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

Europhysics news

From macroscopic quantum circuits to scalable quantum systems

Songyuan Zhao, Martin P. Weides

Published Jan 1, 2026• 1 citation
Publisher

Abstract

Superconducting quantum circuits have reached impressive performance, with individual qubits and operations working extremely well. This maturity was recognized by the 2025 Nobel Prize in Physics, awarded for demonstrating that genuinely quantum phenomena – such as energy quantization and tunnelling – can occur in macroscopic electrical circuits. Yet building large, reliable quantum processors remains challenging. The limitation is no longer a single flaw, but the combined effect of many small imperfections spread across the hardware. Subtle losses in materials, tiny variations in components, unwanted heat, and constraints imposed by wiring, packaging, and control electronics all accumulate as systems grow in size. This article explains how such device-level effects ultimately limit the performance of entire quantum processors, and why understanding this link is essential for turning today’s high-quality quantum devices into scalable and reliable quantum technologies.

DOI
10.1051/epn/2026107

Related papers

From Macroscopic Superconductivity to Quantum Computing

Yonuk Chong

The Nobel laureates of this year have devised an experiment to observe macroscopic quantum tunneling in an electrical circuit made of superconductors. This monumental discovery has sparked numerous innovations and ultimately earned the three pioneers the Nobel prize. Afterwards, superconducting circuits play a key role in the proliferation of quantum technology in the 21st century. Especially, in the heart of the 2nd quantum revolution, quantum information technology is based on the radical development of the quantum computers. Superconducting Josephson junction devices has been the most advanced technology that has been picked up by the global tech giants in quantum computing. I will briefly review how the superconducting quantum chips and the macroscopic quantum effect had led innovation in quantum technology afterwards.

Physics and High Technology•Dec 23, 2025•0 citations

From superconductivity to macroscopic quantum phenomena: a path marked by Nobel Prizes

Sebastián Bergeret

Is it possible to create a Schrödinger’s cat in a laboratory - that is, to make a macroscopic object obey the laws of quantum mechanics? The 2025 Nobel Prize in Physics recognizes experiments showing that this is indeed possible, using superconducting electrical circuits.

Europhysics news•Jan 1, 2026•0 citations

Enabling Technologies for Scalable Superconducting Quantum Computing

Xanthe Croot, Kasra Nowrouzi, Christopher Spitzer +21 more

Experiments with superconducting quantum processors have successfully demonstrated the basic functions needed for quantum computation and evidence of utility, albeit without a sizable array of error-corrected qubits. The realization of the full potential of quantum computing centers on achieving large scale fault-tolerant quantum computers. Science, engineering and industry advances are needed to robustly generate, sustain, and efficiently manipulate an exponentially large computational (Hilbert) space as well as supply the number and quality components needed for such a scaled system. In this article, we suggest critical areas of quantum system and ecosystem development, with respect to the handling and transmission of quantum information within and out of a cryogenic environment, that would accelerate the development of quantum computers based on superconducting circuits.

quant-pharXiv:2512.15001•Dec 18, 2025•0 citations

Superconducting Qubits: An Evaluation of Architectures, Noise Sources, and Quantum Error Correction Strategies

Modou Njie

Superconducting qubits are a leading platform for quantum computation, yet decoherence and scalability challenges continue to limit progress toward fault-tolerant systems. This review synthesizes research on architectures, noise sources, and error correction to clarify performance trade-offs and guide development. The transition from Transmon to Fluxonium has dramatically improved qubit performance, achieving millisecond-scale coherence times. However, this success reveals a fundamental limit of coherence now being primarily restricted by the physical properties of the materials, specifically dielectric losses occurring at the Josephson junction leads and within the surrounding materials. As overcoming these material limits becomes increasingly difficult, system-level engineering determines whether high-coherence qubits can scale.Scaling quantum systems is difficult because current cooling and control systems create too much heat and this forces a shift to integrated digital superconducting circuits and cryogenic light-based links. While these hardware challenges restrict scaling, experiments in error correction show that logical qubits can already outperform physical ones. For example, a distance-7 surface code improved logical qubit lifetime by 2.4×. Achieving practical fault tolerance, however, requires moving beyond simple error models. Future systems must combine techniques like Dynamical Decoupling and Machine Learning-based Optimal Control with dynamic classical control capable of handling complex, correlated faults such as Multi-Bit Burst Errors. Progress in materials, cryogenic system integration for control, and adaptive error management must advance together to realize scalable, high-fidelity quantum hardware.

•Mar 12, 2026•0 citations

Perspective on the 2025 Nobel Prize in Physics: macroscopic quantum coherence becomes an engineered resource

Z. Yamani, Marco Merkli

The 2025 Nobel Prize in Physics recognizes a conceptual shift that has been more than a century in the making: the transition from observing quantum phenomena in materials to deliberately engineering quantum behaviour in macroscopic electrical circuits. Awarded to John Clarke, Michel Devoret, and John Martinis, the prize honours the experimental demonstration and control of macroscopic quantum tunnelling and energy quantization in superconducting circuits. Their work resolved a long-standing question at the heart of quantum mechanics: can an object large enough to wire, probe, and manipulate behave as a single quantum system? The answer, now unequivocally, is yes.

Canadian Journal of Physics•Jan 1, 2026•0 citations

Cryogenic electronics for the read-out of quantum processors

Harald Homulle

Quantum computing promises an exponential speed-up of computation compared to what is nowadays achievable with classical computers. In this way, it enables the evaluation of more complex models and the breaching of current security algorithms. For the operation of a quantum system, many questions remain to be answered. Currently, there are several quantum technologies that promise to be both reliable and scalable, two features required for large scale quantum operations. Common to all technologies is the operating temperature that needs to be close to absolute zero, i.e. below 100 mK, to suppress environment noise and allow the quantum properties to become 'visible'. In order for any quantum processor to be operated, a so-called quantum-classical interface is required for the quantum bit (qubit) read-out and control. This interface consists of various electronic blocks, such as analog-to-digital converters, digital-to-analog converters, mixers, amplifiers and a digital controller. Especially the analog blocks require effort to meet the noise and stability constraints as not to disturb the very sensitive qubits and allow reading of the tiny signals. As the qubits live in extremely deep-cryogenic temperatures, long wires interface the cryogenic with the room temperature environment, where most of the electronics is situated. However, for a scalable system, heat injection becomes a serious problem, with many wires between 300 K and sub-Kelvin. Furthermore, such amount of interconnects is challenging to mechanically place in a dilution refrigerator. Therefore, in this work, we propose to implement the electronics not at room temperature, but at a temperature much closer to the qubits, for example at 4 K. This not only reduces significantly the wiring between room temperature and the qubits, but we can also benefit from lower electronic noise at such a temperature. The operation of conventional electronics almost 200°C below its normal temperature range is not trivial as device properties alter significantly and most circuits no longer operate as intended. In CMOS processes, the main technology in the integrated electronics world, the behaviour of the transistors, required for the implementation of any circuit, deviates considerably at low temperatures. The transistor's threshold voltage goes up, the mobility increases and the subthreshold slope becomes steeper, to name just a few of these deviations. Although there are improvements in performance, there are also some counter effects, and characterization of the transistors is needed to observe the changes. Once devices are characterized at such low temperatures, new models can be built and circuits can be simulated and adapted to operate properly at cryogenic temperatures. Luckily, there are various commercially available devices that can already withstand the chills of cold. We demonstrated various commercially available devices, such as a field-programmable gate array (FPGA) implemented in a 28 nm CMOS process, to be operating without major concerns at 4~K. Its properties alter only slightly, within 5 to 10%, and all tested circuit implementations, working at 300~K, also worked at 4 K. We combined both commercially available devices, that operate 200 K below their specified temperature range, with custom designed CMOS circuits to implement a cryogenic read-out platform for spin qubits. This system comprises amplifiers, an ADC, an FPGA, voltage regulators and a clock generator. It allows to amplify the tiny signal from the qubits and digitize it directly in the FPGA in order to process the data locally at 4~K. This system is one of the first systematic attempts at operating a part of the quantum-classical interface at cryogenic temperatures and forms the basis for future systems comprising the complete electronic interface for qubits to operate at such low temperatures. One of the main problems to tackle for cryogenic electronic systems is their power consumption. Power budgets are simply limited to roughly 1 or 2 Watts at 4 K and exponentially lower at deeper cryogenic temperatures, thus limiting the size of large-scale electronic systems. Our approach of combined commercial and custom circuits will have to be steadily replaced by a single (custom) technology that meets both power and scalability constraints. One of the best candidates is CMOS, a technology that the industry has relied upon for several decades and benefits from many optimizations thanks to Moore's law.

•Apr 9, 2019•23 citations
Superconducting quantum circuits have reached impressive performance, with individual qubits and operations working extremely well. This maturity was recognized by the 2025 Nobel Prize in Physics, awarded for demonstrating that genuinely quantum phenomena – such as energy quantization and tunnelling – can occur in macroscopic electrical circuits. Yet building large, reliable quantum processors remains challenging. The limitation is no longer a single flaw, but the combined effect of many small imperfections spread across the hardware. Subtle losses in materials, tiny variations in components, unwanted heat, and constraints imposed by wiring, packaging, and control electronics all accumulate as systems grow in size. This article explains how such device-level effects ultimately limit the performance of entire quantum processors, and why understanding this link is essential for turning today’s high-quality quantum devices into scalable and reliable quantum technologies.
The Nobel laureates of this year have devised an experiment to observe macroscopic quantum tunneling in an electrical circuit made of superconductors. This monumental discovery has sparked numerous innovations and ultimately earned the three pioneers the Nobel prize. Afterwards, superconducting circuits play a key role in the proliferation of quantum technology in the 21st century. Especially, in the heart of the 2nd quantum revolution, quantum information technology is based on the radical development of the quantum computers. Superconducting Josephson junction devices has been the most advanced technology that has been picked up by the global tech giants in quantum computing. I will briefly review how the superconducting quantum chips and the macroscopic quantum effect had led innovation in quantum technology afterwards.
Experiments with superconducting quantum processors have successfully demonstrated the basic functions needed for quantum computation and evidence of utility, albeit without a sizable array of error-corrected qubits. The realization of the full potential of quantum computing centers on achieving large scale fault-tolerant quantum computers. Science, engineering and industry advances are needed to robustly generate, sustain, and efficiently manipulate an exponentially large computational (Hilbert) space as well as supply the number and quality components needed for such a scaled system. In this article, we suggest critical areas of quantum system and ecosystem development, with respect to the handling and transmission of quantum information within and out of a cryogenic environment, that would accelerate the development of quantum computers based on superconducting circuits.
Superconducting qubits are a leading platform for quantum computation, yet decoherence and scalability challenges continue to limit progress toward fault-tolerant systems. This review synthesizes research on architectures, noise sources, and error correction to clarify performance trade-offs and guide development. The transition from Transmon to Fluxonium has dramatically improved qubit performance, achieving millisecond-scale coherence times. However, this success reveals a fundamental limit of coherence now being primarily restricted by the physical properties of the materials, specifically dielectric losses occurring at the Josephson junction leads and within the surrounding materials. As overcoming these material limits becomes increasingly difficult, system-level engineering determines whether high-coherence qubits can scale.Scaling quantum systems is difficult because current cooling and control systems create too much heat and this forces a shift to integrated digital superconducting circuits and cryogenic light-based links. While these hardware challenges restrict scaling, experiments in error correction show that logical qubits can already outperform physical ones. For example, a distance-7 surface code improved logical qubit lifetime by 2.4×. Achieving practical fault tolerance, however, requires moving beyond simple error models. Future systems must combine techniques like Dynamical Decoupling and Machine Learning-based Optimal Control with dynamic classical control capable of handling complex, correlated faults such as Multi-Bit Burst Errors. Progress in materials, cryogenic system integration for control, and adaptive error management must advance together to realize scalable, high-fidelity quantum hardware.
The 2025 Nobel Prize in Physics recognizes a conceptual shift that has been more than a century in the making: the transition from observing quantum phenomena in materials to deliberately engineering quantum behaviour in macroscopic electrical circuits. Awarded to John Clarke, Michel Devoret, and John Martinis, the prize honours the experimental demonstration and control of macroscopic quantum tunnelling and energy quantization in superconducting circuits. Their work resolved a long-standing question at the heart of quantum mechanics: can an object large enough to wire, probe, and manipulate behave as a single quantum system? The answer, now unequivocally, is yes.
Quantum computing promises an exponential speed-up of computation compared to what is nowadays achievable with classical computers. In this way, it enables the evaluation of more complex models and the breaching of current security algorithms. For the operation of a quantum system, many questions remain to be answered. Currently, there are several quantum technologies that promise to be both reliable and scalable, two features required for large scale quantum operations. Common to all technologies is the operating temperature that needs to be close to absolute zero, i.e. below 100 mK, to suppress environment noise and allow the quantum properties to become 'visible'. In order for any quantum processor to be operated, a so-called quantum-classical interface is required for the quantum bit (qubit) read-out and control. This interface consists of various electronic blocks, such as analog-to-digital converters, digital-to-analog converters, mixers, amplifiers and a digital controller. Especially the analog blocks require effort to meet the noise and stability constraints as not to disturb the very sensitive qubits and allow reading of the tiny signals. As the qubits live in extremely deep-cryogenic temperatures, long wires interface the cryogenic with the room temperature environment, where most of the electronics is situated. However, for a scalable system, heat injection becomes a serious problem, with many wires between 300 K and sub-Kelvin. Furthermore, such amount of interconnects is challenging to mechanically place in a dilution refrigerator. Therefore, in this work, we propose to implement the electronics not at room temperature, but at a temperature much closer to the qubits, for example at 4 K. This not only reduces significantly the wiring between room temperature and the qubits, but we can also benefit from lower electronic noise at such a temperature. The operation of conventional electronics almost 200°C below its normal temperature range is not trivial as device properties alter significantly and most circuits no longer operate as intended. In CMOS processes, the main technology in the integrated electronics world, the behaviour of the transistors, required for the implementation of any circuit, deviates considerably at low temperatures. The transistor's threshold voltage goes up, the mobility increases and the subthreshold slope becomes steeper, to name just a few of these deviations. Although there are improvements in performance, there are also some counter effects, and characterization of the transistors is needed to observe the changes. Once devices are characterized at such low temperatures, new models can be built and circuits can be simulated and adapted to operate properly at cryogenic temperatures. Luckily, there are various commercially available devices that can already withstand the chills of cold. We demonstrated various commercially available devices, such as a field-programmable gate array (FPGA) implemented in a 28 nm CMOS process, to be operating without major concerns at 4~K. Its properties alter only slightly, within 5 to 10%, and all tested circuit implementations, working at 300~K, also worked at 4 K. We combined both commercially available devices, that operate 200 K below their specified temperature range, with custom designed CMOS circuits to implement a cryogenic read-out platform for spin qubits. This system comprises amplifiers, an ADC, an FPGA, voltage regulators and a clock generator. It allows to amplify the tiny signal from the qubits and digitize it directly in the FPGA in order to process the data locally at 4~K. This system is one of the first systematic attempts at operating a part of the quantum-classical interface at cryogenic temperatures and forms the basis for future systems comprising the complete electronic interface for qubits to operate at such low temperatures. One of the main problems to tackle for cryogenic electronic systems is their power consumption. Power budgets are simply limited to roughly 1 or 2 Watts at 4 K and exponentially lower at deeper cryogenic temperatures, thus limiting the size of large-scale electronic systems. Our approach of combined commercial and custom circuits will have to be steadily replaced by a single (custom) technology that meets both power and scalability constraints. One of the best candidates is CMOS, a technology that the industry has relied upon for several decades and benefits from many optimizations thanks to Moore's law.