11,389 research outputs found
Orbit based procedure for doublets of scalar fields and the emergence of triple kinks and other defects
In this work we offer an approach to enlarge the number of exactly solvable
models with two real scalar fields in (1+1)D. We build some new two-field
models, and obtain their exact orbits and exact or numerical field
configurations. It is noteworthy that a model presenting triple-kinks and
double-flat-top lumps is among those new models
Dynamics of deviations from the Gaussian state in a freely cooling homogeneous system of smooth inelastic particles
The time dependence of deviations from the Gaussian state in a freely cooling
homogeneous system of smooth inelastically colliding spheres is investigated by
kinetic theory. We determine the full time dependence of the coefficients of an
expansion around the Gaussian state in Generalized Laguerre polynomials.
Approximating this system of equations to sixth order, we find that the
asymptotic state, where the mean energy T follows Haff's law with time
independent cooling rate, is reached within a few collisions per particle.
Two-dimensional molecular dynamics simulations confirm our results and show
exponential behavior in the high-energy tails.Comment: 11 pages, 13 eps figures, to be published in Granular Matte
Induced higher-derivative massive gravity on a 2-brane in 4D Minkowski space
In this paper we revisit the problem of localizing gravity in a 2-brane
embedded in a 4D Minkowski space to address induction of high derivative
massive gravity. We explore the structure of propagators to find well-behaved
higher-derivative massive gravity induced on the brane. Exploring a special
case in the generalized mass term of the graviton propagator we find a model of
consistent higher order gravity with an additional unitary massive spin-2
particle and two massless particles: one spin-0 particle and one spin-1
particle. The condition for the absence of tachyons is satisfied for both
`right' and `wrong' signs of the Einstein-Hilbert term on the 2-brane. We also
find the Pauli-Fierz mass term added to the new massive gravity in three
dimensions and recover the low dimensional DGP model.Comment: Latex, 12 pages, no figure; refs added, version to appear in PL
Symmetry-preserving contact interaction model for heavy-light mesons
We use a symmetry-preserving regularization method of ultraviolet divergences
in a vector-vector contact interac- tion model for low-energy QCD. The contact
interaction is a representation of nonperturbative kernels used Dyson-Schwinger
and Bethe-Salpeter equations. The regularization method is based on a
subtraction scheme that avoids standard steps in the evaluation of divergent
integrals that invariably lead to symmetry violation. Aiming at the study of
heavy-light mesons, we have implemented the method to the pseudoscalar pion and
Kaon mesons. We have solved the Dyson-Schwinger equation for the u, d and s
quark propagators, and obtained the bound-state Bethe-Salpeter amplitudes in a
way that the Ward-Green-Takahashi identities reflecting global symmetries of
the model are satisfied for arbitrary routing of the momenta running in loop
integrals
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