Zero-temperature limit and statistical quasiparticles in many-body perturbation theory

中子物质的重整化群方法：准粒子相互作用、超流能隙和状态方程

Renormalization group approach to neutron matter: quasiparticle interactions, superfluid gaps and the equation of state

重整化群方法可以应用于核多体问题，采用Shankar提出的方法。我们从两体低动量相互作用V_{low k}出发，利用粒子-空穴通道的RG流计算费米面附近的全散射振幅。这是一个新的直接的方法来解决多体问题，这也适用于凝聚态系统没有长程相互作用，如液体3 He。导出了零温下准粒子相互作用的单圈重整化群方程和散射振幅。RG提出了一个优雅的方法，以保持所有的动量尺度和保持反对称的散射振幅。作为第一个应用程序，我们解决RG方程的中子物质。由此产生的准粒子相互作用包括由于介质的极化而产生的效应，即所谓的巴布和布朗的诱导相互作用。给出了费米液体参数、中子物质状态方程和1 S 0超流对隙的计算结果。

Projection on particle number and angular momentum: Example of triaxial Bogoliubov quasiparticle states

Many quantal many-body methods that aim at the description of self-bound nuclear or mesoscopic electronic systems make use of auxiliary wave functions that break one or several of the symmetries of the Hamiltonian in order to include correlations associated with the geometrical arrangement of the system's constituents. Such reference states have been used already for a long time within self-consistent methods that are either based on effective valence-space Hamiltonians or energy density functionals, and they are presently also gaining popularity in the design of novel ab-initio methods. A ful…

Many-body approach to superfluid nuclei in axial geometry

Starting from a general many-body fermionic Hamiltonian, we derive the equations of motion (EOM) for nucleonic propagators in a superfluid system. The resulting EOM is of the Dyson type formulated in the basis of Bogoliubov's quasiparticles. As the leading contributions to the dynamical kernel of this EOM in strongly-coupled regimes contain phonon degrees of freedom in various channels, an efficient method of calculating phonon's characteristics is required to successfully model these kernels. The traditional quasiparticle random phase approximation (QRPA) solvers are typically used for this p…

准粒子性质的从头算描述

Toward an Ab-initio Description of Quasiparticle Properties

多体格林函数理论在He-4基态的初步从头算应用表明，在所谓的Faddeev随机相位近似方法中可以实现高精度。我们强调的潜力，这种方法的显微镜研究中大型核和报告的应用程序1 s 0 d和1 p0 f壳核。特别是，我们讨论了光谱因素和它们的依赖不对称的长程相关性的作用。

有效场论中的准粒子性质

Quasiparticle Properties in Effective Field Theory

准粒子概念是描述多体系统的重要工具。利用有效场论研究了具有短程排斥作用的稀费米系统的准粒子性质。我们计算了（K_f/λ）^[3]量级的固有自能贡献，其中λ是确定有效射程参数大小的短距离标度，K_f是费米动量。准粒子的能量、宽度和有效质量都是由计算出的自能导出的，其量级为O（K_f/λ）^[3]。

Towards a Unified Description of Isoscalar Giant Monopole Resonances in a Self-Consistent Quasiparticle-Vibration Coupling Approach

"Why is the EoS for tin so soft?" is a longstanding question, which prevents us from determining the nuclear incompressibility $K_\infty$ accurately. To solve this puzzle, a fully self-consistent quasiparticle random phase approximation (QRPA) plus quasiparticle-vibration coupling (QPVC) approach based on Skyrme-Hartree-Fock-Bogoliubov is developed. We show that the many-body correlations introduced by QPVC, which shift the ISGMR energy in Sn isotopes by about 0.4 MeV more than the energy in $^{208}$Pb, play a crucial role in providing a unified description of the ISGMR in Sn and Pb isotopes. …

丰中子核天体物理直接中子俘获反应的连续准粒子无规相近似

Continuum quasiparticle random phase approximation for astrophysical direct neutron capture reaction of neutron-rich nuclei

采用Hartree-Fock-Bogoliubov平均场模型和连续准粒子无规相近似（QRPA），建立了计算直接辐射中子俘获反应截面的多体理论.重点放在非常丰富的中子核和低能量中子动能的范围内的O（1 keV）- O（1 MeV），相关的快速中子俘获过程的核合成。我们从光吸收截面和E1强度函数出发，为了应用倒易定理，我们将光吸收截面分解为对应于光激发态单中子和双中子发射衰变不同通道的部分截面。数值计算了$^{142}$ Sn的光吸收和$^{141}$ Sn的中子俘获。

Many-body perturbation theories for finite nuclei

In recent years many-body perturbation theory encountered a renaissance in the field of ab initio nuclear structure theory. In various applications it was shown that perturbation theory, including novel flavors of it, constitutes a useful tool to describe atomic nuclei, either as a full-fledged many-body approach or as an auxiliary method to support more sophisticated non-perturbative many-body schemes. In this work the current status of many-body perturbation theory in the field of nuclear structure is discussed and novel results are provided that highlight its power as a efficient and yet ac…