4,813 research outputs found
Gauge Fields and Space-Time
In this article I attempt to collect some ideas,opinions and formulae which
may be useful in solving the problem of gauge/ string / space-time
correspondence This includes the validity of D-brane representation, counting
of gauge-invariant words, relations between the null states and the Yang-Mills
equations and the discussion of the strong coupling limit of the string sigma
model. The article is based on the talk given at the "Odyssey 2001" conference.Comment: 20 page
Fluid Dynamics of NSR Strings
We show that the renormalization group flows of the massless superstring
modes in the presence of fluctuating D-branes satisfy the equations of fluid
dynamics.In particular, we show that the D-brane's U(1) field is related to the
velocity function in the Navier-Stokes equation while the dilaton plays the
role of the passive scalar advected by the turbulent flow. This leads us to
suggest a possible isomorphism between the off-shell superstring theory in the
presence of fluctuating branes and the fluid mechanical degrees of freedom.Comment: 24 pages Dedicated to the memory of Ian Koga
Functional integral over velocities for a spinning particle with and without anomalous magnetic moment in a constant electromagnetic field
The technique of functional integration over velocities is applied to the
calculation of the propagator of a spinning particle with and without anomalous
magnetic moment. A representation for the spin factor is obtained in this
context for the particle in a constant electromagnetic field. As a by-product,
we also obtain a Schwinger representation for the first case.Comment: latex, 19 page
Novel hard semiexclusive processes and color singlet clusters in hadrons
Hard scattering to a three cluster final state is suggested as a method to
probe configurations in hadrons containing small size color singlet cluster and
a residual quark-gluon system of a finite mass. Examples of such processes
include
where could be a pion(kaon) or other state of finite mass which
does not increase with momentum transfer (). We argue that different
models of the nucleon may lead to very different qualitative predictions for
the spectrum of states . We find that in the pion model of nonperturbative
sea in a nucleon the cross section of these reactions is comparable
to the cross section of the corresponding two-body reaction. Studies of these
reactions are feasible using both fixed target detectors (EVA at BNL, HERMES at
DESY) and collider detectors with a good acceptance in the forward direction.Comment: 9 pages, 2 figures, to be published in the proceedings of the
Workshop: Exclusive Processes at High Momentum Transfer, Newport News,
Virginia, 15-18 May 200
Instability of (1+1) de sitter space in the presence of interacting fields
Instabilities of two dimensional (1+1) de Sitter space induced by interacting
fields are studied. As for the case of flat Minkowski space, several
interacting fermion models can be translated into free boson ones and vice
versa. It is found that interacting fermion theories do not lead to any
instabilities, while the interacting bosonic sine-Gordon model does lead to a
breakdown of de Sitter symmetry and to the vanishing of the vacuum expectation
value of the S matrix.Comment: 7 page
Stability of the U(1) spin liquid with spinon Fermi surface in 2+1 dimensions
We study the stability of the 2+1 dimensional U(1) spin liquid state against
proliferation of instantons in the presence of spinon Fermi surface. By mapping
the spinon Fermi surface into an infinite set of 1+1 dimensional chiral
fermions, it is argued that an instanton has an infinite scaling dimension for
any nonzero number of spinon flavors. Therefore, the spin liquid phase is
stable against instantons and the non-compact U(1) gauge theory is a good low
energy description.Comment: 14 pages, 7 figures, v3) minor corrections, to appear in PR
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