C. N. Yang: Stony Brook Masters Series

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a theoretical physicist Cen Yang was awarded the Nobel Prize in physics in 1957 among a host of other contributions to his field his work with Robert Mills

resulted in Yang Mills Theory considered the basis of modern physics he has crossed paths with the other great minds in his field Einstein and fairy

Oppenheimer and Teller here at Stonybrook The Institute for theoretical physics which he directed for 33 years now Bears his name Dr Young thanks very

much for taking the time I'm very happy to be here you grew up uh in China the son of a mathematics professor yes can you tell us a little about your early

life I was born in central China but uh I grew up in Beijing uh so my primary school years

and uh four years of high High School were in Beijing and in 1937 I was uh 15

years old uh the signo Japanese war started and uh my family moved to southwestern China to a city called Quin

which is uh famous as the end of the Burma Road MH and uh I went to college there in 1945 I was

23 uh I want a scholarship to come to the United States uh so I came arriving uh on November the

24th uh in New York City uh because at that time there were no commercial traffic between China and

the US and the only way for me to come from kumin in southwestern China to the

US was to fly to Kolkata in India and they wait for a boat a ship one of those uh troop transport

ships of uh the American military forces which were used to transport the over million American soldiers in the China

Burma India theater from that area to the United States so I waited for two months in Kolkata for for a birth on one of

those troop transports and uh the ship was about 5,000 tons and we went through the

Mediterranean and the Atlantic Ocean where we got into a storm and I remembered I was vomiting so much and I said to myself maybe this trip is not

worth it but anyway I arrived uh in New York and uh went to Chicago and became a graduate student at the University of

Chicago that was quite a quite an adventure for a young man yes it was and of course uh to come to the United States from a completely different

culture was I wouldn't say it was a shock but it was uh it required some adjustment was it your um your knowledge

of physics that got you U that sort of bridged that that divide uh uh yes I had a very good uh education

both uh in college in kmin and later for two years in the same University as a graduate student earning a master's

degree um my level of Education in China was uh very Advanced uh such things like uh quantum mechanics I've studied uh thoroughly in

China so when I got to the University of Chicago which was uh which had at that time the world's best physics department uh I found that uh the

quantum mechanics course offered in Chicago was not as uh deep really nor as

uh detailed as the course I had in China so I had a head stall in some sense and uh so I earned a PhD degree in Chicago

in 1948 I was thinking that um when you made your journey to the United States it was at about that time that the United

States had dropped atomic bombs on Hiroshima and Nagasaki yes how did that how did that affect you if at all in

your in your field and as a person uh oh it has a profound effect uh you know uh China was fighting the

Japanese invasion from 37 to 45 uh eight years and um uh China was very weak at that time

and uh it was a miserable time and the Japanese uh were very brutal you may have heard of this uh massacre in nin

yes uh so uh and nobody had any inclin that uh there was this uh new weapon developed in the United States

uh in fact I understand most of the people in the US didn't know about it either right and so the morning in

August when the bomb was dropped when the radio announced the news uh it was a great Elation for the people in

China uh because uh everybody knew that's the end of the misery of the eight years of War uh uh I remembered uh

I was uh I came out of uh our house rented house and got onto the street and suddenly I saw many people uh exploding

firecrackers you know in the Chinese custom if you have something to celebrate you you have hundreds of

firecrackers and uh then I got hold of a newspaper and then realized uh what happened uh of course uh that was a

great event for the American people but I would say the American people did not suffer as much during the war as the Chinese people and as a consequence of

that the happiness and the Elation that was felt in China was proportionately higher did you understand the physics

ramifications of of the atomic bomb at that time uh the General Physics uh uh

principle that uh one can generate tremendous amounts of energy by Neutron

collisions uh was known since uh 38 and 39 and uh that in fact even got into

textbooks but uh the detailed uh procedure by which you can uh do that was a very complicated

Engineering Process and uh uh you probably know that uh it was so difficult that the

Germans in about 1944 or 43 decided uh it uh cannot be done

during that war so they abandoned that project uh fortunately they did uh and

the United States it was uh picked up uh first because of a letter iron wrote to president

Rus but more because of uh the fear among the American government and the F phist

especially that the Germans might uh get it first so they devoted the wholehearted effort at Los Alamos to do

this uh it's uh a most important event of course not only for the 20th century

it's one of the great events in the history of mankind you and I certainly don't wish to to U make this all about the bomb but

it's it's it's uh sort of coincidental that you went to Chicago the University where much of this work was done um and

uh one of your mentors there was fairy I believe yes tell me a little about fairy uh enrio fairy was born in two in

1901 in Italy uh at that time Italian physics was not so great and he was a precocious

young man and he alone uh lifted ital the level of Italian physics to World standards at a

very young age uh he was a remarkable person and I

had uh said that uh familyy was a person with both feet on the ground how so uh

in the sense that um he was very solid he looks like he was a solid person and he

is uh when he uh speculates on something you know that uh it was based already on

concrete thought which he had already uh been thinking about therefore his words carry Authority because you know that

these are not the random or of the top of one's head kind of remarks uh and he was a great theorist

as as well as a great experimentalist you know in early centuries uh many great physicists were both theoretical and

experimental but by the 20th century um theoretical physics has gotten so complicated experimental physics has gotten so complicated so

very few people could do both and uh Enrico FY was the last great physicist who contributed first class work

to both sides how was your relationship with him oh very close uh you see when I got to Chicago very rapidly everybody found

that this young man from China was extremely well trained uh so I had a very close and warm relationship with the

familyy uh Mrs FY uh the fies had two kids

and one of them the older one Nella was uh College age so the family is always uh hold a

square dance party in their house and I was there many times and got to know the family uh very

well uh in later on in 1949 uh FY and I wrote a paper together uh it's called our Meson Elementary

particles and I was very happy to see that that paper is still referred to today because uh we were the first to

publish a paper saying that uh what is known as a Pion uh may be a bound state

of a uh nuclear with an anti-nuclear these are probably two technical terms but anyway uh we wrote a paper together

and uh so I was the one of the favorite students of family in Chicago you of course knew uh

Oppenheimer you at The Institute for advanced study with Oppenheimer yes tell me about your relationship with him uh everybody knows that the opah

hammer became very famous because of it uh uh direction of the atomic bomb project during the war and in 1957 47 he

accepted the the directorship of the institute for advanc studies and um in 1949 he came to

Chicago to give a talk about a new uh development in physics called the renormalization I will not uh explain

why what it is but anyway that was the hottest uh topic around that time so I was

fascinated by his talk and I knew that uh starting that fall the fall of 1949 there'll be many experts on

renormalization uh at his Institute in Princeton so I applied to become a post talk at the

Princeton and uh abam accepted me so starting in 49 the four I went to The Institute for

advanced studies I was originally just going to be there for one year as a post do and returned to

Chicago but uh I remained and allog together I was in Princeton for 17 years from 1949 to

1966 and uh as you know the institute for Advance studies was a well-known Ivory Tower in the best

sense of the word their Scholars uh do their research uh without been bothered by committee work without being bothered by

graduate students and indeed I took great advantage of that that was the period that 17 years was the period I

did my best uh research work I I understood that um Oppenheimer tried to uh convince you to replace him when he left the Institute but that instead you

came here to Stonybrook which was barely uh barely peing out of the ground at the time what what what happened there uh yes uh what happened was the following

in 1965 uh first before President Kennedy was uh assassinated uh he

named alamer as the next enrio FY Prize winner

the enrio FY price was a presidential award it was originally awarded to fairy because uh F was Dy and they quickly

created this price and gave it to him before he died in 1954 and afterwards many distinguished

uh people who contributed to the US uh worldtime scientific work got the uh price including beta including

tellor uh Etc and uh probably or very likely because uh president President

Kennedy wanted to uh erase

the Sorrows that the the US Meed out to opah hammer in the opah hammer hearings of

1954 so he decided to give it give the next one in 62 to obah hammer but before that transpired he was assassinated uh

Kennedy was assassinated so then Johnson became president and uh in fact the rumors were that uh many of the people who are

against op Hammer uh tried to convince Johnson not to give that award but the Johnson did not listen to them so there

was a ceremony uh and alamer did win the world so that was uh I think it was 196 63 or

64 but anyway uh that was at the time so by

1965 uh aaham had just uh had this uh uh great event of the United States

uh government essentially saying implicitly we are sorry right and we apologize now upen Hammer is the director of the insute intitute had

great difficulties with the mathematicians in The Institute that's a long story I'll not bother you with the details he was a director but the

mathematics Group which is the strongest uh at the institute at that time and still today uh were unhappy with him in my

opinion uh they were wrong in a accusing uh upen hammer

of uh not favoring mathematics but anyway they made op Hammer's life very difficult for many

years so one day in 65 I remember opah Hammer dropped by my office and said uh

Frank uh I'm thinking of uh retiring as director how do they think about it I was uh surprised uh but I thought about it for

a few minutes and I said uh I think this is a good decision because I said you have been at the institute for a long time now and

this is the right moment because a there is a law in the opposition on the part of the mathematicians against

you and uh In the Heat of great debate it's difficult for you to say I want to retire and secondly the United States government

has essentially apologized to you uh this is the right moment so he thanked me for my

opinion then he said uh I want to propose you as my successor my instinctive reaction

immediately was that uh I don't want to to do it because uh I'm not a administrative type it's

uh uh so I told him I'm honored that uh you thought so but uh I'll think about it for a few

minut for a few days so I thought about it and uh eventually I wrote him a letter saying that

uh uh how I am not sure I'll be a good director I'm however very sure that I

won't enjoy the life of being a director so that's the end of that part of the story but just around that time a little bit uh before my final decision but

after he had mentioned his proposal to me uh John tol who had just become who had just been nominated as the president

of uh stook uh came to visit me and asked me to join him in stook to develop

stook into a uh great research University uh so uh when I wrote that letter to OB

Hammer I had already decided with my family that I'm going to move to stook that was in

65 and you came on the pretty much on the promise that a great research institution would be built here because there was none at the time yes uh you of

course know that um ston began about 50 years ago but it was uh in another

campus and the the real expansion started uh when it moved here and the great expansion started when jto came in

65 and 66 and uh that was a great period of uh expansion and I think uh what you see

today uh have all in many senses originated with the few

beginning steps that uh John to and his uh Administration put in place and that you helped him with uh yes in

some respects you knew also Einstein uh yes I went to The Institute as I told you in

1949 uh he was uh 70 years old at that time and he had just retired but uh he lived close to the Institute and

he would still walk to the Institute every they he he didn't drive and uh he would walk uh to his office and then stay a

few hours and then walk back now uh at that time uh I irance position in physics was towering

it's I had said uh repeatedly that the Newton and Einstein are the two greatest physicists

of all four times and uh but uh he was at that time no longer working on the things that we

were we young people were interested in so we didn't so much uh bother him uh however I did

hear uh two lectures by him and uh in 1951 I

think uh I think 51 or 52 uh he sent his assistant Brewer cman uh to me and said uh you just

published a paper in the physical review uh about uh gas liquid uh how gas became a liquid how upon

Cooling and uh Professor Einstein would like uh to talk with you about the the paper wow so I went to see him and uh we

must have spent an hour and a half together and I was very much Ed by his presence uh I didn't get very much out of that uh conversation I only

remembered he repeatedly drew a curve which was very famous due to Maxwell a great physicist of the 19th

century and uh indeed uh Einstein's uh Einstein was deeply in the tradition of old physics

of classical physics two branches of that uh statistical physics and uh

electrodynamics were his uh great uh fors and uh using this tradition using

his uh deep perception in these two areas he launched the two and a half revolutions for physics

in the 20th century two and a half yes which was the half uh quantum mechanics okay the three revolutions were that's generally

accepted as the greatest revolution in physics uh after Newton it was special relativity general relativity and quantum

mechanics uh special and general relativity were invented by him MH essentially

alone quantum mechanics was the work of many people and so I count that as half a revolution okay by

Iran I I I'm unable to plumb the depths of physics or scale the heights of physics whichever it is um but I wonder if you could explain to us

non-physicists um the Yang Mills Theory

uh you know what the fundamental physics is about is uh to ask uh how

matter uh is put together in the 19th century finally people realized that everything is made

of uh atoms and molecules in the 20th century we learned that the uh molecules are made of atoms atoms are made of

protons and electrons and neutrons but uh what are protons and neutrons made of now we know they are made of

quarks so that is one aspect of what we do namely we want to take matter apart and look at the

constituents but there's another part of the Endeavor namely how these parts are put together the reason that they are

together is because there's a force between them force is in Daily Language in physics we call it the

interaction so the question is what are the interaction between these constituents uh interaction of

force uh it's well known already since Newton's time there's gravitational force and uh through the 19th century we

know there are electric and magnetic forces in the 20th century we know there are two additional kinds of forces they are called nuclear forces which are

responsible for the atomic bomb nuclear forces nuclear forces and the weak forces which are responsible for such

things like radioactivity so there are now four types of forces the question is what are the precise

nature of these uh four types we know that the gravity through Newton is a inverse Square law you probably learned

that in high school physics so you might say that the basic question that uh one of the basic questions one of the fundamental basic questions we face is

how are these three other forces structured they are not inverse Square laws but what are they and that's where

the young M Theory or gauge Theory comes in gauge Theory gives a principle which

uh uh governed how these forces are structured mathematically precisely and uh when M well

originally in 1918 and 1919 stimulated by Einstein Herman v a great mathematician uh proposed what is called

gauge Theory uh he used that to describe uh electricity and magnetism and that was

successful but it does not apply to the other two the nuclear forces and weak forces MH and what Ms and I did was we

generalized what the V did and that becomes a general principle of forces of why they are these forces

including gravity and that principle is now called the gauge principle M and the gauge principles detailed mathematical

structure is what uh we wrote down in 1954 at the time that we wrote it down nobody

believed uh that was it was important and we didn't know it was that important but we said that this is a beautiful idea and the mathematical structure is

very elegant so we published a paper about it and uh then 20 years later various experiments showed that that in fact was approximately the right

direction then after struggling for another five years it became clear that it's not just approximately right it is

exactly right so that became something which uh uh is now the universally accepted principle of how these forces

are formed 1954 yes how do you feel about that fact that

50 years later something that you created that you propounded has been so so fundamentally U has so fundamentally

changed to your field well of course I feel good about it but uh I tell my

students that uh the structure of uh uh everything uh often times has a hidden

uh Beauty in it if you can sense vaguely some of these Beauty uh do not let

go uh the reason that in 1954 Mir and I were able to do it as I told you it was not in agreement with

experiment and nobody believed this but we saw the beauty of the structure so we wrote it down the Elegance of structure that's right it's uh it's a oh by the

way I should add the following uh and that has something to do with stone book uh okay this uh y m theory was

published and uh gradually originally people didn't believe it gradually more and more people see the beauty of it so people began to work on it but it was

only in the 70s that it was confirmed by experiment and uh so by the 60s there

were not many papers but I would say every year there'll be 10 papers 20 papers about

it and uh I came to Stone in 1966 and one day it must be 68 or 69 I was giving a talk I I was giving a lecture no I was giving a course on

general relativity it's a graduate uh course and I wrote down on the Blackboard uh one long formula a famous formula called

the remon tensor Reon was one of the greatest mathematician of the 19th century and Reon tenser has something to

do with the Einstein's gravity Theory so I copied down on the Blackboard the P

this uh long P long formula of the remon tension as I was coping down it suddenly flashed through my mind that the

structure of this uh reong equation is very similar to the equation that Ms and I had written down when we wrote it down

in 1954 we didn't notice uh we were not uh doing general relativity so we didn't notice there was any

similarity but uh that uh Le during that lecture I found that they were very similar so after the class I went to my office and checked in detail and sure

enough they were not just similar they were exactly the same if you define some quantities correctly so I was a bit excited but I didn't understand it and

uh so I went to see Jim Simons Jim Simons as you know was the young department chairman of mathematics at Stone book and he was a great uh

geometer so he knew uh remon in Geometry very well so I went to his office we were still in that old red brick

building both his office and mine so I said Jim uh here's the reing formula that you are

very acquainted very familiar with and uh some years ago M and I wrote this formula look they are very similar and uh he thought about it for a

while he said that yes yes that's it's not strange they are both fiber bunders so I said what's a fiber bundle uh so he

gave me a book uh written by a famous uh princet the mathematician called stin Rod it's

called fiber bundus so I went back with book and uh but the book was impossible for me to understand uh the mathematicians have a tendency to write

very dry uh uh very abrupt statements they are precise but there is

no flesh to it so it's very difficult to it's all bones and is it's impossible to understand so I didn't understand so I

went back to Jim and said look this book is useless for physic but uh we want to understand what this fiber bundle business is

about and uh could you explain to me me what it is he said the fiber bundles is a new thing in mathematics too but earlier than in physics in starting in

the 40s there were already many papers in mathematics in fiber bundles and it's now a important branch of

geometry and so I said uh could you give us some lectures understandable to theoretical

physicist he said yes so he gave a series of lunch lectures uh

very uh informal there may be 10 of us uh faculty and graduate students of uh The Institute of theoretical physics here at

Stonebrook and uh as he must have uh talked for about a a whole month and that was very useful for us so at the

end of that um we decided to give him a gift for this uh uh series of lectures so

we chipped money together and decided uh to buy something for him and I went to Irving CW a

mathematician whom I knew very well I said Irving we want to give a Jim a gift what should we buy he said the Jim

cannot uh spell give him a dictionary so we bought a big dictionary and gave it to Jim and uh he told me

recently that he's still using it but uh what we learned from Jim in those uh lectures were very important

not only for me not only for stoneberg but in fact it launched a new

trend and that came about this way after I understood the gist of uh what the mathematicians were doing with fiber

bunders I realized indeed both general relativity of Einstein M and uh gaug

Theory were fiber bundles so I wrote a paper with TT of Harvard immediately after that in which

we we explain in detail the relationship between the mathematicians ideas and terminology and the physicist ideas and terminology and

so we made a little dictionary the little dictionary had only maybe 15 entries on the left side are

the physicist terminology on the right side all the mathematicians terminology and there was an exact correspondence so we call called it the dictionary but

there's one item which uh physicist used uh repeatedly its technical term is called

source source actually was due to the idea of source was due to Ampere you know the electric Uh current three amp

five amp yes that was named after the great French physicist 19th Cent Empire and uh

uh now in physics Empire's idea of a source was

a crucial concept so we have to have that in our dictionary on the physics part but on the mathematics part I went

to ask Jim what do you call this he said we don't deal with this concept so we left that the blank so it's a dictionary with maybe 15 entries on one side 14

entries on the other side and nothing to correspond to Source yes but then

uh ye singal from MIT a distinguished mathematician came to visit I had known him so I gave him a copy of our preprint

and he looked at it and there's this blank so he thought about it and decided that is a very interesting concept and they should deal with it

they somehow in their 20 or 30 years of dealing with the fiber bundles had never touched on this

idea so he went to England immediately and he was a great collaborator of uh a perhaps the greatest mathematician today

in Great Britain uh Michael AA it's now sir my CR at that time he was not a sir yet and uh so they looked at

it and found that this concept that they never used but we dealt with since ampire was most interesting that became

now a new branch of mathematics so they wrote a paper and because of the prestige and the fame of a teer and

singer many young mathematicians all began to look into this and now it is a thriving branch of modern mathematics

what do they call it uh well there are many names in particular a student of AA called uh

Donan uh did the Pioneer working it so it's called donon Theory but the all those are related to that blank

spot so in some sense you know know in the first half of the 20th century physics and Mathematics were divorced uh in early centuries physics

and Mathematics were in close collaboration but in the first uh half of the 20th century the mathematicians became more and more

abstract they in fact were very happy that they in fact one of them wrote a article saying that the greatest contrib

tion the greatest achievement of 20th century mathematics was that it finally liberated itself from the shackers of

physics that was by a famous mathematician but with this uh fiber BND business uh the mathematicians and the

physics are not coming together again so if you want to say how did that coming together come

about I would say that uh it has something to do with uh me and Jim and that Blank Spot in that dictionary and

with the stoner book so we are very happy that uh Jim continued to be interested in physics and math and you know now he's a billionaire and uh he

just announced he would give her $25 million to St that's great yeah so you I mean you have this is just

another way you have made connections in in your life uh not only connections having to do with matter but also yes uh

yeah interdisciplinary connections as well uh I moved back my former wife passed away in

203 I moved back to Beijing when I was growing up in Beijing as I told you before my father was a Prof professor at the Singa University

in Beijing uh one of the most uh prestigious universities in China and so I grew up on that U

campus uh in 19 in 203 after my former wife passed away I moved back to that campus and now I'm a professor of physics on that

campus and the Jim and Maryland came to visit us in 20 01 that's before my I moved back I was

uh already visiting that campus very frequently and Jim came and uh I remembered uh what happened

precisely after his visit I came back and he came back and I visit him and in his office here in soket I said uh what's your impression

of China oh he said uh he was very happy with the visit he said I figured the greatest

problem in the world today is poverty and here I see 1.3 billion people pulling themselves uh out of

poverty uh by their own bootstraps that's a great contribution not only to themselves but to the world so they deserve uh

our help what do you need so I said uh uh we have many

visitors in Beijing but the housing was lousy uh how about helping us to have some uh visits

housing so he gave a million dollars and now that the complex prices are still cheap in China

so that uh $1 billion sorry $1 million uh is suff sufficient to have

nine very nice Apartments build and is called CH Simon's hall because uh one of his great contributions to math and

physics was a paper he wrote with churn in the 1970s and uh he and Maryland recently went to uh Beijing

and uh open that Hall so I think that uh through the math physics connection uh there is now a Stonebrook

T connection too I wanted to ask you um you mentioned that when you came to the University of

Chicago from China you were you actually already knew some of the things that they were teaching at the time you were

very very well trained how do you U how do you see the uh the differences in education in in in the United States and in China

today that's a very important question and I've been reflecting on that uh I think there are very fundamental

differences and uh these fundamental differences uh show up on each side uh good points and bad

points uh you know that the the newspaper said that President Bush just

uh appointed the uh committee to study how to address the problem of uh

mathematics education in the primary and secondary schools in the United States

why because uh in many many many uh high school student mathematics examinations International

examinations with maybe 30 Nations the US always is near the bottom it's the Asian countries that are at the

top so of course that gets uh the Educators and the mathematicians worried here and that's why this uh appointment

uh why why is it that uh the US uh high school education in mathematics uh is

not as good it's because the whole educational philosophy and system are different the kids here [Music]

are uh are more treated as uh adults even though they were

young in China if you have a eight-year-old uh child and say you should do homework he or she would just

go to do the homework here if you have a eight or nine year old child and you say you should do homework he or she would say I don't

want to do it why not it's uninteresting is boring the concept that doing homework

might be boring does not exist in China so if you ask a child to do it he would just do it is this a matter of

discipline or something uh yes it's a discipline which is in the air so that the concept that that that a child would only do something that he or she is

interested in does not exist so that that's the difference now the consequence of that is that the kids are well trained they do lots of mathematics

exercises okay so that means the Chinese system is good no because if you go to China they're all discussing this Chinese system is no good all the kids

are trained too much a they have no free time and they cannot develop uh other interests B they have the tendency to

become robot-like they don't think for themselves so they are discussing Iden finding item how to change that system to be more like the American

system so after you have observed both these two you realize that this a very complicated thing it's in fact if

President Bush asks me what this mathematics committee can do I would tellar him they won't be able to do

anything because it's not the education system it's the whole society it's the whole value judgment it's whole idea of

how uh you educate the philosophy behind education is different and um so in fact I believe

that all that one can do on each side is to make small changes so as to most of the kids here uh are not uh

interested in mathematics I would say uh that's okay there's no reason for so many kids to be interested in mathematics but the system

must be such that for those who could be interested who could in fact be extremely interested you must provide the opportunity for them to get into it

on the other hand in China I would say that don't train all these kids all the time it it's too straight lighten up

yes uh so the I think a comparison of uh the educational system

the educational philosophy in the orient and in the United States is a very interesting and very deep subject given all that you've said why would a why

would a a student in China come to Stonybrook to study oh mostly

because graduate school in the United States is uh the best in the world today we were talking about in the last few minutes

about primary and secondary schools when it come to graduate education

the the US the best us uh graduate schools are absolutely the best in the world so so uh I always say that uh if

you have a bright uh child the best thing is for him to get a

good high school education in China a college education in China and get a good graduate education in the United

States I myself benefited exactly from that I had a very good college education

in China where the professors are very devoted they are very responsible they lead you through difficult

things uh going to Great depths and uh covering large areas that's why when I came to Chicago I had a tremendous Advantage compared with my fellow

American graduate students uh but on the other hand when I came to Chicago

I learned how to explore the Frontiers how to be creative in your

thinking about the Frontiers problems so I got the best of uh both words and I think that is I was fortunate and I

would recommend that to any young person who especially is interested in the Sciences I think this is a good note to uh to

turn it over to our audience and uh and find out if there are questions u in the audience U if you'd step up to the microphone if you have a question for Dr

Young uh you mentioned earlier that uh as time went on experimental and theoretical physics uh grew apart because of growing complexities within each of them I'm curious how you uh yourself decided which which one to go

into or did it just sort of happen naturally with the work you were doing experimental versus theoretical physics yes how did how did how they grew apart and how did you adapt to that uh no how

did he actually decide to go into theoretical physics how did you why did you decide to go into the theoretical Branch uh as I said experimental and

theoretical physics have both become so complex by the mid the 20th century uh

it's almost impossible to be EXP in both both and as I said the family was the last physicist who made

first grade contributions to both sides now I myself when I came uh to the United States I knew that I had a very

good grounding in theory I also knew that I had uh almost no knowledge in experimental physics so I said I must uh

broaden my educational basis so I decided I should write an experimental thesis here and

uh I so I worked in fact at Chicago for some 18 or 20 month months in the laboratory of Professor Allison Allison

was uh making a at that time a large accelerator it's about the size of this room uh it's a

400 kilovolt of water circuit and uh so he had maybe five or six graduate students and I became one

of them but quickly I learned that I'm no good at uh experimental physics uh when things go wrong I do not

know why they are wrong and uh I of also often times turn the wrong knob and uh do some very bad things to various

things so my fellow graduate students were all a little bit uh worried when I get close to any equipment uh but uh we were on good

terms because uh I could solve theoretical problems for them very easily uh but anyway after 18 or 20

months of work uh I was very frustrated because uh uh Allison gave me a problem and uh the experiment I was doing on

that problem was not uh going well and uh one day tellor came I had uh be in contact with tellor in theory and tellor

said uh I understand your experiment is not doing well I said right he said why do you stick to experiment you had

already written a paper a short paper uh in theory uh I can sponsor that uh as your thesis if you make it a

little bit longer so I said uh thank you very much I have to think about this because it was uh not according to my

plans for so long thinking about it for a few days I finally went back to him and said uh I accept your uh suggestion

and uh that was uh a very important thing in my life namely to learn what I'm good for what I'm not good for any other

questions I have a question because both of stoneberg and chinai University are very great University in the world and as a professor you have taught all of

the students in both universities and how could you how could you compare the students in both of University one is in

America and another is in China thank you comparing the uh the students in China at the college level with the students in America at the at the

college level yes I me undergraduate in undergraduate yeah yes how would you compare undergraduate you spoke of that's a very important uh topic uh

especially since uh I have some firsthand observation um I taught twice in ster book freshman

physics and I taught uh for one semester in 204 uh freshman physics at s University so I have a firsthand

knowledge about the Freshman students in physics here and in

Beijing uh uh T of course is uh one of the most difficult to get into universities in

China and uh so I found that uh there are two differences difference number one is that the students in uh

Chena are almost all very well trained they did lots of exercises in high school so

such things like uh analytic geometry or trigonometry is no problems for them

here uh at least half of my students here were not well trained in analytic geometry or

trigonometry they know the definitions but they cannot manipulate because they didn't do enough exercise so the first difference is that the the

high school training in China is much more rigorous than here the second difference is that

the the students in China in Singa University were very mature and very motivated they

were they knew they have to work hard they sort of uh appreciate uh that

uh what they want to do and they go full force at it for the stoneberg students I would say at least

half of them we still sort of uh wandering around without any specific aim in life this is I have thought about this

this is um again a product of the difference of uh the two societies now you cannot say which one

is necessarily better the Chinese system is better in training

a lot of people who would uh uh mature who would get channed into some uh wake of way of life which would

make them a useful citizens but uh the American system uh is more free and so therefore

the people's outlook on life on everything is uh uh is less

restrictive and uh the best of them are given enough opportunity so that they can prosper look at Bill Gates Bill gas

is able alone to create uh trillions of dollars not for not only for uh his company for the whole world so that kind

of uh uh Innovative Spirit of free spirit is the kind of things that the United States

educational system and Society is uh good at fostering and that's that's true all over the world I think the Europeans

the Japanese all Marvel at the great success of the United States system which produced all these uh uh

tremendous Innovations and as a consequence wealth okay thank you

questions um Professor uh you said uh to sense the beauty is important in the scientific research uh I want to ask uh

whether you have uh any tricks to sense the beauty can you tell us some you said the importance of sensing the beauty or

the the Elegance of in scientific work do you have any tricks uh that help you to uh to spot the beauty or the the

Elegance uh the the direct answer is certainly no

uh I think for a young person it is uh important and that uh the American

system is uh good good for this to allow uh

oneself to be interested in in quite a number of things and uh to

perceive some things some areas uh some directions that he or she is particularly interested

in and and uh if a person at a young age could uh latch on to something that he or she is interested in and uh fully

develop that that may be the way he or she would find the Elegance the beauty

the usefulness of some things uh it's uh the Chinese system is not good for this the Chinese system has

too much of a tendency to impose what the children what the school

what the society want the young person to look at and

uh discourage him or her to Branch out the American system is better in this respect so it's

uh uh uh I think there are good aspects and bad aspects of uh each system when

you choose is to discuss different directions of what you want to

push Dr Yang thank you very [Music] much