STAGES PER STUDENTI DI SCUOLA SECONDARIA
DI SECONDO GRADO
www.lnf.infn.it/edu/stagelnf/

STAGES INVERNALI 2009
2 febbraio - 20 maggio

Ralf Lehnert is researcher at the Universidad Nacional Autonoma de México.

Here is an inteview to Ralf Lehnert by e-mail, in which he tells us about his life and his work.

My name is Ralf Lehnert. I am originally from Dresden, Germany. I have studied physics in Germany and later in the United States. After graduating with a degree in theoretical physics, I worked as a postdoctoral associate in Portugal, the United States, and Germany. Currently, I am a researcher at the Universidad Nacional Autónoma de México in Mexico City. I would like to become a physics professor at a university because I want to combine my two passions: physics research and teaching.

Q: How and why did you decide to study physics and which is the best memory of your life as a student?

My father is an engineer, and when I was a child, he nurtured my curiosity about how things work in various ways. For example, he would build certain toys with me, demonstrate simple fun experiments, and get me hooked on mathematical puzzles. In high school, physics and mathematics developed into my favorite classes, and I participated in competitions in these subjects at the regional and national levels. I became captivated by the fact that a plethora of natural phenomena can be explained with just a handful of general principles using the precise language of mathematics. The beauty of this simplicity and clarity as well as my drive to understand nature and my penchant for rational reasoning have led to my decision to study physics.
I have numerous lasting memories from my time as a student, and it is difficult to single out one particular experience. I enjoyed the freedom and independence as a student: I could devote most of my time to physics, I lived and studied in another country, I made many new friends, I often went to parties, and in the semester breaks I traveled to remote corners of the world, etc. An example of one exciting physics memory involved a homework problem concerned with classical mechanics, buoyancy, and thermodynamics. My theoretical reasoning could not convince my fellow students of the existence of a certain phenomenon related to this problem. However, the set-up was simple enough to device an immediate test in the laboratory, and it worked just as I had predicted. What made this memory so special for me is fact this was no textbook effect and no textbook experiment; for the first time, I had come up with a theoretical prediction and the corresponding experimental test on my own, and both were in agreement!

Q: Which difficulties did you have to face and what was the most exciting episode of your career?

For the most part, I did not encounter major difficulties in my physics studies. The following did require some adjustment on my part and may perhaps be worth mentioning. The pace of instruction at university is much faster than in high school. While the lectures often transmit the feeling that the subject matter is clear, I found that applying the material (e.g., by working problems) is at least as important.
I have had a range of exciting experiences in my career. One example would be my first scientific publication in a physics journal. I had worked on the topic for a few years; several conceptual and technical problems needed to be resolved; and the results were in some cases surprising and others fit very well with the expectations of my advisor. When these results were finally written up, submitted, and published, it gave me a sense of satisfaction and accomplishment. However, I am still experiencing exciting moments: for example, when I figure out the solution to a difficult research problem that nobody else has solved before. Because of the pleasure I derive from physics research, I became a physicist. I think I will continue to enjoy physics, and the most exciting moments in my career lie perhaps still ahead of me ...

Q: What are you working at presently?

My area of expertise is the theory of elementary particle physics. I am particularly interested in one of its cornerstones: Einstein's theory of relativity. Modern theoretical ideas suggest that there could be tiny deviations from relativity theory. My research involves the following: I consider the established conventional equations for elementary particles, which are in harmony with relativity theory. I then modify these equations, such that they describe situations in which relativity is not quite (but almost) valid. I have to make sure that these modifications satisfy certain important criteria, such as internal consistency, consistency with observations, and consistency with other fundamental physics principles. With these modified equations, I can then make predictions about the outcome of any experiment if relativity theory were indeed not quite correct. These results enable my colleagues in experimental physics to identify and design the best possible tests for relativity theory. No convincing experimental evidence for deviations from Einstein's theory of relativity has been found yet, but the experimentalists keep looking closer and closer ...

Q: Which do you believe will be the next discovery in physics?

Every day, quite a few new physics manuscripts become available that present novel experimental results or theoretical ideas. Each one of these often qualifies as a small discovery. I believe that the next key breakthrough with major impact will most likely be an experimental result. For example, there are quite a few experiments underway that have the potential to discover new particles (the LHC and perhaps the Tevatron), gravitational waves (LIGO etc.), or dark matter (e.g., CDMS, CRESST, and DAMA/LIBRA). In my field of expertise, a number of ultrahigh-precision tests of relativity are underway that could reveal a new structure of spacetime at extremely small scales, and I am particularly looking forward to their results. There are also efforts to measure currently unknown properties of neutrinos. However, I think there are also important theoretical problems overdue to be answered, such as high-temperature superconductivity. In any case, I do believe the coming years will be exciting for physicists because of the potential for substantial leaps forward in our understanding of nature at the fundamental level.

Q: In your opinion, which is the best discovery ever and who is your favorite scientist?

It is difficult to give a definite answer to these questions. Certainly, numerous fascinating scientific discoveries have been made throughout history, and I admire a number of scientists. During my university studies, I was particularly intrigued by quantum theory: apart from employing new mathematical tools, this theory requires a novel type of thinking that is in sharp contrast to that of classical physics. But when the mathematics and the concepts are mastered, the beauty of quantum theory becomes apparent. One of my favorite scientists is Galileo Galilei. In addition to laying the foundations for classical mechanics, he also contributed to various other areas of science. But for me, Galileo is a role model in the following sense: he was one of the first to underscore the connection of science to observations and experimentation, a concept so important that it has survived half a millennium! All his life, he remained firmly convinced of his research results, even when facing the threat of the Roman Inquisition.

Q: How important is the collaboration in scientific research, especially among researchers from different countries?

For various branches of research, such as space exploration or experimental high-energy physics, multinational collaborations are a crucial instrument to ensure funding. In some cases, scientific collaborations between countries can also serve as, e.g., symbols for political integration. But besides the financial and political aspects, the primary reason for collaborations is clearly scientific in nature: merging the expertise of different researchers or institutions. I personally enjoy working together with other researchers: the problem can be viewed from multiple angles due to different scientific backgrounds, it helps me to avoid getting bogged down, I learn much faster when discussing research with my colleagues, and often ideas for further research are born. In short, I would say that for me the net effect of collaborating with other researchers often exceeds the sum of the contributions of each researcher.

Q: How can a scientist be defined and how do talent, intuition and study influence his profession?

A scientist is typically a recognized expert in an area of knowledge (e.g., physics, mathematics, or physiology) and is also engaged in a further systematic study of this area using the scientific method. I believe that good scientists possess analytical and critical minds. Talent is definitely another important attribute: identifying your talents can help you selecting a career. But talent alone does not make a good scientist. It is also necessary to acquire in-depth knowledge in your selected field of study, which implies working hard for several years. Intuition is certainly very helpful for scientists. However, I think other personality traits such as curiosity, creativity, abstraction, diligence, objectivity, and persistence are equally important. But the one underlying quality I consider most important for scientists is a desire and inner drive to understand (certain aspects of) nature. Without this drive, it is difficult to be a scientist.

Q: What are your hobbies and passions and what book would you suggest us to read?

In addition to physics research, I enjoy all kinds of outdoor activities, like hiking, camping, and skiing. When I have only little time and need to take my mind off work, I go swimming or running or watch a good movie. Now that I am in Mexico, I want to visit many of the pre-Columbian archeological sites scattered throughout Central and South America and learn about the Aztecs, Maya, Inca, etc. A light thriller-type novel that you might find enjoyable to read is Angels and Demons by Dan Brown. I found it quite entertaining, especially since part of the novel is set at CERN (the largest physics laboratory in world) and the plot even involves physics. However, not all of the physics reasoning presented in the book is correct. Can you find the inaccuracies?

Q: How do you see the future of research in this period of global economic crisis?

The global economic recession definitely has an effect on science; one example is a temporary hiring freeze at a number of universities. For 2009, a decline in overall R&D expenditures in US--the first drop in a decade--has been forecast. One reason for this decline is the fact that part of the research funding comes from industry, endowments, foundations, and private donations, and all these sources are likely to be affected by the lowered interest rates. In other words, I do believe that there are future challenges for research. However, R&D is a cornerstone of a strong and healthy economy. Increased research funding would therefore seem to be one necessary measure to overcome the crisis. In fact, a stimulus package that includes additional federal research funding of almost $ 9 billion has recently been signed into law in the US. So in this sense, the crisis has the potential to provide opportunities for creative outcomes.