74 citations · 99 across the 8 of their papers we have counts for
8 papers
Families of complex Hadamard matrices
Nuno Barros e Sa, Ingemar Bengtsson
What is the dimension of a smooth family of complex Hadamard matrices including the Fourier matrix? We address this problem with a power series expansion. Studying all dimensions u…
Vacuum Stability in two-Higgs doublet models
Nuno Barros e Sa, Augusto Barroso, Pedro Ferreira +1
In this work we review the status of tree-level vacuum stability in general two-Higgs doublet models. We also discuss the problem of Normal minima in some classes of potentials. In…
Uncertainty for spin systems
Nuno Barros e Sa
A modified definition of quantum mechanical uncertainty D for spin systems, which is invariant under the action of SU(2), is suggested. Its range is shown to be h^2j<D<h^2j(j+1) wi…
Decomposition of Hilbert space in sets of coherent states
Nuno Barros e Sa
Within the generalized definition of coherent states as group orbits we study the orbit spaces and the orbit manifolds in the projective spaces constructed from linear representati…
Hamiltonian analysis of General relativity with the Immirzi parameter
Nuno Barros e Sa
Starting from a Lagrangian we perform the full constraint analysis of the Hamiltonian for General relativity in the tetrad-connection formulation for an arbitrary value of the Immi…
A note on topological brane theories
Ingemar Bengtsson, Nuno Barros e Sa, Maxim Zabzine
We consider the theory of closed -branes propagating on -dimensional space-time manifolds. This theory has no local degrees of freedom. Here we study its canonical and BR…