Papers Published

1. Crain, S; Cahall, C; Vrijsen, G; Wollman, EE; Shaw, MD; Verma, VB; Nam, SW; Kim, J, High-speed low-crosstalk detection of a ¹⁷¹Yb⁺ qubit using superconducting nanowire single photon detectors, Communications Physics, vol. 2 no. 1 (December, 2019) [doi] .
   (last updated on 2025/04/18)

   Abstract:
   Qubits used in quantum computing suffer from errors, either from the qubit interacting with the environment, or from imperfect quantum logic gates. Effective quantum error correcting codes require a high fidelity readout of ancilla qubits from which the error syndrome can be determined without affecting data qubits. Here, we present a detection scheme for 171Yb+ qubits, where we use superconducting nanowire single photon detectors and utilize photon time-of-arrival statistics to improve the fidelity and speed. Qubit shuttling allows for creating a separate detection region where an ancilla qubit can be measured without disrupting a data qubit. We achieve an average qubit state detection time of 11 μs with a fidelity of 99.931(6). The detection crosstalk error, defined as the probability that the data qubit coherence is lost due to the process of detecting an ancilla qubit, is reduced to ~2 × 10−5 by creating a separation of 370 μm between them.