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Joined 2026-09-21 Message
Incoming links: Null string state
Past exam of the mathematics course of the University of Cambridge 2022 iii Paper 306 4 a Solution 2026-09-28
In old covariant quantization, an open-string physical string state obeyswith analogous left- and right-moving conditions for a closed string. A spurious string state is a Virasoro descendant orthogonal to every physical state. A null string state is both physical and spurious; it has zero norm and zero inner product with every physical state, so quotienting by null states removes gauge redundancy without removing observable states.