Semiclassical energy of closed Nambu-Goto strings
Marek Kozoň (Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, CZ-180 00 Praha 8, Czech Republic, Institut für Theoretische Physik, Universität Leipzig, Brüderstr. 16, 04103 Leipzig, Germany); Jochen Zahn (Institut für Theoretische Physik, Universität Leipzig, Brüderstr. 16, 04103 Leipzig, Germany)
We compute semiclassical corrections to the energy of rotating closed Nambu-Goto strings. We confirm the results obtained by means of the Polchinski-Strominger action. We also show that in this semiclassical approximation, the spectrum of physical excitations contains modes that are unphysical nonperturbatively, i.e., to which no physical excitations of the covariantly quantized Nambu-Goto string correspond.
