1,846 research outputs found
Electric-Magnetic Dualities in Non-Abelian and Non-Commutative Gauge Theories
Electric-magnetic dualities are equivalence between strong and weak coupling
constants. A standard example is the exchange of electric and magnetic fields
in an abelian gauge theory. We show three methods to perform electric-magnetic
dualities in the case of the non-commutative gauge theory. The first
method is to use covariant field strengths to be the electric and magnetic
fields. We find an invariant form of an equation of motion after performing the
electric-magnetic duality. The second method is to use the Seiberg-Witten map
to rewrite the non-commutative gauge theory in terms of abelian field
strength. The third method is to use the large Neveu Schwarz-Neveu Schwarz
(NS-NS) background limit (non-commutativity parameter only has one degree of
freedom) to consider the non-commutative gauge theory or D3-brane. In
this limit, we introduce or dualize a new one-form gauge potential to get a
D3-brane in a large Ramond-Ramond (R-R) background via field redefinition. We
also use perturbation to study the equivalence between two D3-brane theories.
Comparison of these methods in the non-commutative gauge theory gives
different physical implications. The comparison reflects the differences
between the non-abelian and non-commutative gauge theories in the
electric-magnetic dualities. For a complete study, we also extend our studies
to the simplest abelian and non-abelian -form gauge theories, and a
non-commutative theory with the non-abelian structure.Comment: 55 pages, minor changes, references adde
Dimensional Reduction of the Generalized DBI
We study the generalized Dirac-Born-Infeld (DBI) action, which describes a
-brane ending on a -brane with a (+1)-form background. This action has
the equivalent descriptions in commutative and non-commutative settings, which
can be shown from the generalized metric and Nambu-Sigma model. We mainly
discuss the dimensional reduction of the generalized DBI at the massless level
on the flat spacetime and constant antisymmetric background in the case of flat
spacetime, constant antisymmetric background and the gauge potential vanishes
for all time-like components. In the case of , we can do the dimensional
reduction to get the DBI theory. We also try to extend this theory by including
a one-form gauge potential.Comment: 29 pages, minor change
Ethyl 3-{[(3-methylanilino)(1H-1,2,4-triazol-1-yl)methylidene]amino}-1-benzofuran-2-carboxylate
The crystal structure of the title compound, C21H19N5O3, is stabilized by intermolecular N—H⋯N and C—H⋯O hydrogen bonds. The molecule contains a planar [maximum deviations = −0.026 (1) and 0.027 (2) Å] benzofuran ring system, which forms dihedral angles of 78.75 (8) and 39.78 (7)° with the benzene and triazole rings, respectively
6-Allyl-3-(6-chloro-3-pyridylmethyl)-6,7-dihydro-3H-1,2,3-triazolo[4,5-d]pyrimidin-7-imine
The title compound, C13H12ClN7, crystallizes with two independent molecules in the asymmetric unit, each with similar geometries. The dihedral angles between the triazole and pyrimidine rings are 0.45 (9) and 1.00 (10)° in the two molecules. A number of N—H⋯N hydrogen bonds co-operate with C–H⋯N contacts, forming a supramolecular array in the ab plane. C—H⋯π interactions are also present. One of the vinyl groups was found to be disordered so that the C(H)=CH2 atoms were resolved over two positions with the major component having a site occupancy factor of 0.539 (4)
3-Benzyl-6-isopropyl-5-phenoxy-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one
In the title compound, C20H19N5O2, all atoms of the 1,2,3-triazolo[4,5-d]pyrimidine ring system are essentially coplanar [maximum deviation = 0.015 (2) Å], indicating the existence of a conjugate system in which each carbon and nitrogen atom is sp
2 hybridized and ten π electrons (three from carbon atoms and seven from nitrogen atoms) constitute an aromatic heterocycle. The ring system forms dihedral angles of 68.37 (10) and 71.57 (9)° with the phenyl rings. The crystal packing is stabilized by van der Waals interactions and intermolecular C—H⋯π interactions
Integrated Behavior Planning and Motion Control for Autonomous Vehicles with Traffic Rules Compliance
In this article, we propose an optimization-based integrated behavior
planning and motion control scheme, which is an interpretable and adaptable
urban autonomous driving solution that complies with complex traffic rules
while ensuring driving safety. Inherently, to ensure compliance with traffic
rules, an innovative design of potential functions (PFs) is presented to
characterize various traffic rules related to traffic lights, traversable and
non-traversable traffic line markings, etc. These PFs are further incorporated
as part of the model predictive control (MPC) formulation. In this sense,
high-level behavior planning is attained implicitly along with motion control
as an integrated architecture, facilitating flexible maneuvers with safety
guarantees. Due to the well-designed objective function of the MPC scheme, our
integrated behavior planning and motion control scheme is competent for various
urban driving scenarios and able to generate versatile behaviors, such as
overtaking with adaptive cruise control, turning in the intersection, and
merging in and out of the roundabout. As demonstrated from a series of
simulations with challenging scenarios in CARLA, it is noteworthy that the
proposed framework admits real-time performance and high generalizability.Comment: 7 pages, 5 figures, accepted for publication in The 2023 IEEE
International Conference on Robotics and Biomimetics (ROBIO
3D Theory of Microscopic Instabilities Driven by Space-Charge Forces
Microscopic, or short-wavelength, instabilities are known for drastic
reduction of the beam quality and strong amplification of the noise in a beam.
Space charge and coherent synchrotron radiation are known to be the leading
causes for such instabilities. In this paper we present rigorous 3D theory of
such instabilities driven by the space-charge forces. We define the condition
when our theory is applicable for an arbitrary accelerator system with 3D
coupling. Finally, we derive a linear integral equation describing such
instability and identify conditions when it can be reduced to an ordinary
second order differential equation.Comment: 38 pages, 3 figures. arXiv admin note: substantial text overlap with
arXiv:2101.0410
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