Luck in grad school

I am continuing my blogging series on why grad school sucks.  This series has only had one entry so far, in which I talk about how bad physics talks are, and how this worsens impostor syndrome.  Today I will talk about how scientific success is based on luck.

If you have ever read any popularizations of science, you’ve likely heard that many scientific discoveries are made by serendipity.  This makes sense, because if a discovery isn’t a big surprise, then it’s not much of a discovery, is it?

We have one of these stories in the field of superconductivity too.  Kamerlingh Onnes is credited with the discovery of superconductivity in 1911.  But that’s not what his work was really about.  His real accomplishment was being the first person to liquefy helium.  He just tried cooling a bunch of things, and that’s how superconductivity was discovered.  That’s serendipity!  Kinda?

The thing is, serendipitous discoveries might make for a fun story, but it’s garbage to actually live through.  If you go to grad school, will you hit upon something truly interesting?  Or will you just produce a bunch of unremarkable studies that nobody cares about?  Nobody knows!  But your career success depends on it!

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One: the universe’s favorite digit

This is a repost of an article I wrote way back in 2011.  I’m still proud of figuring this one out.

Out of all the digits, from zero to nine, one is the most common.  This has to do with the log scale.

The log scale captures an important fact that is true of many quantities in life.  Take money for instance.  If you have one dollar, then earning another dollar is great because you’ve doubled your money!  If you have a million dollars, earning another dollar does not make much of a difference.  Small changes matter less the more you already have.

This is true on a log scale too.  On a log scale, 1 is the same distance from 2 as 100 is from 200.  The higher you go up, the more the numbers all get smooshed together.  What does that mean for the digits from zero to nine?

A picture of a log scale, highlighting the regions that have 1 as their first digit (eg 1-2 and 10-20)

In the above picture, I show a log scale.  And on that scale, I highlighted in blue all the regions where 1 is the first digit of the number.  You should see that the blue regions cover more than one tenth of the log scale.  In fact, they cover about 30%.  And so, if we pick numbers randomly on the log scale, about 30% of those numbers will have 1 as their first digit.

Just for fun, let’s apply this concept on the fundamental constants of nature.  I will compare two hypotheses: [Read more…]

I am graduating

I have been hinting for months that I am close to graduating.  Well, the time has come.  I am graduating with a Ph.D. in physics.

In the immediate future, I will be unemployed.  I am taking my time looking for a job in data science.  That means I’ll find some tech company and analyze data for them.  And before you comment on that career choice, let me just say that I know more physics students moving into data science than staying in physics.  When I do find a job I probably won’t make any announcement about it.


Given that most of my time blogging has been while I was at grad school, the impact on my blogging is unknown.  I may have more free time while unemployed, but I won’t necessarily spend that time blogging.  (Note that I often take a blogging break near Christmas, and that has nothing to do with graduating.)

Ah, one thing that might make an impact on blogging, is that I will lose journal access.  I can still get physics papers on ArXiV, but most of what I’d want to blog about would be in social sciences or humanities.  So, that’s a bit tougher.

After this post, I intended to write at least a couple more blog posts about why grad school can be such a bad experience.  It’s not too late, I’ll get around to it eventually.


If you are unwise enough to wonder what my dissertation is about, I’ll tell you.

I worked on photoemission spectroscopy of cuprate superconductors.  Photoemission spectroscopy is the technique of shining light on a material, and measuring the electrons that come out.  The technique tells us about how the electrons were behaving in the material.  A superconductor is material in a special state where electricity is conducted with zero resistance.  Cuprates are a particular class of superconductors.  Cuprates are famous for being in a superconducting state up to relatively high temperatures (but “high temperature” still means minus ~170 degrees Celsius).  Cuprates are not fully understood, and have been a longstanding mystery since they were discovered in the 80s.

Photoemission spectroscopy of cuprates sounds very specific, but it’s a well-established and competitive field of research.

On the social construction of electrons

One interesting fact about electrons is that they are all literally identical. And I really do mean completely and literally identical, in the sense of sharing all properties. Yes, even the spatial distribution of their wavefunctions.

To illustrate how this is possible, consider a simple scenario, where we have two electrons, one at point A, and the other at point B. At first it would seem that electron 1 has a different location from electron 2. But in fact, the universe is in a quantum superposition of two states–the first state has electron 1 at A and electron 2 at B, while the second state has electron 2 at A and electron 1 at B. So even though we observe electrons at two distinct locations, the two electrons involved are actually identical.

The fact that electrons are identical has really important consequences.  One consequence is the Pauli Exclusion Principle, which states that no single state can be occupied by two electrons simultaneously. So when we have a large atom, electrons will occupy many different orbitals of the atom, instead of having all electrons occupy the one orbital with lowest energy.

Of course, it’s not really practical to think of it this way all the time. Generally we prefer to think of each electron as being at a distinct location, and then we tack on additional rules like the Pauli Exclusion Principle.

The point is that the individuality of electrons is an idea that arises from practical necessity, and not from the fundamental physics. Practical necessities arise from social context. And in principle, a different social context could have different needs that are better fulfilled by some other way of thinking about it. Therefore, the concept of individual electrons is a social construct.

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Why are physics talks so bad?

As I get closer to the end of my PhD, I wanted to talk about why grad school sucks so much. For my first complaint, let’s talk about physics talks. I’m not referring to popular stuff like Stephen Hawking’s TED Talk or whatever. I’m referring to talks given by physicists to other physicists in their field.

By design, a physics talk starts out with a broadly accessible introduction, and dives into technical details that only two people in the audience understand. This is followed by a Q&A where those two people ask (apparently) extremely intelligent questions, and everyone else silently feels stupid as they listen to arguments over arcane details.

When I started out my PhD, approximately 0% of physics talks made sense. I thought that maybe when I got further into my PhD I would understand much more. Nope! Now, maybe 10% of talks make sense. And even that high rate comes from knowing when to avoid going to a talk in the first place.

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Trump’s past light cone

When Trump was elected, and for many months following, people kept on talking about why he was elected. What caused it? This conversation irritates me deeply, because people lack a base-level understanding of what causation is. But I’ve waited to say anything because I thought it might be too crass to insert a philosophical discussion into a political one, at least while it was still hot.

Cause and effect is often thought to be a fundamental part of the way the world works, but I and other physicists understand that it is not. For a brief explanation, I recommend this video by Sean Carroll. It is better to think of causality as an emergent property, more in the realm of philosophy than physics.

What does physics have to say about the cause of Trump’s election? It’s everything in Trump’s past lightcone! It was the DNC, it was Clinton, it was Comey, it was Russia, it was neoliberalism, it was identity politics, it was ancient supernovae. This answer is rather naive, but what did you expect from us? Physics can’t provide all the answers.

When we talk about causes, we’re typically just selecting a few things from the past lightcone, and highlighting those things as important. In philosophy, this is known as causal selection. Sean Carroll talks a little bit about causal selection. He says that one way of thinking about it is that a cause is something that has great leverage over the future. But that’s just one way we might think about it.

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Quantum games

Last March, I attended the APS March Meeting, which is the largest annual physics conference in the country (and perhaps world?). During the conference, one of the particularly memorable sessions was about quantum gamification, making games using concepts from quantum physics.

Quantum games are an interesting concept, because usually “physics-based games” are only based on classical physics, specifically gravity and collision. The point of having a physics-based game is to have a relatively complex system where you don’t need to teach players every single detail, because they already have an intuition for how gravity and collision work. But obviously, when it comes to quantum physics, players don’t have an intuition, thus the physics must serve some other purpose.

In most of these games, the nominal purpose is either (a) teach physics, or (b) use player data to help physicists. Although I get the sense that the nominal purpose is not always the true purpose. I’m not that confident in the value of collecting player data, and suspect that the true purpose is more about public outreach. And some of the “outreach” projects kinda felt like they were just a way for physicists to do something fun. Well, whatever persuades people to give you grant money.

Anyways, let’s check out some of these games.

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