Communications in Mathematical Physics

, Volume 170, Issue 1, pp 101–116 | Cite as

Dispersionless Toda hierarchy and two-dimensional string theory

  • Kanehisa Takasaki


The dispersionless Toda hierarchy turns out to lie in the heart of a recently proposed Landau-Ginzburg formulation of two-dimensional string theory at self-dual compactification radius. The dynamics of massless tachyons with discrete momenta is shown to be encoded into the structure of a special solution of this integrable hierarchy. This solution is obtained by solving a Riemann-Hilbert problem. Equivalence to the tachyon dynamics is proven by deriving recursion relations of tachyon correlation functions in the machinery of the dispersionless Toda hierarchy. Fundamental ingredients of the Landau-Ginzburg formulation, such as Landau-Ginzburg potentials and tachyon Landau-Ginzburg fields, are translated into the language of the Lax formalism. Furthermore, a wedge algebra is pointed out to exist behind the Riemann-Hilbert problem, and speculations on its possible role as generators of “extra” states and fields are presented.


Neural Network Correlation Function Complex System Nonlinear Dynamics Quantum Computing 
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Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Kanehisa Takasaki
    • 1
  1. 1.Department of Fundamental Sciences, Faculty of Integrated Human StudiesKyoto UniversitySakyo-ku, KyotoJapan

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