1,506 research outputs found
Controlling synchrony by delay coupling in networks: from in-phase to splay and cluster states
We study synchronization in delay-coupled oscillator networks, using a master
stability function approach. Within a generic model of Stuart-Landau
oscillators (normal form of super- or subcritical Hopf bifurcation) we derive
analytical stability conditions and demonstrate that by tuning the coupling
phase one can easily control the stability of synchronous periodic states. We
propose the coupling phase as a crucial control parameter to switch between
in-phase synchronization or desynchronization for general network topologies,
or between in-phase, cluster, or splay states in unidirectional rings. Our
results are robust even for slightly nonidentical elements of the network.Comment: 4 pages, 4 figure
New BPS Objects in N=2 Supersymmetric Gauge Theories
We explore BPS soliton configurations in N=2 supersymmetric Yang-Mills theory
with matter fields arising from parallel D3 branes on D7 branes. Especially we
focus on two parameter family of 1/8 BPS equations, dyonic objects, and 1/8 BPS
objects and raise a possibility of absence of BPS vortices when the number of
D3 branes is larger than that of D7 branes.Comment: 28 pages, LaTeX, no figur
Lorentz Invariance in Chiral Kinetic Theory
We show that Lorentz invariance is realized nontrivially in the classical
action of a massless spin- particle with definite helicity. We find
that the ordinary Lorentz transformation is modified by a shift orthogonal to
the boost vector and the particle momentum. The shift ensures angular momentum
conservation in particle collisions and implies a nonlocality of the collision
term in the Lorentz-invariant kinetic theory due to side jumps. We show that
2/3 of the chiral-vortical effect for a uniformly rotating particle
distribution can be attributed to the magnetic moment coupling required by the
Lorentz invariance. We also show how the classical action can be obtained by
taking the classical limit of the path integral for a Weyl particle.Comment: 5 pages, 1 figur
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