In the Wilson's lattice formulation of QCD, a fermionic Fock space of states can be explicitly built at each time slice using canonical creation and annihilation operators. The partition function Z is then represented as the trace of the transfer matrix, and its usual functional representation as a path integral of exp(−S) can be recovered in a standard way. However, applying a Bogoliubov transformation on the canonical operators before passing to the functional formalism, we can isolate a vacuum contribution in the resulting action which depends only on the parameters of the transformation and fixes them via a variational principle. Then, inserting in the trace defining Z an operator projecting on the mesons subspace at each time slice and making the physical assumption that the true partition function is well approximate by the projected one, we can also write an effective quadratic action for mesons. We tested the method in the renowned 't Hooft model, namely QCD in two spacetime dimensions for large number of colours, in Coulomb gauge.
Lattice QCD$_2$ effective action with Bogoliubov transformations / S. Caracciolo, M. Pastore. - In: POS PROCEEDINGS OF SCIENCE. - ISSN 1824-8039. - 336(2019). ((Intervento presentato al 13. convegno Confinement2018 Quark Confinement and the Hadron Spectrum : 31 July - 6 August tenutosi a Maynooth University, Ireland nel 2018.
|Titolo:||Lattice QCD$_2$ effective action with Bogoliubov transformations|
CARACCIOLO, SERGIO (Primo)
PASTORE, MAURO (Ultimo) (Corresponding)
|Settore Scientifico Disciplinare:||Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici|
|Data di pubblicazione:||2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.22323/1.336.0056|
|Appare nelle tipologie:||01 - Articolo su periodico|