NEWS

MARIA SPYROPOULOU

Maria Spyropoulou, just 33 years old, is working at Harvard at the cutting edge of research, with the world’s largest accelerator, Fermilab’s Tevatron. Last September 19, Spyropoulou and Dr Kevin Burkett of Harvard University published a paper claiming that if there are other space dimensions, they would take the form of something smaller than a trillionth of a meter. Spyropoulou hails from Kastoria, where she finished high school with the top grade of 20 in all subjects, but it was physics that really inspired her. When she received a prize from the then-President Christos Sartzetakis and the congratulations of her friends and relatives, she said: «When I go to Harvard, then you can congratulate me.» First she studied physics at Thessaloniki University, then worked in European research networks and later as a technical assistant at CERN, before deciding to cross the Atlantic. So what are you trying to find? For the past 30 years, the question of the basic structure of matter was considered, in a way, resolved by the so-called standard model. However, it didn’t explain all phenomena. For example, if one looks through a microscope at the molecular composition of a table, one sees that there is a lot of «empty space.» Yet when we put a plate on the table, or if we sit on it ourselves, it holds us, we don’t slide down through the spaces. So we see that electromagnetic forces that develop within the table’s matter are much stronger than gravity. But therein lies the problem. Why? Because gravity cannot be so different from the other forces. It is related to them and has to be of similar magnitude. We work with quantum mechanics, and new theories are being developed, such as the SuperChords. The question is that these theories are still only assumptions. We experimental physicists are seeking the evidence to prove them. In what way? A theoretical explanation for gravity is that there are other dimensions beyond the three spatial dimensions and that of time. It is a wonderful theory that talks about 10 to 11 dimensions. In this case, gravitational force appears to be weaker, because it is distributed throughout the other dimensions, while other forces are distributed only through the three known dimensions. How are you looking for these additional dimensions? We are using accelerators, where high energies are developed by causing collisions between microscopic particles. We are seeking the signal of new particles inside the accelerator. To be more specific, we are looking for a collision between a proton and an anti-proton (or quarks and the glutons within them) that will give rise to a graviton, the hypothetical particle of force that carries gravity. The signal In reality, this signal will not come from the presence of a particle, but its absence. We know what the absence of a great quantity of energy looks like. If something like that happens, we will be justified in claiming that this particle has disappeared into the extra dimension. If that happens, you can be sure that we’ll start dancing about. Have you ever felt that you are a hair’s breadth away from discovering something that will change the face of physics? Sometimes, but I have always been disappointed. Nevertheless, you have to keep trying, experimenting, persisting. How close are we to finding another dimension? No one knows. But what is certain is that we have taken enormous steps in recent years. It took us thousands of years to go from the atom to the quark and now we have so many new, impressive ideas. Naturally, the questions being raised are enormous. The expansion of the universe keeps creating a new space-time. Where is it coming from? Or, for example, we talk about dark energy, dark matter. But we don’t know what it is made of. How exciting is it to look for something so small that might answer so many major questions? It is hard to express. Physics is not my job, it is my life. The battle between hope and disappointment is terrible. For me it is far more important to be on the front line of this wonderful battle. And my colleagues are also wonderful. What has been the hardest part of your career? Naturally there have been many obstacles, but strangely, I had a very hard time finishing my degree in Thessaloniki. I had already begun to work on international research programs, but I remember the final courses as being a nightmare. Was the faculty difficult? Very difficult. In my opinion, at the level of theoretical physics, Thessaloniki University, like other Greek universities, is one of the best in the world.