• Canonical realization of (2+1)-dimensional Bondi-Metzner-Sachs symmetry 

    Batlle Arnau, Carles; Campello, Víctor; Gomis Torné, Joaquin (2017-07-12)
    Article
    Accés obert
    We construct canonical realizations of the (2+1)-dimensional Bondi-Metzner-Sachs (bms3) algebra as symmetry algebras of a free Klein-Gordon (KG) field in 2+1 dimensions for both massive and massless cases. We consider two ...
  • Equivalence between the Hamiltonian and Lagrangian formalisms for constrained systems 

    Batlle Arnau, Carles; Gomis Torné, Joaquin; Pons Ràfols, Josep Maria; Román Roy, Narciso (1986-08)
    Article
    Accés obert
    The equivalence between the Lagrangian and Hamiltonian formalism is studied for constraint systems. A procedure to construct the Lagrangian constraints from the Hamiltonian constraints is given. Those Hamiltonian constraints ...
  • Extended Galilean symmetries of non-relativistic strings 

    Batlle Arnau, Carles; Gomis Torné, Joaquin; Not, Daniel (2017-02-09)
    Article
    Accés obert
    We consider two non-relativistic strings and their Galilean symmetries. These strings are obtained as the two possible non-relativistic (NR) limits of a relativistic string. One of them is non-vibrating and represents a ...
  • Non-relativistic Bondi-Metzner-Sachs algebra 

    Batlle Arnau, Carles; Delmastro, Diego; Gomis Torné, Joaquin (2017-09-21)
    Article
    Accés obert
    We construct two possible candidates for non-relativistic bms(4) algebra in four space-time dimensions by contracting the original relativistic bms(4) algebra. bms(4) algebra is infinite-dimensional and it contains the ...
  • Tachyons in the Galilean limit 

    Batlle Arnau, Carles; Gomis Torné, Joaquin; Mezincescu, Luca; Townsend, Paul K. (2017-04-20)
    Article
    Accés obert
    The Souriau massless Galilean particle of “colour” k and spin s is shown to be the Galilean limit of the Souriau tachyon of mass m = ik and spin s. We compare and contrast this result with the Galilean limit of the Nambu-Goto ...