Science / Medicine : Scientist Pursue a Theory of EVERYTHING

Crisp, white manuscripts are carefully arranged in a row of sharp stacks across the top of his desk. Two shelves of books, their bindings flush with each other, hang on one wall, two small photos on another. All other walls are free of clutter.

Physicist John Schwarz’s Caltech office epitomizes orderliness. And so also, say his admirers, does a theory Schwarz and his collaborators have devised that may solve a problem even Albert Einstein failed to solve after more than two decades of intense work.

Called superstring theory, Schwarz’s idea could be the one that ties the four forces of nature together. It could be the theory that will underlie all theories that try to explain why matter behaves as it does.

It could be as important as Einstein’s theory of relativity or Copernicus’s discovery that the earth revolves around the sun. It could mean, in its most simplistic form, that people, plants, animals, stars, the whole universe are made up of billions of tiny loops.

If it is validated, the theory will cause “a complete change of our view of the universe,” said Caltech physicist Murray Gell-Mann, who in 1972 brought Schwarz to Caltech from Princeton, where the young physicist was a junior faculty member.

Schwarz did not begin his research with the intention of finding what lay observers are now calling the theory of everything.

‘Not On Our Mind at All’

“That was not on our mind at all,” Schwarz said about an early string theory he and French physicist Andre Neveu developed in 1971. Instead, they were attempting to describe the strong nuclear force that binds protons and neutrons inside the atom’s nucleus.

Superstring theory evolved from that research.

Superstring theory remains unproven, and it could be decades before anyone knows whether it is in fact the unified field theory that eluded Einstein and others. Nevertheless, it is creating intense excitement in theoretical physics as physicists and mathematicians who had been otherwise occupied turn their attention to superstrings.

At the heart of superstring theory is the notion that elementary particles--the particles that make up atoms--are not points as scientists have previously assumed. Instead, the theory goes, the particles are shaped like minute looped strings, and as looped strings, they undergo certain kinds of motions.

Until now, physicists have identified various types of elementary particles with cosmic-sounding names such as neutrino and muon. With superstring theory, there is just one fundamental type of particle--a looped string--and a lot of different motions that correspond to the various elementary particles.

Generally, scientists believe there are four forces at work in nature: the strong force, the weak force, the electromagnetic force and gravity. But until now, scientists could not find the important link connecting all the four forces. They could not find the common bond that explained why they worked as they did.

Gravitational Force Elusive

Moreover, though physicists had successfully explained what particles were at work within the strong force, the weak force and the electromagnetic force, they had not been able to adequately describe the particle dynamics of the gravitational force.

Superstring theory appears to do for gravity what other theories have done for the other forces. At the same time, it links all the forces in a complex mathematical package that Gell-Mann describes as a “beautiful, self-consistent scheme.”

Some recent research suggests that there may be more than four forces in nature. So far, this has not affected string research. But if string theory proves to hold for four forces, it is possible that it would hold as well for additional forces.

Today, physics journals are packed with esoteric papers on string theory. Schwarz, who until 1984 worked on string theory in relative obscurity with three different collaborators for 15 years, is in demand as a lecturer around the globe. And in 1987, Schwarz, 45, won a MacArthur Foundation “genius” award recognizing the importance of his work and encouraging him to continue it.

In addition, superstring theory has introduced increasingly complex mathematics into the practice of theoretical physics, much of it unfamiliar to traditionally trained physicists. The theory has been an agent in reuniting the mathematics and physics communities.

‘Pure Math So Far Away’

“Many of us thought that would never happen again. Pure mathematics seemed so far away,” said Gell-Mann, a Nobel laureate.

Some physicists are concerned that intense attention to string theories may be drawing too much research--and too many graduate students--away from other theoretical physics problems.

“Now there’s a whole bunch of people who think superstrings is the core of the subject (of theoretical physics),” Alan Chodos, a physicist at Yale University, said recently.

Yet if it proves to be correct, superstring theory could well become the core of theoretical physics.

Validating the theory, though, could take another dozen years or more as physicists and mathematicians struggle to develop the best mathematical formulation and test the theory. And even then, some physicists doubt that the theory itself will ever be able to undergo direct experimentation. The energy that would be required for such experiments cannot be created with known technologies.

This characteristic has been a focus of unusually harsh criticism by one prominent Harvard theoretical physicist, Sheldon Glashow.

“It’s not exactly a theory. It doesn’t have a beginning, it doesn’t have an end,” said Glashow, who won a Nobel Prize in 1979 for a theory describing the weak and electromagnetic forces. “It’s just math, some of it very good math.”

Began on Blackboard

Glashow’s loudest complaint is that the theory evolved not from laboratory observation or a general principle, as most theories do. Instead, it appeared during long years of mathematical calculations begun by Schwarz in 1969 when he was at Princeton.

Gell-Mann, one of Schwarz’s strongest supporters in the theoretical physics community, irritably dismisses such criticism.

“They’re being silly,” he said of critics during a recent interview at Caltech. “This is not the first time that such a bold extrapolation in energy has been proposed in a fundamental theory of the elementary particles. . . . The first one was by Glashow and his collaborators when they tried to unify electromagnetic, weak and strong forces in the 1970s.”

“I don’t claim and I don’t think anybody claims superstring theory is necessarily correct. It’s just exciting that for the first time in history we have a serious candidate for a completely unified theory,” he continued. “It’s dramatic. Why not solve the equation and see if it’s any good?. I can’t imagine why anybody would be anything but upbeat about it.”

Schwarz built his work on a string theory proposed in 1968 by Italian physicist Gabriele Veneziano. That theory proved almost immediately to be loaded with problems. Most in the scientific community then abandoned string theory.

Four Maintain Interest

Only Schwarz and a few others--including his three principal collaborators over the years, Neveu, Joel Scherk and Michael Green--maintained any interest in strings.

And until five years after he began his string work, Schwarz said, even he did not realize he might be on the path to a theory that would tie all the forces together.

When Scherk and Schwarz published a paper in 1974 saying superstring theory could be the elusive unification theory most scientists had stopped looking for, they were largely ignored.

“It was a little frustrating because we thought it was a good idea,” Schwarz said. “In retrospect, it’s all worked out very well because it meant for 10 years I had the subject pretty much to myself, along with Scherk and Green and a couple of others.”

That Schwarz stuck to superstring research for another decade, despite the disappointing response from his peers, is not surprising, Gell-Mann said.

“He’s a very unusual researcher in our field because he has, through almost all of his career, stuck to this program and not bent so much to the winds of fashion as most people.”

In 1984, obscurity ended when Schwarz and Green discovered some miraculous cancellations of unwanted terms in the superstring equations. It was the most convincing sign that the string theory could lead to something grand.

String Quartet at Work

A few months later, a four-member team at Princeton--commonly referred to by physicists as the Princeton String Quartet--introduced another superstring theory called the heterotic string theory. That theory seems even more promising than his own to describe nature, Schwarz said.

One problem with any of the existing theories is that they suggest the universe has 10 dimensions, although we can observe only four. Schwarz and others are now trying to find solutions to the equations that might describe the shape--or topology--of such unseen dimensions.

Succeeding at that task is a critical step toward proving the correctness of superstring theory.

If that happens, and superstrings prove to be as important as many believe, what will the practical applications be?

No one knows.

It often takes decades for the practical consequences of research to be realized, Gell-Mann said. For instance, Einstein and others suggested principles between 1917 and 1920 that were not used until more than three decades later to produce the maser and laser.

For Schwarz, the practical consequences are almost irrelevant.

“I think the justification of this work is not in terms of the technological fallout, but just that it’s sort of a lofty enterprise of the human spirit to see where we fit into the greater scheme of things,” he said.

“I don’t see any practical, technological consequence of doing this kind of work. In a way I like that fact because I don’t have to worry about anything evil coming out of it. I can work on it with a clear conscience that I’m not going to hurt anybody.”

SOLVING THE PUZZLE OF OUR UNIVERSE

For centuries, scholars and scientists have struggled to explain the forces that control our physical universe--from the atom to the cosmos.

A series of landmark discoveries, from

Newton’s apple to Einstein’s E = mc 2, have peeled away the mysteries of the universe like some Russian nesting doll.

We know there are four fundamental forces:

Gravity--the universal force of attraction;

Electromagnetism--the force that produces electricity and magnetic force; and the two forces that affect only atomic particles: the Strong Force--which binds the particles together and the Weak Force--the slow disintegration of particles.

Atop these scientific building blocks came the emergence of quantum theory. The Electroweak Theory relates electromagnetism to the weak forces of the atom. Further refinements led to Supersymmetry, a mathematically consistent theory which accounts for all the forces of the subatomic and atomic world.

Einstein’s General Gravity (theory of relativity) now explained how gravity related to the structure of space and time. And further research led to Supergravity, which attempts to explain how gravity, the weakest of all forces, relates to Supersymmetry.

But despite all these theories, no one theory can explain why there are electrons, or explains

why there is gravity. The string theory,

which says that vibrating loops are the

essence of all matter, not points or

specks, offers an mathematical explanation

of how all matter--large and small--works.

SUPERSTRING THEORY

‘UNIFIED’ THEORY

SUPERSYMMETRY

This theory suggests that particles that transmit forces and the particles that make up matter are mathematically equivalent.

STRONG NUCLEAR FORCE

The atomic nucleus is held together chiefly by a powerful force called the strong force. This force, effective only at extremely short distances, causes the neutrons and protons in the nucleus to interact and bind together.

ELECTROWEAK THEORY

The theory unified descriptions for both electromagnetism and the weak force.

ELECTROMAGNETIC FORCE

The electromagnetic force acts over short distances, producing both electrical and magnetic forces. It is millions of times as strong as gravity and is the force that binds atoms together

forming molecules.

Electromagnetic theory has many contributors but its beginnings may be attributed to the work of two British physicist, James Clerk Maxwell (published 1865) and earlier, Michael Faraday (published 1846) in their attempts to explain light as an electromagnetic disturbance.

WEAK NUCLEAR FORCE

Known for the transmutation (slow decay of particles) it produces rather than the force it exerts. The force has never been detected directly but is responsible for the decay of uranium to form lead.

SUPERGRAVITY

Theories resulting from attempts to combine Einstein’s theory of gravity with supersymmetry.

GENERAL GRAVITY

GRAVITY

Gravity, the weakest known force in nature, is the universal force of attraction acting between all matter.

Gravitational theory grew from the work of Sir Isaac Newton, first published in 1687. In the early 20th century, Albert Einstein contributed his modern field theory of general relativity making precise applications of the theory possible and advancing conceptual physics., Los Angeles Times

UNDERSTANDING THE SUPERSTRING THEORY

Superstring theory depends upon the belief that other dimensions lie beyond the four we can observe: length, width, depth and time. Theorists believe that when our universe expanded after the ‘Big Bang,’ four dimensions expanded, but six others remained tightly curled, theoretically affecting only the smallest element of matter--the string.

Why can’t we observe or detect these hidden six dimensions? It’s because we live in the larger, four-dimensional world. Let’s say we lived in a two-dimensional world and we tried to observe the movement of a spherical ball. The ball, moving through our flat world, would first appear as a point, then a circle, then a point again. We could not comprehend the ball’s third dimension.

The essence of matter was first believed to be particles or ‘points’. Now it is theorized that matter is made of closed-loop strings that vibrate like a stringed instrument. The interaction of strings joining and splitting apart is thought to be the fundamental mechanism from which all forces of nature flow.

The strings whirl within the six other dimensions on scale call the Planck scale, a scale so tiny that it compares to the atom as the atom compares to the solar system. What would these curled-up dimensions look like? One dimension curled up would form a circle; two would form a doughnut or possibly a sphere. But six? Mathematicians are now theorizing a topology--or shape--that would account for the movement of strings within those dimensions. And such a topology must relate to the movement544171552That movement is what Einstein described as the “space-time” continuum.

In the diagram, time is the horizontal axis; strings enter from the left and leave at the right., Los Angeles Times