Words of wisdom
Dr. Mohapatra has to be one of the most quotable professors I've ever taken a class from. So compiled here are snippets of "wisdom" and humor and dorkyness that I felt the need to write down at the time, most from 624, some from 851:
Of course, you go to more realistic theories [models] and life gets more complicated, but you don't do that in public. You lock yourself in a room, put on air conditioning and do it.
Of course real ultimate things are never true
Let me check my notes... (stops lecturing and flips through lecture notes) It says 'you are on my own'
We never calculate the effective action. If we could, we would be superhuman. And we know we are not.
Anybody know Grassman? Well you don't know him, he lived 300 years ago, say 1708. He was a schoolteacher all his life and applied for a university job and they asked for a letter of recommendation. The letter said he did good things, but in a messy way. He did not get the job
This will raise a few eyebrows. But we are not using our eyebrows here, so that is OK
When you don't understand something, give it a big long german name. Are you familiar with bremstrahllung?
Formulate things in terms of things you know, not what you don't know.
Physicists are familiar with things they are familiar with.
If it makes sense, tell everyone. If it doesn't, well, you don't say anything.
You cannot be older than your grandmother
The building burns down, we run out. We don't run out beforehand. Though that may be a good idea.
(This was wednesday) The material which I wrote all over the board last year. Last week? Monday.
They're just numbers, they don't change. When you are in an airplane you count 1 2 3 4, not 1' 2' 3' 4'
I don't know why someone invented the minus sign. It just confuses everything.
There are 26 letters in the English language, pick one. How about "new"?
I want to leave 5 minutes early... so then I hopefully won't miss my plane.
We define nothing as something... something with 0 momentum and energy
You might see books where they associate a_k with e^ikx, but that is because they have chosen the wrong metric.
In this class we will set hbar=c=1. If anything confuses you, just set it to 1.
You don't want to get your PhD without a good course in quantum field theory... or not really a good course.... a course in field theory.
If you find an interaction which violates CPT let me know right away.
In physics we need rules. Otherwise things become unruly.
And those of you who aren't here... Well, those of you who are here should tell those who aren't.
We thought Lambda = 0, so the ultimate theory would be supersymmetric, but it turns out Lambda != 0, so we still think the ultimate theory is supersymmetric.
-ve = negative. as opposed to +ve = positive
That I skipped through. I skipped about 25 lines.
Can you see both sides of the board? Not at the same time! One at a time: you see this side, then you look over there.
I want to go slower [today]. Not because I didn't do much over the weekend, but so you can catch up.
Student: So we haven't even touched psi yet? M: You want me to touch it? Here *pokes blackboard*
You see a green sheep and say all sheep are green. Another possibility is that the sheep is simply sick.
(On arbitrary diagrams) You walk in to the class, you walk out of the class. No one knows what went on inside.
You don't want to spend the rest of your life wondering "why did he set that to 0?"
This is really the meat of this course. Unless you are a vegetarian. Then it is the something else of this course.
One two three, one two three four. Three is not equal to four, so no.
I will stick with my normalization, and if I were you I would still stick with my normalization. Just stick with my normalization.
(On omitting disconnected diagrams) When you do a measurement you do not look down the beam, you will hurt your eyes.
Written on board: "more loops -> more such things."
I did mumble at one point that we assume this is an asymptotic series.
We did this all last week. And you spent all weekend studying it, I assume. So now you know everything.
Then you go from Feynman rule to physical processes. Well, elementary particle processes. You cannot do cooking with Feynman rules.
(On Reggie Poles) History is mostly useless.
Of course, you go to more realistic theories [models] and life gets more complicated, but you don't do that in public. You lock yourself in a room, put on air conditioning and do it.
Of course real ultimate things are never true
Let me check my notes... (stops lecturing and flips through lecture notes) It says 'you are on my own'
We never calculate the effective action. If we could, we would be superhuman. And we know we are not.
Anybody know Grassman? Well you don't know him, he lived 300 years ago, say 1708. He was a schoolteacher all his life and applied for a university job and they asked for a letter of recommendation. The letter said he did good things, but in a messy way. He did not get the job
This will raise a few eyebrows. But we are not using our eyebrows here, so that is OK
When you don't understand something, give it a big long german name. Are you familiar with bremstrahllung?
Formulate things in terms of things you know, not what you don't know.
Physicists are familiar with things they are familiar with.
If it makes sense, tell everyone. If it doesn't, well, you don't say anything.
You cannot be older than your grandmother
The building burns down, we run out. We don't run out beforehand. Though that may be a good idea.
(This was wednesday) The material which I wrote all over the board last year. Last week? Monday.
They're just numbers, they don't change. When you are in an airplane you count 1 2 3 4, not 1' 2' 3' 4'
I don't know why someone invented the minus sign. It just confuses everything.
There are 26 letters in the English language, pick one. How about "new"?
I want to leave 5 minutes early... so then I hopefully won't miss my plane.
We define nothing as something... something with 0 momentum and energy
You might see books where they associate a_k with e^ikx, but that is because they have chosen the wrong metric.
In this class we will set hbar=c=1. If anything confuses you, just set it to 1.
You don't want to get your PhD without a good course in quantum field theory... or not really a good course.... a course in field theory.
If you find an interaction which violates CPT let me know right away.
In physics we need rules. Otherwise things become unruly.
And those of you who aren't here... Well, those of you who are here should tell those who aren't.
We thought Lambda = 0, so the ultimate theory would be supersymmetric, but it turns out Lambda != 0, so we still think the ultimate theory is supersymmetric.
-ve = negative. as opposed to +ve = positive
That I skipped through. I skipped about 25 lines.
Can you see both sides of the board? Not at the same time! One at a time: you see this side, then you look over there.
I want to go slower [today]. Not because I didn't do much over the weekend, but so you can catch up.
Student: So we haven't even touched psi yet? M: You want me to touch it? Here *pokes blackboard*
You see a green sheep and say all sheep are green. Another possibility is that the sheep is simply sick.
(On arbitrary diagrams) You walk in to the class, you walk out of the class. No one knows what went on inside.
You don't want to spend the rest of your life wondering "why did he set that to 0?"
This is really the meat of this course. Unless you are a vegetarian. Then it is the something else of this course.
One two three, one two three four. Three is not equal to four, so no.
I will stick with my normalization, and if I were you I would still stick with my normalization. Just stick with my normalization.
(On omitting disconnected diagrams) When you do a measurement you do not look down the beam, you will hurt your eyes.
Written on board: "more loops -> more such things."
I did mumble at one point that we assume this is an asymptotic series.
We did this all last week. And you spent all weekend studying it, I assume. So now you know everything.
Then you go from Feynman rule to physical processes. Well, elementary particle processes. You cannot do cooking with Feynman rules.
(On Reggie Poles) History is mostly useless.