Compressing Green's function using intermediate representation between imaginary-time and real-frequency domains
This work provides a general framework to enhance diagrammatic and quantum Monte Carlo methods for many-body systems, though it appears incremental as it builds on prior numerical findings.
The authors tackled the problem of compactly representing imaginary-time data in many-body systems by introducing an intermediate representation (IR) method, which they demonstrated on an Anderson impurity model using quantum Monte Carlo calculations, achieving significantly compressed forms of correlation functions.
New model-independent compact representations of imaginary-time data are presented in terms of the intermediate representation (IR) of analytical continuation. This is motivated by a recent numerical finding by the authors [J. Otsuki et al., arXiv:1702.03056]. We demonstrate the efficiency of the IR through continuous-time quantum Monte Carlo calculations of an Anderson impurity model. We find that the IR yields a significantly compact form of various types of correlation functions. The present framework will provide general ways to boost the power of cutting-edge diagrammatic/quantum Monte Carlo treatments of many-body systems.