Perturbation Calculation of Charge Radii in Nuclear Lattice Effective Field Theory

With recent years of development, Nuclear Lattice Effective Field Theory (NLEFT) is becoming a powerful and high-fidelity ab initio method. It takes advantage of the chiral effective field theory and quantum Monte Carlo on lattice and can build nuclear forces and solve quantum many-body problems in the same framework. The newly developed wave function matching method and perturbative quantum Monte Carlo method pave the way to avoid the "sign problem". In this work, we implement all these new techniques along with the two-point correlation function to measure the charge radii on lattice. Benchmark calculations show our method is solid and full N³LO calculation can well reproduce the experiment data of ⁴He, ¹²C and ¹⁶O.