Jonathan Bagger & Neil
Lambert talk with ScienceWatch.com and answer a
few questions about this month's Emerging Research Front
Paper in the field of Physics.

Article: Gauge symmetry and supersymmetry of
multiple M2-branes
Authors: Bagger,
J;Lambert, N
Journal: PHYS REV D, 77 (6): art. no.-065008 MAR 2008
Addresses: Johns Hopkins Univ, Dept Phys & Astron, 3400
N Charles St, Baltimore, MD 21218 USA.
Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD
21218 USA.
Kings Coll London, Dept Math, London WC2R 2LS, England.

RELATED: View a Research Front Map
from the field of Physics titled:
"
BAGGER-LAMBERT THEORY."

Why do you think your paper is highly
cited?

Our paper presents the construction of a new highly supersymmetric
Lagrangian field theory. This Lagrangian was not previously thought to
exist and enables a definition of the interacting theory of multiple
2-branes in M-theory.

Does it describe a new discovery, methodology, or
synthesis of knowledge?

Coauthor
Neil Lambert

Our result is novel in that it is the first example of a field theory with
a maximum amount of supersymmetry that is not a simple Yang-Mills theory.
One of the new ingredients that we used was the notion that a Lie algebra
should be generalized to something known as a 3-algebra, where the bilinear
commutator of matrices that appears in Lie theory is replaced by a triple
product of matrices.

Would you summarize the significance of your paper in
layman's terms?

The five known consistent string theories are widely believed to be unified
into a single 11-dimensional theory known as M-theory. Relatively little is
known about M-theory, apart from the fact that its low-energy dynamics at
large scales are governed by 11-dimensional supergravity and that it also
possesses additional soliton states known as 2-branes and 5-branes.

A p-brane is an object that has p-extended dimensions; they are now
recognized as playing a very important role within string theory. In string
theory, we know that multiple branes can sit on top of each other and the
resulting dynamics are described by a non-Abelian Yang-Mills gauge theory
on their worldvolume. This construction has been successfully used to embed
the physics associated with the standard model of particle physics into
string theory.

It was known that there should be an analogous treatment of multiple branes
in M-theory. Our work was the first to provide a concrete Lagrangian for
multiple 2-branes in M-theory, an essential first step towards the
development of a complete picture of multiple 2-branes.

How did you become involved in this research and were
any particular problems encountered along the way?

We were both drawn to this problem as we felt that there had to be some
Lagrangian description for at least a part of the theory. Furthermore, we
were convinced that there must somehow be a new maximally supersymmetric
theory that would play this role. The chief technical obstacle to the work
was to understand how the gauge symmetry arose and how it was related to
the familiar gauge symmetries that arise in Yang-Mills theories.

Where do you see your research leading in the
future?

Our main hope for this work is that it will lead to a greater understanding
of multiple branes in M-theory. Most notable would be the development of a
theory of multiple 5-branes.

Jonathan A. Bagger
Krieger-Eisenhower Professor
Department of Physics and Astronomy
The Johns Hopkins University
Baltimore, MD, USA Web

Dr. Neil Lambert
Department of Mathematics
Theoretical Physics Group
King's College London
London, UK Web

Keywords: highly supersymmetric lagrangian field theory,
interacting theory of multiple 2-branes in m-theory, lie theory,
11-dimensional supergravity, non-abelian yang-mills gauge theory,
worldvolume, particle physics, string theory, development of a theory of
multiple 5-branes.