Modifying partition functions: a way to solve the sign problem

Understand

A possible method to solve the sign problem is developed by modifying the original theory.

• Considering several modifications of the partition function, the observable in the original theory is reconstructed from the identity connecting the observables in the original and modified theories.
• We demonstrate that our method gives the correct results even if the original theory has the severe sign problem by using a simple 1-dimensional integral.