Welcome to the web page of Nergis Mavalvala
I'm on the Physics faculty at MIT. Want to know more about my professional life?
Check out my MIT Physics Department web site.
I work mainly in two fields of physics: (1) Gravitational wave astrophysics and (2) Quantum measurement science. Here you can read about some of the exciting work we're doing in my group, and in collaboration with scientists around the world.
Presently, our knowledge of the Universe comes from observing the light that is radiated by stars; from the spectacular light shows that accompany the explosive births and deaths of stars; and ancient light from the Big Bang itself. But light may not be the only messenger to carry the secrets of the distant Universe to us. Many of these spectacular events also emit another kind of radiation known as “gravitational waves.” Gravitational waves are ripples in the fabric of space and time that were predicted to exist by Einstein in 1916. They are very faint, however, and have never been directly observed. My work involves making instruments called interferometers that are sensitive enough to detect gravitational waves.
So why should we look for these faint and elusive gravitational waves? Directly detecting gravitational waves will open a new window to further our understanding of Universe. Gravitational waves will tell us about Black Holes that gobble up light, but radiate gravitational waves, and about the earliest moments after the Big Bang, when light could not escape the birth throes of the Universe.
The idea of using an
interferometer to detect gravitational waves was proposed by Rainer Weiss and also by
Robert Forward in the early 1970's. The visionary ideas and bold designs
proposed by Rai Weiss, Kip Thorne, and many other
scientists gave birth to the Laser Interferometer Gravitational-wave
Observatory (LIGO) and its international
counterparts (Virgo, GEO600, LCGT, ACIGA). Today, some thirty
years after the idea was first proposed, detectors with the exquisite
sensitivity required to observe gravitational radiation from our nearby
Universe are operating in the high
The LIGO interferometers are 2.5 mile long instruments that use laser beams to precisely measure the positions of mirrors separated by long distances. These measurements can tell us if a gravitational wave is passing by. My work has involved designing and perfecting different parts of this complicated instrument. I began working on gravitational wave detection in the early 1990's when I was a graduate student in Rai Weiss's group at MIT. And I've been completely addicted ever since.
The sensitivity of a detector determines how far into the distant skies it can "see." Over the years, as the LIGO detectors have become increasingly more sensitive in the quest to see ever more distant events in our Universe, the very basic laws of quantum mechanics have become an impediment to the LIGO mission. This problem has fascinated me almost as much as the quest for the elusive gravitational wave itself. So this leads me to the second part of my work: quantum measurement science (and art!).
I lead a group of scientists exploring how quantum mechanics limits the performance of the LIGO detectors. Our goal is to find ways to get around these quantum limits. One example of our work is that we have used laser beams to cool a dime-sized object tantalizingly close to absolute zero, the temperature at which atoms lose all thermal energy and have only their quantum motion. This cooling technique, developed with Thomas Corbitt and Yanbei Chen, forces the mirror to behave like a quantum particle, and could allow us to confirm for the first time that large objects obey the laws of quantum mechanics just as atoms do.
Our work continues to get us closer and closer to the goal of reaching the quantum limit. If we succeed in making the laws of quantum mechanics govern the behavior of human-scale objects, such as the mirrors of a LIGO detector, we would not only increase sensitivity to gravitational waves, but we would also be able to look at the very strange quantum world with objects of far larger size than has been done before. The prospect of being able to watch quantum mechanics in action on objects of unprecedented size is so exciting that many scientists worldwide are working on variants of these ideas (Aspelmeyer, Harris, Kimble, Kippenberg, Lehnert, Painter, Regal, Schwab, Vahala).
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Last modified: Saturday August 21 2010