TY - JOUR

T1 - Reply to 'Comment on' gravity and the Poincare group'

AU - Nardelli, Giuseppe

AU - Grignani, Gianluca

PY - 1993

Y1 - 1993

N2 - In the first order form, the model considered by Strobl presents, besides local Lorentz and diffeomorphism invariances, an additional local non-linear symmetry. When the model is realized as a Poincar\'e gauge theory according to the procedure outlined in Refs.[1,2], the generators of the non-linear symmetry are responsible for the ``nasty constraint algebra''. We show that not only the Poincar\'e gauge theoretic formulation of the model is not the cause of the emerging of the undesirable constraint algebra, but actually allows to overcome the problem. In fact one can fix the additional symmetry without breaking the Poincar\'e gauge symmetry and the diffeomorphisms, so that, after a preliminary Dirac procedure, the remaining constraints uniquely satisfy the Poincar\'e algebra. After the additional symmetry is fixed, the equations of motion are unaltered. The objections to our method raised by Strobl in Ref.[3] are then immaterial. Some minor points put forward in Ref.[3] are also discussed.

AB - In the first order form, the model considered by Strobl presents, besides local Lorentz and diffeomorphism invariances, an additional local non-linear symmetry. When the model is realized as a Poincar\'e gauge theory according to the procedure outlined in Refs.[1,2], the generators of the non-linear symmetry are responsible for the ``nasty constraint algebra''. We show that not only the Poincar\'e gauge theoretic formulation of the model is not the cause of the emerging of the undesirable constraint algebra, but actually allows to overcome the problem. In fact one can fix the additional symmetry without breaking the Poincar\'e gauge symmetry and the diffeomorphisms, so that, after a preliminary Dirac procedure, the remaining constraints uniquely satisfy the Poincar\'e algebra. After the additional symmetry is fixed, the equations of motion are unaltered. The objections to our method raised by Strobl in Ref.[3] are then immaterial. Some minor points put forward in Ref.[3] are also discussed.

KW - gauge theory of gravity

KW - gravity

KW - gauge theory of gravity

KW - gravity

UR - http://hdl.handle.net/10807/8565

UR - http://prd.aps.org/abstract/prd/v48/i10/p5032_1

U2 - 10.1103/PhysRevD.48.5032

DO - 10.1103/PhysRevD.48.5032

M3 - Article

VL - 1993

SP - 5032

EP - 5035

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

ER -