European Physical Society Conference on High Energy Physics (EPS-HEP)
Scalable Readout Architecture for Large-Scale Quantum Sensor Arrays in Fundamental Physics
Luis Eduardo Ardila-Perez, Daniel Crovo, Luciano Ferreyro, Marvin Fuchs, Manuel Elías García Redondo, R. Gartmann, Matías Rolf Hampel, Timo Muscheid, M. Platino, Oliver Sander, Lukas Scheller, Mario Schlösser, Frank Simon
Modern experiments in particle physics, astroparticle physics, and cosmology increasingly rely on large cryogenic sensor arrays to achieve the sensitivity needed to probe phenomena beyond the Standard Model, including the neutrino-mass scale, dark-matter interactions, neutrinoless double-beta decay, and B-mode polarization of the cosmic microwave background. These efforts require the simultaneous readout of tens to hundreds of thousands of detectors, pushing current data-acquisition technologies and motivating the use of frequency-division multiplexing, particularly microwave SQUID multiplexing (𝜇MUX), to scale to such array sizes. In this work we present the Quantum Interface Controller (QIC), a modular software-defined radio platform for high-fidelity, scalable readout of cryogenic detectors and superconducting qubits. Based on Xilinx Zynq UltraScale+ MPSoC and RFSoC technology, the QIC integrates multi-gigahertz DACs/ADCs, FPGA-based real-time processing, and a unified software stack, supporting both DirectRF generation and super-heterodyne sampling to synthesize and demodulate thousands of microwave tones per unit. A firmware-integrated Cryogenic Detector Emulator (CryoDE) provides a digital detector twin for hardware-in-the-loop validation. This paper presents the QIC architecture, firmware and software environment, it is currently being utilized in the ECHo neutrino-mass experiment, the BULLKID-DM dark-matter search, and for superconducting-qubit readout in quantum-computing applications, demonstrating its suitability as a scalable platform for next-generation quantum-sensor arrays.
Modern experiments in particle physics, astroparticle physics, and cosmology increasingly rely on large cryogenic sensor arrays to achieve the sensitivity needed to probe phenomena beyond the Standard Model, including the neutrino-mass scale, dark-matter interactions, neutrinoless double-beta decay, and B-mode polarization of the cosmic microwave background. These efforts require the simultaneous readout of tens to hundreds of thousands of detectors, pushing current data-acquisition technologies and motivating the use of frequency-division multiplexing, particularly microwave SQUID multiplexing (𝜇MUX), to scale to such array sizes. In this work we present the Quantum Interface Controller (QIC), a modular software-defined radio platform for high-fidelity, scalable readout of cryogenic detectors and superconducting qubits. Based on Xilinx Zynq UltraScale+ MPSoC and RFSoC technology, the QIC integrates multi-gigahertz DACs/ADCs, FPGA-based real-time processing, and a unified software stack, supporting both DirectRF generation and super-heterodyne sampling to synthesize and demodulate thousands of microwave tones per unit. A firmware-integrated Cryogenic Detector Emulator (CryoDE) provides a digital detector twin for hardware-in-the-loop validation. This paper presents the QIC architecture, firmware and software environment, it is currently being utilized in the ECHo neutrino-mass experiment, the BULLKID-DM dark-matter search, and for superconducting-qubit readout in quantum-computing applications, demonstrating its suitability as a scalable platform for next-generation quantum-sensor arrays.
This thesis presents the development of a superconducting qubit control and readout system based on FPGA technology, with a focus on the design of a pulse sequencer and the integration of frequency-multiplexed control. The system leverages the Quantum Instrumentation Control Kit (QICK), an open-source Xilinx RFSoC-based platform capable of direct digital synthesis and acquisition of microwave signals up to 10 GHz. The QICK firmware was extended to support the simultaneous generation and readout of multiple frequency-multiplexed tones, enabling the control and measurement of several qubits coupled to a shared feedline. This approach optimizes the number of controllable qubits relative to the available ADC and DAC resources on the RFSoC 4x2 board. Furthermore, this work includes the development of Qubase, a Python-based pulse sequencer that allows users to easily define and execute complex sequences of control and measurement pulses through the QICK Python interface. The resulting architecture is both flexible and scalable, providing a foundation for efficient multi-qubit experiments and enabling advanced techniques such as quantum error correction and real-time feedback.
We present a control and measurement setup for superconducting qubits based on the Xilinx 16-channel radio-frequency system-on-chip (RFSoC) device. The proposed setup consists of four parts: multiple RFSoC boards, a setup to synchronize every digital to analog converter (DAC) and analog to digital converter (ADC) channel across multiple boards, a low-noise direct current supply for tuning the qubit frequency, and cloud access for remotely performing experiments. We also designed the setup to be free of physical mixers. The RFSoC boards directly generate microwave pulses using sixteen DAC channels up to the third Nyquist zone, which are directly sampled by its eight ADC channels between the fifth and the ninth zones.
We present FIREQ (FPGA Instrumentation for Readout and Qubit control), an open-source RFSoC-based framework for the control and readout of superconducting qubits. FIREQ combines a modular AXI-compliant firmware architecture with a PYNQ-based software stack designed to support extensible hardware integration, deterministic experiment timing, and low-overhead execution of repeated calibration and characterization workflows. The firmware implements direct RF synthesis and acquisition, trigger-based sequencing, programmable pulse generation, frequency-multiplexed readout, and memory-efficient acquisition and waveform buffering. The software adopts a client-server architecture with streamed data transfer and dependency-aware configuration updates to reduce host-device and reconfiguration overhead during parameter sweeps. On an AMD Zynq UltraScale+ RFSoC ZCU216, FIREQ generates RF pulses up to 9.3 GHz with a pulse-duration resolution of 107 ps and an event-timing resolution of 1.7 ns. FPGA resource utilization is compared with representative open-source RFSoC control frameworks, showing a low BRAM footprint while retaining full-rate I/Q generation and acquisition. The RF output is characterized in terms of phase noise, noise spectral density, and inter-channel timing skew. End-to-end operation is validated on a superconducting qubit through resonator spectroscopy, Rabi, Ramsey, and relaxation measurements, yielding T1 = 6.94 us and T2* = 13.50 us. FIREQ can therefore be used both as a qubit-control platform and as an experimental environment for evaluating alternative control and readout IP architectures.
This work reports the performance evaluation of an SDR readout system based on the latest generation (Gen3) of the AMD's Radio Frequency System-on-Chip (RFSoC) processing platform, which integrates a full-stack processing system and a powerful FPGA with up to 32 high-speed and high-resolution 14-bit Digital-to-Analog Converters (DACs) and Analog-to-Digital Converters (ADCs). The proposed readout system uses a previously developed multi-band, double-conversion IQ RF-mixing board targeting a multiplexing factor of approximately 1,000 bolometers in a bandwidth between 4 and 8 GHz, in line with state-of-the-art microwave SQUID multiplexers (μMUX). The characterization of the system was performed in two stages, under the conditions typically imposed by the multiplexer and the cold readout circuit. First, in transmission, showing that noise and spurious levels of the generated tones are close to the values imposed by the cold readout. Second, in RF loopback, presenting noise values better than -100 dBc/Hz totally in agreement with the state-of-the-art readout systems. It was demonstrated that the RFSoC Gen3 device is a suitable enabling technology for the next generation of superconducting detector readout systems, reducing system complexity, increasing system integration, and achieving these goals without performance degradation.
The dark photon is a well-motivated dark matter candidate that appears in many extensions of the standard model. A fundamental mass-range-sensitivity dilemma is always haunting the dark photon search experiments: resonant haloscopes have excellent sensitivity but are narrowband, while nonresonant haloscopes are broadband but not as sensitive as the resonant ones. A scalable architecture integrating numerous resonant haloscopes would be a desirable solution to this dilemma. However, even the concept of a scalable search remains rarely explored due to the size limitation of conventional haloscopes imposed by the dark photon wavelength. Here, we propose and demonstrate a novel architecture using superconducting qubits as subwavelength haloscope units. By virtue of the scalability of superconducting qubits, it is possible to integrate multiple qubits with different frequencies on a chip-scale device. Furthermore, the frequencies of the qubits can be tuned to extend the search mass range. Thus, our scalable architectures allow for sweepable high-sensitivity dark photon searches at multiple frequencies simultaneously. As a proof-of-principle experiment, we designed and fabricated a three-qubit chip and successfully demonstrated a scalable dark-photon search. Our Letter established constraints on dark photons in the mass range of 15.632-15.638, 15.838-15.845, and 16.463-16.468 μeV, simultaneously, and the constraints are much more stringent than the cosmology constraints. In the future, our Letter can be scaled up to boost the scrutiny of new physics.
Superconducting qubits are pivotal in advancing quantum computing, poised for scale but limited by the complexity and fidelity of their control and readout systems, relying on RF and signal processing infrastructure. This survey serves as a comprehensive and technically grounded review of control and readout architectures tailored for superconducting qubits. Synthesizing insights from device physics, circuit design, microwave engineering, signal processing, and cryogenic integration, this work details the practicalities of RF pulse generation, signal synthesis, and readout signal analysis for quantum systems. it covers key requirements, parameters, and pulse engineering techniques, including commonly used envelopes like Gaussian and DRAG designs. Moving to the system level, this survey systematically classifies and critically analyses current architectural strategies (covering key areas like frequency conversion, waveform management, and system infrastructure) and technology platforms (including adaptive classical control stacks, cryogenic CMOS circuits, and novel interconnects and interfaces), evaluating their trade-offs in performance. Extensive literature analysis identifies prevailing limitations such as wiring complexity, thermal budget constraints, latency, and power consumption, while highlighting underexplored opportunities for on-chip signal processing and novel interconnects, drawing analogies to advanced communication systems design. By consolidating diverse control paradigms and critically evaluating their trade-offs, this survey provides a unified foundation for designing next-generation quantum control stacks. Finally, a forward-looking roadmap outlines key trends in monolithic integration, cryo-compatible digital architectures, and physics-informed hardware co-design, offering both a retrospective synthesis and a prospective vision for quantum hardware engineering beyond the NISQ era.