标题： 量子蒙特卡罗计算中子物质 显示英文标题

标题： Quantum Monte Carlo Calculations of Neutron Matter

摘要： 均匀中子物质被近似为一个包含有限数量中子的立方箱，具有周期性边界条件。 我们报告了使用阿贡$\vep $两核相互作用在密度高达核物质密度的一倍半的情况下，对周期箱中十四个中子基态的变分和格林函数蒙特卡洛计算。 通过变分波函数结合簇展开和链求和技术来估计有限箱尺寸的影响。 在亚核密度下，这些影响较小。 我们讨论了低密度中子气体能量按费米动量幂次的展开。 这种展开受到大的 nn 散射长度的强烈影响，并不以费米气体动能作为起始项，这与斯科尔梅和相对论平均场理论中的假设不同。 中子气体能量的主要项约为费米气体动能的一半。 量子蒙特卡洛结果还用于校准采用费米超网状和单算符链求和方法的变分计算的准确性，以研究更大密度范围内的核子物质，并使用包含三核子相互作用的更现实的哈密顿量。 显示英文摘要

摘要： Uniform neutron matter is approximated by a cubic box containing a finite number of neutrons, with periodic boundary conditions. We report variational and Green's function Monte Carlo calculations of the ground state of fourteen neutrons in a periodic box using the Argonne $\vep $ two-nucleon interaction at densities up to one and half times the nuclear matter density. The effects of the finite box size are estimated using variational wave functions together with cluster expansion and chain summation techniques. They are small at subnuclear densities. We discuss the expansion of the energy of low-density neutron gas in powers of its Fermi momentum. This expansion is strongly modified by the large nn scattering length, and does not begin with the Fermi-gas kinetic energy as assumed in both Skyrme and relativistic mean field theories. The leading term of neutron gas energy is ~ half the Fermi-gas kinetic energy. The quantum Monte Carlo results are also used to calibrate the accuracy of variational calculations employing Fermi hypernetted and single operator chain summation methods to study nucleon matter over a larger density range, with more realistic Hamiltonians including three-nucleon interactions.