Join The Dark Side


Join the department of Physics and Astronomy


Physics is an extraordinairly fulfulling career path. Despite being notoriously absentminded, physicsts are, in some sense, the only people who really know how the world works. And the best part for a young scientist is that not all the rules are known. Physicists contribute to the discovery of the rules governing any phenomina amenible to modeling by math. Historically, physicists have studied the very large exponents (stars, galaxies, astrophysics) and very small exponents (fundamental particles, atoms, nucleai, field theory, particle physics). Currently, physicists are moving more into problems of a human scale such as the workings of proteins in the human body, traffic flow and quantum computing.

Experiment

Experimentalists use equipment worth literally billions of dollars. Fancy cars loose some luster by contrast. Friends at U. C. Riverside use is the Fermilab accelerator, the main tunnel of which is imaged below. They helped to find the top quark which is the sixth, and most massive, quark found to date. Quarks are called fundamental particles because, as far as we know, they cannot be broken into smaller parts. There is good reason to believe the top quark may be the last quark ever discovered

The detectors for this experiment alone are enormous. The image below is of one of the detectors. At the very bottom you can see some people working on them.


An experiment I worked on is the Rossi X-Ray Timing Experiment. I had the privledge of working at UCSD on one of the detectors aboard the XTE. The XTE is being used to find pulsars and accurately determine the timing of them. Since X-rays are mostly filtered out by our atmosphere, X-ray detectors have to be put in orbit to detect X-rays coming from distant stars. Ordinary stars do not produce many x-rays, but certain "dead" or "dying" stars do. Stars produce light through thermonuclear fusion and when this process ends, we say the star is dead or dying. The "dead" states are all very dense. The smallest stars will form white dwarfs, the mid sized stars will form neutron stars, and the largest will become black holes. Below is an image of the XTE. It is roughly the size of a van. The detectors I worked on are visible near the bottom. There are two banks of four detectors. Three of the four on the lower right side are covered in bright orange signs.

The XTE was launched on board a Delta-II rocket in early January, 1996. Below is an artists rendition of the rocket and the payload. You can see most of the space is occupied by the fuel needed to generate the considerable speed needed to keep the XTE in orbit. Two kinds of energy must be overcome for orbit: kinetic and gravitational potential.


Tabletop Experiments

There are smaller scale experiments, such as the NMR experiment imaged below, which do not require huge budgets or large collaborations. I have also had the privledge to work on such a project, with equipment similar to this NMR equipment. My project worked with small low temperature magnetism signals measured over very long times (sometimes up to four days!) Since noise was a major issue, our apparatus was stored underground where it was insulated from electrical signals and vibrations. Also our lab area was not as orderly. One advantage to running your own experiment is that you get to know all the secrets of the apparatus. Thus, you are in a better position to know what is possible and what is not. It makes for a quicker cycle from a new idea to new experiment to new results. However, with increased flexibility comes increased responsibility. When the equipment breaks, you are usually the one to fix it. If it is a professional manufactured piece of equipment, the company can, at times, help out. I enjoyed the freedom of running my own equipment, and the responsibility of fixing it. Since I was the only graduate student in the lab for nearly two and a half years, I had to get help from others frequently just because I needed an extra pair of hands. That is not a typical situation for students. More likely, you have help and guidance from older students for the first half of your time and spend the second half teaching younger students.

Theory

Theoretical physicists explain natural phenomina in terms of equations. Below is an image of perhaps the greatest living theorist, Hans Bethe. He has made contributions to astrophysics, particle physics and condensed matter physics (all three experiments imaged above). His early work was explaining the interactions between the protons and neutrons in the nuclei of atoms. The nuclear reactions in the Sun are an example of this and Bethe helped work out how stars can fuse light elements such as hydrogen and helium into heavier elements such as carbon, nitrogen and oxygen (the so called CNO cycle.) He was awarded the Nobel Prize and in 1967 gave a Nobel lecture on energy production in stars. Bethe also worked on inelastic collisions of atoms, a field called scattering theory. He also worked in condensed matter physics (physics of many interacting atoms) and made significant contributions to that field also. The picture below is from the 1940s. Bethe is alive today and I have had the pleasure of hearing him speak.

The Future

Scientific progress is unpredictable. Great people struggle for years in areas and have little progress to show for it. Some exciting projects on which physicsts have not made much progress for a long time are higher temperature superconductors, a theory for which was awarded the Nobel prize this year (2003), dark energy in the universe (which is still elusive although dark matter may well have been detected it is not enough to explain all experiments) and a unified theory of all forces (specifically, to unify gravity with the other three forces (electromagnetism, strong and weak nuclear forces) which seem to play by different rules.

Yet while these problems have recieved a great deal of attention, there are new problems physicists are beginning to work on which are also not well understood. One new problem to physics is an old problem from biochemistry: why do proteins fold in the way that they do? How can they fold exactly the same way each time on very short time scales and pick the right form out of so many possible other forms? This is a problem we are approaching computationally here at CSUN. Another problem is quantum computing. Eventually the limit to which silicon can be etched will be reached limiting the number of transistors on a single chip and, in some sense, the speed of computers. The exponential growth which we have seen in our lifetimes of the speed of computers will come to an end at some point (such growth always does) but quantum computing may make an enormous leap forward to the power of computers. The speeds achievable with quantum computing are difficult to predict, but may be unimaginably vast.

Physics is an old discipline, but one which is addressing issues of great concern to all people. There is much left to do with so many old questions unanswered and new questions arising all the time. In ten years, cars and personal computers will look and function about the same, but the questions asked in physics will involve concepts we cannot now imagine. It is a pretty good time to be a physicist.