Circuit QED: Encoding quantum information in harmonic oscillators*

‘Circuit quantum electrodynamics’ is the theory of non-linear quantum optics extended to the study of microwave photons strongly interacting with ‘artificial atoms’ (Josephson junction qubits) embedded in superconducting electrical circuits. Recent remarkable theoretical and experimental progress in our ability to measure and manipulate the quantum states of individual microwave photons is leading to novel applications including: accelerating axion dark matter searches, using boson sampling to simulate the optical spectra of small molecules, and quantum error correction using bosonic codes that have successfully extended the lifetime of quantum information. This talk will present an elementary introduction to the basic concepts underlying circuit QED and describe several recent experiments demonstrating these novel capabilities [1,2].
[1] ‘Quantum information processing and quantum optics with circuit quantum electrodynamics,’ Alexandre Blais, Steven M. Girvin and William D. Oliver, Nature Physics 16, 247–256 (2020).
[2] ‘Circuit Quantum Electrodynamics,’ Alexandre Blais, Arne L. Grimsmo, S. M. Girvin, and Andreas Wallraff, arXiv:2005.12667.