A professor of Electrical Engineering, Physics and Astronomy at the University of Southern California since 1980, Martin Gundersen, Ph.D, has had more than a few interests in the world of science. He’s been teaching and conducting research in areas from pulsed power science and technology to lasers, applied plasma physics and quantum electronics. His work has led him to a wide variety of honors and stints at places like MIT, CERN, CalTech and UCLA. An intriguing biographical note is that he has organized workshops with the American Film Institute for scientists interested in writing for TV and film. Fans of Professor Gundersen know that he was the technical advisor for the extensive science and laser scenes in the cult film, Real Genius. But it is not generally known that he inspired the parameters for the academic work and accomplishments of the film’s scheming Professor Hathaway, portrayed by William Atherton. It should be duly noted, it was clearly not Professor Gundersen’s affable (and frequently funny) personality on which the character was based. We caught up with the professor in one of his favorite cities, Monterey, California, to explore how quantum mechanics can be made practical for the general population and other related subjects.
WHAT IS QUANTUM MECHANICS ANYWAY?
Q. Just a quick clarification, what’s the difference between the terms quantum mechanics and quantum physics? Are they interchangeable?
A. It’s mainly just a different usage. The terms quantum theory and wave mechanics along with quantum physics, which implies more broadly the applications of quantum mechanics are interchangeable.
Q. Why do you think there’s more of a focus on quantum mechanics now than before?
A. More and more there are applications of quantum mechanics in devices. Quantum mechanics describes the behavior of electrons in solids such as metals and in semiconductors used to make computer chips and light sources. A critical part of the behavior of the electron is described by quantum mechanics. You have the traditional Newton’s Laws. People remember F=MA or Force equals mass times acceleration. For every action there’s a reaction. People could take a force law like gravity and Newton gave them tools for how to use the force law. You take F=MA, then you plug in the force law and you can calculate what happens. Quantum mechanics is an upgrade of Newton’s Laws and also takes into account the wave properties of electrons and other elementary particles. It’s a deeper tool for describing electrons at the microscopic level that’s necessary to describe the behavior of things. Quantum mechanics by itself isn’t a force. Forces are things like gravity and electricity and magnetism. But like Newton’s Laws, quantum mechanics is a way to take these forces and calculate what happens to things they’re applied to.
Q. Quantum mechanics is relatively new in terms of the world, isn’t it?
A. It really developed in the 1920’s. The dawn of quantum mechanics came with the discovery of Planck’s Constant which Max Planck found necessary to explain a puzzle that traditional physics could not explain. His seminal paper in 1900 wasn’t quite quantum mechanics but it opened that era because it introduced this fundamental constant that shows up in quantum mechanics all the time. Over the next quarter century, people realized that there were these fundamental properties of the electron–for example, that the electron acts like a wave–and the need to describe that led to the development of a quantum theory.
Q. Proportionately, how many scientists deal with quantum theory as compared to those like you, who utilize the principles to create things?
A. According to one survey a couple of years ago, about a third of physicists are engaged in basic research, but only a fraction of those would be fundamental quantum physicists who deal with the theory itself and do ‘why is it and what does it do’ kind of research.
QUANTUM MECHANICS IS ALL AROUND US
Q. For people who feel quantum physics has little relation to their lives, can you give some examples of where it’s part of our everyday existence?
A. The cell phone is one example. The structure of matter is based on quantum mechanical principles that describe how atoms and molecules bind, emit light, form solids and other things. The cell phone is a hugely complicated device comprised of light emitters and transistors and mechanisms for storing information. In such tiny devices, quantum mechanics is part of transistors and light emitters. Another place you run into it is the supermarket check-out stand where they use scanners based on semiconductor emitters.
Q. Oh yes, the laser scanners.
A. And the way the laser operates has some quantum mechanics in it.
Q. Is it the same device when you go to a department store and they scan the UBC code?
A. Yes. Light is emitted when an electron fills an empty space called a hole in the semiconductor. The physics is somewhat complex. It’s involved in the conceptualization and design of light emitting laser diodes.
Q. Quantum mechanics is obviously part of computers.
A. Right. The semiconductor devices have quantum mechanical properties. It’s basically the way electrons move around in semiconductors.
LASERS AND A POPULAR MOVIE
Q. Are you still working with lasers?
A. Yes, but I’m not doing much to improve them these days. We use them as tools. I’ve gone off into other areas of research.
Q. What were you doing with lasers in the past?
A. I was looking for better ways to make infra-red and ultraviolet lasers. One of the MacGuffins in Real Genius that the Val Kilmer character uses to invent his laser was based on ideas we were working on for storing energy and extracting ultraviolet laser light. That’s where the idea came from in a scene in Real Genius. The writers of The Big Bang Theory liked Real Genius because it was sensitive to the science. They recently reproduced some of the white boards that we used in the movie.
Q. Can you explain how you’re using lasers as tools?
A. We’re using lasers as a trigger for a pulsed power switch or we use a light source to trigger it. We’re trying to switch a lot of energy. We use the laser for certain types of spectroscopy. We shine light on something, look at the light that comes out, then we analyze information about what’s going on with the molecules and atoms. We also use it for an optical probe to look at certain types of reactions.
USING SCIENCE TO IMPROVE HOW WE LIVE
Q. A long time ago, you were working on an emissions project for cars.
A. It’s closely related to research we’re doing now on how to influence combustion and emissions, so you can say it’s next generation. In a car you have a spark plug unless you have a diesel. And the spark plug forms a small arc that’s basically like lighting a match–a thermal source that initiates combustion between fuel and air in the cylinder chamber. We’re working on a technique that takes the energy in that spark and compresses it in time from a thousandth of a second to ten billionths of a second. It’s the same amount of energy but in a shorter time. It has a higher electric field so it produces some different reactions that affect the combustion.
Q. And this would improve the quality of emissions ultimately?
A. Yes. We’re exploring that to improve the efficiency of combustion and emissions reduction. We’ve got a serious project on emissions reduction now.
Q. Does quantum mechanics come into play in this project?
A. A little bit. The way the atoms and molecules work is fundamentally quantum mechanics. If you say ‘solve the Schrödinger Equation,’ that’s a quantum mechanics thing you do to try to understand what’s happening. We take information that’s known about molecules and atoms and incorporate it into models of behavior of a lot of things mixed together.
PARTICLES AND ANTI-PARTICLES–AN ENERGETIC LOVE STORY
Q. Aren’t people still trying to get to answers about how things work?
A. Yes. There are still major things that aren’t understood. To give examples—why does Planck’s Constant have a certain value? It’s a number. Why is it that particular number? We don’t know why. Mass of the electron is a certain number. It’s about half a million electron volts. It’s a certain number. Why is it that number? The fundamental charge of the electron is a certain number. Why is it that number? These are things that aren’t answered yet.
Q. I read a question I thought was so interesting: Is it true that electrons pop in and out of existence? And if they do, where do they go?
A. What happens is an electron by itself doesn’t seem to disappear, but an electron and its anti-particle together can appear or disappear. The anti-particle, which is called a positron, was predicted by the Dirac Equation. It predicted the existence of states for the electron that have these anti-matter characteristics. Carl Anderson at Cal Tech observed the positron in the early 1930’s.
Q. Do all particles, all electrons have an opposite or anti-particle?
A. Physics tells you there’s an electron and there’s also a positron. That doesn’t mean for every electron there’s a positron floating around. It means there’s a possibility of a particle called a positron.
Q. It’s not attached to the electron?
A. No, no. You have to make them and they’re not just floating around. There has to be energy sufficient to supply the equivalent of the mass energy of the particle. There are a couple of Nobel-prize winning experiments observing these things. One was called ‘Anderson observing the positron.’ That’s been around for eighty years. Then the existence was postulated for the proton and demonstrated at an experiment at Berkeley in ’59 or ’60. They had a special accelerator called the Bevatron that provided protons with enough energy to crash into other protons. The mass that came out of that resulted in some anti-protons that were observed in a bubble chamber at Berkeley. Owen Chamberlin and Emilio Segrè were awarded a Nobel prize for that. After I finished my Bachelor’s Degree, I actually took a job working on that bubble chamber. I was training to become one of the technicians on it. It was a tremendously interesting thing to do and it was one of the things that impelled me to go on to graduate study and become a physicist who does research.
Q. Before, when you said that particles and their anti-particles are not always together—
A. Probably a good simile would be black and white, sort of opposites. Every time you see black, you don’t see white. You might be in a room where there’s no white, because it’s black. But still there’s the possibility that there’s white some place. It’s a little like that. It’s embedded in the correct equations. For the electron, the Dirac Equation is correct, but the Dirac Equation is very difficult.