29,195 research outputs found
Quantum mechanics explained
The physical motivation for the mathematical formalism of quantum mechanics
is made clear and compelling by starting from an obvious fact - essentially,
the stability of matter - and inquiring into its preconditions: what does it
take to make this fact possible?Comment: 29 pages, 5 figures. v2: revised in response to referee comment
Decoding the matrix: Coincident membranes on the plane wave
At the core of nonperturbative theories of quantum gravity lies the
holographic encoding of bulk data in large matrices. At present this mapping is
poorly understood. The plane wave matrix model provides a laboratory for
isolating aspects of this problem in a controlled setting.
At large boosts, configurations of concentric membranes become superselection
sectors, whose exact spectra are known. From the bulk point of view one expects
product states of individual membranes to be contained within the full
spectrum. However, for non-BPS states this inclusion relation is obscured by
Gauss law constraints. Its validity rests on nontrivial relations in
representation theory, which we identify and verify by explicit computation.Comment: 43 pages, 2 figure
String Webs from Field Theory
The spectrum of stable electrically and magnetically charged supersymmetric
particles can change discontinuously as one changes the vacuum on the Coulomb
branch of gauge theories with extended supersymmetry in four dimensions. We
show that this decay process can be understood and is well described by
semiclassical field configurations purely in terms of the low energy effective
action on the Coulomb branch even when it occurs at strong coupling. The
resulting picture of the stable supersymmetric spectrum is a generalization of
the ``string web'' picture of these states found in string constructions for
certain theories.Comment: 53 pages, 6 figures; more references adde
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