Sandwich Quantum Constraints, Strings and Null Branes

• Ida Mehin Rasulian (School of Physics, Institute for Research in Fundamental Sciences (IPM))

We revisit the canonical quantization of free bosonic closed string theory and observe that the physicality of states requires vanishing of the worldsheet Virasoro algebra generators sandwiched between any two physical states. This requirement yields four classes of physical states, depending on discrete worldsheet symmetries: parity and time reversal. The usual string states which are highest weight states of the Virasoro algebra, preserve both, while the other new three classes break one or both. We initiate the quantization of a null p-brane in light-cone gauge using the idea of sandwich quantum constraints and show that solutions to the sandwich conditions are classified into p+1 distinct classes, which we completely specify.