Emergent causality and the N-photon scattering matrix in waveguide QED

Sánchez-Burillo, E. ; Cadarso, A. ; Martín-Moreno, L. (Universidad de Zaragoza) ; García-Ripoll, J.J. ; Zueco, D. (Universidad de Zaragoza)

Resumen: In this work we discuss the emergence of approximate causality in a general setup from waveguide QED - i.e. a one-dimensional propagating field interacting with a scatterer. We prove that this emergent causality translates into a structure for the N-photon scattering matrix. Our work builds on the derivation of a Lieb-Robinson-type bound for continuous models and for all coupling strengths, as well as on several intermediate results, of which we highlight: (i) the asymptotic independence of space-like separated wave packets, (ii) the proper definition of input and output scattering states, and (iii) the characterization of the ground state and correlations in the model. We illustrate our formal results by analyzing the two-photon scattering from a quantum impurity in the ultrastrong coupling regime, verifying the cluster decomposition and ground-state nature. Besides, we generalize the cluster decomposition if inelastic or Raman scattering occurs, finding the structure of the -matrix in momentum space for linear dispersion relations. In this case, we compute the decay of the fluorescence (photon-photon correlations) caused by this S-matrix.

Idioma: Inglés

DOI: 10.1088/1367-2630/aa9cc2

Año: 2018

Publicado en: NEW JOURNAL OF PHYSICS 20, 1 (2018), 013017 [20 pp]
ISSN: 1367-2630

Factor impacto JCR: 3.773 (2018)

Categ. JCR: PHYSICS, MULTIDISCIPLINARY rank: 12 / 81 = 0.148 (2018) - Q1 - T1

Factor impacto SCIMAGO: 1.664 - Physics and Astronomy (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/CAM/QUITEMAD-S2013-ICE-2801
Financiación: info:eu-repo/grantAgreement/ES/DGA/FENOL-GROUP
Financiación: info:eu-repo/grantAgreement/ES/MINECO/FIS2015-70856-P
Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2014-53432-C5-1-R

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)