Simulating the All-Order Strong Coupling Expansion I: Ising Model Demo

Understand

We investigate in some detail an alternative simulation strategy for lattice field theory based on the so-called worm algorithm introduced by Prokof'ev and Svistunov in 2001.

• It amounts to stochastically simulating the strong coupling expansion rather than the usual configuration sum.
• A detailed error analysis and an important generalization of the method are exemplified here in the simple Ising model.
• It allows for estimates of the two point function where in spite of exponential decay the signal to noise ratio does not degrade at large separation.