160 research outputs found
Ordinary-derivative formulation of conformal totally symmetric arbitrary spin bosonic fields
Conformal totally symmetric arbitrary spin bosonic fields in flat space-time
of even dimension greater than or equal to four are studied. Second-derivative
(ordinary-derivative) formulation for such fields is developed. We obtain gauge
invariant Lagrangian and the corresponding gauge transformations. Gauge
symmetries are realized by involving the Stueckelberg and auxiliary fields.
Realization of global conformal boost symmetries on conformal gauge fields is
obtained. Modified de Donder gauge condition and de Donder-Stueckelberg gauge
condition are introduced. Using the de Donder-Stueckelberg gauge frame,
equivalence of the ordinary-derivative and higher-derivative approaches is
demonstrated. On-shell degrees of freedom of the arbitrary spin conformal field
are analyzed. Ordinary-derivative light-cone gauge Lagrangian of conformal
fields is also presented. Interrelations between the ordinary-derivative gauge
invariant formulation of conformal fields and the gauge invariant formulation
of massive fields are discussed.Comment: 51 pages, v2: Results and conclusions of v1 unchanged. In Sec.3,
brief review of higher-derivative approaches added. In Sec.4, new
representations for Lagrangian, modified de Donder gauge, and de
Donder-Stueckelberg gauge added. In Sec.5, discussion of interrelations
between the ordinary-derivative and higher-derivative approaches added.
Appendices A,B,C,D and references adde
Gauge fields in (A)dS within the unfolded approach: algebraic aspects
It has recently been shown that generalized connections of the (A)dS space
symmetry algebra provide an effective geometric and algebraic framework for all
types of gauge fields in (A)dS, both for massless and partially-massless. The
equations of motion are equipped with a nilpotent operator called
whose cohomology groups correspond to the dynamically relevant quantities like
differential gauge parameters, dynamical fields, gauge invariant field
equations, Bianchi identities etc. In the paper the -cohomology is
computed for all gauge theories of this type and the field-theoretical
interpretation is discussed. In the simplest cases the -cohomology is
equivalent to the ordinary Lie algebra cohomology.Comment: 59 pages, replaced with revised verio
Spin 3 cubic vertices in a frame-like formalism
Till now most of the results on interaction vertices for massless higher spin
fields were obtained in a metric-like formalism using completely symmetric
(spin-)tensors. In this, the Lagrangians turn out to be very complicated and
the main reason is that the higher the spin one want to consider the more
derivatives one has to introduce. In this paper we show that such
investigations can be greatly simplified if one works in a frame-like
formalism. As an illustration we consider massless spin 3 particle and
reconstruct a number of vertices describing its interactions with lower spin 2,
1 and 0 ones. In all cases considered we give explicit expressions for the
Lagrangians and gauge transformations and check that the algebra of gauge
transformations is indeed closed.Comment: 17 pades, no figure
Higher spin interactions with scalar matter on constant curvature spacetimes: conserved current and cubic coupling generating functions
Cubic couplings between a complex scalar field and a tower of symmetric
tensor gauge fields of all ranks are investigated on any constant curvature
spacetime of dimension d>2. Following Noether's method, the gauge fields
interact with the scalar field via minimal coupling to the conserved currents.
A symmetric conserved current, bilinear in the scalar field and containing up
to r derivatives, is obtained for any rank r from its flat spacetime
counterpart in dimension d+1, via a radial dimensional reduction valid
precisely for the mass-square domain of unitarity in (anti) de Sitter spacetime
of dimension d. The infinite collection of conserved currents and cubic
vertices are summarized in a compact form by making use of generating functions
and of the Weyl/Wigner quantization on constant curvature spaces.Comment: 35+1 pages, v2: two references added, typos corrected, enlarged
discussions in Subsection 5.2 and in Conclusion, to appear in JHE
Half-integer Higher Spin Fields in (A)dS from Spinning Particle Models
We make use of O(2r+1) spinning particle models to construct linearized
higher-spin curvatures in (A)dS spaces for fields of arbitrary half-integer
spin propagating in a space of arbitrary (even) dimension: the field
potentials, whose curvatures are computed with the present models, are
spinor-tensors of mixed symmetry corresponding to Young tableaux with D/2 - 1
rows and r columns, thus reducing to totally symmetric spinor-tensors in four
dimensions. The paper generalizes similar results obtained in the context of
integer spins in (A)dS.Comment: 1+18 pages; minor changes in the notation, references updated.
Published versio
Effective action in a higher-spin background
We consider a free massless scalar field coupled to an infinite tower of
background higher-spin gauge fields via minimal coupling to the traceless
conserved currents. The set of Abelian gauge transformations is deformed to the
non-Abelian group of unitary operators acting on the scalar field. The gauge
invariant effective action is computed perturbatively in the external fields.
The structure of the various (divergent or finite) terms is determined. In
particular, the quadratic part of the logarithmically divergent (or of the
finite) term is expressed in terms of curvatures and related to conformal
higher-spin gravity. The generalized higher-spin Weyl anomalies are also
determined. The relation with the theory of interacting higher-spin gauge
fields on anti de Sitter spacetime via the holographic correspondence is
discussed.Comment: 40 pages, Some errors and typos corrected, Version published in JHE
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
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