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arXiv · 1610.10065

Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling

N. K. Langford·R. Sagastizabal·M. Kounalakis·C. Dickel·A. Bruno·F. Luthi·D. J. Thoen·A. Endo·L. DiCarlo
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Abstract

The quantum Rabi model describing the fundamental interaction between light and matter is a cornerstone of quantum physics. It predicts exotic phenomena like quantum phase transitions and ground-state entanglement in the ultrastrong-coupling (USC) regime, where coupling strengths are comparable to subsystem energies. Despite progress in many experimental platforms, the few experiments reaching USC have been limited to spectroscopy: demonstrating USC dynamics remains an outstanding challenge. Here, we employ a circuit QED chip with moderate coupling between a resonator and transmon qubit to realise accurate digital quantum simulation of USC dynamics. We advance the state of the art in solid-state digital quantum simulation by using up to 90 second-order Trotter steps and probing both subsystems in a combined Hilbert space dimension $\sim80$, demonstrating the Schrödinger-cat like entanglement and build-up of large photon numbers characteristic of deep USC. This work opens the door to exploring extreme USC regimes, quantum phase transitions and many-body effects in the Dicke model.

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N. K. Langford, R. Sagastizabal, M. Kounalakis, C. Dickel, A. Bruno, F. Luthi, D. J. Thoen, A. Endo, L. DiCarlo. 2016-10-31. Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling. https://doi.org/10.1038/s41467-017-01061-x

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