International Business Machines Corporation

Devin L Underwood

Jiri Stehlik

David Zajac

Timothy Phung

Matthias Steffen

Systems and techniques that facilitate mitigation of baseband pulse distortion via radiofrequency-to-baseband conversion are provided. In various embodiments, a system can comprise a qubit. In various aspects, the system can further comprise a signal generator that can produce a radiofrequency signal. In various instances, the system can further comprise a signal converter coupled between the qubit and the signal generator. In various cases, the signal converter can convert the radiofrequency signal into a baseband signal. In various aspects, such radiofrequency-to-baseband conversion can reduce a dispersion-induced distortion associated with driving the qubit.

Mitigating baseband pulse dispersion via radiofrequency-to-baseband conversion

Devices and/or computer-implemented methods to facilitate a quantum gate between qubits using a tunable coupler and a capacitor device are provided. According to an embodiment, a quantum coupler device can comprise a tunable coupler coupled between terminals of a same polarity of a first qubit and a second qubit, the tunable coupler configured to control a first coupling between the first qubit and the second qubit. The quantum coupler device can further comprise a capacitor device coupled to terminals of an opposite polarity of the first qubit and the second qubit, the capacitor device configured to provide a second coupling that is opposite in sign relative to the first coupling.

Tunable quantum coupler facilitating a quantum gate between qubits

Techniques for creating a low pass filter associated with a flux line are presented. A qubit device can comprise a first substrate and second substrate. A low pass filter, comprising at least one inductor and at least one capacitor can be formed, wherein respective components of or associated with the low pass filter can be formed on the first or second substrates, and wherein one or more bump bonds can extend between the substrates to connect respective components that are on respective substrates. The filter can receive an input signal via an input line and filter the signal to produce a filtered signal as output to a flux line that is in proximity to a coupler with SQUID loop and one or more flux-tunable qubits that are formed on one of the substrates. The filter can reduce electrical noise and Purcell decay associated with the flux line.

Flux line filter

A method of multiplexing control lines of a qubit array includes applying a qubit control signal to a single driveline. The qubit control signal is split on the single driveline between a first resonator and a second resonator. The first driveline is operative to control a first qubit, a second tunable qubit, a third qubit, and a fourth tunable qubit. The first qubit is coupled to the second tunable qubit by the first resonator. The third qubit is coupled to the fourth tunable qubit by the second resonator. A variation in amplitude of the qubit control signal is compensated by adjusting a frequency of the second tunable qubit and a frequency of the fourth tunable qubit.

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Bronx, NY, United States of America

Devin L Underwood