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arXiv · 2212.09047

Probing many-body correlations using quantum-cascade correlation spectroscopy

Lorenzo Scarpelli·Cyril Elouard·Mattias Johnsson·Martina Morassi·Aristide Lemaitre·Iacopo Carusotto·Jacqueline Bloch·Sylvain Ravets·Maxime Richard·Thomas Volz
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Abstract

The radiative quantum cascade, i.e. the consecutive emission of photons from a ladder of energy levels, is of fundamental importance in quantum optics. For example, the two-photon cascaded emission from calcium atoms was used in pioneering experiments to test Bell inequalities. In solid-state quantum optics, the radiative biexciton-exciton cascade has proven useful to generate entangled-photon pairs. More recently, correlations and entanglement of microwave photons emitted from a two-photon cascaded process were measured using superconducting circuits. All these experiments rely on the highly non-linear nature of the underlying energy ladder, enabling direct excitation and probing of specific single-photon transitions. Here, we use exciton polaritons to explore the cascaded emission of photons in the regime where individual transitions of the ladder are not resolved, a regime that has not been addressed so far. We excite a polariton quantum cascade by off-resonant laser excitation and probe the emitted luminescence using a combination of spectral filtering and correlation spectroscopy. Remarkably, the measured photon-photon correlations exhibit a strong dependence on the polariton energy, and therefore on the underlying polaritonic interaction strength, with clear signatures from two- and three-body Feshbach resonances. Our experiment establishes photon-cascade correlation spectroscopy as a highly sensitive tool to provide valuable information about the underlying quantum properties of novel semiconductor materials and we predict its usefulness in view of studying many-body quantum phenomena.

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BibTeXRIS

Lorenzo Scarpelli, Cyril Elouard, Mattias Johnsson, Martina Morassi, Aristide Lemaitre, Iacopo Carusotto, Jacqueline Bloch, Sylvain Ravets, Maxime Richard, Thomas Volz. 2022-12-18. Probing many-body correlations using quantum-cascade correlation spectroscopy. https://doi.org/10.1038/s41567-023-02322-x

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