting offered an interview for this grant, and since the ERC doesn’t give any way to withdraw in their system I ended up going through with the interview. I didn’t get the grant, but I think it would have had a solid chance if I had had the time to focus and prepare for it (rather than mostly being busy applying for industry jobs). If anyone wants to write their own proposal building on some of the research directions I’m proposing here, I’m happy to chat and give you advice. In particular, a few things to keep in mind:

  • You need a good list of pheno applications. In particular, unless you focus your proposal heavily on the gravitational wave side, you need a good list of particle physics applications, because the particle physicists generally won’t think that the gravitational wave side “counts”. I was asked in the interview to name three particle physics measurements this would help with, I had mentioned two in the proposal and could only come up with one off the top of my head. You can do a lot better with preparation.
  • Relatedly, you need some idea of what the pipeline looks like, what these calculations eventually get used for, including the looming question of “why do this analytically rather than numerically?”
  • If you’re including the N=4 super Yang-Mills side of the story, you’ll have to overcome some skepticism. Some of that skepticism can be brushed aside by emphasizing the theory’s track record (canonical differential equations probably wouldn’t exist without research in N=4 symbols), but a meaningful source of skepticism is just whether you can work with dim reg. This is an issue currently facing a few other approaches, so it’s good to have a good answer for it!
  • If you’re relying a lot on the expertise of the people you plan on hiring (I definitely was, especially in planning to hire a mathematician) then ideally you should have some idea of who you could hire. I wasn’t in a position to do this for obvious reasons, but anyone that has a stable position should consider talking to potential hires in advance so you have a list of names.
  • Have justifications in mind for your budget. Yes, you’ll be encouraged by your home institution to just increase every budget line as far as you can get. But you will be asked about anything unusually high, so you really need a picture for what you will spend it on. Along these lines, if your institution imposes any unusual expenses (since my budget was written for the CEA, it had to pay for Mathematica and Maple licenses since the CEA is technically a private business and doesn’t have access to site licenses at academic rates) then you need to be able to justify why it’s still a good host despite that.

Why We Are Leaving France: The Misadventures of a Trailing Spouse

In last week’s announcement, I mentioned I’d have a few follow-up posts. This week is a guest post. I want to let my wife tell her side of the story, to talk publicly about what she’s experienced over the last six months.


If you are a frequent reader of this blog, you probably know that 4gravitons relocated last year to France, following a long-coveted permanent academic position at the Institute for Theoretical Physics (IPhT) of CEA Paris-Saclay. Along with 4gravitons, I also moved to France as a trailing spouse. This is not an unusual situation, academic spouses agreeing to leave behind their friends and career to allow the academic in the relationship to develop their career. I had even set some conditions that I thought were necessary for me to successfully integrate elsewhere (access to employment, an intelligible healthcare system, good public transit), a list of desirable traits (in or near a medium-to-large city, prior knowledge of the language, walkable neighborhood),  and some places I was unwilling to move to. When the offer for a position in France arrived, we thought it was almost ideal:

  • France is an EU country, which would give me direct access to employment (by the EU directive on Freedom of Movement),
  • France is also somewhat renowned for having a sensible working healthcare system, even though in recent times it has been stretched thin,
  • IPhT is less than an hour away from Paris, and
  • Both 4gravitons and I already had a B1/B2 level in French (you can find the CEFR level descriptors here). 

However, we have decided to leave France only 6 months after arriving. What happened?

I wanted to put one of Escher’s labyrinths here, but they’re still under copyright.

The quest for a Carte de Séjour (and access to the labor market) 

As I wrote earlier, being able to work was a necessary condition for me to relocate. I work in education, which often requires a good deal of paperwork (since countries correctly want to make sure their young people are in a safe, nurturing environment). I had heard that France was facing a shortage of teachers, so I was hopeful about my prospects. I applied for one position which seemed like a perfect fit and got through a couple of interviews before the legal right to work issues started. EU law states that EU spouses have access to employment in EU countries on arrival (they should get the same rights as their European partners); however, in France employers are liable if they hire someone illegally so they are extremely cautious when hiring foreigners. In practice, this means employers will NOT hire EU spouses if they do not have a document from the French authorities explicitly stating their right to work. Since it is not possible to start the process to get such a document before arriving in France, finding work would have to wait.

One day after arriving in France, still hoping things would go smoothly and we could build a good life there, I collected all the document required by EU law to apply for a Carte de Séjour (residence card), went to the neighborhood Photomaton to have compliant photos taken, and uploaded the documents and photo-ID to the website of ANEF, the agency that handles the digital side of French immigration. EU law grants EU spouses 3 months to apply for the Carte de Séjour, but I wanted to have the process started as soon as possible so I could work. Naïvely, I thought I would be issued a document stating that I had applied for a Carte de Séjour under EU law and thus was allowed employment, the way it works in other EU countries. This was not the case. I was, instead, given a letter saying that I had applied for a Carte de Séjour, and that the document did not grant access to either employment or social benefits (such as healthcare, more on this below). To make matters worse, our sous-préfécture (the part of local government that handles the application) listed average waiting times for first demands at 161 days.

Well, at least the process was started and, in my head, the long wait times would likely only apply to complicated cases. I was arriving as an EU spouse, after having lived in another EU country (since 4gravitons had been working at the Niels Bohr Institute, in Denmark) for quite some time. It would likely be a short wait. It was just a matter of waiting for an e-mail when the process actually started and making sure to submit further documentation quickly, if it was deemed necessary.

A couple of months later, the email had not yet arrived (and work opportunities kept vanishing due to lack of papers), so we started asking for confirmation that my documents had indeed been received by our local sous-préfécture. We wrote to ANEF (“due to a technical error, we cannot answer your question”), called the sous-préfécture (“nobody here can answer your question”), support organizations (“You have the wrong visa! Can you go to another country and apply for a long-term visa from there?”), and so on. This went on for a long time despite local contacts reaching out to our sous-préfécture, our préfect, and other connections to try and accelerate the process. I finally received the e-mail starting the process (requesting some more documents, as well as some I had already sent) about 5 months after submitting the application (it took exactly 148  days, I counted). At this point, I was also granted a new letter attesting that I was legally in France (my short-term Schengen visa having expired much earlier) and that explicitly did not grant access to either employment (without a work authorization) or social benefits.

Healthcare for the undocumented

To make things even more complicated, I started having unusual symptoms a few weeks after our move to France. In the worst instance, the symptoms were worrying enough that an ambulance was sent to take me to the emergency room for an MRI (luckily, it was not serious). Note that I did not have a health card, so the ambulance had to be paid in cash before they would move me, the hospital sent a bill for the MRI by mail some weeks later, and the government sent a bill for the emergency care four months later. Luckily, we bought private insurance before moving, since we have relocated before and know that sometimes it takes a little time before one is signed up with the local healthcare institutions. Unluckily, hospitals here will not deal with insurance companies directly so we had to pay and file for reimbursement (this involves papers called feuille de soins, and the ambulance did not give us one, so no reimbursement for that). The following 3 or 4 months involved many specialist visits, lots of labs, lots of feuilles de soins… and very limited improvement on my symptoms. Since we could not have a family doctor (this requires a health card and an infinite amount of patience given that most general doctors have no space for new patients), appointments often consisted of the same questions, more referrals, confusion over a patient arriving with a giant file of previous documents, and no answers. At the end, the only answer proposed was that it may all be a physical expression of stress and anxiety.

The aforementioned situation was adding significant complications to our lives so, France being a country with socialized medicine, we started the process required to register me for a Carte Vitale (this is the name of the French health card). Residents in France aren’t automatically covered, but they are either registered for coverage by their employer or register themselves as dependents of someone with coverage. We reached out to CPAM (the French agency that controls socialized health insurance) and were given the forms to apply for coverage and a list of documents, which included a valid residency document (long-term visa or Carte de Séjour). EU spouses are not required to get a long-term visa (the French embassy explicitly told us I should get a short-term visa, and only because our residency cards for Denmark were expiring around the time of relocation) and the Carte de Séjour process was still ongoing, so we had a problem. Regardless, we made a file, and included our marriage certificate, the letter stating I had applied for a residence card, and proof of residency and work in France for 4gravitons, which shows the legality of my residence in France under EU regulations. The instructions are to send the file by mail to the corresponding CPAM office, which we tried to do but the postal office lost the letter. We eventually got an appointment to hand the documents in person and were told directly that I had the wrong visa and my request would likely be denied due to the lack of Carte de Séjour. We repeated the rules established by the EU (lack of a Carte de Séjour CANNOT be used to justify the denial of rights to EU families) and gave them the dossier. A month or so later, a letter came in the mail stating that my request had been denied because I had not been a resident for three months (at that point, I had been a resident for 2 and a half months so that was not much of an issue); a few weeks later, once my three-month visa had expired, a different letter arrived changing the reason for refusal to the lack of legal resident status.

Everyone ♥️ Paris, France

As you may well imagine, I was not feeling much appreciation for the City of Lights given our difficulties settling in and the isolation imposed by my status (legal resident but undocumented). Yet, whenever I have tried to explain why I was anxious, frustrated, or depressed, I encountered very little empathy or understanding. It often felt as if, by describing my experiences in the city, I was criticizing a core belief for people: that Paris is a magical place where one eats wonderful food and strolls about beautiful places. 

In sensing my unhappiness in (or near) Paris, I was often advised to go spend more time in the museums (the ones I am most interested in are quite expensive and permanently crowded) or walking around the nice areas of Paris (but beware not to take a wrong turn, for it is easy to find oneself in a less-than-nice place). This continued even if I explained that I have been to Paris, have seen the beautiful museums and manicured parks, and I never much enjoyed it. 

I moved here knowing that Paris was not a city I loved, but expecting it would provide access to entertainment (art, theater, gaming, etc) and to a variety of other resources (like materials for artwork or ingredients for my traditional foods). I was quite unhappy when the reliability of the RER-B became a problem: we ended up defaulting to scheduling almost two hours for any Paris trip to ensure we would arrive on time. Despite the extended time, there were occasions when we almost missed a meeting time due to train delays and cancellations. In the end, access to all the nice things in Paris was limited by logistics.

An unintegrated immigrant

Until this move, I thought that integration into developed countries was mostly a matter of individual effort: learn the language, find employment and connections to the local community, and understand that things are different than in your previous home. I can no longer hold this belief. I tried, as much as I could, to interact with our local community. I took any opportunity to speak French, and often was made to feel dumb for not finding the right terms; an ophthalmologist once welcomed me by saying “Oh, you’re the patient who does not speak French” in French (try describing different kinds of eye pain in a foreign language). I signed-up for more French lessons which seemed to focus more on local slang than on useful words (my vocabulary needs more help than my grammar for French). I also joined some art lessons and a local vocal ensemble, where I met some lovely people but had little chance of creating more in-depth connections. 

Finally, after months of trying and failing to integrate, Newtonmas came. The few friends we had here all left to visit their families. I still had no papers and could not leave France. On top of this, there was an unexpected death in my family in the lead-up to the holidays. I found myself, almost 5 months after arriving, unemployed (and with no access to the job market), uninsured (and paying for healthcare and a lot of counseling out of pocket), undocumented (at this point, with no valid visa and no way to prove I was in France legally), and grieving alone in a foreign country. We knew that I could not stay here. And thus, we cannot stay here.

Integration requires effort from the immigrant, but it also requires effort from the country. It requires a country willing to give basic access to the requirements of life, to let immigrants step into the public sphere under fair conditions, and to do so consistently and reliably. France, in its current state, cannot do this. I hope it can improve, but I am not required to wait here for it. We’ll be elsewhere, integrating into another country and contributing to their community instead.

Well That Didn’t Work

Apologies to anyone who finds the title too flippant. This is a serious situation, and I am taking it seriously. But this is how I write. I mix the absurd and the profound. I build stories.

In May, I was offered the kind of position I’d been searching for for years, the kind of position almost everyone in my life at that point was searching for: a permanent position as a theoretical physicist. As these positions almost always do, it required an international move: I’d be leaving Denmark, and going to France.

Originally, I had planned to defer the position for a year, to have time for my wife and I to tie up loose ends. That, it turned out, wasn’t possible: the position would have to start before the end of 2023. I talked things over with my wife, and we decided to move in August. She works in education, so it would, we hoped, let her start a job with the start of the school year. We’d settle in, get to know a new country and find our place in it.

She didn’t end up finding that place. That wasn’t because she couldn’t find work: that came easy. It was because, as far as employers here understood, she wasn’t allowed to work. The EU Directive on Freedom of Movement is very clear: spouses of EU citizens (I’m German) have the right to work EU-wide, independent of whether they have any document from their host country saying so, as long as they live with their spouse. But different countries implement this differently. The Danish government makes this right clear on their website. As soon as the spouse of an EU citizen registers with Danish immigration, shortly after they arrive, they get a letter saying their case is in process, and they conditionally can work. If they happen to have been lying, their case can still be rejected, but if it is only the employee is punished: the employer couldn’t have known, after all.

France is different. If an employer hires someone who lies about their right to work, the employer is at fault, so employers are afraid to hire without explicit documentation from the French government. Government websites do not mention that spouses of EU citizens have the right to work, and leaves it off of lists where it should appear. And the French documentation is slow. My wife applied the day after we arrived, in August. Five months later, the French government finally opened the file. They gave her a document saying she had the right to remain in the country…but not yet the right to travel or work.

In the end, my wife decided that she didn’t want to stay in the country that did this to her, and seeing the effect it has had on her I have to agree.

Academics don’t get to choose where to live. People do, though, especially in places like the EU. I can choose for us to live in Denmark, to build a life in a country that has treated us well. I just have to leave academia to do it.

So that’s the plan. I have resigned from my position in France, the moving truck has picked up our stuff. We’re headed back to Denmark. I’ll spend a couple months as a visiting professor at the Niels Bohr Institute, courtesy of some extremely generous former colleagues.

After that? Something else. Probably Data Science, that seems like what most of the ex-physicists are doing these days. Ultimately, I’m up for anything I can do in Copenhagen that leverages my skills. I’ve got ten years of experience coding in weird programming languages, learning new kinds of math, and writing once a week for you guys. I’m optimistic I’ll find something. (And if you’re looking for someone like that in Copenhagen, let me know!)

I do still care about physics, even if I won’t be researching it. So I’ll keep blogging, and the blog will keep having physics content. I’ve dabbled in science journalism more recently, and I’ll keep doing more. It won’t be a full-time job for the moment, but in the long run who knows? For my physics contacts, if you’re willing to be a sounding-board for dumb questions, that would be really valuable. And if you run into a story, something that sounds like it would make good science news, then let me know!

For all those attending the conference I’m organizing: it will still go on, even if I’m less likely to be a part of it. I still have four capable co-organizers, after all.

Over the next few weeks I’ll have a few more posts about this, from different angles. I have a few more things to say, some personal, some practical (for example, a guide for EU citizens bringing non-EU spouses to France). My wife will have a guest post: she’s had some crazy things happen to her here, and deserves to have her story told.

In the meantime, I’d be happy to hear from people. I know many of you will be shocked. (Props to the old friend who figured it out from my LinkedIn posts!) I’ve met a lot of support so far, a lot of very understanding people. But whatever your reaction, I’m willing to talk through it.

What’s in a Subfield?

A while back, someone asked me what my subfield, amplitudeology, is really about. I wrote an answer to that here, a short-term and long-term perspective that line up with the stories we often tell about the field. I talked about how we try to figure out ways to calculate probabilities faster, first for understanding the output of particle colliders like the LHC, then more recently for gravitational wave telescopes. I talked about how the philosophy we use for that carries us farther, how focusing on the minimal information we need to make a prediction gives us hope that we can generalize and even propose totally new theories.

The world doesn’t follow stories, though, not quite so neatly. Try to define something as simple as the word “game” and you run into trouble. Some games have a winner and a loser, some games everyone is on one team, and some games don’t have winners or losers at all. Games can involve physical exercise, computers, boards and dice, or just people telling stories. They can be played for fun, or for money, silly or deadly serious. Most have rules, but some don’t even have that. Instead, games are linked by history: a series of resemblances, people saying that “this” is a game because it’s kind of like “that”.

A subfield isn’t just a word, it’s a group of people. So subfields aren’t defined just by resemblance. Instead, they’re defined by practicality.

To ask what amplitudeology is really about, think about why you might want to call yourself an amplitudeologist. It could be a question of goals, certainly: you might care a lot about making better predictions for the LHC, or you could have some other grand story in mind about how amplitudes will save the world. Instead, though, it could be a matter of training: you learned certain methods, certain mathematics, a certain perspective, and now you apply it to your research, even if it goes further afield from what was considered “amplitudeology” before. It could even be a matter of community, joining with others who you think do cool stuff, even if you don’t share exactly the same goals or the same methods.

Calling yourself an amplitudeologist means you go to their conferences and listen to their talks, means you look to them to collaborate and pay attention to their papers. Those kinds of things define a subfield: not some grand mission statement, but practical questions of interest, what people work on and know and where they’re going with that. Instead of one story, like every other word, amplitudeology has a practical meaning that shifts and changes with time. That’s the way subfields should be: useful to the people who practice them.

What Referees Are For

This week, we had a colloquium talk by the managing editor of the Open Journal of Astrophysics.

The Open Journal of Astrophysics is an example of an arXiv overlay journal. In the old days, journals shouldered the difficult task of compiling scientists’ work into a readable format and sending them to university libraries all over the world so people could stay up to date with the work of distant colleagues. They used to charge libraries for the journals, now some instead charge authors per paper they want to publish.

Now, most of that is unnecessary due to online resources, in my field the arXiv. We prepare our papers using free tools like LaTeX, then upload them to arXiv.org, a website that makes the papers freely accessible for everybody. I don’t think I’ve ever read a paper in a physical journal in my field, and I only check journal websites if I think there’s a mistake in the arXiv version. The rest of the time, I just use the arXiv.

Still, journals do one thing the arXiv doesn’t do, and that’s refereeing. Each paper a journal receives is sent out to a few expert referees. The referees read the paper, and either reject it, accept it as-is, or demand changes before they can accept it. The journal then publishes accepted papers only.

The goal of arXiv overlay journals is to make this feature of journals also unnecessary. To do this, they notice that if every paper is already on arXiv, they don’t need to host papers or print them or typeset them. They just need to find suitable referees, and announce which papers passed.

The Open Journal of Astrophysics is a relatively small arXiv overlay journal. They operate quite cheaply, in part because the people running it can handle most of it as a minor distraction from their day job. SciPost is much bigger, and has to spend more per paper to operate. Still, it spends a lot less than journals charge authors.

We had a spirited discussion after the talk, and someone brought up an interesting point: why do we need to announce which papers passed? Can’t we just publish everything?

What, in the end, are the referees actually for? Why do we need them?

One function of referees is to check for mistakes. This is most important in mathematics, where referees might spend years making sure every step in a proof works as intended. Other fields vary, from theoretical physics (where we can check some things sometimes, but often have to make do with spotting poorly explained parts of a calculation), to fields that do experiments in the real world (where referees can look for warning signs and shady statistics, but won’t actually reproduce the experiment). A mistake found by a referee can be a boon to not just the wider scientific community, but to the author as well. Most scientists would prefer their papers to be correct, so we’re often happy to hear about a genuine mistake.

If this was all referees were for, though, then you don’t actually need to reject any papers. As a colleague of mine suggested, you just need the referees to publish their reports. Then the papers could be published along with comments from the referees, and possibly also responses from the author. Readers could see any mistakes the referees found, and judge for themselves what they show about the result.

Referees already publish their reports in SciPost much of the time, though not currently in the Open Journal of Astrophysics. Both journals still reject some papers, though. In part, that’s because they serve another function: referees are supposed to tell us which papers are “good”.

Some journals are more prestigious and fancy than others. Nature and Science are the most famous, though people in my field almost never bother to publish in either. Still, we have a hierarchy in mind, with Physical Review Letters on the high end and JHEP on the lower one. Publishing in a fancier and more prestigious journal is supposed to say something about you as a scientist, to say that your work is fancier and more prestigious. If you can’t publish in any journal at all, then your work wasn’t interesting enough to merit getting credit for it, and maybe you should have worked harder.

What does that credit buy you? Ostensibly, everything. Jobs are more likely to hire you if you’ve published in more prestigious places, and grant agencies will be more likely to give you money.

In practice, though, this depends a lot on who’s making the decisions. Some people will weigh these kinds of things highly, especially if they aren’t familiar with a candidate’s work. Others will be able to rely on other things, from numbers of papers and citations to informal assessments of a scientist’s impact. I genuinely don’t know whether the journals I published in made any impact at all when I was hired, and I’m a bit afraid to ask. I haven’t yet sat on the kind of committee that makes these decisions, so I don’t know what things look like from the other side either.

But I do know that, on a certain level, journals and publications can’t matter quite as much as we think. As I mentioned, my field doesn’t use Nature or Science, while others do. A grant agency or hiring committee comparing two scientists would have to take that into account, just as they have to take into account the thousands of authors on every single paper by the ATLAS and CMS experiments. If a field started publishing every paper regardless of quality, they’d have to adapt there too, and find a new way to judge people compatible with that.

Can we just publish everything, papers and referee letters and responses and letters and reviews? Maybe. I think there are fields where this could really work well, and fields where it would collapse into the invective of a YouTube comments section. I’m not sure where my own field sits. Theoretical particle physics is relatively small and close-knit, but it’s also cool and popular, with many strong and dumb opinions floating around. I’d like to believe we could handle it, that we could prune back the professional cruft and turn our field into a real conversation between scholars. But I don’t know.

A Significant Calculation

Particle physicists have a weird relationship to journals. We publish all our results for free on a website called the arXiv, and when we need to read a paper that’s the first place we look. But we still submit our work to journals, because we need some way to vouch that we’re doing good work. Explicit numbers (h-index, impact factor) are falling out of favor, but we still need to demonstrate that we get published in good journals, that we do enough work, and that work has an impact on others. We need it to get jobs, to get grants to fund research at those jobs, and to get future jobs for the students and postdocs we hire with those grants. Our employers need it to justify their own funding, to summarize their progress so governments and administrators can decide who gets what.

This can create weird tensions. When people love a topic, they want to talk about it with each other. They want to say all sorts of things, big and small, to contribute new ideas and correct others and move things forward. But as professional physicists, we also have to publish papers. We can publish some “notes”, little statements on the arXiv that we don’t plan to make into a paper, but we don’t really get “credit” for those. So in practice, we try to force anything we want to say into a paper-sized chunk.

That wouldn’t be a problem if paper-sized chunks were flexible, and you can see when journals historically tried to make them that way. Some journals publish “letters”, short pieces a few pages long, to contrast with their usual papers that can run from twenty to a few hundred pages. These “letters” tend to be viewed as prestigious, though, so they end up being judged on roughly the same standards as the normal papers, if not more strictly.

What standards are those? For each journal, you can find an official list. The Journal of High-Energy Physics, for example, instructs reviewers to look for “high scientific
quality, originality and relevance”. That rules out papers that just reproduce old results, but otherwise is frustratingly vague. What constitutes high scientific quality? Relevant to whom?

In practice, reviewers use a much fuzzier criterion: is this “paper-like”? Does this look like other things that get published, or not?

Each field will assess that differently. It’s a criterion of familiarity, of whether a paper looks like what people in the field generally publish. In my field, one rule of thumb is that a paper must contain a significant calculation.

A “significant calculation” is still quite fuzzy, but the idea is to make sure that a paper requires some amount of actual work. Someone has to do something challenging, and the work shouldn’t be half-done: as much as feasible, they should finish, and calculate something new. Ideally, this should be something that nobody had calculated before, but if the perspective is new enough it can be something old. It should “look hard”, though.

That’s a fine way to judge whether someone is working hard, which is something we sometimes want to judge. But since we’re incentivized to make everything into a paper, this means that every time we want to say something, we want to accompany it with some “significant calculation”, some concrete time-consuming work. This can happen even if we want to say something that’s quite direct and simple, a fact that can be quickly justified but nonetheless has been ignored by the field. If we don’t want it to be “just” an un-credited note, we have to find some way to turn it into a “significant calculation”. We do extra work, sometimes pointless work, in order to make something “paper-sized”.

I like to think about what academia would be like without the need to fill out a career. The model I keep imagining is that of a web forum or a blogging platform. There would be the big projects, the in-depth guides and effortposts. But there would also be shorter contributions, people building off each other, comments on longer pieces and quick alerts pinned to the top of the page. We’d have a shared record of knowledge, where everyone contributes what they want to whatever level of detail they want.

I think math is a bit closer to this ideal. Despite their higher standards for review, checking the logic of every paper to make sure it makes sense to publish, math papers can sometimes be very short, or on apparently trivial things. Physics doesn’t quite work this way, and I suspect part of it is our funding sources. If you’re mostly paid to teach, like many mathematicians, your research is more flexible. If you’re paid to research, like many physicists, then people want to make sure your research is productive, and that tends to cram it into measurable boxes.

In today’s world, I don’t think physics can shift cultures that drastically. Even as we build new structures to rival the journals, the career incentives remain. Physics couldn’t become math unless it shed most of the world’s physicists.

In the long run, though…well, we may one day find ourselves in a world where we don’t have to work all our days to keep each other alive. And if we do, hopefully we’ll change how scientists publish.

IPhT-60 Retrospective

Last week, my institute had its 60th anniversary party, which like every party in academia takes the form of a conference.

For unclear reasons, this one also included a physics-themed arcade game machine.

Going in, I knew very little about the history of the Institute of Theoretical Physics, of the CEA it’s part of (Commissariat of Atomic Energy, now Atomic and Alternative Energy), or of French physics in general, so I found the first few talks very interesting. I learned that in France in the early 1950’s, theoretical physics was quite neglected. Key developments, like relativity and statistical mechanics, were seen as “too German” due to their origins with Einstein and Boltzmann (nevermind that this was precisely why the Nazis thought they were “not German enough”), while de Broglie suppressed investigation of quantum mechanics. It took French people educated abroad to come back and jumpstart progress.

The CEA is, in a sense, the French equivalent of the some of the US’s national labs, and like them got its start as part of a national push towards nuclear weapons and nuclear power.

(Unlike the US’s national labs, the CEA is technically a private company. It’s not even a non-profit: there are for-profit components that sell services and technology to the energy industry. Never fear, my work remains strictly useless.)

My official title is Ingénieur Chercheur, research engineer. In the early days, that title was more literal. Most of the CEA’s first permanent employees didn’t have PhDs, but were hired straight out of undergraduate studies. The director, Claude Bloch, was in his 40’s, but most of the others were in their 20’s. There was apparently quite a bit of imposter syndrome back then, with very young people struggling to catch up to the global state of the art.

They did manage to catch up, though, and even excel. In the 60’s and 70’s, researchers at the institute laid the groundwork for a lot of ideas that are popular in my field at the moment. Stora’s work established a new way to think about symmetry that became the textbook approach we all learn in school, while Froissart figured out a consistency condition for high-energy physics whose consequences we’re still teasing out. Pham was another major figure at the institute in that era. With my rudimentary French I started reading his work back in Copenhagen, looking for new insights. I didn’t go nearly as fast as my partner in the reading group though, whose mastery of French and mathematics has seen him use Pham’s work in surprising new ways.

Hearing about my institute’s past, I felt a bit of pride in the physicists of the era, not just for the science they accomplished but for the tools they built to do it. This was the era of preprints, first as physical papers, orange folders mailed to lists around the world, and later online as the arXiv. Physicists here were early adopters of some aspects, though late adopters of others (they were still mailing orange folders a ways into the 90’s). They also adopted computation, with giant punch-card reading, sheets-of-output-producing computers staffed at all hours of the night. A few physicists dove deep into the new machines, and guided the others as capabilities changed and evolved, while others were mostly just annoyed by the noise!

When the institute began, scientific papers were still typed on actual typewriters, with equations handwritten in or typeset in ingenious ways. A pool of secretaries handled much of the typing, many of whom were able to come to the conference! I wonder what they felt, seeing what the institute has become since.

I also got to learn a bit about the institute’s present, and by implication its future. I saw talks covering different areas, from multiple angles on mathematical physics to simulations of large numbers of particles, quantum computing, and machine learning. I even learned a bit from talks on my own area of high-energy physics, highlighting how much one can learn from talking to new people.