We present predictions for the neutron matter equation of state, from leading to fourth order of chiral effective field theory, using recently developed, accurate chiral nucleon-nucleon potentials. For the many-body method, we employ the nonperturbative particle-particle ladder approximation, that is, we solve the $G$-matrix equation. We find the impact of subleading three-neutron forces to be mild and attractive. We also show order-by-order predictions for the symmetry energy, and discuss its density dependence in relation to empirical constraints. For the nuclear matter equation of state, in this work we adopt an empirical parametrization with good saturation properties. This is to highlight, specifically, the energy and pressure in neutron matter, particularly when comparing with empirical constraints.

中文翻译：

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手征有效场论四阶以下的中子物质状态方程和对称能分析

我们使用最近开发的准确手性核子-核子势，对中子物质状态方程进行了预测，从导致手性有效场理论的四阶。对于多体方法，我们采用非微扰粒子-粒子阶梯近似，即我们求解$G$-矩阵方程。我们发现子引三中子力的影响是温和而有吸引力的。我们还展示了对对称能量的逐级预测，并讨论了与经验约束相关的密度依赖性。对于核物质状态方程，在这项工作中，我们采用具有良好饱和特性的经验参数化。这是为了突出中子物质中的能量和压力，特别是在与经验约束进行比较时。