Dr. Alexei A. Abrikosov, Argonne Distinguished Scientist,
Condensed Matter Theory Group, Materials Science Division,
Argonne National Laboratory, and winner of the 2003 Nobel
Prize for Physics
Panel Chairman: Dr. Raymond L. Orbach, Director, Office
of Science, Department of Energy
Superconductivity
ORBACH: It is my great
pleasure to introduce to you one of the new, newest,
Nobel Laureates in physics, Alexei Abrikosov. All of
us who have studied superconductivity learned from the
very beginning the Abrikosov lattice. His contributions
to that field and many others are immense and we are
indebted to him for his contribution to our understanding
of nature. Dr. Abrikosov.
ABRIKOSOV: Thank you
for you applause. I will try to be as short as possible.
I’m also going to speak about science but much
more to earth I will say than what we have heard. We
have heard today a lot about various sources of energy.
I am going to discuss another question, namely, the
saving of energy. You see, I have in mind, not switching
off of unnecessary appliances, but much more from the
metal(?) things, namely a huge loss of energy due to
the resistance of wires through which the ...(inaudible)
electric energy is transferred.
And so, therefore, that of course, loss
would be completely absent if we could use superconductivity,
which Ray mentioned. So, what is the problem of using
superconductivity? The main problem is, of course, is
that this phenomenon exists only at low temperatures.
These low temperatures actually increase very much in
the last year and now their highest critical temperature
is 135 Kelvins. That means higher than the boiling temperature
of liquid nitrogen and so, therefore, liquid nitrogen
can be used in cryos ...(inaudible) instead of liquid
helium and that, of course, is a great progress.
However, the materials which have these
properties, layer cuperides(?), they unfortunately are
brittle and therefore they are inconvenient for technical
applications. Despite that, they are really applied
and much more projects are existing with application
of these materials and so on. So the need is very strong.
So, therefore, the question is, what is the future?
What can we say about the future? Is there any possibility
to increase the critical temperature or bring it even
higher than room temperature?
Of course, if that would be possible,
there would be a revolution comparable to the discovery
of fission of uranium. Because in every household there
would be in the devices used there, there would be superconductors.
And in order to do that, we must analyze, how actually
the discovery of new superconductors with higher critical
temperatures, how did it happen? And I had a very interesting
discussion once with Alex Muller who was the person
who discovered the copper oxides, the layer of copper
oxides, which are responsible for the most(?) high critical
temperatures.
So Alex Muller was fascinated by the fact
that some chemical compounds, consisting of barium,
lead, and bismuth and oxygen, that such an oxide had
a rather high critical temperature for those days, 14
Kelvins and, at the same time, they electron density
in this substance, was two orders of magnitude less
than in conventional superconductors. According to the
existing ...(inaudible) Theory, the higher density would
enhance the critical temperature. And so, therefore,
it was not understandable how just the opposite led
to a pretty high critical temperature.
So then Alex Muller, since his whole life
he studied this ferro electrics of ...(inaudible) structures,
he had a guess how this could happen. In order to check
it, he had to find another substance of this kind and
try to change it and so on in order to get the higher
critical temperature. He was extremely lucky because
in France a chemist, Bernard DaVau(?) has discovered
such a basic substance, which could be useful for Alex
Muller’s intentions and that was lanthanum(?)
2, copper 04.
So Alex replaced part of lanthanum by
barium and got the critical temperature of 30 Kelvins.
This opened the field of layer of copper oxides and
led to this high critical temperature. But I believe
that nowadays these substances have exhausted their
potential and one cannot expect radical increase of
critical temperature with these substances. So the question
is how to move further and, you see, I think that many
people have some ideas in this respect. I, personally,
have one also. How to reach even higher critical temperatures,
for example, ten times higher? So, that, of course,
it is simply an idea, a dream, which of the type, what
Alex Muller had. But he was lucky that there was DaVau
who discovered a suitable substance.
Now in order, actually, to follow this,
we must analyze what is happening. Scientists nowadays
want to have fast results. It is the same, except maybe
elementary particle physicists and astrophysicists.
They are not limited in time. But other people are really
limited. They are in rush all the time. And, of course,
the rush does not stimulate such kind of search for
new substances. Even if you have some idea, you have
to search quite a lot.
And so, therefore, I think that this question
is very important for practical applications. So, I
would suggest the following, since we have Dr. Ray Orbach,
yes, so I would suggest the following, maybe it could
be the initiative of the office of basic research in
the DOE or maybe they should-- But anyhow they should
somehow call for the project.
The project should have no promise that
they will indeed discover such a high temperature superconductor.
And the judgments have to be done by the idea, whether
it is reasonable or it is absolutely fantastic. So,
reasonable project of this kind should be funded and
supported. And maybe in this way we can go to high temperature
superconductors, really high temperature, because nothing
limits the critical temperature. There is no principal
limitation. So that was what I wanted to say. Thank
you.
[applause]
Questions and Answers:
ORBACH: The floor is now open for questions.
QUISH: My name is Alan
Quish. I’m a physics professor at the University
of Michigan. One important benefit of the Atoms for
Peace Proposal was the start of exchange visits between
Russian and American scientists and students, especially
in high energy and nuclear physics. This seemed an excellent
and successful example of what Susan Eisenhower this
morning mentioned as her father’s hope that the
Atoms for Peace Program would build good relations between
scientists and students who would later become scientific
leaders and help this, to have better relations between
the two sides of the Iron Curtain. I think this had
worked.
I’ve been involved in this program
since the late 1960s. Unfortunately, this mutually beneficial
exchange was significantly reduced when the now expired
Department of Energy “Min(?) Atom Peaceful Use
of Atomic Energy, Memorandum of Cooperation” was
not signed when it was expired in February 2002. Has
any progress been made in getting this signed again
so this can continue.
ORBACH: I think the question
was addressed at me and not the panel. Would any members
of the panel like to respond to that? (laughter) Yes
there is progress made an, in fact, in today’s
newspaper you will see one of the reasons why that progress
will now accelerate. Thank you.
Are there other questions addressed to
the panel?
GERKY: Bob Gerky, INNEL,
to one of the three panelists. We’ve heard a lot
about, where did the water come from on earth. And I’d
be curious as to what the latest thinking is. There
are some who have said the water on earth has come from
comets. Does that hold any water?
ORBACH: Michael?
TURNER: I’m looking for an astronomer
or planetary side on my left side here but I don’t
see one. Well, it certainly came from the quarks (laughter)
in the Big Bang and it went through the Big Bang nucleus
synthesis. I cannot tell you what the best idea for
where the water on earth came from. I can only tell
you the early origin of water, which is extremely exciting.
__: Is there any reason
that it should have come from any different than all
the rest of the elements that we have here on earth?
TURNER: Well, chemistry
plays an important role in the formation of the solar
system because some of the elements are more volatile
than other elements. So, here on earth we don’t
see the primordial mix. Most of the universe is-- Most
of the atoms in the universe are hydrogen. We certainly
don’t see that here on earth. But the earth’s
gravity isn’t strong enough to hold the hydrogen
and the helium, whereas in the sun and in the giant
planets it’s possible. So, chemistry plays a very
important role in what we see here.
ORBACH: Questions? As
Chairman, then, I am going to take the liberty of asking
my own, which has been driving me nuts for five years.
I would like to ask the panel to speculate on just what
this dark energy is.
TURNER: Well, I think
my son’s idea’s pretty good.
ORBACH: Are we really
that bereft of ideas?
TURNER: No, I think we
are at the phase right now where we need a really crazy
idea. One of the exciting things about science is that
when you get the very toughest problems, they involve
some creative break, thinking outside of the box and
so I tell this to graduate students and undergraduates
and I also put a footnote saying, “Not every crazy
idea is a solution to a profound problem. Some of them
are just crazy ideas.”
The range of things that we’re thinking
about run from something as mundane as the energy of
the quantum vacuum. The problem there is that Jonathan
and his friends can’t calculate how much the quantum
vacuum weighs. When they try to calculate it they get
an absurdly large number before they say it must be
zero.
(Laughter) It could be-- I describe very,
very briefly inflation, speed up in the early universe.
Maybe this is a milder form of inflation. And an idea
that I really, really like, because it seems crazy enough
to be correct is that there is no dark energy; we just
don’t understand gravity. And that a theme, again,
that Jonathan was talking about, was that this marriage
between gravity and quantum mechanics will require a
modification of general relativity. If you’d ask
Jonathan and his colleagues five years ago where that
modification would be, they would say, “Oh, it
is going to be at very, very short distances. It’s
not going to affect the cosmos.”
But you never know where the clues are
going to come from and this could be the clue that tells
us about how we have to modify general relativity. And
so I think that the solution to this problem that we
go back and look at Jonathan’s paper and find
in page five that there is a two that should have been
a 1.5. I think it’s that we find something out
very profound about matter, space, time and energy.
BAGGER: Mike is completely
right about that. I showed a graph, which showed quarks
and leptons and so forth, but that is really just a
schematic for a whole structure which allows you to
do calculations that are tested at experiments to better
than a tenth of a percent level. And that whole structure
completely breaks down on the subject of dark energy.
As Mike was saying, if you use that, basically, you
calculate that the dark energy should be infinite and
in particle theory if it is infinite, well, maybe it’s
zero; you missed something.
The fact that it’s not zero and
it’s not infinite, is something that is just completely
beyond anything that we can understand and so something
brand new has to happen and we just don’t have
a clue what it is.
ORBACH: Are there other
questions?
__: Well, it is sort
of a comment. I’m an experimenter so I don’t
really believe much of anything that can’t be
measured. There was an article in Scientific American
within the last year and I’m bad with names so
I forget the guy’s name but he proposed a good
solution would be to have a very small extra term to
Newton’s Law that deviated from it at large distances.
As far as I know there is no direct experiment that
shows that you can’t have something which would
only cause 1020 deviations from Newton’s Law nearby.
And a bunch of my theory colleagues dumped
on me and started explaining why that couldn’t
work but I think it is something to look at.
__: The problem is that the violence that
you have to do to the theory has to be consistent with
that suite of precisions measurements that you have
made so far. And so that imposes constraints. You have
to be consistent. Yet, I agree. The answer has got to
be crazy. So there is not much wiggle room but there
is a hole somewhere and we have to find it.
ORBACH: I think one has
to be careful of empirical fits. I mean you can play
games with the laws but why, and are the microscopics
behind them was my response with I read the article.
It was certainly a clever argument but it doesn’t
answer anything. In the same way that the cosmological
constant can change the sign and it gives you expansion,
it doesn’t tell you where it comes from and that
is what these gentlemen have been struggling with. But
you actually said something, Michael, that was quite,
and, again, Jonathan, quite extraordinary. You believe
that the structure of general relativity may be inaccurate.
TURNER: Well, certainly
in science we know that in any give point in time, our
description of the natural world is just an approximation
and what’s exciting about the scientific process
is that it is never over. Newton wasn’t wrong;
he just didn’t get the whole story. Einstein’s
theory encompasses-- In science successive theories
eat their predecessors whole if we are doing our job
right. And so, Einstein just didn’t get the whole
story. He got a big, big, chunk that we’re still
trying to swallow. We’re still trying to understand
black holes and their meaning and we’re still
trying to understand the Big Bang.
But I think if you took a poll among physicists,
I think most of us would say, Einstein didn’t
get it all. He did not have the last word on gravity
and we have more to learn and we’re looking for
clues and maybe the cosmic speed-up is a clue to tell
us which direction to go.
BAGGER: Also it’s
quite possible, that because ...(inaudible) constant
is related to the extra dimension, because it’s
a question of how our four-dimensional world is embedded
in this higher dimensional space, it could be just related
to that as well. Again, we don’t know.
ORBACH: In the spirit
of experiment, can you give us some clues as to how
these extra dimensions might actually be observed?
__: Well, in particle
physics, everything is a particle. So, actually, if
they are the right size, the could be seen as a set
of new particles that-- New accelerators like the LHC,
or they could be seen through deviations from Newton’s
Laws and table top experiments, depending exactly on
what variety of new dimensions we are talking about
or they might be so small that they are only seen indirectly
here or there. We don’t know.
The great advance in the last few years--
Previously, people thought that these extra dimensions
had to be so small that, well, you basically can’t
see them. But recently theorists have figured out how
they can be infinitely large and you still wouldn’t
know that they’re there. And so the story is wide,
wide open.
ORBACH: Further questions?
Yes.
DOWNEY: Jim Downey, again,
at Harvard. And I would have to say I’m not much
of a string theorist except for what it involves in
tying my shoes. My question is a follow-on to that.
It seems from what I have read about string theory that
one of the flaws is that it’s heavily on the word
theory and that experiments to validate it are extremely
limited. I’m wondering if we have to find multiple
universes or if we can be comfortable at some point
with the fact that this may, in fact, be the only universe
that ever was.
__: String theory is,
at this point, so-- It’s so early in the development
of string theory that one can’t even say, really,
what it predicts. How it connects to experiments, we
don’t know. It’s more of also a paradigm
at this point, than an actual precise theory with predictions.
We’ll have to see. Time will tell how it fits
in, how it is detected, if it’s detected.
__: To comment on your multi-verse possibility,
I think what intrigues people are the questions that
string theory addresses and the mathematical beauty.
Then if you marry string theory with this idea of inflation
that I was talking about, you could have had multiple
Big Bangs and the rules, what we call the laws of physics,
the local bylaws of physics, could be different in the
different inflationary events and so the universe could
have a structure that is infinitely larger than we can
imagine and, if this is so, this would be a breakthrough
on the same level of Copernicus getting us out of the
center of the universe and the idea that there a multi-verse
structure would bring us back down to earth.
As you say, we can’t test that yet.
So it’s this intriguing idea because the hallmark
of science is testability. And so I think even you find
the string theorists who are desperate to find little
ways to test the theory because you have to test these
ideas in science.
__: Is that idea giving
up this universe-- There are billions of universes and
this one is the way it is just because it is? Are we
giving up to say that?
__: Well, you’re
talking about the anthropic principle, which I’m
not a fan of--
__: Well, it’s related to what you
are saying.
__: If the universe has this multi-universe
structure that you asked about, and we’re very
far from saying that, then it’s a fact of nature
that we have to accept. So, let’s wait and see
if we have to accept that fact.
ORBACH: There’s
a book by Martin Reese called The Six Numbers that Determine
the Universe, which raises this question, pointing out
that these six number, which are the cause for existence,
are accurate to an incredible limit for us to exist.
And, therefore, why those six, which forms the basis
for the second book that he wrote, and I refer you to
that.
Burt--
RHICHTER: Burt Richter
from Stanford. The whole history of physics is the history
of metaphysics turning into physics because of experiments.
And right now what we are suffering from is a dearth
of experiments because the experiments are getting more
complicated, bigger, and more expensive. My poor theory
colleagues don’t have any data to anchor them
and so they are floating in the ether multi-verses and
strings and all the rest of that sort of thing.
But sitting up there is one person controlling
the budget of the Department of Energy, another person
controlling the budget in certain areas of the National
Science Foundation and what we’ve got coming along
now are not only things like the LHC, this great accelerator,
but we’re going to have new telescopes, we’re
going to have new X-Ray satellites. And I think in the
next ten or 15 years, I wish it were faster, we’re
going to have some new facts and new facts are going
to bring some of theory friends back from floating around
in the ether to having to make contact, once again,
with the real world and then we’re going to start
to move to a new concept.
__: I hate to dispute. I hate to disagree
with Burt Richter. You’re absolutely right. We
have wonderful possibilities in front of us and we have
a plate that is very, very full and we will have a hard
time getting everything done. But I think what’s
very exciting in this connection between the quarks
and the cosmos, is that this astronomical fact that
the universe is speeding up is not just of interest
to astronomers but it’s of great interest, as
you well know, to your theorists and it may be--
Maybe it’s not the clue that they
wanted. Maybe they wanted the Hink’s particle
first but science is always orderly and so we’ve
go other clues coming in, the dark matter, the dark
energy. But I take you point on the possibilities before
us and finding a way to carry out the experiments and
realize our dreams.
ORBACH: I’m going
to have Rob Goldsten ask the last question.
GOLDSTEN: Since some
areas of particle physics are deferring from making
predictions yet and there are these 17 or 19, depending
on how you want to count them, basic numbers that are
behind the standard theory, we had Roger Penrose come
to Princeton to take the occasion to go after string
theory as being irrelevant. That was kind of an interesting
experience at Princeton. But I asked him this question
and his answer-- And I’m curious how your response
is, what your answer is-- Since we can’t have
a prediction, how about a meta-prediction, so to speak,
a prediction about the predictions. When will one of
these numbers come out of string theory? The first one?
[pause]
ORBACH: Would you like
me to predict when Jonathan will answer this question?
(Laughter)
__: So to speak, a meta, meta-prediction.
BAGGER: To be honest,
I’m not a string theorist. I’m backpedaling
fast. I actually believe in effective field theory.
I’m more like a condensed matter physicist, mucking
around with my effective Hamiltonian of the standard
model and I can look further and see that either great
things coming in the next factor ten in energy. To get
all the way to the string theory scale, is more than
I can imagine. But I can use string theory for inspiration
and to take the big picture of string theory and use
it as a guide, but actually detailed calculations, it’s
like trying to drive, perhaps chemistry from first principles
of quarks and leptons. There are many steps in between.
It may be very hard.
ORBACH: As one of those
guys who mucks around with materials, let me thank the
members of the panel and all of you in the audience.
I think Burt Richter’s plea, that this will come
faster than 15 years, is upon us. We have four to five
more years of operation of Fermilab. These issues, these
new particles, the experiments that have been called
for may well emerge from that. One has, as you saw the
large hadron collider at Cern, the possibility of the
linear collider in parallel. We have in front of us
machines and theories that address the very fundamentals
of our existence. It’s an exciting time to be
alive and I thank you all for joining us this afternoon.