Fast reset and suppressing spontaneous emission of a superconducting qubit

By M. Reed, Blake R. Johnson, Andrew A. Houck, Leonardo DiCarlo, Jerry M. Chow, David I. Schuster, Luigi Frunzio, Robert J. Schoelkopf. 2010

320 citations recorded by the source corpus.

Spontaneous emission through a coupled cavity can be a significant decay channel for qubits in circuit quantum electrodynamics. We present a circuit design that effectively eliminates spontaneous emission due to the Purcell effect while maintaining strong coupling to a low-Q cavity. Excellent agreement over a wide range in frequency is found between measured qubit relaxation times and the predictions of a circuit model. Using fast (nanosecond time-scale) flux biasing of the qubit, we demonstrate in situ control of qubit lifetime over a factor of 50. We realize qubit reset with 99.9% fidelity in 120 ns.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/f18a8dfee2216a64d731ac4a8a46087635f6f33a

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Circuit QED: Superconducting Qubits Coupled to Microwave Photons (2015, background): “Dissipation into a cold resistor can in fact be useful for qubit reset(Reed et al., 2010b) to the ground state since reset requires removal of entropy to a cold bath.”
Rapid High-fidelity Multiplexed Readout of Superconducting Qubits (2018, methodology): “Furthermore, the use of Purcell filters [11, 20, 21] led to the implementation of faster readout circuits resulting in a reduction of the readout time down to 50 ns for a single qubit without introducing additional qubit decay [22].”
Circuit quantum electrodynamics (2020, background): “…while the non-QNDness at moderate measurement photon number mentioned above leads to small measurement fidelity, it was observed by a fearless graduate student that, in the limit of very large measurement power, a fast and high-fidelity single-shot readout is recovered (Reed et al., 2010a).”
Low-Disorder Microwave Cavity Lattices for Quantum Simulation with Photons (2012, background): “For quantum information processing it is often preferable to operate within this limit because the qubit will not directly absorb cavity photons [12], furthermore the Purcell effect on the qubit is weaker when the qubit is energetically far away from the cavity [85].”
Single-Shot Quantum Nondemolition Detection of Individual Itinerant Microwave Photons (2017, methodology): “Both resonators are coupled to a Purcell filter [29], allowing a large bandwidth of readout and detection while protecting the qubit from Purcell decay into the output lines.”