Quantum Monte Carlo Calculations of Nucleon Systems

核子系统的量子蒙特卡罗计算

• 批准号: 1404405
• 负责人: Kevin Schmidt
• 金额: $ 33万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404405&HistoricalAwards=false
• 关键词: Quantum; Monte; Carlo; Calculations; Nucleon

Many nuclear processes in our universe occur under extreme conditions in supernovae and neutron stars. The properties of nuclei and nuclear matter under these conditions, which are difficult or impossible to reproduce in the laboratory, must necessarily be calculated theoretically. These data are needed to understand astrophysically important systems and processes such as neutron rich matter, neutron stars, supernovae, and r-process nucleosynthesis and neutrino scattering. The quantum many-particle methods developed within this project have broad applications across many areas of physics. These include the nuclear physics aspects directly relating to the project, cold atomic gas research, and electronic structure. Methods previously developed within this project have been applied in each of these areas. The project will train both undergraduate and graduate students, give them exposure at national and international conferences, and provide for dissemination of the results.This project will continue work developing and using accurate techniques to calculate the properties of nuclei and nuclear matter using quantum Monte Carlo methods, i.e. stochastic sampling methods for the large number of quantum degrees of freedom. A primary aim is to develop auxiliary field quantum Monte Carlo methods to sample both the space and spin-isospin degrees of freedom of protons and neutrons in nuclei with all important parts of the nuclear interaction. These include both the spin-orbit and three-body interactions. New wave functions which can be efficiently evaluated for nuclei are being developed, with the goal of obtaining accurate properties for medium to large and neutron rich nuclei. Superfluidity has major consequences in neutron star matter. The investigator and his students will use the same methods to study both the nuclear systems and the related phenomena in cold atomic gases. Many of the pairing and superfluid mechanisms important in nuclei and nuclear matter can be studied and verified in these systems where detailed experimental measurements can be made using table-top experimental setups.

我们宇宙中的许多核过程发生在超新星和中子星的极端条件下。在这些条件下，原子核和核物质的性质是很难或不可能在实验室中再现的，必须从理论上进行计算。这些数据是理解天体物理上重要的系统和过程所必需的，如富中子物质、中子星、超新星、r过程核合成和中微子散射。在这个项目中开发的量子多粒子方法在物理学的许多领域都有广泛的应用。这些方面包括与该项目直接相关的核物理方面、冷原子气体研究和电子结构。以前在该项目内制定的方法已应用于上述每一个领域。该项目将培养本科生和研究生，让他们在国内和国际会议上露面，并提供结果的传播。该项目将继续开发和使用精确的技术来计算原子核和核物质的性质，使用量子蒙特卡罗方法，即大量量子自由度的随机抽样方法。主要目的是发展辅助场量子蒙特卡罗方法来采样原子核中质子和中子的空间自由度和自旋-同位旋自由度，以及核相互作用的所有重要部分。这既包括自旋轨道相互作用，也包括三体相互作用。可以有效地评估原子核的新的波函数正在被开发，目的是获得中到大和丰中子核的准确性质。超流性对中子星物质有重大影响。研究人员和他的学生将使用相同的方法来研究核系统和冷原子气体中的相关现象。在原子核和核物质中，许多重要的配对和超流体机制可以在这些系统中研究和验证，其中详细的实验测量可以使用桌面实验装置进行。