Irreducible self-adjoint representations of quantum Teichmüller space and the phase constants

Research output: Contribution to journalArticlepeer-review


Quantization of the Teichmüller space of a non-compact Riemann surface has emerged in 1980s as an approach to three dimensional quantum gravity. For any choice of an ideal triangulation of the surface, Thurston's shear coordinate functions on the edges form a coordinate system for the Teichmüller space, and they should be replaced by suitable self-adjoint operators on a Hilbert space. Upon a change of triangulations, one must construct a unitary operator between the Hilbert spaces intertwining the quantum coordinate operators and satisfying the composition identities up to multiplicative phase constants. In the well-known construction by Chekhov, Fock and Goncharov, the quantum coordinate operators form a family of reducible representations, and the phase constants are all trivial. In the present paper, we employ the harmonic–analytic theory of the Shale–Weil intertwiners for the Schrödinger representations, as well as Faddeev–Kashaev's quantum dilogarithm function, to construct a family of irreducible representations of the quantum shear coordinate functions and the corresponding intertwiners for the changes of triangulations. The phase constants are explicitly computed and described by the Maslov indices of the Lagrangian subspaces of a symplectic vector space, and by the pentagon relation of the flips of triangulations. The present work may generalize to the cluster X-varieties.

Original languageEnglish
Article number104103
JournalJournal of Geometry and Physics
StatePublished - Apr 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.


  • Fock–Goncharov intertwiner
  • Mapping class group representation
  • Quantum Teichmüller space
  • Quantum dilogarithm
  • Representation of quantum cluster variety
  • Shale–Weil intertwiner for Schrödinger representations and metaplectic representation of symplectic group


Dive into the research topics of 'Irreducible self-adjoint representations of quantum Teichmüller space and the phase constants'. Together they form a unique fingerprint.

Cite this