Enhanced qubit readout using locally generated squeezing and inbuilt Purcell-decay suppression

We introduce and analyze a dispersive qubit readout scheme where two-mode squeezing is generated directly in the measurement cavities. The resulting suppression of noise enables fast, high-fidelity readout of naturally weakly coupled qubits, and the possibility to protect strongly coupled qubits fro...

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Bibliographic Details
Published inNew journal of physics Vol. 19; no. 2; pp. 23044 - 23058
Main Authors Govia, Luke C G, Clerk, Aashish A
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 23.02.2017
Subjects
Accuracy
Circuits
Compressing
Decay
Physics
quantum computing
quantum measurement
quantum metrology
squeezed light
Squeezed states (quantum theory)
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Summary:We introduce and analyze a dispersive qubit readout scheme where two-mode squeezing is generated directly in the measurement cavities. The resulting suppression of noise enables fast, high-fidelity readout of naturally weakly coupled qubits, and the possibility to protect strongly coupled qubits from decoherence by weakening their coupling. Unlike other approaches exploiting squeezing, our setup avoids the difficult task of transporting and injecting with high fidelity an externally generated squeezed state. Our setup is also surprisingly robust against unwanted non-QND backaction effects, as interference naturally suppresses Purcell decay: the system acts as its own Purcell filter. Our setup is compatible with the experimental state-of-the-art in circuit QED systems, but the basic idea could also be realized in other systems.
Bibliography:NJP-106173.R1
ISSN:1367-2630
1367-2630
DOI:10.1088/1367-2630/aa5f7b