Quantum computing and condensed matter physics with microwave photons

Observation of a dissipative phase transition in a one-dimensional circuit QED lattice

Mattias Fitzpatrick, Neereja Sundaresan, Andy C. Y. Li, Jens Koch, and A. A. Houck

Condensed matter physics has been driven forward by significant experimental and theoretical progress in the study and understanding of equilibrium phase transitions based on symmetry and topology. However, nonequilibrium phase transitions have remained a challenge, in part due to their complexity in theoretical descriptions and the additional experimental difficulties in systematically controlling systems out of equilibrium.

Quantum Electrodynamics Near a Photonic Band-Gap

Yanbing Liu and Andrew A. Houck

Photonic crystals provide an extremely powerful toolset for manipulation of optical dispersion and density of states, and have thus been employed for applications from speelautomaten photon generation to quantum sensing with NVs and atoms.

Suppresion of Photon Shot Noise Dephasing in a Tunable Coupling Superconducting Qubit

Gengyan Zhang, Yanbing Liu, James J. Raftery, and Andrew A. Houck

We demonstrate the suppression of photon shot noise dephasing in a superconducting qubit by eliminating its dispersive coupling to the readout cavity. This is achieved in a tunable coupling qubit, where the qubit frequency and coupling rate can be controlled independently. We observe that the coherence time approaches twice the relaxation time and becomes less sensitive to thermal photon noise when the dispersive coupling rate is tuned from several MHz to 22 kHz.

Digital Quantum Simulators in a Scalable Architecture of Hybrid Spin-Photon Qubits

A. Chiesa, P. Santini, D. Gerace, J. Raftery, A. A. Houck, and S. Carretta

Resolving quantum many-body problems represents one of the greatest challenges in physics and physical chemistry, due to the prohibitively large computational resources that would be required by using classical computers. A solution has been foreseen by directly simulating the time evolution through sequences of quantum gates applied to arrays of qubits, i.e. by implementing a digital quantum simulator.

Broadband Filters for Abatement of Spontaneous Emission in Circuit Quantum Electrodynamics

Nicholas T. Bronn, Yanbing Liu, Jared B. Hertzberg, Antonio D. C ́orcoles, Andrew A. Houck, Jay M. Gambetta, and Jerry M. Chow


Imaging Photon Lattice States by Scanning Defect Microscopy

D. L. Underwood, W. E. Shanks, Andy C. Y. Li, Lamia Ateshian, Jens Koch, A. A. Houck

Microwave photons inside lattices of coupled resonators and superconducting qubits can exhibit surprising matter-like behavior. Realizing such open-system quantum simulators presents an experimental challenge and requires new tools and measurement techniques. Here, we introduce Scanning Defect Microscopy as one such tool and illustrate its use in mapping the normal-mode structure of microwave photons inside a 49-site Kagome lattice of coplanar waveguide resonators. Scanning is accomplished by moving a probe equipped with a sapphire tip across the lattice.