Signatures of a dissipative phase transition in photon correlation measurements

• Published in: Nature physics Vol. 14; no. 4; pp. 365 - 369
• Main Authors: Fink, Thomas, Schade, Anne, Höfling, Sven, Schneider, Christian, Imamoglu, Ataç
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2018; Nature Publishing Group
• Subjects: 639/624/400/2797; 639/624/400/385; 639/624/400/482; Atomic; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Correlation analysis; Dissipation; Gallium arsenide; Interferometry; Letter; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; Optical bistability; Phase transitions; Physics; Physics and Astronomy; Polaritons; Quantum phenomena; Theoretical
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/s41567-017-0020-9

Understanding and characterizing phase transitions in driven-dissipative systems constitutes a new frontier for many-body physics 1 – 8 . A generic feature of dissipative phase transitions is a vanishing gap in the Liouvillian spectrum 9 , which leads to long-lived deviations from the steady state as the system is driven towards the transition. Here, we show that photon correlation measurements can be used to characterize the corresponding critical slowing down of non-equilibrium dynamics. We focus on the extensively studied phenomenon of optical bistability in GaAs cavity polaritons 10 , 11 , which can be described as a first-order dissipative phase transition 12 – 14 . Increasing the excitation strength towards the bistable range results in an increasing photon-bunching signal along with a decay time that is prolonged by more than nine orders of magnitude as compared with that of single polaritons. In the limit of strong polariton interactions leading to pronounced quantum fluctuations, the mean-field bistability threshold is washed out. Nevertheless, the functional form with which the Liouvillian gap closes as the thermodynamic limit is approached provides a signature of the emerging dissipative phase transition. Our results establish photon correlation measurements as an invaluable tool for studying dynamical properties of dissipative phase transitions without requiring phase-sensitive interferometric measurements. Photon correlation measurements in driven-dissipative systems reveal the dynamical properties of dissipative phase transitions, as shown for optical bistability of cavity polaritons in GaAs.