Marcus Spradlin
Assistant Professor of Physics:
Physics
Phone: +1 401 863 1468
Marcus_Spradlin@brown.edu
Professor Spradlin is interested in string theory and its applications to particle and gravitational physics. In particular he studies dualities equating quantum gravity to ordinary quantum field theories similar to QCD, which describes the strong nuclear force binding quarks together inside of protons and neutrons. Professor Spradlin explores the implications of dualities and exploits these insights to develop novel calculational tools, aiming towards a mathematical solution of QCD.
Biography
A.B. Princeton University 1996
Ph.D. Harvard University 2001
Research Description
One of the most exciting developments in string theory in the last decade has been the discovery of dualities relating various string theories to each other or to ordinary quantum field theories. These dualities provide new ways of thinking about important long-standing problems in theoretical physics, such as the problem of quark confinement in QCD or the problem of understanding the quantum microscopic degrees of freedom of black holes. In certain cases dualities enable some of string theory's powerful tools to provide precise quantitative understanding of some aspects of strongly-coupled Yang-Mills theories. These methods are widely viewed as being the most promising road towards a solution of QCD.
Much of my recent research has focused on exploiting string theory to develop tools for understanding the structure of supersymmetric Yang-Mills theory. In 2002-2003 I studied a certain limit of the Yang-Mills theory where one focuses on states with very large charge under an R-current of the supersymmetry algebra. In the dual string description, these states correspond to a sector of the string theory which can be solved exactly at infinite N (the number of colors). Volovich and I initiated the study of light-cone string field theory in this context to understand the structure of 1/N corrections, which correspond to string interactions, and formulated the precise rule for extracting gauge theory quantities from the string theory calculation. In a paper with He and Schwarz we derived analytic expressions for the matrix elements of the tree-level light-cone string field theory Hamiltonian which are exact to all orders in the effective gauge theory coupling constant, although we showed with Klebanov that there exist new effects which cannot be recovered by perturbation theory on the gauge theory side.
More recently my work has focused on twistor string theory, another fascinating example where insights from string theory have shed light on the mathematical structure of gauge theories. In 2003 Witten conjectured that some interesting properties of scattering amplitudes in Yang-Mills theory could be understood as arising from an equivalence between this theory and a certain string theory in twistor space. Roiban, Volovich and I showed that Witten's proposed string theory indeed encapsulates, in a mathematically fascinating way, the entire tree-level S-matrix of Yang-Mills theory. This was a genuinely `stringy' calculation and provides the best evidence that there is some kind of string theory underlying perturbative Yang-Mills theory.
Looking forward, I continue to explore the implications of string theory dualities, in whatever guise they may manifest themselves, and wherever possible exlpoit them to develop new quantitative methods useful for studying quantum gauge theories and quantum gravity.
Honors and Awards
Department of Energy Outstanding Junior Investigator Award, 2007
Richard B. Salomon Faculty Research Award, 2008
Affiliations
N/A
Funded Research
Department of Energy Outstanding Junior Investigator Award Mathematical Structures in Gauge and String Theory.
Grant amount -- $210,000. 2007-2010.
NSF PHY-0638520, String Theory Applications to Particle and Gravitational Physics.
Grant amount -- $120,000. 2006-2009.
NSF PHY-0714747, Northeast Regional String Theory Conference Program.
Grant amount -- $5,000. 2007-2008.
Curriculum Vitae
Read Marcus Spradlin's full Faculty Research Profile.
