訊號輸入

量子比特測量單元

訊號輸出

讀出脈衝產生器

一般規格

¹ 所有波形存儲模組均可自由配置和觸發。

The Zurich Instruments SHFQA Quantum Analyzer integrates in a single instrument a full real-time readout setup for up to 64 superconducting and spin qubits. The SHFQA operates in a frequency range from 0.5 to 8.5 GHz with a clean analysis bandwidth of 1 GHz and without the need for mixer calibration. Each of its 2 or 4 readout channels can analyze up to 16 qubits, 8 qutrits or 5 ququads. For the 2-channel instrument, this performance requires the SHFQA-16W option.

The SHFQA enables multi-state discrimination with optimal signal-to-noise ratio and minimal latency thanks to its advanced sequencer and its low-latency signal processing chain with matched filters and result correlation. The data are transmitted in real time to other instruments for active qubit reset or global error correction protocols. Controlled through the LabOne software suite comprising the user interface, several APIs and the LabOne QCCS control software, the SHFQA supports quantum computing projects with sizes ranging from a few to several hundreds of qubits.

Applications

Quantum computing applications

• Frequency-multiplexed readout
• Single-shot dispersive readout
• Resonator spectroscopy and characterization
• Real-time, low-latency and global feedback for error correction

Supported qubit types

• Superconducting qubits
• Spin qubit/superconducting resonator hybrids
• Qubits, qutrits and ququads

Other applications

• Amplifier noise characterization
• External IQ mixer calibration

Highlights

Fast readout with high fidelity
Zurich Instruments SHFQA Quantum Analyzer analysis chain
The SHFQA performs pulsed measurements to determine the transmission amplitude and phase of the device under test. There are two methods to maximize the signal-to-noise ratio (SNR): pulse shaping and matched filtering. Pulse shaping with an arbitrary waveform generator minimizes the ring-up and ring-down time even for a device with a slow response.

The step response of the SHFQA's digital filters can be matched to the transient response of the device by programming a 4-kSa-long weight function for each filter. Compared to a simple, unweighted integration, applying a properly matched filter significantly improves the SNR. In addition, the real-time analysis chain makes it possible to discriminate up to 4 states per qubit and to correlate the qubit results.

Scalable quantum setup
Measuring 16 qubits or 8 qutrits on a single microwave line means optimizing the cryogenic amplification chain. The freely configurable integration weights reduce qubit crosstalk and, consequently, relax tolerances in device fabrication. The memory blocks (up to 16) in the arbitrary waveform generator enable the readout and trigger readout of the qubits, qutrits or ququads in a time-staggered manner. The possibility to choose 2 or 4 readout channels, and to extend the number of integration weights from 8 to 16 for the 2-channel version (with the SHFQA-16W option), means that users can tailor the instrument to their specific system requirements.

For maximum integration, the SHFQA can be efficiently interfaced with other instruments too. For example, the low-latency 32-bit DIO VHDCI interface enables feed-forward of the multi-qubit state to a few HDAWGs for fast active qubit reset. For systems with larger qubit counts, several SHFQAs, SHFSGs, HDAWGs, and a PQSC can be combined to form a scalable Quantum Computing Control System (QCCS). The Zurich Instruments ZSync interface links the SHFQA to all other instruments in the QCCS through the central PQSC, which is especially important for global error correction protocols.

Clean and calibration-free frequency conversion to 8.5 GHz
When reading out multiple qubits through resonators coupled to the same readout line, even small spurs can lead to a confusing or smaller readout signal if they are sub-optimally located. As the SHFQA's double superheterodyne up- and down-conversion scheme up to 8.5 GHz relies on filtering rather than on interference, it performs over a wider frequency band and with better linearity than standard IQ-mixer-based conversion. As a result, even a single tone can be generated with fewer spurs and straight out of the box. Importantly, the performance is stable and does not require tedious mixer calibrations. This approach, combined with an analysis bandwidth of 1 GHz, affords more flexibility when designing the resonator frequencies for frequency-multiplexed qubit readout; it also simplifies greatly the system's tune-up and maintenance.

Quantum system control software
As part of our Quantum Computing Control System, the SHFQA can be fully integrated into new or existing setups using the LabOne QCCS control software. As a standalone unit, it can be controlled with LabOne and its APIs for Python, C, MATLAB®, LabVIEW™ and .NET. An extended example library facilitates integration into established measurement frameworks. Thanks to the data structuring and processing functionality offered by the LabOne Data Server, the user portion of the software stack remains simple and easy to maintain.