Zurich Instruments offers Quantum Computing researchers a fast track to unleashing the power of parametric amplification for qubit readout. While being critical to achieve the high measurement speed and low error rates needed for quantum error correction, parametric amplification often requires dedicated control electronics for microwave signal conditioning.

Figure 1: A fast track to unleashing the power of parametric amplification for qubit readout.

Figure 1 shows thatthe new SHFPPC Parametric Pump Controller, users have, for the first time, access to a fully integrated solution, eliminating the need for home-built designs, and automating a core piece of parameter tuning.

High-fidelity and fast qubit readout are critical for feedback operations in Quantum Computing. Near-quantum-limited parametric amplification is the state-of-the-art technology to maximize performance in these parameters, without compromising on quantum processor or algorithm design. [1]

In many implementations of parametric amplification, it is necessary to cancel the high-power pump tone required to drive these amplifiers in the readout return signal, to avoid degrading the performance of the subsequent amplification stages. [2]

Obtaining the lowest possible level of noise is critical in building quantum computers. And one of the key areas that engineers look at is the circuitry to readout the qubit state for measurement. For this reason, engineers designing superconducting or spin qubit quantum processors can often choose to use parametric amplifiers for amplifying the readout signals after they are detected.

These amplifiers can provide a significantly lower noise figure because they operate by varying the capacitance in a varactor diode rather than using resistance elements that generate thermal noise as used in a more traditional transistor amplifier. The result will be lower noise when reading out qubit status resulting in improved measurement fidelity and fewer errors.

To facilitate the use of parametric amplifiers, Zurich Instruments has introduced their SHFPPC parametric amplifier controller that generates the necessary pump signals and active pump tone cancellation so that parametric amplification can be used.

The unit is available to support either 2 channels or 4 channels, but since many of the newer designs now have multiple qubits per readout channel, the number of qubits that can be readout with this technique will be greater.[3]

The signal conditioning units feature an operating frequency band from 5 to 10 GHz and an automatic self-cancellation of the pump tone at the touch of a button. For rapid tune-up, characterization, or performance monitoring it is possible to generate a probe tone signal together with a pump tone signal on a single output port. [1]

References:

1. https://thequantumhubs.com/zurich-instruments-introduces-qubit-amplifier-controller/
2. https://thequantuminsider.com/2022/08/03/zurich-instruments-introduces-amplifier-controller-for-easy-access-to-high-fidelity-qubit-readout/
3. https://quantumcomputingreport.com/zurich-instruments-introduces-a-parametric-amplifier-controller/

Cite this article:

Sri Vasagi K (2022), New Technique to Unleash the Power of Amplification for Qubit Readout, Anatechmaz, pp.64