Exact solution of a boundary conformal field theory

Curtis G. Callan, Igor R. Klebanov, Andreas W.W. Ludwig, Juan M. Maldacena

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We study the conformal field theory of a free massless scalar field living on the half-line with interactions introduced via a periodic potential at the boundary. An SU(2) current algebra underlies this system and the interacting boundary state is given by a global SU(2) rotation of the left-moving fields in the zero-potential (Neumann) boundary state. As the potential strength varies from zero to infinity, the boundary state interpolates between the Neumann and the Dirichlet values. The full S-matrix for scattering from the boundary, with arbitrary particle production, is explicitly computed. To maintain unitarity, it is necessary to attribute a hidden discrete "soliton" degree of freedom to the boundary. The same unitarity puzzle occurs in the Kondo problem, and we anticipate a similar solution.

Original languageEnglish (US)
Pages (from-to)417-448
Number of pages32
JournalNuclear Physics, Section B
Issue number3
StatePublished - Jul 11 1994

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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