WebB Imaginary-time formalism 153 ... time-path formalism of Schwinger and Keldysh is extended by an imaginary-time path, leading to a unification of the real-time methods with the older imaginary-time (Matsubara) formalism via ana-lytic continuition. Later, we shall consider more generall off-equilibrium situations, concentrating Webas the Schwinger-Keldysh formalism [18, 19], often used in more general spacetimes. This formalism agrees with the so-called in-in (also known as closed-time path or real-time) formalism of quantum field theory if the con-dition called factorization is satisfied [20]. In the in-in for-malism, one computes expectation values and correlation
Lecture Notes1, Theory of Condensed Matter II, Karlsruhe ... - KIT
Web33.2 Effective actions from Schwinger proper time The next method we discuss for computing effective actions is through Schwinger proper time. The idea here is to evaluate the propagator for the particle we want to integrate out as a functional of the other fields. Pictorially, we can write this as GA(x,y) = + + +··· . (33.8) WebA. From the quantum master equation to the Keldysh functional integral11 B. Examples16 1. Single-mode cavity, and some exact properties16 2. Driven-dissipative condensate20 C. Semiclassical limit of the Keldysh action21 D. Symmetries of the Keldysh action23 1. Thermodynamic equilibrium as a symmetry of the Keldysh action24 2. manuka catholic church
A mathematical account of the NEGF formalism
Web27 Oct 2014 · Lecture 14: Open quantum systems: quantum process formulation Mohan Sarovar (Dated: October 27, 2014) I. TWO MISSING PIECES Before we start on the bulk of this lecture, we need to cover two concepts that haven’t been covered so far. The rst is the concept of the entropy of a quantum state, which is de ned as: S(ˆ) = tr(ˆlogˆ) (1) Webnon-equilibrium states is introduced: Schwinger’s closed time path formulation of non-equilibrium quantum field theory, quantum statistical mechanics. Perturbation theory for non-equilibrium states is constructed starting from the canonical operator formalism presented in the previous chapters. In Chapter 5 we develop the real-time WebSchwinger-Keldysh superspace in quantum mechanics Michael Geracie,1,* Felix M. Haehl,2,† R. Loganayagam,3,‡ Prithvi Narayan,3,§ David M. Ramirez,1,∥ and Mukund Rangamani1,¶ 1Center for Quantum Mathematics and Physics (QMAP), Department of Physics, University of California, Davis, California 95616, USA 2Department of Physics and … kpmg herbalife