28 research outputs found
Magnetothermodynamics of BPS baby skyrmions
The magnetothermodynamics of skyrmion type matter described by the gauged BPS
baby Skyrme model at zero temperature is investigated. We prove that the BPS
property of the model is preserved also for boundary conditions corresponding
to an asymptotically constant magnetic field. The BPS bound and the
corresponding BPS equations saturating the bound are found. Further, we show
that one may introduce pressure in the gauged model by a redefinition of the
superpotential. Interestingly, this is related to non-extremal type solutions
in the so-called fake supersymmetry method. Finally, we compute the equation of
state of magnetized BSP baby skyrmions inserted into an external constant
magnetic field and under external pressure , i.e., , where
is the "volume" (area) occupied by the skyrmions. We show that the BPS baby
skyrmions form a ferromagnetic medium.Comment: Latex, 39 pages, 14 figures. v2: New results and references added,
physical interpretation partly change
Exact vortex solutions in a CP^N Skyrme-Faddeev type model
We consider a four dimensional field theory with target space being CP^N
which constitutes a generalization of the usual Skyrme-Faddeev model defined on
CP^1. We show that it possesses an integrable sector presenting an infinite
number of local conservation laws, which are associated to the hidden
symmetries of the zero curvature representation of the theory in loop space. We
construct an infinite class of exact solutions for that integrable submodel
where the fields are meromorphic functions of the combinations (x^1+i x^2) and
(x^3+x^0) of the Cartesian coordinates of four dimensional Minkowski
space-time. Among those solutions we have static vortices and also vortices
with waves traveling along them with the speed of light. The energy per unity
of length of the vortices show an interesting and intricate interaction among
the vortices and waves.Comment: 21 pages, plain latex, no figure
Placental transfusion: a review
Recently there have been a number of studies and presentations on the importance of providing a placental transfusion to the newborn. Early cord clamping is an avoidable, unphysiologic intervention that prevents the natural process of placental transfusion. However, placental transfusion, although simple in concept, is affected by multiple factors, is not always straightforward to implement, and can be performed using different methods, making this basic procedure important to discuss. Here, we review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking and cut-umbilical cord milking, and the evidence in term and preterm newborns supporting this practice. We will also review several factors that influence placental transfusion, and discuss perceived risks versus benefits of this procedure. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution
Stationary ring solitons in field theory - knots and vortons
We review the current status of the problem of constructing classical field
theory solutions describing stationary vortex rings in Minkowski space in 3+1
dimensions. We describe the known up to date solutions of this type, such as
the static knot solitons stabilized by the topological Hopf charge, the
attempts to gauge them, the anomalous solitons stabilized by the Chern-Simons
number, as well as the non-Abelian monopole and sphaleron rings. Passing to the
rotating solutions, we first discuss the conditions insuring that they do not
radiate, and then describe the spinning -balls, their twisted and gauged
generalizations reported here for the first time, spinning skyrmions, and
rotating monopole-antimonopole pairs. We then present the first explicit
construction of global vortons as solutions of the elliptic boundary value
problem, which demonstrates their non-radiating character. Finally, we describe
the analogs of vortons in the Bose-Einstein condensates, analogs of spinning
-balls in the non-linear optics, and also moving vortex rings in superfluid
helium and in ferromagnetics.Comment: 103 pages, 31 figures. Numerous modifications in the text, a strongly
expanded description of Faddeev-Skyrme knots, a new section on spinning
Q-balls as light bullets, many new references. To appear in Physics Report