Picture (string theory)

In superstring theory, a picture is a choice of Fock space or, equivalently, a choice of ground state that defines a representation of the theory's state space. Each picture is denoted by a number, such as the 0 picture or −1 picture, and picture-changing operators transform from one representation to another.^[1][2][3] The use of these operators in BRST quantization is credited to Daniel Friedan, Emil Martinec, and Stephen Shenker in the 1980s, though it has a predecessor in the dual models of the early 1970s.^[1][4][5]

The difference between the ground states is indicated by the action of the superghost oscillators on them, and the number of the picture (plus 1/2) reflects the highest superghost oscillator which does not annihilate the ground state.^{[citation needed]}

Further reading

• Polchinski, Joseph (2005). String Theory, Volume II: Superstring Theory and Beyond. Cambridge University Press. pp. 108–110, 118–121, 126, 469. ISBN 978-0-521-63304-8.