Laughlin shares Nobel
Prize; four in a row for physics
BY DAVID SALISBURY
Within hours of getting a pre-dawn call from the Royal
Swedish Academy of Science, the fourth Stanford professor
to win the Nobel Prize in physics in as many years was
using the award as a forum for public support of
research.
Robert B. Laughlin, professor of physics and applied
physics and the Anne T. and Robert M. Bass Professor in
the School of Humanities and Sciences, said he wants the
public to understand that nature is a wonderful thing
that has many surprises. He also wants people to know
that providing tax money to scientists to enable them to
make fundamental discoveries about nature is vital.
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"I owe a debt of gratitude to the taxpayers in my
parents' generation," Laughlin told a roomful of
reporters and well-wishers, including his mother, wife
and son, at a news conference Oct. 13 in Tresidder Union.
"I accuse my generation of not living up to their
responsibility to support basic research for future
generations."
Laughlin shares the 1998 Nobel award with Horst L.
Störmer, a professor at Columbia University and Bell
Laboratories, and Daniel C. Tsui, a professor at
Princeton University. All three scientists worked
together at AT&T's Bell Laboratories in the early
1980s.
In a 1982 experiment, Störmer and Tsui discovered
that the electrons in a semiconductor could be forced to
behave like a liquid made of quasi-particles, with only
one-third of the electrical charge of individual
electrons. That was something no one had even dreamed was
possible.
Although it is unlikely the phenomenon known as the
fractional quantum Hall effect will ever have any
practical applications, Laughlin said it has important
cosmological implications.
When he was pressed to expand on its significance,
Laughlin turned on the professorial charm.
"You have ordinary particles, obeying ordinary
quantum mechanical laws, in ordinary conditions, that
behave in unprecedented ways," he said.
"There are new things everywhere, if only we have
eyes to see them. It is a mistake to think that, just
because you know the microscopic rules, you know
everything."
In what has become an autumnal event on the Stanford
campus, Laughlin faced a room crammed with reporters, TV
cameras, Nobel laureates, colleagues, friends and family.
He expressed his gratitude for the public support that he
said has made his career possible.
"The results being awarded today are the result
of careful investments made by people in the previous
generation," Laughlin said.
SLAC physicist Martin Perl was awarded the Nobel Prize
in physics in 1995, and Stanford's Douglas Osheroff and
Steven Chu were the recipients in 1996 and 1997. Both
Laughlin and Chu have joint appointments in the
departments of physics and applied physics, and both were
recruited to Stanford as a result of the joint efforts of
Alexander Fetter, then chair of physics, and Malcolm
Beasley, then chair of applied physics and now dean of
the School of Humanities and Sciences.
Stanford President Gerhard Casper praised the
cooperation Fetter and Beasley demonstrated, noting that
they "overcame the traditional splits between the
two departments, and got together to recruit top people
like Robert Laughlin."
The Nobel laureate accepted the kudos with
characteristic self-deprecating humor.
"I've made a couple of discoveries in my time,
and let me tell you, it ain't easy," he said to
laughter. "It's much easier to make discoveries that
aren't real, that are wrong."
Earlier that morning, when the call Laughlin said
"every scientist hopes for" had come, the
telephone in the Laughlins' bedroom was not working. So
it was their 13-year-old son, Todd, who answered it on
his own Mickey Mouse phone.
"He came into our room, woke me up, and said,
'Dad, there's some guy from Sweden on the phone who wants
to talk to you,'" Laughlin said.
The new Nobel laureate contended that he took the news
calmly, but also acknowledged that his wife accused him
of screaming after he hung up.
Laughlin's mother, who rushed to his campus home after
hearing the news, told him, "I never thought it
would happen. I thought it was just your childhood
dream."
As reporters and television crews also began to arrive
at his campus home in the early hours of what would
become a long and memorable day, Laughlin took the
attention in good-natured stride.
"This reminds me of a play I saw once, where more
and more people kept coming into this little room."
He answered endless questions from reporters
throughout the day and at one point let slip that a
particle he has studied, called the anyon, once ended up
in an episode of the cult science-fiction television
series, "Star Trek." In the show, the Starship
Enterprise is shot with a beam of anyons, but escapes
unharmed because the anyons don't have any physical
effect.
At a celebratory party on the lawn outside the Varian
physics building later in the afternoon that was fueled
by 24 bottles of champagne, Laughlin was hailed by
colleagues. Chu, last year's Nobel winner in physics,
picked up a piece of curled eucalyptus bark from the
ground and handed it to Laughlin with mock solemnity,
saying that he wanted to "pass the baton."
"Let this be the standard for the rest of the
faculty," Chu added.
"Steve is right," Laughlin shot back.
"I'd love to give this to one of you."
Margaret Martin, Laughlin's younger sister, reminisced
about how he used to build things out of junk in the
garage. Sometimes he melted the wrong chemicals and ended
up in the hospital with burns. And once he built a
television, she said.
"He also took the vacuum apart, just before
someone was going to use it," Martin recalled.
"But. . . he got it all back together again."
That early experimentation may have provided the
impetus that nudged Laughlin into a physics career.
Störmer and Tsui discovered the bizarre effect while
applying strong magnetic fields to semiconducting
material cooled to extremely low temperatures and then
measuring what happens to the electrons flowing through
it.
Their experiment was based on the Hall effect that was
discovered in 1879 and is now a standard tool used in
laboratories around the world to measure the density of
electrical charges in various conducting and
semiconducting materials. In 1980, the German physicist
Klaus von Klitzing discovered that under certain
conditions the Hall effect does not vary in a continuous
fashion, but varies "stepwise" with the
strength of the magnetic field. In technical terms, the
effect exhibited quantum properties.
In 1982, Störmer and Tsui decided to push this effect
to its limits by applying extremely strong magnetic
fields. They hoped to force the electrons to
"crystallize," but found the fractionally
charged quantum fluid instead.
"They pushed the effect into a regime where it
shouldn't exist," Laughlin said of Störmer and
Tsui. "The result was a quantum state without any
precedent in physics."
When they got the effect, Störmer and Tsui knew that
they had discovered something extremely important, but it
was left to Laughlin to explain it. "When I saw
their data I knew that they had found a fractional
charge," Laughlin recalled. So he began writing down
equations to see if he could explain the effect using
quantum dynamics, the rules that describe the motion of
subatomic particles.
"Actually, my first attempt was wrong," he
said. "Fortunately, a referee bounced the original
paper back to me. So I thought about it some more and
came up with a better explanation."
According to the Nobel Foundation, "Through
theoretical analysis [Laughlin] showed that the electrons
in a powerful magnetic field can condense to form a kind
of quantum fluid related to the quantum fluids that occur
in superconductivity and in liquid helium. What makes
these fluids particularly important for researchers is
that events in a drop of quantum fluid can afford more
profound insights into the general inner structure and
dynamics of matter."
Laughlin argues that the effect is an important clue
to the rules that regulate the universe. Our
understanding of the universe is based on an amalgam of
experimental results and physical analogies. Without the
experiments, he said, there is insufficient information
to construct the analogies. So, said Laughlin, the
fractional quantum Hall effect is a breakthrough because
it proves that the ordinary laws of quantum mechanics can
do things that we cannot anticipate.
The discovery may provide an important insight into
the vacuum state, the fundamental unit of space-time. In
classical physics, a vacuum is the absence of all matter.
But experiments with high-energy particle accelerators
conducted since the end of World War II paint a much
different picture. Although it appears empty, the vacuum
state is full of all kinds of matter with strange
properties.
"Vacuum is something like a pane of window
glass," Laughlin said. "It is perfectly
transparent, but when you hit it hard enough, you get
matter, the stuff it is made from, coming out.
"There is a group of us who are very interested
in understanding what this stuff is."
The fractional quantum Hall effect suggests that the
strange properties of vacuum may result from the
collective behavior of particles operating under ordinary
quantum dynamics, rather than consisting of fundamentally
different kinds of particles or new laws.
Laughlin also sees some striking similarities between
the fractional quantum Hall effect and high-temperature
superconductivity, which he has been studying since he
came to Stanford in 1985.
"In both cases you have groups of electrons
behaving in an entirely unanticipated manner," he
said.
The case of superconductivity is more complicated,
however, because scientists must disentangle collective
effects from other important factors.
At the news conference, Laughlin noted that AT&T,
IBM and Xerox were the three companies that once
supported research in basic physics. But all have pulled
out due to stockholder pressure. More recently, Lucent
Technologies has begun trying to put back together what
it had disassembled.
"So the ideal is still there," Laughlin
said.
In contrast to the corporate labs, Laughlin said,
university research is highly political because of the
involvement of the government. He added that federal
officials are "impossible to work with."
"They are control freaks," he said.
"They would not have supported the experiments that
are being recognized by the award being given
today."
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