I am 18 and I want to be a physicist but I feel sad and depressed when I look at genius child prodigies that are way younger and miles ah…

Answer by David Kahana:

About Jacob Barnett and other so-called genius child prodigies: you might want to read the following article in Skeptic.

The Spark and the Hype


Now, stop comparing yourself with all the child prodigies and genius physicists in history, it's far too long a list: you'll never finish if once you start down this road.

All this mythology about child geniuses is some of the most damaging talk for young intellects that can be found anywhere. You should avoid such discussions like you would avoid the plague. This kind of talk is poison, it will rob all the joy from you.

Here is a fact for you. It's not a myth. Physics is hard to do and mathematics is hard to do.  These subjects are hard for everyone, not just for you and me. They are hard for Jacob Barnett, too.

They are hard because they are fundamentally creative endeavours, just like poetry, or painting or writing are. Creative endeavours all require intense and sustained work as well as a gift for doing that work to become any good or to produce anything good.

But the reward for all that effort is that you'll know it when you've learned something new, and you'll know it when you've done something good. There's nothing like that feeling.

You'll never be a Julian Schwinger – now Schwinger was an authentic child prodigy in physics, I. I. Rabi gave him a problem in quantum mechanics when he was 12 years old and he solved it, but he had to wait until age 18 for Harvard to give him his PhD. So it's probably true, you'll never be a Julian Schwinger if you don't have his gift and motivation at a very young age. But you can go a very long way if you realize that Julian Schwinger had to work just as hard as anyone else, and he probably worked much harder than most, or he would never have done anything at all no matter what his gifts were.

If you doubt that Schwinger worked hard, then I would recommend doing the following exercise. When he was a bit more mature he wrote a very famous paper in which he calculated the lowest order correction to the electron magnetic moment in quantum electrodynamics: he showed it was different from what you expect to get according to the Dirac equation and that the difference agreed with the experiments. Go and look this paper up and have a look through the whole thing. You don't have to check it or follow any of it, you just need to have a look through it, that's all.

I don't mean the two paragraph letter in which he first announced the result and which actually contains a typographical error in it if you look carefully. I mean the paper in which he lays out the theory and gives the actual details of his calculation. The calculation is a tour de force, and what you will find is that it is a massive and an almost completely brute force calculational effort that was all done in the days before anything like Mathematica even existed.

Then, go and look up how the exact same result is obtained by using Feynman's diagrammatic approach. And don't feel any despair when you do any of this: don't think to yourself that you could never have done anything like any of it. Just feel a little bit of admiration for the two of them for what they did and then go on.

It wasn't all easy for Feynman either – he also worked like hell before he figured out his diagrams.

So you need to do the work, and to do the work, you absolutely need to enjoy doing it. The two go hand in hand, they are inseparable.

Concentrate on what you need to do to make yourself into a physicist if that's your goal. It's the work that you do starting now that matters, not what some other people did, or what you imagine that some other people did by the time they reached your age, sometime in the past. There are plenty of very good physicists who were not child prodigies.

You are entering a very hierarchical and competitive profession if you choose to do physics for a living. You need to start to learn do things that will raise your self-confidence rather than destroying it, if you want to succeed. Ideally your studies to come will raise your confidence.

Don't be sidetracked into discussions of personalities and biographies: remember to do the primary thing. Buy a book on a physics subject you're interested in and start learning, start doing problems. Keep on moving.

And another thing, maybe more important than all the rest of it. You're young. You write like a very young man. This is a great advantage!

Physics is not the only thing in life. Go have an adventure, find a girlfriend, throw yourself into something else, preferably something physical rather than intellectual. Strive for a little bit of balance in your life.

There's an old saying from Juvenal: "orandum est ut sit mens sana in corpore sano", meaning: you should pray for a healthy mind in a healthy body.

You should not be studying to write your autobiography at the age of 18, or thinking about how it will all look to posterity. It doesn't make a whit of difference in the long run if you were a child prodigy or you weren't.

You can write your memoirs when there is nothing more interesting for you to do, or tell your biographers how to polish things up for the record, if that's what matters to you as, at the end of a hopefully long and successful life, you drift into senescence.

I can list many friends who were "child prodigies" in many subjects, from music to mathematics. Guess what? The vast majority of them never did anything at all noteworthy. They all vanished into the machine.

Cheer up, for god's sake, and best of luck to you!

I am 18 and I want to be a physicist but I feel sad and depressed when I look at genius child prodigies that are way younger and miles ah…

From Griffiths to Peskin: a lit review for beginners


A nice guide. I am currently following it.

Originally posted on An American Physics Student in England:

a.k.a. “How to get started learning QFT as an undergraduate.”

5 Jan 07: Slight updates (added more details) to a few of the reviews, and an added caveat.

Quantum Field Theory (QFT) plays a key role in all branches of theoretical physics. For students interested in high energy theory, exposure to QFT at any early stage is slowly becoming the standard for top American graduate schools. This is already the case for the Mathematics Tripos at Cambridge.

However, the ‘standard’ American undergraduate physics curriculum doesn’t typically encourage Quantum Field Theory, nor do smaller liberal arts college regularly offer QFT courses. It is often expected that a student will take a second year of ‘graduate’ quantum mechanics before taking QFT.

An inspired student with adequate background should be able to take quantum mechanics in his/her second or third year and then progress directly to a ‘real’ QFT course with a bit…

View original 3,430 more words

A reflection on my study of physics

大学生涯转眼已过两年,观吾物理学习之路,感慨颇多。近日遍寻研究而不得,可谓一憾,自以为与蒋爷当年的差距越来越大,复其之路似无望。不过正因如此,我要走出自己的道路,为自己的theoretical physics之梦而努力。可回顾这两年来物理的学习,颇感不得其法。虽成绩尚可,可是自感学习过程只是机械式的读书,未有太多自己的思考。常自省这点,可是需所学之theory甚多,而无所见至今只是当代物理之皮毛,便只得囫囵吞枣的看书以求知道个一二。恐如此这般,并非是学物理之正道。希望今乘暑假之良机,可调整心态,得习物理之法门。


The first chapter of Shankar

Just finished the first chapter of Shankar, which is truly amazing. Shankar’s introduction to Hilbert space and Delta function is clear and thorough. The material is indeed quite new to me, but I just felt exciting learning all these new concepts. Certainly, I think I need to go back to this chapter later and reread in order to really learn the stuff well.

I have a feeling that this quarter shall be amazing.