Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2304.13442 · Physical Review Applied

Multimodule microwave assembly for fast readout and charge-noise characterization of silicon quantum dots

Felix-Ekkehard von Horstig, David J. Ibberson, Giovanni A. Oakes, Laurence Cochrane, David F. Wise, Nadia A. Stelmashenko, Sylvain Barraud, Jason W. A. Robinson, Frederico Martins, M. Fernando González-Zalba

Published Apr 8, 2024• 13 citations
arXivHTMLPDF

Abstract

Fast measurements of quantum devices is useful in areas such as quantum sensing, quantum computing, and nanodevice quality analysis. Here, we develop a superconductor-semiconductor multimodule microwave assembly to demonstrate charge-state readout at the state of the art. The assembly consist of a superconducting readout resonator interfaced to a silicon-on-insulator (SOI) chiplet containing quantum dots (QDs) in a high- κ nanowire transistor. The superconducting chiplet contains resonant and coupling elements as well as L C filters that, when interfaced with the silicon chip, result in a resonant frequency f = 2.12 GHz, a loaded quality factor Q = 850 , and a resonator impedance Z = 470 Ω . Combined with the large gate lever arms of SOI technology, we achieve a minimum integration time for single and double QD transitions of 2.77 and 13.5 ns, respectively. We utilize the assembly to measure charge noise over 9 decades of frequency up to 500 kHz and find a 1 / f dependence across the whole frequency spectrum as well as a charge-noise level of 4 μ eV / Hz at 1 Hz. The modular microwave circuitry presented here can be directly utilized in conjunction with other quantum devices to improve the readout performance as well as enable large bandwidth noise spectroscopy, all without the complexity of superconductor-semiconductor monolithic fabrication. Published by the American Physical Society 2024

DOI
10.1103/physrevapplied.21.044016

Related papers

A Multi-Module Silicon-On-Insulator Chip Assembly Containing Quantum Dots and Cryogenic Radio-Frequency Readout Electronics

David J. Ibberson, J. Kirkman, John J. L. Morton +2 more

Quantum processing units will be modules of larger information processing systems containing also digital and analog electronics modules. Silicon-based quantum computing offers the enticing opportunity to manufacture all the modules using the same technology platform. Here, we present a cryogenic multi-module assembly for multiplexed readout of silicon quantum devices where all modules have been fabricated using the same fully-depleted silicon-on-insulator (FDSOI) CMOS process. The assembly is constituted by three chiplets: (i) a low-noise amplifier (LNA), (ii) a single-pole eight-throw switch (SP8T), and (iii) a silicon quantum dot (QD) array. We integrate the chiplets into modules and show respectively, (i) a peak gain over 35 dB with a 3-dB bandwidth from 709 MHz to 827 MHz and an average noise temperature of 6.2 K (minimum 4.2 K), (ii) an insertion loss smaller than 1.1 dB and a noise temperature less than 1.1 K over the 0–2 GHz range, and (iii) single-electron box (SEB) charge sensors. Finally, we combine all modules into a single demonstration showing time-domain radio-frequency multiplexing of two SEBs paving the way to an all-silicon quantum computing system.

arXiv:2405.04104•IEEE International Conference on Electronics, Circuits and Systems (ICECS)•Nov 18, 2024•0 citations

Dispersive Readout of a SiMOS Quantum Dot Using a Flip-Chip Integrated Microwave Resonator

Vo Kim Hieu Van, Santiago Serrano, Cédric Bohémier +11 more

Heterogeneous integration provides a promising route to combine semiconductor quantum dot devices and superconducting microwave circuits, while allowing each component to be fabricated using an optimized process flow. Here, we demonstrate a flip-chip integrated platform for dispersive readout of silicon metal-oxide semiconductor (SiMOS) quantum dot devices. A SiMOS double quantum dot chip is bonded to a superconducting aluminum resonator chip using indium bump interconnects to enable microwave coupling to the quantum dot gate. We show that the developed flip-chip process is compatible with cryogenic operation of both the SiMOS device and the superconducting resonator, and demonstrate resonator-based detection of charge transitions in the quantum dot system. The readout signal-to-noise ratio follows a dependence of $\sqrt{t}$ with the integration time, reaching SNR = 1 at an integration time of approximately 0.3 ms. These results establish flip-chip bonding as a viable integration approach for SiMOS quantum dot devices operating at both dc and microwave frequencies, with potential applications for resonator-based techniques such as spin-photon coupling.

arXiv:2607.14559•Jul 16, 2026•0 citations

Fast Readout in Semiconductor Quantum Dots

Wilson, Tim J

The need for fast readout to measure the state of a quantum dot device has important applications in the capabilities of using them as a means for quantum information processing. Traditional charge sensors used to readout the charge state of a quantum dot device are very robust and sensitive electrometers that have been in use since the late 1980s. They pose an issue to the future of quantum dots as a viable means of quantum computing, and that is in their slow acquisition times of the charge state of the quantum dot. This rate of measurement means that implementing any quantum error correction scheme becomes very difficult or even unfeasible as the coherence times of these semiconductor systems is short compared to charge sensor’s acquisition times. A possibility to speed up the measurement process of the charge state is possible thanks to the atomic molecular and optical (AMO) physics community.Cavity quantum electrodynamics (CQED) is the study of light-matter interactions when both the light and matter are taken to be quantized. A photon may interact with an atom via a dipole interaction to excite it from its ground state to its excited state, and the reverse can occur where the atom emits a photon and decays from its excited state ii to the ground state. This fundamental interaction which has been extensively studied in the AMO community since the early 1960s had been adopted by the superconducting qubit community to measure the state of their qubits. These superconducting qubits, representing atoms, which are coupled to a resonant structure on chip, which represents the photons that can interact with the artificial atom. Since these systems were not traditional trapped or neutral atoms interacting with a photon via a laser, but instead planar circuit structures, the superconducting qubit community re-coined the term cavity quantum electrodynamics to circuit quantum electrodynamics, which we will refer to as cQED.The quantum dot community adapted these methods of what is known as dispersive readout; a capacitive change of the atomic like system, results in a dispersive shift which then alters the characteristic frequency response of the resonant structure. This has allowed for a new kind of charge sensor by means of measuring the resonators response due to its coupling to a quantum dot system. This can be done with very high frequency microwave circuitry, allowing much faster readout than is capable via traditional charge sensors. Thus, allowing a pathway to implement quantum error correction schemes with reasonable times compared to any dephasing or decoherence times of the semiconductor system. Furthermore, such fast readout allows for feedback protocols to be implemented to the system to correct for certain undesirable effects due to instruments or the system itself. Our work focuses on a limit of this cQED interaction of the quantum dots to a resonant structure allowing us to do fast readout of the quantum dot charge states via a dispersive shift.The work I will demonstrate in this dissertation will be in the efforts of fast readout on the charge occupation of a double quantum dot system which is galvanically coupled to a superconducting microwave resonator. This was done in a Si/SiGe heterostructure system where I designed, simulated, and fabricated the device which was optimized to have a stronger dispersive shift signal due to an enhanced gate lever arm that couples to the resonator. I will discuss our results of attaining a minimum integration time of 34.54 ns for a unity signal to noise ratio. This demonstrates a fast readout system in the community iii which could be extended to allow for even better readout speeds with faster instruments than what were available to me for the experiment. I will further discuss our characterization of the hybrid system and how we extracted a charge noise due to charging events between the two dots in our system up to around 10 kHz. This work demonstrates a robust dispersive readout scheme which helps in the scalability of hybrid superconducting-semiconducting architectures for means of quantum information processing.

•Dec 12, 2025•0 citations

Flip-Chip-Based Fast Inductive Parity Readout of a Planar Superconducting Island

Manuel Hinderling, Sofieke C. ten Kate, D. Z. Haxell +8 more

The properties of superconducting devices depend sensitively on the parity (even or odd) of the quasiparticles that they contain. Encoding quantum information in the parity degree of freedom is central in several emerging solid-state qubit architectures, including in hybrid superconductor-semiconductor devices. In the latter case, accurate, nondestructive, and time-resolved parity measurements are a challenging issue. Here, we report on control and real-time parity measurement in a superconducting island embedded in a superconducting loop and realized in a hybrid two-dimensional heterostructure using a microwave resonator. To avoid microwave losses impeding time-resolved measurements, the device and readout resonator are located on separate chips, connected via flip-chip bonding, and couple inductively through vacuum. The superconducting resonator detects the parity-dependent circuit inductance, allowing for fast parity readout. We have resolved even- and odd-parity states with a signal-to-noise ratio of SNR ≈ 3 for an integration time of 20 μ s and a detection fidelity exceeding 98 % . The real-time parity measurement shows a state lifetime extending into the millisecond range. Our approach will lead to a better understanding of coherence-limiting mechanisms in superconducting quantum hardware and help to advance inductive-readout schemes for hybrid qubits. Published by the American Physical Society 2024

arXiv:2307.06718•PRX Quantum•Aug 20, 2024•7 citations

Development of a Silicon Semiconductor Quantum Dot Qubit with Dispersive Microwave Readout

Edward Henry

Semiconductor quantum dots in silicon demonstrate exceptionally long spin lifetimes as qubits and are therefore promising candidates for quantum information processing. However, control and readout techniques for these devices have thus far employed low frequency electrons, in contrast to high speed temperature readout techniques used in other qubit architectures, and coupling between multiple quantum dot qubits has not been satisfactorily addressed.This dissertation presents the design and characterization of a semiconductor charge qubit based on double quantum dot in silicon with an integrated microwave resonator for control and readout. The 6 GHz resonator is designed to achieve strong coupling with the quantum dot qubit, allowing the use of circuit QED control and readout techniques which have not previously been applicable to semiconductor qubits. To achieve this coupling, this document demonstrates successful operation of a novel silicon double quantum dot design with a single active metallic layer and a coplanar stripline resonator with a bias tee for dc excitation.Experiments presented here demonstrate quantum localization and measurement of both electrons on the quantum dot and photons in the resonator. Further, it is shown that the resonator-qubit coupling in these devices is sufficient to reach the strong coupling regime of circuit QED. The details of a measurement setup capable of performing simultaneous low noise measurements of the resonator and quantum dot structure are also presented here.The ultimate aim of this research is to integrate the long coherence times observed in electron spins in silicon with the sophisticated readout architectures available in circuit QED based quantum information systems. This would allow superconducting qubits to be coupled directly to semiconductor qubits to create hybrid quantum systems with separate quantum memory and processing components.

•Jan 1, 2013•0 citations

Integrated multiplexed microwave readout of silicon quantum dots in a cryogenic CMOS chip

Andrea Ruffino, Tsung-Yeh Yang, John Michniewicz +3 more

Solid-state quantum computers require classical electronics to control and readout individual qubits and to enable fast classical data processing [1-3]. Integrating both subsystems at deep cryogenic temperatures [4], where solid-state quantum processors operate best, may solve some major scaling challenges, such as system size and input/output (I/O) data management [5]. Spin qubits in silicon quantum dots (QDs) could be monolithically integrated with complementary metal-oxide-semiconductor (CMOS) electronics using very-large-scale integration (VLSI) and thus leveraging over wide manufacturing experience in the semiconductor industry [6]. However, experimental demonstrations of integration using industrial CMOS at mK temperatures are still in their infancy. Here we present a cryogenic integrated circuit (IC) fabricated using industrial CMOS technology that hosts three key ingredients of a silicon-based quantum processor: QD arrays (arranged here in a non-interacting 3x3 configuration), digital electronics to minimize control lines using row-column addressing and analog LC resonators for multiplexed readout, all operating at 50 mK. With the microwave resonators (6-8 GHz range), we show dispersive readout of the charge state of the QDs and perform combined time- and frequency-domain multiplexing, enabling scalable readout while reducing the overall chip footprint. This modular architecture probes the limits towards the realization of a large-scale silicon quantum computer integrating quantum and classical electronics using industrial CMOS technology.

arXiv:2101.08295•Jan 20, 2021•7 citations
Fast measurements of quantum devices is useful in areas such as quantum sensing, quantum computing, and nanodevice quality analysis. Here, we develop a superconductor-semiconductor multimodule microwave assembly to demonstrate charge-state readout at the state of the art. The assembly consist of a superconducting readout resonator interfaced to a silicon-on-insulator (SOI) chiplet containing quantum dots (QDs) in a high- κ nanowire transistor. The superconducting chiplet contains resonant and coupling elements as well as L C filters that, when interfaced with the silicon chip, result in a resonant frequency f = 2.12 GHz, a loaded quality factor Q = 850 , and a resonator impedance Z = 470 Ω . Combined with the large gate lever arms of SOI technology, we achieve a minimum integration time for single and double QD transitions of 2.77 and 13.5 ns, respectively. We utilize the assembly to measure charge noise over 9 decades of frequency up to 500 kHz and find a 1 / f dependence across the whole frequency spectrum as well as a charge-noise level of 4 μ eV / Hz at 1 Hz. The modular microwave circuitry presented here can be directly utilized in conjunction with other quantum devices to improve the readout performance as well as enable large bandwidth noise spectroscopy, all without the complexity of superconductor-semiconductor monolithic fabrication. Published by the American Physical Society 2024
Quantum processing units will be modules of larger information processing systems containing also digital and analog electronics modules. Silicon-based quantum computing offers the enticing opportunity to manufacture all the modules using the same technology platform. Here, we present a cryogenic multi-module assembly for multiplexed readout of silicon quantum devices where all modules have been fabricated using the same fully-depleted silicon-on-insulator (FDSOI) CMOS process. The assembly is constituted by three chiplets: (i) a low-noise amplifier (LNA), (ii) a single-pole eight-throw switch (SP8T), and (iii) a silicon quantum dot (QD) array. We integrate the chiplets into modules and show respectively, (i) a peak gain over 35 dB with a 3-dB bandwidth from 709 MHz to 827 MHz and an average noise temperature of 6.2 K (minimum 4.2 K), (ii) an insertion loss smaller than 1.1 dB and a noise temperature less than 1.1 K over the 0–2 GHz range, and (iii) single-electron box (SEB) charge sensors. Finally, we combine all modules into a single demonstration showing time-domain radio-frequency multiplexing of two SEBs paving the way to an all-silicon quantum computing system.
Heterogeneous integration provides a promising route to combine semiconductor quantum dot devices and superconducting microwave circuits, while allowing each component to be fabricated using an optimized process flow. Here, we demonstrate a flip-chip integrated platform for dispersive readout of silicon metal-oxide semiconductor (SiMOS) quantum dot devices. A SiMOS double quantum dot chip is bonded to a superconducting aluminum resonator chip using indium bump interconnects to enable microwave coupling to the quantum dot gate. We show that the developed flip-chip process is compatible with cryogenic operation of both the SiMOS device and the superconducting resonator, and demonstrate resonator-based detection of charge transitions in the quantum dot system. The readout signal-to-noise ratio follows a dependence of t\sqrt{t}t​ with the integration time, reaching SNR = 1 at an integration time of approximately 0.3 ms. These results establish flip-chip bonding as a viable integration approach for SiMOS quantum dot devices operating at both dc and microwave frequencies, with potential applications for resonator-based techniques such as spin-photon coupling.
The need for fast readout to measure the state of a quantum dot device has important applications in the capabilities of using them as a means for quantum information processing. Traditional charge sensors used to readout the charge state of a quantum dot device are very robust and sensitive electrometers that have been in use since the late 1980s. They pose an issue to the future of quantum dots as a viable means of quantum computing, and that is in their slow acquisition times of the charge state of the quantum dot. This rate of measurement means that implementing any quantum error correction scheme becomes very difficult or even unfeasible as the coherence times of these semiconductor systems is short compared to charge sensor’s acquisition times. A possibility to speed up the measurement process of the charge state is possible thanks to the atomic molecular and optical (AMO) physics community.Cavity quantum electrodynamics (CQED) is the study of light-matter interactions when both the light and matter are taken to be quantized. A photon may interact with an atom via a dipole interaction to excite it from its ground state to its excited state, and the reverse can occur where the atom emits a photon and decays from its excited state ii to the ground state. This fundamental interaction which has been extensively studied in the AMO community since the early 1960s had been adopted by the superconducting qubit community to measure the state of their qubits. These superconducting qubits, representing atoms, which are coupled to a resonant structure on chip, which represents the photons that can interact with the artificial atom. Since these systems were not traditional trapped or neutral atoms interacting with a photon via a laser, but instead planar circuit structures, the superconducting qubit community re-coined the term cavity quantum electrodynamics to circuit quantum electrodynamics, which we will refer to as cQED.The quantum dot community adapted these methods of what is known as dispersive readout; a capacitive change of the atomic like system, results in a dispersive shift which then alters the characteristic frequency response of the resonant structure. This has allowed for a new kind of charge sensor by means of measuring the resonators response due to its coupling to a quantum dot system. This can be done with very high frequency microwave circuitry, allowing much faster readout than is capable via traditional charge sensors. Thus, allowing a pathway to implement quantum error correction schemes with reasonable times compared to any dephasing or decoherence times of the semiconductor system. Furthermore, such fast readout allows for feedback protocols to be implemented to the system to correct for certain undesirable effects due to instruments or the system itself. Our work focuses on a limit of this cQED interaction of the quantum dots to a resonant structure allowing us to do fast readout of the quantum dot charge states via a dispersive shift.The work I will demonstrate in this dissertation will be in the efforts of fast readout on the charge occupation of a double quantum dot system which is galvanically coupled to a superconducting microwave resonator. This was done in a Si/SiGe heterostructure system where I designed, simulated, and fabricated the device which was optimized to have a stronger dispersive shift signal due to an enhanced gate lever arm that couples to the resonator. I will discuss our results of attaining a minimum integration time of 34.54 ns for a unity signal to noise ratio. This demonstrates a fast readout system in the community iii which could be extended to allow for even better readout speeds with faster instruments than what were available to me for the experiment. I will further discuss our characterization of the hybrid system and how we extracted a charge noise due to charging events between the two dots in our system up to around 10 kHz. This work demonstrates a robust dispersive readout scheme which helps in the scalability of hybrid superconducting-semiconducting architectures for means of quantum information processing.
The properties of superconducting devices depend sensitively on the parity (even or odd) of the quasiparticles that they contain. Encoding quantum information in the parity degree of freedom is central in several emerging solid-state qubit architectures, including in hybrid superconductor-semiconductor devices. In the latter case, accurate, nondestructive, and time-resolved parity measurements are a challenging issue. Here, we report on control and real-time parity measurement in a superconducting island embedded in a superconducting loop and realized in a hybrid two-dimensional heterostructure using a microwave resonator. To avoid microwave losses impeding time-resolved measurements, the device and readout resonator are located on separate chips, connected via flip-chip bonding, and couple inductively through vacuum. The superconducting resonator detects the parity-dependent circuit inductance, allowing for fast parity readout. We have resolved even- and odd-parity states with a signal-to-noise ratio of SNR ≈ 3 for an integration time of 20 μ s and a detection fidelity exceeding 98 % . The real-time parity measurement shows a state lifetime extending into the millisecond range. Our approach will lead to a better understanding of coherence-limiting mechanisms in superconducting quantum hardware and help to advance inductive-readout schemes for hybrid qubits. Published by the American Physical Society 2024
Semiconductor quantum dots in silicon demonstrate exceptionally long spin lifetimes as qubits and are therefore promising candidates for quantum information processing. However, control and readout techniques for these devices have thus far employed low frequency electrons, in contrast to high speed temperature readout techniques used in other qubit architectures, and coupling between multiple quantum dot qubits has not been satisfactorily addressed.This dissertation presents the design and characterization of a semiconductor charge qubit based on double quantum dot in silicon with an integrated microwave resonator for control and readout. The 6 GHz resonator is designed to achieve strong coupling with the quantum dot qubit, allowing the use of circuit QED control and readout techniques which have not previously been applicable to semiconductor qubits. To achieve this coupling, this document demonstrates successful operation of a novel silicon double quantum dot design with a single active metallic layer and a coplanar stripline resonator with a bias tee for dc excitation.Experiments presented here demonstrate quantum localization and measurement of both electrons on the quantum dot and photons in the resonator. Further, it is shown that the resonator-qubit coupling in these devices is sufficient to reach the strong coupling regime of circuit QED. The details of a measurement setup capable of performing simultaneous low noise measurements of the resonator and quantum dot structure are also presented here.The ultimate aim of this research is to integrate the long coherence times observed in electron spins in silicon with the sophisticated readout architectures available in circuit QED based quantum information systems. This would allow superconducting qubits to be coupled directly to semiconductor qubits to create hybrid quantum systems with separate quantum memory and processing components.
Solid-state quantum computers require classical electronics to control and readout individual qubits and to enable fast classical data processing [1-3]. Integrating both subsystems at deep cryogenic temperatures [4], where solid-state quantum processors operate best, may solve some major scaling challenges, such as system size and input/output (I/O) data management [5]. Spin qubits in silicon quantum dots (QDs) could be monolithically integrated with complementary metal-oxide-semiconductor (CMOS) electronics using very-large-scale integration (VLSI) and thus leveraging over wide manufacturing experience in the semiconductor industry [6]. However, experimental demonstrations of integration using industrial CMOS at mK temperatures are still in their infancy. Here we present a cryogenic integrated circuit (IC) fabricated using industrial CMOS technology that hosts three key ingredients of a silicon-based quantum processor: QD arrays (arranged here in a non-interacting 3x3 configuration), digital electronics to minimize control lines using row-column addressing and analog LC resonators for multiplexed readout, all operating at 50 mK. With the microwave resonators (6-8 GHz range), we show dispersive readout of the charge state of the QDs and perform combined time- and frequency-domain multiplexing, enabling scalable readout while reducing the overall chip footprint. This modular architecture probes the limits towards the realization of a large-scale silicon quantum computer integrating quantum and classical electronics using industrial CMOS technology.