165 research outputs found
A new constraints separation for the original D=10 massless superparticle
We study the problem of covariant separation between first and second class
constraints for the Brink-Schwarz superparticle. Opposite to the
supersymmetric light-cone frame separation, we show here that there is a
Lorentz covariant way to identify the second class constraints such that,
however, supersymmetry is broken. Consequences for the superstring are
briefly discussed.Comment: 13 page
A new spin-2 self-dual model in
There are three self-dual models of massive particles of helicity +2 (or -2)
in . Each model is of first, second, and third-order in derivatives.
Here we derive a new self-dual model of fourth-order, \cL {SD}^{(4)}, which
follows from the third-order model (linearized topologically massive gravity)
via Noether embedment of the linearized Weyl symmetry. In fact, each self-dual
model can be obtained from the previous one \cL {SD}^{(i)} \to \cL
{SD}^{(i+1)}, i=1,2,3 by the Noether embedment of an appropriate gauge
symmetry, culminating in \cL {SD}^{(4)}. The new model may be identified with
the linearized version of \cL {HDTMG} = \epsilon^{\mu\nu\rho}
\Gamma_{\mu\gamma}^\epsilon (\p_\nu\Gamma_{\epsilon\rho}^\gamma +
(2/3)\Gamma_{\nu\delta}^\gamma \Gamma_{\rho\epsilon}^\delta) /8 m +
\sqrt{-g}(R_{\mu\nu} R^{\nu\mu} - 3 R^2/8) /2 m^2 . We also construct a master
action relating the third-order self-dual model to \cL {SD}^{(4)} by means of
a mixing term with no particle content which assures spectrum equivalence of
\cL {SD}^{(4)} to other lower-order self-dual models despite its pure higher
derivative nature and the absence of the Einstein-Hilbert action. The relevant
degrees of freedom of \cL {SD}^{(4)} are encoded in a rank-two tensor which
is symmetric, traceless and transverse due to trivial (non-dynamic) identities,
contrary to other spin-2 self-dual models. We also show that the Noether
embedment of the Fierz-Pauli theory leads to the new massive gravity of
Bergshoeff, Hohm and Townsend.Comment: 14 pages, no figures, typos fixed, reference (19) modifie
A note on the nonuniqueness of the massive Fierz-Pauli theory and spectator fields
It is possible to show that there are three independent families of models
describing a massive spin-2 particle via a rank-2 tensor. One of them contains
the massive Fierz-Pauli model, the only case described by a symmetric tensor.
The three families have different local symmetries in the massless limit and
can not be interconnected by any local field redefinition. We show here
however, that they can be related with the help of a decoupled and non dynamic
(spectator) field. The spectator field may be either an antisymmetric tensor
, a vector or a scalar field ,
corresponding to each of the three families. The addition of the extra field
allows us to formulate master actions which interpolate between the symmetric
Fierz-Pauli theory and the other models. We argue that massive gravity models
based on the Fierz-Pauli theory are not expected to be equivalent to possible
local self-interacting theories built up on the top of the two new families of
massive spin-2 models.
The approach used here may be useful to investigate dual (nonsymmetric)
formulations of higher spin particles.Comment: 9 pages, no figure
Massive spin-2 particle from a rank-2 tensor
Here we obtain all possible second-order theories for a rank-2 tensor which
describe a massive spin-2 particle. We start with a general second-order
Lagrangian with ten real parameters. The absence of lower spin modes and the
existence of two local field redefinitions leads us to only one free parameter.
The solutions split into three one-parameter classes according to the local
symmetries of the massless limit. In the class which contains the usual massive
Fierz-Pauli theory, the subset of spin-1 massless symmetries is maximal. In
another class where the subset of spin-0 symmetries is maximal, the massless
theory is invariant under Weyl transformations and the mass term does not need
to fit in the form of the Fierz-Pauli mass term. In the remaining third class
neither the spin-1 nor the spin-0 symmetry is maximal and we have a new family
of spin-2 massive theories.Comment: 17 pages, no figure
Generalized duality between local vector theories in
The existence of an interpolating master action does not guarantee the same
spectrum for the interpolated dual theories. In the specific case of a
generalized self-dual (GSD) model defined as the addition of the Maxwell term
to the self-dual model in , previous master actions have furnished a
dual gauge theory which is either nonlocal or contains a ghost mode. Here we
show that by reducing the Maxwell term to first order by means of an auxiliary
field we are able to define a master action which interpolates between the GSD
model and a couple of non-interacting Maxwell-Chern-Simons theories of opposite
helicities. The presence of an auxiliary field explains the doubling of fields
in the dual gauge theory. A generalized duality transformation is defined and
both models can be interpreted as self-dual models. Furthermore, it is shown
how to obtain the gauge invariant correlators of the non-interacting MCS
theories from the correlators of the self-dual field in the GSD model and
vice-versa. The derivation of the non-interacting MCS theories from the GSD
model, as presented here, works in the opposite direction of the soldering
approach.Comment: 11 pages, no figures, to appear in J. of High Energy Phy
Dual descriptions of massive spin-3 particles in via Noether gauge embedment
We present here a relationship among massive self-dual models for spin-3
particles in via the Noether Gauge Embedment procedure.
Starting with a first order model (in derivatives) we have obtained
a sequence of four self-dual models where . We
demonstrate that the procedure generate the correct action for the
auxiliary fields automatically. We obtain the whole action for the order
self-dual model including all the needed auxiliary fields to get rid of the
ghosts of the theory.Comment: 16 pages, 1 tabl
Master actions for massive spin-3 particles in D=2+1
We present here a relationship among massive self-dual models for spin-3
particles in via the master action procedure. Starting with a first
order model (in derivatives) we have constructed a master action
which interpolates among a sequence of four self-dual models where
. By analyzing the particle content of mixing terms, we give
additional arguments that explain why it is apparently impossible to jump from
the fourth order model to a higher order model. We have also analyzed
similarities and differences between the fourth order -term in the spin-2
case and the analogous fourth order term in the spin-3 context.Comment: 16 page
Ghost free dual vector theories in 2+1 dimensions
We explore here the issue of duality versus spectrum equivalence in abelian
vector theories in 2+1 dimensions. Specifically we examine a generalized
self-dual (GSD) model where a Maxwell term is added to the self-dual model. A
gauge embedding procedure applied to the GSD model leads to a
Maxwell-Chern-Simons (MCS) theory with higher derivatives. We show that the
latter contains a ghost mode contrary to the original GSD model. On the other
hand, the same embedding procedure can be applied to fermions minimally
coupled to the self-dual model. The dual theory corresponds to fermions
with an extra Thirring term coupled to the gauge field via a Pauli-like term.
By integrating over the fermions at in both matter coupled
theories we obtain effective quadratic theories for the corresponding vector
fields. On one hand, we have a nonlocal type of the GSD model. On the other
hand, we have a nonlocal form of the MCS theory. It turns out that both
theories have the same spectrum and are ghost free. By figuring out why we do
not have ghosts in this case we are able to suggest a new master action which
takes us from the local GSD to a nonlocal MCS model with the same spectrum of
the original GSD model and ghost free. Furthermore, there is a dual map between
both theories at classical level which survives quantum correlation functions
up to contact terms. The remarks made here may be relevant for other
applications of the master action approach.Comment: 15 pages, 1 figur
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