Quotes

These quotes are (mostly) real things said by real physicists.

Since these quotes are the collective wisdom fault of the physics community, no quotes have attribution. If you made it onto this page, consider it a private opportunity to reflect.

Everything in italics is commentary and not a quote (depending on if you consider graduate students humans physicists).

Mathematics

Mathematics is the bedrock of physics, because without it we would not be able understand physics. (Some would say philosophy is the bedrock of physics, because without it we would not be able to misunderstand physics.) But mathematics is just a tool to physicists. Sometimes the tools you have just aren’t quite the right tool for the job, like when you have a Phillips head screw and a flathead screwdriver. And most of the time, you use the tool anyway.


If you define one meter as the amount of time it takes for light to travel 1 meter, then the speed of light is one meter per one meter, or 1.


I sometimes work in units where 4 pi equals 1.


If you want to know why curl and time derivatives commute, you can go down to the math department and ask them. In the class, the answer is because I told you they commute.


There’s a k in here, but of course I work in units where k = 1.


And this becomes a sum on – God help us – on q one prime.


What is the most important sign in physics? “Dot-dot-dot.”


If you don’t prove these at least one in your life then you go to hell, you will not get to the heavens.

(About the Cauchy-Schwartz inequality)


You cannot stop me from choosing this gauge, no matter how hard you try.


At this point in your sad lives, when you see an integral like this, your first thought is to complete the square. I am sorry it turned out this way, but there’s nothing I can do about it, you have to deal with it.


3x3 matrices should only be handled by Mathematica. Humans can only handle 2x2 matrices.


There are various theorems that tell you maybe this thing doesn’t exist. I’m just going to ignore this.


We are now going to do “monkey math.”


I’m just giving you a number. I don’t want you to say that I never gave you a number in this course.


Don’t be shy about calling me out on things, I’m notoriously bad at this.

(Said about solving a separable ODE)


This is called a bullshit integral.


Pedagogy

One of the most important jobs a physicst has is to train the next generation of physicists. It is also the job they are the worst at.


The reason I am teaching you this is because it’s beautiful and totally useless.


You might have heard of spin in your undergraduate.
You might have heard of Schrodinger’s cat before.
Many of you have seen [the hydrogen atom] in undergraduate.

(Three statements made at different times in a graduate-level quantum mechanics class)


I don’t like this textbook.

(About the textbook assigned to the class)


I can’t stand the way this book is structured.

(About the textbook the professor wrote and assigned to the class)


The book really sucks. (Looks at the printed out page for a few seconds). This is really stupid, I would not do it this way.


Where do we go to look for things? Wikipedia.


Of course, I will not make you derive this metric because I do not want to write the solutions.


I’ll use my classic tactic of saying “I’ll get back to you on that,” and then never get back to you on it.


I may be using a lot of words to try and convince you of something you already know.


My dream is to one day give a lecture where every variable is the same symbol.


So again, I will teach a class to only 3 students.
More people should show up.
Yeah, more people usually show up. I’m just insecure.


I have two minutes, that’s just enough time.
[…]
In the -1 minute I have left I will write the solutions.


(Professor:) What is the first thing you do when you are faced with 10^27 particles?

(Student:) You approximate?

(Professor:) No, you run. But maybe you are frozen with fear.


(Professor:) What is the definition of a conductor?

(Student:) A conductor is where the electric field in the materi-

(Professor:) A conductor is something that conducts electricity.


I have deflected your question successfully.


We want to describe crystals in a way that is more complex than a sine function. I could teach you about lie algebras and you would understand nothing about crystals. We need an approach that is less general than that. That has a name and unfortunately it is called chemistry.


If you think you know what momentum is, you’re wrong.


Next class I’ll teach you how to calculate cross sections. That’s part of the course, unfortunately you have to learn to do something that is useful for everybody.


If we do not fourier transform before the end of class, sue me.


I’m doing a little fudge here, so if you catch it, keep it to yourself. The true argument is mutch harder.


Alright guys, it’s happening.

(Takes off jacket and proceeds to wipe the whiteboard with it.)

Some of you may remember when I wiped the board with American bread. Then I ate it.


I used to use a Stargate analogy, but nobody has seen Stargate anymore, so instead I’m going to use Portal.

(Explaining reciprocal space)


Student: Are you going to return the first midterm before we have to take the second one?

Professor: No.


As a physicist, I see in momentum space. I don’t see you sitting in this classroom, I see the scattering pattern caused by the seats in this classroom.


The periodic potential comes from the dirtiest science, chemistry…

Actually, next week two people from the college are coming to inspect my teaching for my promotion… and one of them is a chemist, so I’ll see if I can keep my jokes to a minimum. I think they sent her on purpose.


This is great time to make a cultural note about french bread.

(When introducing the density of states in 3D)


Have I ranted about American vs French cookbooks before?

(Introducing two particle interactions)


You need to read the question before you grade the answer.


Sorry it’s so technical but you have to do a calculation, you can’t just be a tourist.


Don’t believe me when I say shit like this. But in a sense, it’s correct.


I got this question wrong ten times, and there’s only two possible answers.


Theory

Theoretical physicists bring order to the chaos of data that experimentalists obtain. Not only can they explain what happens, they can predict new things, making their research a guiding light for others. All in all, they make fantastic quantative finance employees.


If you’re fighting a demon, you need another demon. If you have two demons, they cancel out.

(Teaching the hydrogen atom)


Particle physics […] makes no contribution to explaining how the world actually works.


We did our experiment.

(After drawing Feynman diagrams)


This is a toy model, but never say “toy model” in a grant application, because they’ll tell you that they aren’t “playing” around… So we call this a “testbed.”


We don’t know the real origin of mass. Yeah, the Higgs mechanism… That is Mickey Mouse stuff. Nobody knows the real story.


It’s spaghetti. Topological spaghetti. Toppo-logic Spaghet.


“You said you had a field theory?”

“Yes.”

“Well, what does it look like?”

“What?”

“Yeah, what does it look like?”


It’s like france, you know. The hexagons.

(When drawing graphene)


Where the fuck are the electrons?


Now we come to the internationally accepted definition of a crystal: something that in momentum space is a sum of delta functions.


Majorana fermions – or Marijuana fermions as one of my colleagues calls it.


This term is minus infinity, and the next term is plus infinity, and the next term is minus infinity, and so on. When you sum all of these terms, you get 0.026.


What is topology? I have no idea. All I know is what it says on Wikipedia.


Condensed matter physicists borrowed some ideas from particle physics, finally useful, to solve an actual problem.


Everyone cannot just sit with their feet up smoking a cigar and thinking big thoughts… you have to back it up with calculations.


Experiment

Experimentalists do the work of an engineer for a tenth of the pay. Some do it out of love, or dedication, but most do it because they didn’t know where else to go besides graduate school.


Of course stupid, crystals exist, we do not need to justify studying them.


I love specific heat measurements, because you can say whatever you want.


Liquid nitrogen is cheaper than beer.


If you raise the magnetic field, you will kill the butterfly.

You can also kill the butterfly by raising the temperature of the sample.

At 2 kelvin, the butterfly is gone.


What exactly is the bubble? We already know that in the bubble there are wings that correspond to spin-correlated half metals.


The mirrors are scanned at one of two velocities (“slow” and “fast”) and over one of two lengths (“short” and “long”).


The data are sorted, “deglitched,” “averaged”, calibrated, averaged again, and “descripted” by a series of programs.


It’s now how short your pulse is, it’s what you do with it.


Alice and Bob have no way of communiciating, so Alice cannot say to Bob, “You better measure spin up or else we won’t get our grant.”


We can charge an extra $20,000 for our laser system if we can claim the shorter pulse lengths from autocorrelation.


You know they milk the shit out of astrophysics. They say “with LIGO we understand more about chemistry.”


When people visit an ultrafast optics lab, the first thing they ask is “How short is your pulse?” There are obvious analogies to this, but I won’t go there.


I always like to think of my magnetic field as a very big knife.


This is highly toxic. One milligram will kill a graduate student; PIs will survive.

Sociology

Like all sciences, physics is ultimately made up of people. Jealousy and respect, fame and obscurity, rivalry and collaboration: all of these human aspects affect the study of physics almost as much as the actual world does. Of course, everyone denies this. Not because they don’t believe in it, but because we will never give the social “sciences” an inch.


I’m more groupie to Feynman than to Dirac.


Chemists failing to predict the band structure of graphene is the single biggest failure in the history of the science.


You can see the citations going down. This one only has 960, that’s kinda crazy.


Fermi surfaces are to solid state what Taylor Swift is to pop culture.


As we all know, atoms are for chemists and chemists are not very creative. They have to see tiny metal balls.

Actually, this joke should have been directed to the material scientists. I apologize to the chemists.


Brillouin Zone = Las Vegas

(Written on the board)


What I wrote was on the front page of reddit for 4 days, it was even ahead of the Victoria’s Secret sexiest model contest.


Why do people study physics? Some people study physics because it is beautiful. Really, this is a philosophy of science question. The actual motiviation to study physics is to be as lazy as possible. This is why French citizens make such good physicists.


The world is separated into two groups: mortals and those who study quantum mechanics.


Anything is a harmonic oscillator if you’re brave enough.


If you have two operators that commute, then, then … It’s like winning $100 in Vegas. It’s not a lot, but it makes you want to play more.


Stark was definitely a Nazi.

(When introducing the Stark effect)


When you try to use a microscopic hamiltonian to describe a MAGA rally, you see that something fundamentally new has emerged.