Just what does a postdoctoral theoretical physicist do all day?

Coffee… mostly, I drink coffee.

A kindergartener once asked me, “why don’t you wear science clothes?” I gathered that she meant a lab coat. Then there is the utter surprise my neighbors show when I tell them—yes—I am on my way to work wearing sandals, shorts and a t-shirt. Take a moment and do a google image search of “scientist”. You have to scroll through several pages before you see a person not wearing a lab coat. So if I don’t wear a lab coat while staring into a beaker as if the colorful liquid inside contained a part of my soul, what do I do all day?

Generally speaking, a postdoctoral researcher (postdoc) is someone at a stage in their academic career between a graduate student and a professor. This usually involves traveling around the world working on short-term contracts. In theoretical physics the typical situation is to move several times over a period of 5–10 years before landing a permanent position as a professor or leave academia for an industry job.

While that sounds kind of horrible, as far as responsibilities go, it’s the best job in the world. I have the freedom of a graduate student, but I don’t have to write exams or engage in any of the administrative duties of a professor. I get to focus on my passion: research.

Now, you might be thinking “wait, pictures of physicists still have lab equipment surrounding them. Presumably, instead of beakers, you still have to be doing something technical with your hands.” No. Let me explain. There are two types of physicists: experimental and theoretical. The distinction is easy to make. Experimental physicists (experimentalists) spend at least some of their time in a lab building devices to probe and test hypotheses about the world. Theoretical physicists (theorists) do not. I am one of the latter.


OK, so I don’t wear a lab coat, I don’t use beakers, I don’t build anything, I don’t even step foot into a lab, what exactly do I do?

What does the internet say:

Theoretical physicists have a fascinating job that combines observation with mathematics in order to create complex formulas that describe the workings of the universe around us.

Not bad, but still not very illuminating in terms of my day-to-day life. In a business sense, I do create products: journal articles. These are usually 5–15 page papers which summarize a successful result, which can takes months to years to obtain. What they do not contain is any semblance of the blood, sweat and tears which make up the chaotic mess that went into them.

This mess can broken down into four tasks:

  1. Discuss problems with colleagues
  2. Perform mathematical calculations
  3. Read journal articles
  4. Write computer software

I don’t do every task every day, but on average my time is about equally spent on each.

A day in the life of a postdoctoral theoretical physicist.

Much of every day is spent discussing problems with colleagues. Sometimes I seek advice on the problems I’m working from a co-worker; sometimes I am providing advice to others; and sometimes I am discussing a problem we are jointly working on. These are often brainstorming session which involve scribbling notes on a whiteboard and plenty of coffee.

Next, I perform mathematical calculations. This involves a lot of paper covered in the kinds of symbols pictured above. You’ll notice there is no arithmetic. These are abstract manipulations of symbols according to some rules. The fun part is that I sometimes get to make the rules! Most of the work done in this category gets trashed due to dead ends or errors and the rest gets heavily compressed if and when a journal article is written.

In order to find out what things others have tried and what techniques I can use to solve a problem, I read journal articles written by other scientists. Finding the right articles is a skill on its own given that over 2.5 million scientific journal articles are written each year. Often I find myself skimming over papers, picking out specific pieces. Occasionally, I am asked by a journal to evaluate the scientific merit of another article. This process is called peer review and could very well be the subject of a future post.

Lastly, there is coding. I write computer software that helps answer the scientific questions I have. For example, with my long-time friend and colleague Chris Granade I co-wrote Qinfer, which is statistical software for debugging small quantum computers. You’ll see examples of this and other software projects in future blog posts.

So there you have it. A day in the life of a postdoctoral theoretical physicist.

Quantum Physics for Babies

Why Quantum Physics for Babies? This is the most common question I get and, I must admit, the answer is not as reasoned as you might expect from an academic researcher. But, it is entirely obvious if you know me: it started as a joke.

Though I don’t remember now the exact reason why, in 2013 I wanted to have a prop nerdy baby book. Probably to do something like this:

Initially I had quickly put together a bunch of pages to give it some girth and had it printed by  an online photobook printing company. It didn’t end up looking like a real book. But, my wife and kids liked it enough to encourage me to spend a little more time on the interior.

This time around I was determined to get it printed to look like a real book. Through some online research I came across CreateSpace, which is a self-publishing platform. It was easy enough to upload my files and order a copy for myself  (as the author, I just paid the shipping of $4). It turned out great. My daughter brought it to her preschool class and the teachers were all very excited about it. It was at that point when I clicked the button to have it go live on

I was surprised that it started selling a few copies per day. Some initial positive reviews prompted me to write more books. I followed Quantum with Newtonian Physics for Babies and Optical Physics for Babies. Over the next few years things were going quite well. I was writing more books in my spare time and they were all selling a few copies per day. I didn’t think it was something I could make a living at, but it paid for coffee anyway. Then this happened:

As it turns out, Mark Zuckerberg is pretty popular. And, although he shared the book as a joke, I received lots of interest following this. I still don’t make a living from the books, but it is kind of fun when all your friends and colleagues think you are famous.

Since then, I’ve written some more books with some ideas that I’m really excited about. Stay tuned to find out more in the coming months.