מ. רונן פלסר M. Ronen Plesser
Professor of Physics,
Mathematics, and
Education
Center for Geometry and Theoretical Physics
Research Student
Research Teaching Outreach Contact Curriculum Vitae Personal
My research is in String
Theory, the most ambitious attempt yet at a comprehensive theory of the
fundamental structure of the universe.
In some (rather imprecise) sense, string theory replaces the particles
that form the fundamental building blocks for conventional theories (the
fields, or wave phenomena, we observe are obtained starting from particles when
we apply the principles of quantum mechanics) with objects that are not
point-like but extended in one dimension – strings.
At present, the theory is not
precisely formulated, as we still seek the conceptual and technical tools
needed. The structures we do have in
hand suggest that, when formulated precisely, the theory will provide a
consistent framework encompassing the two greatest achievements of twentieth
century theoretical physics: Einstein’s
general theory of relativity, which
describes gravitational forces objects in terms of deformations of the geometry
of spacetime; and quantum mechanics, a
model of fundamental physics in which microscopic objects exhibit the
properties of particles under some circumstances and those of waves under
others. Both of these theories have
been tested with extraordinary precision and yield predictions that agree with
our observations of the physical universe.
Relativistic effects are manifest at the largest scales in the universe,
in the interactions of stars, galaxies, etc.
The differences between a quantum mechanical description and a classical
nineteenth century description of these objects are so small they can be
neglected. Quantum effects dominate at
the smallest scales – atoms and their constituents. In this realm, the effects of gravitation can be completely
neglected. And yet, under extreme
conditions of density, such as may obtain in the final instant of the
evaporation of a black hole, both kinds of effects are important. A universal theory of physics thus requires
a consistent quantum theory of gravity. Thus far, string theory is the most
promising candidate for producing such a theory. Investigations of this theory have already yielded rich insights,
and continue to produce more.
My own research centers
on the crucial role played in the theory by geometric structures. There is an obvious role for geometry in a
theory that incorporates gravitation, which as discussed above is tantamount to
the geometry of spacetime. Related to
this are several other, less obvious, geometric structures that play an
important role in determining the physics of the theory. Indeed, advances in mathematics and in the
physics of string theory have often been closely linked. An example of how the two fields have interacted
in a surprising way is the ongoing story of mirror
symmetry. A more detailed
description of my research can be found here, and a
list of my published papers here.
Students participate in
my research in several modes. Because
of the very technical nature of the work, most student research is performed by
fairly advanced graduate students.
Currently, two graduate students in the physics department, Sven Rinke
and Ilarion Melnikov, are working towards their Ph.D. under my
supervision. Details of our joint work
may be found on the research page.
Occasionally,
outstanding, highly motivated undergraduates find a way to contribute to this
work. In the past, Mark Jackson and
Chris Beasley have worked with me on their senior honors theses. You can find the theses here. Currently, David Marks, a junior mathematics
major, is working with our group through a PRUV fellowship.
In the fall of
2004 and the spring of 2003, I
will be teaching Physics 342, an advanced
course in quantum field theory.
In the past, I
have also taught introductory astronomy and advanced quantum
mechanics, as well as a graduate class on classical
mechanics. I enjoy sharing my love
of science, and children are my favorite audience. Over the past five years, I have been developing an increasingly
close and productive partnership with Durham public schools, beginning with
Forest View elementary. Together, we
have developed programs that take advantage of the knowledge and resources
available through the Duke physics department to enhance science teaching. This work has evolved into a
broad range of activities involving several schools and a large number
of volunteers from the Duke community. For more details
please contact me, or see here for more details.