Critical boundary sine-Gordon revisited

M. Hasselfield, Taejin Lee, G. W. Semenoff, P. C.E. Stamp

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states.

Original languageEnglish (US)
Pages (from-to)2849-2875
Number of pages27
JournalAnnals of Physics
Issue number12
StatePublished - Dec 2006

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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