For some time, theoretical physicists have been exploring the idea
that the basic building blocks of nature are strings, tiny
vibrating loops. Although there are many theoretical arguments in
support of this idea, the very small size of the strings has made
experimental tests difficult. Under certain conditions, strings
produced shortly after the big bang will grow along with the
expanding universe, so that today they would be of cosmic size.
Such cosmic strings can be detected in various ways. In
particular they emit intense gravitational waves, and could be the
brightest objects visible in the new era of gravitational wave
astronomy. For more information,
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Joe Polchinski has been a Permanent Member of the KITP and a
professor in the Department of Physics since 1992. He received his
B.S. from Caltech in 1975 and his Ph.D. from UC Berkeley in 1980.
He then held postdoctoral positions at the Stanford Linear
Accelerator Center and Harvard, and was a member of the faculty of
the University of Texas at Austin from 1984 to 1992. His awards
include a Fannie and John Hertz graduate fellowship (1975-80), a
National Science Foundation postdoctoral fellowship (1980-82), and
an A.P. Sloan Foundation research fellowship (1985-89). He was
elected a Fellow of the American Physical Society in 1997. In 1998
he completed a two volume graduate textbook on string theory,
which has become the standard text and reference in the field.