In the framework of stochastic quantization, the conformal anomaly of Fujikawa's string theory is derived and the standard dimension $D=26\mathrm{}$ is obtained once again. It is shown that the quantum origin of that anomaly comes from a breaking of the naive Leibnitz formula in stochastic processes.

• Received 4 October 1990

DOI:https://doi.org/10.1103/PhysRevD.43.2050