Verlinde algebra

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Short description: Algebra used in certain conformal field theories

In mathematics, a Verlinde algebra is a finite-dimensional associative algebra introduced by Erik Verlinde (1988), with a basis of elements φλ corresponding to primary fields of a rational two-dimensional conformal field theory, whose structure constants Nνλμ describe fusion of primary fields.

Verlinde formula

In terms of the modular S-matrix, the fusion coefficients are given by[1]

[math]\displaystyle{ N_{\lambda \mu}^\nu = \sum_\sigma \frac{S_{\lambda \sigma} S_{\mu \sigma} S^*_{\sigma \nu}}{S_{0\sigma}} }[/math]

where [math]\displaystyle{ S^* }[/math] is the component-wise complex conjugate of [math]\displaystyle{ S }[/math].

Twisted equivariant K-theory

If G is a compact Lie group, there is a rational conformal field theory whose primary fields correspond to the representations λ of some fixed level of loop group of G. For this special case (Freed Hopkins) showed that the Verlinde algebra can be identified with twisted equivariant K-theory of G.

See also

Notes

  1. Blumenhagen, Ralph (2009). Introduction to Conformal Field Theory. Plauschinn, Erik. Dordrecht: Springer. pp. 143. ISBN 9783642004490. OCLC 437345787. https://archive.org/details/introductiontoco00blum_953. 

References