Interview transcript

Professor Veltman, you have long experience of research, teaching and students in the United States, and in Europe, what would you say are the main differences between the United States and Europe in this respect?

Martinus Veltman: The main difference, at least in Holland, I think on the average I got students of a higher level. This is something that you never know for sure and sometimes you get much better students in America as well of course, but on the average, and that’s because of the difference between the American and European system. In America, students get different shares of and the best go to Harvard and the next one goes to Princeton and the next one goes to Yale, and we got sort of number ten. So that is a pre-selection in America, and in Holland there is no pre-selection, and generally in Europe there is not accepted /- – -/ England. So the consequence is that we got student of which the best we had selected out in America.

What is the difference between being a student today and when you were a student?

Martinus Veltman: Being what?

Being a student today and when you were a student.

Martinus Veltman: The difference now as then? I don’t know, it was less disciplined. In my student time you could do nothing for a few years and then start working again and I liked that a lot, I did do nothing for a number of years.

I’m very strongly in favour of a system where someone can momentarily go out and later on come back again …

But today in Europe that’s no more possible because they stop supporting you and so on, and they make the system such that you cannot do it. I’m very strongly in favour of a system where someone can momentarily go out and later on come back again. For whatever reason. Maybe he’s not mature enough, or maybe he wants to have other experiences. But the present day systems compare as, and that was the way the system was in my time. Today I think that is no more possible, very difficult. Is it possible here in Sweden that you can study for a very long time without you being kicked out of the University?

I don’t really know; can you get kicked out?

In principle you can, but it very seldom happens.

Martinus Veltman: Of course it happens very seldom and it is the one ray of hope in the life of many miserable people!

What is really a Higgs particle?

Martinus Veltman: A Higgs particle is just one of the many particles that are part of the game of the standard model, but the special thing about a Higgs particle and the reason that we are talking so much about it, is because we know which experiments to do to get at it. There are many things in the standard model that we don’t understand, we don’t know why there are three generations, we don’t know why the top quark is so heavy, or the bottom quark, of all these quarks, we don’t know why the towers are so heavy. We know nothing, there are so many of these questions, but we do not know what experiment to do to find an answer to these questions.

Now in the case of the Higgs particle we know what experiment to do to get an answer. We must go to /- – -/ of the order of 500 GeV and then you will have access, you should either make the extr,a see something, so what is special about Higgs I would say is mainly because it’s accessible to experiments. So we’re talking a lot about it, and we know how to make a machine that looks at it, but there are many other questions I would just as well want to know the answer to, except I don’t know how to go about it.

What would be the consequences if this elusive Higgs particle isn’t found?

Martinus Veltman: Well, by all the rules of logic, which I believe do apply in particle physics, we will have to find something, because it has to appear as some sort of a cut off in intervals that we have observed here or there, so we see a /- – -/ correction to which either the Higgs or whatever goes for its contributes, so we know there is something there, unless of course the rules of logic don’t hold any more, then everything stops. So don’t ever say what would happen if we don’t see it, I think that would mean that there’s something wrong with the rules of logic and that we cannot have. So far that’s not the way it works.

I wonder how did you develop your interest in research and physics?

And in physics, you are in another domain, unknown, you are truly an explorer …

Martinus Veltman: I don’t know, like most of us, we go into the domain of particle physics and you start with an experiment and you see results coming, and you find it very exciting discovering new particles and interactions and stuff, and my whole life which started out by looking at a neutrino experiment, and that experiment was a total failure otherwise, but standing there and seeing these events coming and seeing these reaction coming, and try to guess what’s going on, it’s a very exciting something. It’s like entering a domain that no other person has been before. That’s the very wonderful stuff about this. And in physics, you are in another domain, unknown, you are truly an explorer. I liked that very much. It’s a pity that much of what you see today is no more so simple, but at that time that was like that. So that has always fascinated me from the first day that I saw it onwards.

For a student or later in your work?

Martinus Veltman: No, this happened in around 1961 when I got to CERN or ’62 something like that. Before that I did all kinds of stupid theory, you know, /- – -/ theory and operators and commutations, no-one knows what that has to do with experiments. I found it sort of boring but you do it in any case because you think that’s what you have to do, so you do it as sort of abstract mathematics which has little or no relation to the real world, and then some day for some reason you step out and there’s the real world, and you see how it connects. That’s simply is the day where it becomes interesting. It’s the real world which is interesting.

One of the primary goals of physics is to understand the wonderful variety of nature in a unified way, the December issue of the Scientific American has the theme What science will be known in 2050. 50 years from now. Do you share Steven Weinberg‘s … when he says that a unified theory of all forces probably requires radical new ideas?

Martinus Veltman: Well, it’s usually what I find these things very annoying, if not stupid, because there is nothing in nature that says that we should have unifying field series, we could equally well have non-unified field series, that’s up to nature to do it. We don’t know about it. So I don’t know why these people are always talking about united field series. I really don’t know, I honestly don’t know, and the unfortunate thing is that on top of it in the past 20 years or so they have been making propaganda of us having unified the weak and the electromagnetic interactions, but if you look at it, there’s been no unification. None whatsoever. The electric coupling constant is independent of the weak coupling constant so what’s the unification? I honestly don’t know, and the main unification is that you write the laws on the same page.

Other than that I honestly don’t know what is this unification they talk about. It’s SU(2) cross U(1) remember? SU(2) is weaker but actually U(1) is electro magnetism, there’s a cross in between, they are not connected. So I don’t know why they talk about unification. They only do it to sell it, and then they speak about unified field series, because people have been told this so often because Mr. Einstein has been saying these things for a while, but it is, in my opinion, not a correct thing to say.  Nature is whatever nature is. If nature is unified – fine. If nature is not unified – fine too. There is no intrinsic law in physics that says that we should have a unified gauge series, and so far we don’t have any and moreover have no indication of that, and even unification of weak and electromagnetic interactions is a pseudo unification, it’s not a real one, despite what they say.

I wonder is there some other subject that interests you except physics?

Martinus Veltman: That I know about except physics?

No, that you’re interested in.

… beyond physics, well I guess I’m sort of a professional idiot …

Martinus Veltman: Oh yes. We don’t want to talk about that. I used to always to be very interested in electronics and things like that, so it’s sorts of pseudo physics and making computer programs and stuff like that. It’s not always in the same domain. I am not good in things like music or the arts, so there I have, well, I have some interest but I’m not very good at it. So beyond physics, well I guess I’m sort of a professional idiot. Physics, well, and surrounding things in all honesty.

Why, to follow up on that, I mean why is it that you became a theorist, you were sort of quite skilled experimentally when you were young, making all …

Martinus Veltman: These things always happen when you are young, and so when I was six years or something like it, I don’t know it well, a member of my family gave me a box with wires and little lamps and batteries and switches and I started making circuits and switching lamps on and off, and as a little boy I felt that so exciting. And then a little bit later that became electronics and I started working with radio tubes and stuff, and so you sort of automatically go in that direction.

And then a main factor in my life has been the high school teacher of my high school. When I did my final exam he jumped on his bicycle and he drove to the other end of town where I lived and he told to my parents that I should go study physics at University of Utrecht. Had he not done that I would not be sitting here, and it is an example of what a teacher can do. I liked the man very much at the time, and I guess he liked me and he saw something in me. So he did that, he did the extra piece that sometimes somebody does and which has big consequences for your life.

So then I went to the University of Utrecht but that was in those days a very rare thing because you would go to the university only if your parents had a lot of money in those days, and my parents, my father was a school teacher, he was the Head of a primary school, they lived comfortably but they are not rich, so normally they would not dream of sending their son to university. But times were changing, and I think this marked the beginning of the change, so I went to study and we were about 10 or 15 students starting in physics, and when I came back to Utrecht in 1966 those 10-15 students had become 200, so that is where the universities had become popular institutions. Populated by students from everywhere and all segments of life. But in those old days that was a very rare thing. I believe in my village of 20,000 people I was either the first or the second to ever go to university.

Some people say that the 20th century was a century for physics …

Martinus Veltman: Well, it certainly is so far.

… and that the 25th century would be that on biology, what do you think about that?

Research brings you into situations you didn’t know …

Martinus Veltman: I don’t think anything about it because you know perfectly well if you had put such a question to somebody in 1899 he would for sure have given you the wrong answer. He would not have known Max Planck who did his invention the first year in 1900 which changed everything, and this you cannot know. Research brings you into situations you didn’t know. We don’t know what’s going on and maybe physics comes to some sort of a dead end, if we sort of get bogged down in the Higgs sector one way or the other, and if you don’t know how to follow that up then that might be a very hard time for particle physics and it might be another century before we get over that. But you never know. You know it, you have, think of the difference in life that we had when you and I started to know, gigantic difference, and you couldn’t have guessed it. Could we have guessed at ’65 what we have today?

Certainly not.

Martinus Veltman: Certainly not. Three generations, everything.

That’s right, another change that has taken place is a very rapid development of electronic communication and publishing the last few decades, what does it mean to collaboration between people you think, this …

Martinus Veltman: I really don’t know because today I’m retired and I’m no more part of the publicity game. But of course publishing has become a lot easier. You make a manuscript and we all know how to type tech and we submit it to this electronic thing in Los Alamos and whoever wants to have it takes it off, publication has become almost superfluous. I was very astonished that the last time I wrote something, like two years ago or so, and I did send it in to Los Alamos and immediately you get some reaction of people who read it, and after that well it’s done, they get a disc and they, they’ve still got to do a journal but that doesn’t mean too much anymore, the journals have become only sort of archives for what’s going on.

But does it change something in terms of competition between people and groups?

Martinus Veltman: It probably does but I don’t know to what extent. Everything goes faster and quicker and so on, so I have no experience with it, how it is today. I notice that still the same people are accusing the other people of not quoting properly, many things remain as they always were.

I wonder what do you do when you’re not working?

Martinus Veltman: Spare time, what is this?

Doesn’t it exist for you – spare time.

Martinus Veltman: It exists and it doesn’t exist because I was very free all of my life. Most of my life I never had to set an alarm clock, and I would have like two or three lectures a week, and the rest of the time you do research, talk to students, what have you. Now going on retirement, well of course the students have disappeared out of my life, but for the rest it doesn’t change so much. You just, I’m used to keeping myself busy one way or the other, what I do a little bit more today is taking long walks, because you need some movement to keep your body in shape, so I do that for that purpose.

Other than that my life is very much as it was over the past 40 years. It doesn’t change that much. That’s the nice thing about this profession, you know. It would be different if I were an experimentalist because there you need an experimental environment and all kinds of things and I don’t need that, all I need is my hat, and as long as there is no hole in there it’s okay.

You received the last prize of this century. Most Nobel Prize winners of this century are men, do you think that we will see a change in that in the next century and what would be the causes on this dominance of men?

Martinus Veltman: This is a very difficult question because you know that I have a daughter who did her thesis also in this high energy physics, she did her thesis with Mary Gaillard if you know that lady, from Berkeley. So I’ve seen it with my daughter, extra difficult if you are a woman, and they are serious, they’re really serious, that puts an extra degree of complication on your relationship. When you sit together with a man there’s always some tension in the room, in the collaboration, only if you work together with other women that’s not there but then that happens very rarely because there are not enough women. So what happens is that these women are there and they have a problem of finding a good collaboration and well usually there it goes usually wrong one way or the other. It’s very difficult, it’s very difficult. So in a sense they are more isolated than everybody else, because there’s always sex playing a role. You can’t help it.

It’s a major difference between some of the countries in Europe, the southern part there are more women in physics than …

Martinus Veltman: Oh yes. I remember when my daughter tried to get another job as a post doc she got the possibility in the South of Italy but she quickly found out that the man who was running that place used the post docs only to have affairs with. So you don’t go there. Can’t. Your life gets too complicated. Quite apart if you would want it. No I’ve seen that she has extra problems. Problems that I would not have. Of course in my case she has still other problems that whatever she does they say that I did it, you see, because in physics when somebody does something you try to explain why he did it and not you. So there is always where did he get it from if he did something real, and in the case of my daughter, they would always say she really got it from me, you see. So she has this extra thing which is really a pain, and it plays quite a role in her life. Very sad, but it is a fact of life. It made her professional life extra difficult. So the two effects being a female and being my daughter were almost too much to survive this.

What does this Nobel Prize mean to you?

… it means of course appreciation of the things you did in the past  …

Martinus Veltman: Well, that’s often asked of me, but I have no ready-made answer. I think if anything it means of course appreciation of the things you did in the past which I always thought people had more or less forgotten. So I’m happy that they didn’t forget it, what can I say? Every man of course likes to have appreciation for what he did, so in this I’m no different from anybody else. Money wise it doesn’t mean that much to me because I had a comfortable existence anyway. So well it’s nice to be recognised. But after that I think I will go back to my existence and live quietly, so as far as that goes it will probably not make so much of a difference. So to a large extent it’s in your own head. I think that’s right, yes.

Do people ask you questions about physics when you are at parties with non-physicists?

Martinus Veltman: Oh no. No. If they do I may start, but after about two minutes they walk away! No problem! Sometimes I do and I go at it full /- – -/ but it is certainly at a party it’s not possible, just not possible, so you give that up. The only way to do it would be as some organised contacts, give lectures or so, and I plan to do that a little bit more than I did in the past. But in ordinary life we never get to deal with this. Not that I, no, never.

We have talked about the possibilities to find the Higgs accelerators and accelerators is the tool that is sort of necessary to find them, and while we have seen the success of Europe and CERN over the years to be the number one in the world, so how do you think that that evolution can continue? How will the support for that …

Martinus Veltman: It will continue and it is due to something which I am very proud to say I invented.

What was that?

Martinus Veltman: In 1975 I was asked to become a member of CERN’s scientific policy committee, that committee advises the council of CERN as to what they should do in the future concerning physics. So we discussed about the next machine and everything, and experiments and stuff, in other words scientific things, scientific policy. Should we announce this sector or the other, and this in 1975 I was thinking at home for a long time before I accepted this, to become a member of this committee because I thought what have I got to do there? For sure all these people don’t do much and most of it is done by CERN one way or the other, which is true.

But in 1975 me more than anyone else was convinced of the standard model and so I felt we needed to have LEP with as high an energy as possible, and so I decided to go into that committee and I made a programme of three points. Point number one we must have LEP, part number two we cannot go all the times through the traumatising experience of fighting for a new accelerator, making it and then fall back and so on, so I came to the concept of a constant budget. Now at that time we were just at the peak of the SPS budget, we were constructing the SPS and I proposed that we try to tell the governments that they should always keep the budget at this level which would give you some two to three hundred million Swiss francs buffer, I don’t know what it is today, and which you would use exclusively to make more accelerators.

And that was done, and the governments sort of agreed, and so LEP was constructed out of that access and the LAC’s constructed out of that access and the next one probably CLIC will be constructed out of that access too, and if you compare that with the United States they gave us the /- – -/ machine, it went higher and higher in cost til the congress got fed up with it and closed the door. Now they are waiting to come with the next machine which costs eight billion dollars, a linear accelerator, and so they have again we’ll have a very traumatising fight to get that money and if it will work or not we do not know. So I would say that to CERN and to Europe this constant budget has been a major, a very strong, importance, in getting the machines that we have. At least we’ve got two machines, LEP and the LAC, and think after the LAC in due time we will get another one, CLIC.

How do you consider the discussion about the muon collider versus the linear e+ e-?

Martinus Veltman: I’ve looked at them but I’m not too clear about what kind of knowledge they would add and so I can’t really tell you. I have listened to them but I’m not clear about it. Especially the muon collider, I don’t know what it will do.

One of the questions coming in to the website was the following: The electron is supposed to be a point like particle without any dimensions, but still it has a mass, can you therefore consider it as that a little mini black hole?

Martinus Veltman: This question you must not direct to me, you must direct it to ‘t Hooft. You will not get an answer, but it will sound very impressive what he will tell you.

Thank you very much.

Martinus Veltman: I think it’s just a dilemma you have, because in principle a mass concentrated in a point is a black hole. Now the distance where this happens is very, very small so you’d, before you get there it’s a long way off. But there is a method of principle and if ‘t Hooft has some glib answer that I don’t know. I think it’s a problem. It’s the electron or black hole, or the muon or every other elementary particle. So pose it to him. Maybe he’ll say something meaningful. But you have to work at it.

Thank you very much Professor Veltman.

Did you find any typos in this text? We would appreciate your assistance in identifying any errors and to let us know. Thank you for taking the time to report the errors by sending us an e-mail.