Hopping parameter expansion to all orders using the complex Langevin equation

Understand

We propose two novel formulations of the hopping parameter expansion for finite density QCD using Wilson fermions, while keeping the gauge action intact.

• We use the complex Langevin equation to circumvent the sign problem in the theory.
• We perform simulations at very high order of the expansion, such that convergence is directly observable.
• We compare results to the full QCD results, and see agreement at sufficiently high orders.