4,390 research outputs found
Anomalously light mesons in a (1+1)-dimensional supersymmetric theory with fundamental matter
We consider N=1 supersymmetric Yang-Mills theory with fundamental matter in
the large-N_c approximation in 1+1 dimensions. We add a Chern-Simons term to
give the adjoint partons a mass and solve for the meson bound states. Here
mesons are color-singlet states with two partons in the fundamental
representation but are not necessarily bosons. We find that this theory has
anomalously light meson bound states at intermediate and strong coupling. We
also examine the structure functions for these states and find that they prefer
to have as many partons as possible at low longitudinal momentum fraction.Comment: 14 pages, 3 figures, LaTe
A Lower Bound for the First Passage Time Density of the Suprathreshold Ornstein-Uhlenbeck Process
We prove that the first passage time density for an
Ornstein-Uhlenbeck process obeying to reach
a fixed threshold from a suprathreshold initial condition
has a lower bound of the form for positive constants and for times exceeding some
positive value . We obtain explicit expressions for and in terms
of , , and , and discuss application of the
results to the synchronization of periodically forced stochastic leaky
integrate-and-fire model neurons.Comment: 15 pages, 1 figur
Heating Up and Cooling Down: Modifying the Provocation Defense by Expanding Cooling Time
This Note argues for expanding the provocationdefense for criminal defendants by broadening theapplicability and recognition of both cooling time andrekindling. This expansion can be accomplished bytransforming cooling time and rekindling into subjectivestandards that focus on the unique internal and externalqualities of the defendant. Doing so would not only beconsistent with the underlying purpose of the defense butalso appropriate considering our modern understandingof the psychological effects of trauma and reactivity toprovoking stimuli. Accordingly, courts should practiceleniency with respect to cooling time and rekindling. Thebest approach to provocation is one that considers theconcept of cooling time as a means of evaluating the factsand circumstances of the defendant’s situation ratherthan a tool to bar the defense. This Note concludes thatbecause the provocation defense results only inmitigation and not acquittal, courts should abandon thecategorical approach to provocation and the objectivestandard of cooling time altogether to allow forflexibility across individual and cultural contexts
N=1 super Yang-Mills on a (3+1) dimensional transverse lattice with one exact supersymmetry
We formulate =1 super Yang-Mills theory in 3+1 dimensions on a two
dimensional transverse lattice using supersymmetric discrete light cone
quantization in the large- limit. This formulation is free of fermion
species doubling. We are able to preserve one supersymmetry. We find a rich,
non-trivial behavior of the mass spectrum as a function of the coupling
, and see some sort of "transition" in the structure of a bound
state as we go from the weak coupling to the strong coupling. Using a toy model
we give an interpretation of the rich behavior of the mass spectrum. We present
the mass spectrum as a function of the winding number for those states whose
color flux winds all the way around in one of the transverse directions. We use
two fits to the mass spectrum and the one that has a string theory
justification appears preferable. For those states whose color flux is
localized we present an extrapolated value for for some low energy bound
states in the limit where the numerical resolution goes to infinity.Comment: 23(+2 for v3) pages, 19 figures; v2: a footnote added; v3: an
appendix, comments, references added. The version to appear PR
Two-dimensional super Yang-Mills theory investigated with improved resolution
In earlier work, N=(1,1) super Yang--Mills theory in two dimensions was found
to have several interesting properties, though these properties could not be
investigated in any detail. In this paper we analyze two of these properties.
First, we investigate the spectrum of the theory. We calculate the masses of
the low-lying states using the supersymmetric discrete light-cone (SDLCQ)
approximation and obtain their continuum values. The spectrum exhibits an
interesting distribution of masses, which we discuss along with a toy model for
this pattern. We also discuss how the average number of partons grows in the
bound states. Second, we determine the number of fermions and bosons in the
N=(1,1) and N=(2,2) theories in each symmetry sector as a function of the
resolution. Our finding that the numbers of fermions and bosons in each sector
are the same is part of the answer to the question of why the SDLCQ
approximation exactly preserves supersymmetry.Comment: 20 pages, 10 figures, LaTe
(1+1)-Dimensional Yang-Mills Theory Coupled to Adjoint Fermions on the Light Front
We consider SU(2) Yang-Mills theory in 1+1 dimensions coupled to massless
adjoint fermions. With all fields in the adjoint representation the gauge group
is actually SU(2)/Z_2, which possesses nontrivial topology. In particular,
there are two distinct topological sectors and the physical vacuum state has a
structure analogous to a \theta vacuum. We show how this feature is realized in
light-front quantization, with periodicity conditions used to regulate the
infrared and treating the gauge field zero mode as a dynamical quantity. We
find expressions for the degenerate vacuum states and construct the analog of
the \theta vacuum. We then calculate the bilinear condensate in the model. We
argue that the condensate does not affect the spectrum of the theory, although
it is related to the string tension that characterizes the potential between
fundamental test charges when the dynamical fermions are given a mass. We also
argue that this result is fundamentally different from calculations that use
periodicity conditions in x^1 as an infrared regulator.Comment: 20 pages, Revte
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