Accelerating convergence to the thermodynamic limit with twist angle selection applied to methods beyond many-body perturbation theory

Perturbation Theory Methods Applied to Critical Phenomena

Different perturbation theory treatments of the Ginzburg–Landau phase transition model are discussed. This includes a criticism of the perturbative renormalization group (RG) approach and a proposal of a novel method providing critical exponents consistent with the known exact solutions in two dimensions. The new values of critical exponents are discussed and compared to the results of numerica...

Convergence of iterative methods applied to Burgers-Huxley equation

Third-order many-body perturbation theory applied to Kondo-type dynamics in diluted magnetic semiconductors

Introduction to Green functions and many-body perturbation theory

2 The single-particle retarded Green function and its spectral function 4 2.1 Retarded, advanced, “greater”, and “lesser” single-particle Green functions . 4 2.2 The meaning of 〈· · ·〉 and the time dependence . . . . . . . . . . . . . . . . . 5 2.3 Some other forms of the Green functions . . . . . . . . . . . . . . . . . . . . 6 2.3.1 Transformations to other bases . . . . . . . . . . . . . . ....

Introduction to Green functions and many-body perturbation theory

2 The single-particle retarded Green function and its spectral function 4 2.1 Retarded, advanced, “greater”, and “lesser” single-particle Green functions . 4 2.2 The meaning of 〈· · ·〉 and the time dependence . . . . . . . . . . . . . . . . . 5 2.3 Some other forms of the Green functions . . . . . . . . . . . . . . . . . . . . 6 2.3.1 Transformations to other bases . . . . . . . . . . . . . . ....