4 citations · 5 across the 4 of their papers we have counts for
4 papers
Improper currents in theories with local invariance
Nuno Barros e Sá
We present a proof that the currents arising from Noether's first theorem in a physical theory with local invariance can always be decomposed into two terms, one of them vanishing…
Covariant conservation laws, local invariance and Noether's second theorem
Nuno Barros e Sá, Miguel A. S. Pinto, Tomás Trindade
We lay down a set of requirements for a field theory to produce a covariant conservation law out of Noether's second theorem, and show that neither local invariance implies a covar…
Dirac bracket and time dependent constraints
Nuno Barros e Sá
We provide a simultaneous derivation of the Dirac bracket and of the equations of motion for second-class constrained systems when the constraints are time-dependent. The necessity…
From Quantum Field Theory to Quantum Mechanics
Nuno Barros e Sá, Cláudio Gomes
We construct the algebra of operators acting on the Hilbert spaces of Quantum Mechanics for systems of identical particles from the field operators acting in the Fock space of…