Measuring the imaginary-time dynamics of quantum materials. Issue 19 (1st October 2020)

• Record Type: Journal Article
• Authors: Lederer, S.; Jost, D.; Böhm, T.; Hackl, R.; Berg, E.; Kivelson, S. A.
• Is Part Of: Philosophical magazine. Volume 100:Issue 19(2020)
• Page Start: 2477
• Page End: 2490
• Publication Date: 2020-10-01
• Subjects: Quantum critical phenomena -- spectroscopy -- strongly correlated electrons; Condensed matter -- Periodicals; Physics -- Periodicals; Matière condensée -- Périodiques; Physique -- Périodiques; 530.41
• DOI: 10.1080/14786435.2020.1768604
• Languages: English
• ISSNs: 1478-6435

Abstract

ABSTRACT: Theoretical analysis typically involves imaginary-time correlation functions. Inferring real-time dynamical response functions from this information is notoriously difficult. However, as we articulate here, it is straightforward to compute imaginary-time correlators from the measured frequency dependence of (real-time) response functions. In addition to facilitating comparison between theory and experiment, the proposed approach can be useful in extracting certain aspects of the (long-time relaxational) dynamics from a complex data set. We illustrate this with an analysis of the nematic response inferred from Raman scattering spectroscopy on the iron-based superconductor B a ( F e 1 − x C o x ) 2 A s 2, which includes a new method for identifying a putative quantum-critical contribution to that response.