Recent collaborative research from Pennsylvania State University, the University of Chicago’s Pritzker School of Molecular Engineering, and the U.S. Department of Energy’s National Quantum Information Science Research Center Q-NEXT, led by Argonne National Laboratory, has illuminated this enigmatic phenomenon. By synthesizing high-purity diamond films and meticulously isolating minute electronic signals from background noise, the team has uncovered fundamental mechanisms previously concealed. Their breakthrough opens new frontiers for quantum chip development, potentially allowing the integration of multiple qubit types on a single chip—a holy grail for quantum technology efficiency and versatility.

The innovation lies in understanding the complex interplay of distinct qubit functionalities within diamond, a material that simultaneously acts as a superconductor and a semiconductor. Diverse qubit varieties—each with unique strengths—have posed integration challenges in quantum devices. Engineering a single material platform accommodating multifaceted quantum operations could transform quantum computation, communication, and sensing. Diamond’s intrinsic properties position it as an exemplary candidate for this multifunctional role, promising seamless interfacing with classical electronics due to its robust thermal and electrical traits.

Central to this phenomenon is the process of doping diamond with boron atoms. Doping introduces desirable electrical characteristics by infusing foreign atoms into a host lattice. The collaborative team at Penn State employed state-of-the-art facilities to synthesize diamond films with randomly positioned boron atoms. Surprisingly, even films displaying microscopic uniformity revealed an intrinsic granularity in superconductivity. Instead of a homogeneous superconducting state, the material exhibited a “mosaic” pattern composed of superconducting “puddles.” These puddles, interlaced within the diamond matrix, must connect coherently to enable resistance-free electrical flow, a state described as “granular superconductivity.”

The discovery of this nanoscale inhomogeneity puzzled the researchers initially. Nitin Samarth, a leading author and professor at Penn State, remarked on the unexpected complexity: homogeneous crystalline films exhibited macroscopic electrical behaviors not explained by classical superconductivity models. This granularity appears intrinsic, arising despite random doping and structural uniformity, suggesting subtle electronic or atomic clustering effects. Moreover, the superconducting mosaic proved to be tunable by external parameters such as magnetic fields, electrical currents, and temperature variations, enabling dynamic control over its behaviors.

Deciphering the electron dynamics within and between these superconducting puddles is now guiding the researchers on how to “stitch” these superconducting regions together more effectively. By optimizing inter-puddle connectivity, it becomes feasible to enhance superconducting coherence length and elevate the operational temperature range of the material. Such advances are crucial since current diamond-based superconducting devices require ultra-low temperatures that limit practical applications. Increasing the critical temperature could pave the way for more energy-efficient, accessible quantum devices with broader usage.

David Awschalom, a prominent figure in quantum science at UChicago and director of the Chicago Quantum Exchange, emphasized that this research redefines how physicists and engineers can approach multifunctional quantum devices. The seamless integration of superconductivity, semiconductivity, optical activity, spin interactions, and magnetic phenomena within a single diamond chip heralds a new era for quantum technologies. Envisioning devices that couple light, spin states, superconducting currents, and magnetic ordering simultaneously unlocks extraordinary potential for both fundamental science and technological innovation.

Another transformative aspect stems from diamond’s unique spin-photon interface, whereby intrinsic properties naturally link photonic (light) modes with spin-based quantum information without requiring complex external apparatus. This capability makes diamond an ideal platform for multiplexing quantum functionalities—a vital requirement for scaling quantum communication and computation. Moreover, developing a domestic and robust supply chain for high-quality quantum-grade diamond amplifies its prospects for commercialization, bridging the gap between laboratory breakthroughs and real-world quantum infrastructure.

To harness these multifaceted advantages, the research highlights strategic pathways for precise atomic-scale engineering. By independently tuning critical material parameters such as boron doping concentration, crystalline orientation, strain, and dimensional thickness, scientists can delimit the superconducting puddle size, shape, and interaction networks. This fine control permits customizable quantum chip designs, tailored for specific performance metrics in quantum sensing, information processing, and hybrid classical-quantum systems, effectively converting diamond from a scientific curiosity into a versatile technological workhorse.

The implications extend beyond quantum science into classical electronics and spintronics, where diamond’s outstanding thermal and mechanical properties promise novel device architectures. Integrating superconducting diamond components in classical circuits may improve heat dissipation and operational speeds, pushing the boundaries of microelectronic performance. This convergence of quantum and classical functionalities on a single platform could catalyze new classes of hybrid devices, bridging the technologies that power tomorrow’s information economy.

While the study solidifies foundational knowledge on diamond superconductivity, it also sparks numerous questions and opportunities for future exploration. How precisely boron clustering influences granularity, the nature of electron pairing mechanisms at interfaces, and the interplay between mechanical strain and electronic phases remain rich fields of inquiry. These insights will be essential for pushing transition temperatures higher and achieving robust, scalable quantum devices suitable for widespread implementation.

Ultimately, the discovery provides a reliable roadmap for engineering diamond superconductors with bespoke characteristics. Samarth notes that beyond mere observation, this research enables the rational design of diamond-based quantum components by modulating doping density, crystalline structure, strain patterns, and dimensional constraints. The exciting possibilities encompass both quantum and classical realms, potentially ushering in a new generation of multifunctional quantum chips that marry superconductivity, photonics, spintronics, and magnetism in a single, thermally resilient platform.

As the quantum landscape evolves, diamond’s combined roles as a superconductor and semiconductor exemplify the powerful synergy achievable through precise material design. The fusion of disparate quantum effects into a unified, tunable system foreshadows a future where quantum chips can handle complex tasks while interfacing effortlessly with existing technologies. This breakthrough heralds a step-change in quantum device engineering, offering a clear, implementable pathway toward multifunction quantum systems that could redefine computing, communications, and sensing in the decades to come.

Subject of Research: Superconductivity and quantum multifunctionality in boron-doped diamond

Article Title: “Designer” superconducting diamond: researchers uncover path to multi-modality quantum chips

Web References:

• Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2607730123)
• Chicago Quantum Exchange
• Quantum Prairie Diamond Supply Chain

Image Credits: Pennsylvania State University (PSU)

Keywords

Superconductivity, Diamond, Quantum chips, Boron doping, Granular superconductivity, Quantum information science, Quantum computing, Spin-photon interface, Quantum materials, Atomic-scale engineering, Quantum communication, Multifunction quantum devices

This innovative research centers on the behavior of quantum systems under the influence of time-dependent magnetic fields—fields that periodically change, or “switch,” over time. By meticulously modeling these interactions through computational simulations, Powell alongside former student researcher Louis Buchalter illuminated a novel class of quantum states that do not have stationary analogs, meaning such states cannot be realized when the system remains static. Their findings, published under the title “Flux-Switching Floquet Engineering” in the prestigious journal Physical Review B, extend the conceptual framework of Floquet engineering, an approach that exploits periodic driving to engineer quantum phases with unique temporal properties.

At the core of this study lies a transformative notion: the properties of quantum matter are not solely dictated by the intrinsic nature of materials but can be dramatically influenced by how these materials are driven through time-dependent controls. Specifically, they demonstrate that periodically varying a magnetic flux through a quantum system orchestrates exotic phases characterized by robust topological features absent in equilibrium states. Such driven phases manifest as stable quantum behaviors that resist typical disruptions from environmental noise, hinting at profound implications for designing resilient quantum devices.

These exotic phases open promising avenues for enhancing quantum information technologies, particularly in quantum computing and simulation domains. Unlike conventional qubits reliant on static configurations, flux-switching protocols could yield quantum bit implementations exhibiting increased coherence times and resilience against error-inducing perturbations. The ability to precisely manipulate these time-dependent driving fields could usher in quantum architectures that maintain operational integrity even amid inevitable imperfections and decoherence mechanisms, a formidable challenge in the field.

Technically, the research contributes a comprehensive topological phase diagram—a visual map outlining distinct quantum phases classified by immutable topological invariants. This diagram not only catalogs the emergent phases resulting from flux-switching but also reveals an intriguing mathematical symmetry akin to higher-dimensional quantum systems, indicating a rich interplay between dimensionality and temporal dynamics. Such insights bridge concepts traditionally reserved for complex theoretical physics with experimentally accessible setups, particularly ultracold atom experiments that offer unparalleled control over quantum states.

The implications of this work extend beyond theoretical physics, illuminating potential pathways for experimental validation and engineering of quantum devices that utilize time-dependent control parameters. By establishing a mathematical backbone for these driven phases, the study sets the stage for future explorations toward practical quantum hardware implementations, blending deep computational modeling with experimental quantum science. This paradigm shift underscores the essence of quantum information science: leveraging intricate physical laws to craft technological solutions unattainable by classical means.

Magnetic fields serve a foundational role in quantum technologies, acting as indispensable instruments for qubit manipulation and readout. In quantum computing, qubits embody the basic units of quantum information, analogous yet significantly more powerful than classical bits represented by binary states. The flux-switching mechanisms investigated by Powell’s team manipulate the magnetic environment to dynamically tailor qubit characteristics, enhancing tunability and controllability crucial for scaling quantum processors.

Reflecting on his research journey, co-author Louis Buchalter highlighted the intricate and often non-linear nature of scientific inquiry. The process demanded persistent experimentation, creative problem-solving, and effective communication of nuanced concepts to the broader scientific community. This experience underscored the significance of Floquet engineering as a versatile toolkit for realizing quantum systems with highly tunable attributes and showcased how time-dependent quantum matter can pave the way for emergent quantum information applications.

Buchalter’s future endeavors involve pursuing a Master of Science degree in materials science and engineering at the University of Washington, focusing on experimental quantum matter research. His aspirations include contributing to the development of quantum electronic and photonic devices, reflecting the broader vision of advancing quantum technologies from theoretical frameworks to tangible, impactful innovations.

As quantum technology matures, studies like “Flux-Switching Floquet Engineering” mark critical milestones, dictating how we comprehend, control, and ultimately harness quantum matter’s dynamic richness. By orchestrating quantum phases through time-variant magnetic fields, this research exemplifies a paradigm where the dimension of time becomes an active player in the material’s quantum landscape. The path forward invites collaborative efforts spanning computational, theoretical, and experimental realms to transform these foundational insights into robust, scalable quantum technologies with transformative industrial ramifications.

Subject of Research:
Not applicable

Article Title:
Flux-Switching Floquet Engineering

News Publication Date:
1-May-2026

Web References:
http://dx.doi.org/10.1103/c28t-x1dh

References:
Powell, I., & Buchalter, L. (2026). Flux-Switching Floquet Engineering. Physical Review B. https://doi.org/10.1103/c28t-x1dh

Keywords
Quantum mechanics, Quantum matter, Quantum information science, Quantum information processing, Quantum computing, Qubits, Mathematical principles, Magnetism

Nuclear magnetic resonance (NMR), a venerable technique traditionally used for chemical analysis and structural elucidation in materials science, has been revitalized in this context as a tool for quantum information processing. The capacity to manipulate nuclear spins with optical precision presents an extraordinary opportunity to utilize nuclei as qubits — the fundamental units of quantum computation — with enhanced coherence times and isolation from electron spin noise. The research conducted by KIT demonstrates that molecular crystals containing europium ions exhibit these properties robustly, allowing the preparation, control, and optical readout of nuclear spin states within a solid-state environment.

A pivotal component of this study lies in the ability to suppress decoherence mechanisms that ordinarily plague quantum bits in solid media. By applying high-frequency electromagnetic fields, the researchers dynamically decoupled the nuclear spins from environmental perturbations, thereby prolonging the coherence times significantly. The reported coherence times of up to two milliseconds enable complex quantum operations to be executed within a duration wherein the quantum information remains stable and uncorrupted, making these systems highly attractive for quantum memory and quantum information transfer applications.

Professor David Hunger of KIT’s Physikalisches Institut emphasized the profound implications of these findings, noting the unique advantage of addressing nuclear spins without the interference of electron spins. This distinction is crucial because electron spins, while easier to manipulate, are more susceptible to environmental noise and decoherence. The selective optical addressability of the nuclear spins within the molecular framework paves the way for constructing dense qubit arrays characterized by exceptional stability — a critical requirement for scalable quantum computing architectures.

The molecular crystals studied were engineered and synthesized under the direction of Professor Mario Ruben, whose expertise in molecular chemistry has enabled the creation of systems tailored for quantum technological applications. The precise chemical customization possible in molecular platforms affords atomically accurate control over qubit arrangements and interactions, offering a versatility unattainable in conventional solid-state qubit systems. Such tailorability promises considerable advances in the development of quantum registers with unprecedented control and scalability.

Beyond computational applications, the implications of optically detected nuclear magnetic resonance extend to the analytical realm, where enhanced NMR techniques facilitated by these molecular systems could revolutionize material characterization. The optical detection mechanism enhances sensitivity and spatial resolution, potentially allowing new high-precision NMR methodologies that can unravel the complexities of intricate materials and molecular architectures with previously unattainable detail.

The strategic integration of optical and radio-frequency techniques for spin control in these molecular crystals heralds the emergence of optically networked quantum processing units. Such units, capable of interfacing via photonic channels, are essential for the realization of distributed quantum computing networks and quantum communication systems. The controlled nuclear spins act as quantum nodes or memory elements that can be coherently manipulated and interconnected by light, dramatically enhancing the prospects for scalable quantum information infrastructures.

This research elucidates how molecular systems, traditionally viewed within the realm of chemistry and materials science, are rapidly becoming central players in quantum technologies. The interdisciplinary approach combining synthetic chemistry, quantum physics, and advanced spectroscopy underscores the multifaceted efforts necessary to transition quantum concepts from theoretical constructs to practical, deployable devices.

The extended coherence times achievable in these europium-based nuclear spins compare favorably with other solid-state qubit platforms, many of which struggle with much shorter coherence windows due to environmental interference and material imperfections. The combination of chemical precision in molecular synthesis and advanced photonic control techniques clearly demonstrates a pathway toward overcoming the longstanding challenges of qubit stability and scalability.

Moreover, the demonstrated technique of optical readout sidesteps many of the limitations imposed by conventional magnetic resonance detection methods, such as the requirement for ultra-low temperatures and large magnetic fields. This accessibility enhances the feasibility of integrating these molecular quantum systems with existing photonic and electronic quantum devices, facilitating hybrid quantum architectures poised to expand the functionality and application scope of quantum computers.

The convergence of molecular chemistry and quantum technology, as exemplified by this research, points toward an era where the atomic and molecular design of materials will play a decisive role in shaping the future of quantum information science. The technique not only broadens the landscape of candidate qubit materials but also establishes a versatile platform for future innovations in coherent spin manipulation, quantum memory devices, and quantum networking.

In summary, the exploration of nuclear spin coherence in europium-containing molecular crystals represents a landmark achievement that combines chemical ingenuity and quantum engineering. Achieving millisecond-scale coherence times with optical control channels affirms the potential of these molecular systems as foundational components in future quantum technologies, promising enhanced qubit stability, precise qubit arrangement, and new paradigms in quantum sensing and computation.

Subject of Research: Nuclear spin control in europium-based molecular crystals for quantum information applications.

Article Title: Optically Detected Nuclear Magnetic Resonance of Coherent Spins in a Molecular Complex.

News Publication Date: 2026.

Web References: https://www.nature.com/articles/s41563-026-02539-0

References: Evgenij Vasilenko, Vishnu Unni Chorakkunnath, Jeremias Resch, Nicholas Jobbitt, Diana Serrano, Philippe Goldner, Senthil Kumar Kuppusamy, Mario Ruben, David Hunger: Optically detected nuclear magnetic resonance of coherent spins in a molecular complex. Nature Materials, 2026. DOI: 10.1038/s41563-026-02539-0.

Image Credits: Jo Richers

Keywords: quantum coherence, nuclear spins, molecular crystals, europium ions, optically detected NMR, quantum information processing, quantum computing, nuclear magnetic resonance, qubits, molecular quantum systems, spin control, quantum memory

The fundamental issue stems from the fact that microwave photons, with frequencies ranging roughly from 0.3 to 30 gigahertz, do not possess enough energy to induce observable electrical changes when they interact with materials in the same way optical photons do. In the domain of visible light, efficient photon detection is typically achieved through photodiodes or photomultiplier tubes, which translate photon absorption into measurable electrical signals by releasing electrons. However, at microwave frequencies, the absence of sufficient photon energy means these processes do not naturally occur, making direct detection of individual microwave photons nearly impossible with established semiconductor or material-based detectors. This challenge has driven significant interest within the quantum research community to develop novel methodologies and devices capable of performing this task with high fidelity.

Addressing this formidable obstacle, a pioneering research team led by Pasquale Scarlino at the École Polytechnique Fédérale de Lausanne (EPFL) has unveiled a breakthrough device that marks a critical advancement in microwave photon detection. Their work introduces a semiconductor-based detector system that can continuously detect single microwave photons, an achievement that could transform the landscape of quantum microwave optics and open new avenues for quantum sensing and information processing. This device elegantly combines two key elements: a double quantum dot semiconductor configuration and a superconducting microwave cavity, jointly orchestrating the conversion of elusive microwave photons into a tangible electrical signal.

At the heart of this novel detector lies a double quantum dot structure, a nanoscale semiconductor system where two closely spaced “dots” serve as tiny islands capable of confining single electrons. These quantum dots are fabricated on a gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) heterostructure, which hosts a high-quality two-dimensional electron gas. Using finely tuned metallic gates on this material, researchers can manipulate and control individual electrons with precision. The double quantum dot essentially acts as a quantum system with manageable energy levels that can interact resonantly with microwave photons under the right conditions, making it an ideal platform for sensitive photon detection.

Complementing the quantum dots is the superconducting microwave cavity, a meticulously engineered resonant circuit built from an array of Josephson junctions. These junctions consist of two superconducting electrodes separated by a thin insulating barrier, allowing for quantum tunneling of Cooper pairs and producing a highly tunable electromagnetic environment with exceptional sensitivity. This cavity stores incoming microwave photons at frequencies between 3 and 5.2 gigahertz, confining their electromagnetic fields. Importantly, the cavity is designed with high electrical impedance, significantly enhancing the electric field strength inside it. This enhancement drastically increases the interaction between the electromagnetic field and the electron charges within the quantum dots, facilitating the absorption of single photons.

The detection process hinges on the energy exchange between the microwave photon and the double quantum dot system. When a photon enters the cavity and its energy precisely corresponds to the energy splitting between the two quantum dots, the photon is absorbed by the electron occupying one of the dots. This absorption excites the electron, prompting it to tunnel between the two dots and then move into a nearby electron reservoir. This electron motion manifests as a minute but measurable direct electric current flowing between the source and drain terminals of the quantum dot system. Thus, the device translates the quantum event of photon absorption into an electrical signature, enabling real-time monitoring of individual photon interactions.

To quantify the performance of their microwave photon detector, the researchers undertook meticulous measurements of the source-drain current as they varied the microwave signal power, ensuring that the photon flux was carefully controlled. They calibrated the device’s energy levels to ascertain the microwave signal strength accurately. When the system operated under conditions where the average photon occupancy was less than one—meaning single photons dominated—the current exhibited a linear relationship with the photon number, confirming that the device was detecting photons individually with high sensitivity and fidelity.

This innovative detector showcased remarkable efficiency, achieving a detection rate between 55% and 67.7% depending on tuning parameters, with the highest efficiency approaching 70%. Such a performance level represents a significant leap forward for semiconductor-based microwave photon detection technologies. The continuous operation mode of the device is particularly noteworthy; following photon absorption and the subsequent electron movement, the system resets itself in just a few nanoseconds. This ultrafast reset time means the detector can handle high photon arrival rates, distinguishing it from many other photon detection approaches that operate in pulsed or non-continuous modes.

The implications of this research extend far beyond simply measuring microwaves with greater precision. Since the detector is based on semiconductor quantum dots, it can potentially be integrated onto the same chip as quantum bits (qubits) realized through electron spins in these dots. This integration could lead to compact, scalable quantum information processing platforms where microwave photonics and semiconductor quantum computing coexist seamlessly. This unification could accelerate the development of quantum networks and sensors that rely on the transmission and detection of microwave photons, marking a decisive step toward practical quantum technologies.

Moreover, the enhanced interaction between the double quantum dot and the superconducting cavity offers new opportunities to explore quantum microwave optics, a field that investigates the quantum properties of microwave radiation analogous to visible-light quantum optics but in a regime where energy scales and interaction mechanisms differ dramatically. This detector can serve as a fundamental tool to probe quantum states of microwave fields, enabling experiments that test the boundaries of quantum mechanics and help develop ultra-sensitive measurement technologies, potentially benefiting disciplines ranging from astronomy to condensed matter physics.

The research effort represented a collaborative achievement, involving not only the EPFL team but also contributions from other prestigious institutions including the University of Basel, ETH Zürich, and Lund University. This multi-institutional collaboration underscores the complex, interdisciplinary nature of developing advanced quantum technologies, combining expertise across semiconductor physics, superconducting circuits, and quantum information science to bring novel device architectures to fruition.

This transformative work, published in Science Advances, embodies a milestone in the pursuit of quantum measurement technologies. By bridging the gap between microwave photon detection and semiconductor quantum devices, it paves the way for novel quantum sensors, quantum communication networks, and scalable quantum computing platforms. As microwave photonics continues to rise in importance, innovations such as this semiconductor-based photon detector will play a crucial role in realizing the promise of quantum technologies across scientific and technological frontiers.

Subject of Research: Quantum detection of single microwave photons using semiconductor quantum dots and superconducting microwave cavities.

Article Title: Tunable high-efficiency microwave photon detector based on a double quantum dot coupled to a superconducting high-impedance cavity.

News Publication Date: 3-Apr-2026

Web References: https://doi.org/10.1126/sciadv.aeb9784

References:
Fabian Oppliger, Wonjin Jang, Aldo Tarascio, Franco De Palma, Christian Reichl, Werner Wegscheider, Ville F. Maisi, Dominik Zumbühl, Pasquale Scarlino. (2026). Tunable high-efficiency microwave photon detector based on a double quantum dot coupled to a superconducting high-impedance cavity. Science Advances, DOI: 10.1126/sciadv.aeb9784

Keywords

Microwave photon detection, quantum dots, superconducting cavity, Josephson junctions, quantum sensing, quantum information, microwave quantum optics, semiconductor quantum devices, high-impedance cavity, quantum measurement, single-photon detection, quantum computing integration

Superconductivity is unique among electronic phenomena in that it allows electric currents to flow with zero resistance, eliminating energy losses that plague conventional conductors. This perfect conductivity can lead to electronic systems and power distribution networks with dramatically reduced energy consumption. However, in practice, superconductors require extreme cooling, often down to cryogenic temperatures near minus 200 degrees Celsius, to maintain their superconducting state. Additionally, strong magnetic fields—common in many high-tech applications—tend to degrade or destroy superconductivity, limiting the range of viable uses.

The pivotal breakthrough by the team at Chalmers involves a fundamentally different strategy than traditional chemical manipulation or material substitution. Instead, they have focused on nanoscopic engineering of the substrate—the microscopic foundation on which ultrathin superconducting films are grown. By sculpting the substrate’s surface at the nanoscale, creating a pattern of tiny ridges and valleys far smaller than a millionth of a human hair’s width, they discovered a way to guide the atomic arrangement in the superconducting layer above in a way that enhances its properties.

The specific superconducting material used in this study belongs to the cuprate family of copper-oxide compounds. These materials have long intrigued physicists because they exhibit superconductivity at relatively elevated temperatures compared to conventional superconductors, yet the complexity of their crystal chemistry makes optimizing their performance challenging after synthesis. The ultrathin superconducting films, deposited on specially patterned magnesium oxide substrates, displayed an unexpected resilience—maintaining superconductivity at significantly higher temperatures while enduring intense magnetic environments.

This enhancement arises from the interface between the substrate and the superconducting layer, where the nanofacet patterns induce an “electronic landscape” that fundamentally alters how electrons organize and behave. The electronic structure near this interface develops preferential directional properties, creating a stabilized and stronger superconducting state. The research team demonstrated this using advanced vacuum and high-temperature treatments to pre-condition the substrate surface, which then imprints its sculpted pattern onto the developing atomic layers.

The implications of this nano-engineering approach are profound. Instead of endlessly searching for new superconducting compounds or attempting difficult chemical doping, scientists can now manipulate existing high-performance materials via precise control of substrate morphology. This work carves out a new principle in materials science: functional properties like superconductivity can be strategically enhanced through substrate-induced nano-patterning, a method likely applicable across various material systems.

This novel design principle opens exciting prospects for the future integration of superconductors into everyday technology. For one, by increasing the operational temperature and magnetic field tolerance, the need for costly and cumbersome cryogenic setups may be relaxed, accelerating the transition of superconducting devices from laboratory curiosities to practical components. Applications could range from ultra-efficient quantum computers that rely on stable superconducting qubits to next-generation sensors, power electronics, and advanced communication infrastructure demanding minimal energy loss.

Moreover, this work highlights the subtle but critical role played by nanoscale structural details in governing macroscopic electronic behavior. The researchers’ insight into the interplay between atomic-scale topology and electron dynamics underscores the rich complexity of interfacial phenomena, an area ripe for further exploration. Such interfacial engineering strategies could potentially unlock even higher temperature superconductivity, edging closer to the elusive goal of room-temperature superconductors that have long tantalized physicists.

In a collaborative effort spanning across institutions in Sweden, Italy, India, France, and Germany, the team combined expertise in experimental physics, quantum device engineering, and material science to achieve this milestone. Part of the experimental work was carried out in the cleanroom facilities at Myfab Chalmers, demonstrating the importance of advanced fabrication environments for manipulating matter at the nanoscale with atomic precision.

This breakthrough also addresses the global need for sustainable technology innovation. With ICT infrastructure accounting for an increasingly significant share of worldwide electricity use—estimated between 6 to 12 percent—solutions that drastically improve energy efficiency are critical. Superconductors, once plagued by impractical operational constraints, are now poised to play a transformative role in reducing the carbon footprint of digital technologies through advancements such as those unlocked by Chalmers researchers.

By revealing how subtle nanoscale sculpting can control and boost superconducting behavior, the study published in the esteemed scientific journal Nature Communications sets a fresh agenda for future superconducting material development. As this approach is refined and extended to other compound families, the prospect of superconductors functioning effectively under ambient conditions and common magnetic field environments grows ever more tangible.

Professor Floriana Lombardi, the study’s lead author, emphasizes the significance of their findings: “Our work shows that minute changes on the order of nanometers at the substrate interface can have a dramatic impact on the macroscopic properties of superconductors. This opens new pathways for engineering robust superconducting devices that could revolutionize electronics and quantum technology.”

Alongside Lombardi, notable contributors such as Eric Wahlberg and Riccardo Arpaia have underlined the interdisciplinary and international nature of this research, which benefits from the coordinated support of funding bodies including the Swedish Research Council, the Knut and Alice Wallenberg Foundation, and the European Union’s EIC Pathfinder grant.

Ultimately, this work represents a leap forward in solving the longstanding challenges of making high-temperature superconductivity practical and robust. By harnessing interfacial nano-engineering, the dream of superconducting technologies that operate efficiently in real-world environments—far beyond the confines of specialized laboratories—edges much closer to reality. As such, it marks a seminal advance in the quest for ultralow-energy electronics and pushes the frontier of quantum materials science into a promising new dimension.

Subject of Research: Not applicable
Article Title: Boosting superconductivity in ultrathin YBa2Cu3O7−δ films via nanofaceted substrates
News Publication Date: 7-Jan-2026
Web References: https://doi.org/10.1038/s41467-025-67500-2
References: Lombardi, F., Wahlberg, E., Arpaia, R., et al. Nature Communications, 2026.
Image Credits: Chalmers University of Technology / Riccardo Arpaia

Keywords

Superconductivity, Electromagnetic fields, Nanotechnology, Quantum materials, Energy efficiency, Cuprate superconductors, Substrate engineering, Ultrathin films, Quantum devices, High magnetic field superconductivity

Electronic noise, particularly low-frequency flicker noise, is a notorious adversary in electronic devices, where fluctuating currents degrade signal integrity and sensor sensitivity. At the microscopic level, this noise arises from the random scattering of electrons by lattice vibrations—phonons—and inherent material defects. Despite decades of efforts to minimize such noise through improved fabrication and material purity, the fundamental mechanisms have remained stubbornly resistant to elimination. This latest research injects fresh optimism by unveiling a quantum mechanical regime in which electrons and phonons move in remarkable harmony, synchronizing their dynamics and effectively silencing the disruptive noise contributions that historically plagued conductive materials.

The heart of this noise-mitigation mechanism lies in a phenomenon known as charge density waves (CDWs), a quantum state where electrons condense into periodic patterns along certain crystallographic axes of low-dimensional materials. In essence, electrons travel collectively, riding synchronized phonon waves across the nanowire, analogous to surfers catching an ocean swell rather than being tossed by turbulent waters. This coordinated electron-phonon coupling marks a departure from the traditional picture of incoherent electron motion interrupted by thermal vibrations, offering a fresh paradigm where quantum coherence in strongly correlated materials reduces electronic noise beyond classical limits.

This December 2025 study reveals that tantalum-based nanowires exhibit progressively reduced electrical noise as current increases, eventually reaching levels beneath the threshold of practical measurement at cryogenic temperatures near -100 °F. Even more striking is the observation that niobium-based analogues maintain this suppressed noise state at room temperature and above, heralding practical real-world applications without the need for elaborate cooling systems. Such behavior challenges established models that anticipated noise revival at elevated currents or temperatures, prompting the theorists to develop revised frameworks that incorporate the full complexity of electron-phonon correlations in quasi-1D CDW systems.

The experimental fabrication of these nanowires demanded atomic precision in synthesizing compounds with unidirectional strong atomic bonding, achieved in sophisticated facilities like the UCLA NanoLab. Microscopic imaging confirms the intricate architecture, where metal electrodes interface with the slender ribbons—thousands fold thinner than a human hair—allowing high-resolution probing of their electrical responses. Performing electrical characterization necessitated suppression of extrinsic noise and the use of novel spectroscopic techniques, such as Brillouin–Mandelstam Inelastic Light Scattering, to unravel the interplay between phonons and electron density fluctuations, crucial to establishing the collective transport mechanism.

Quantum mechanics plays a pivotal role in enabling this coherent transport regime. Unlike conventional conduction where electron trajectories deviate randomly due to phonon collisions, in strongly correlated quasi-1D materials, electrons form spatially periodic wave packets synchronized with phonon modes. The result is a collective current with drastically reduced statistical fluctuations, roughly analogous to a regimented troop marching in unison rather than individual soldiers wandering independently. Exploiting this regime not only advances fundamental understanding but also opens avenues for engineering ultra-low-noise conductors critical for next-generation electronics.

The implications of this discovery stretch far beyond academic curiosity. Ultra-low-noise materials could revolutionize sensor technologies by enhancing their ability to detect faint signals, ranging from biomedical diagnostics to environmental monitoring. In the quantum computing arena, the fidelity of quantum bits depends critically on the suppression of electrical noise to maintain quantum coherence and reduce errors. Achieving such noise reduction at or near room temperature, as exhibited in the niobium-based nanowires, could significantly relax the stringent cooling requirements that currently constrain quantum device architectures, accelerating their practical deployment.

This research also prompts the reevaluation of existing theoretical models. Previously, strongly correlated materials were often oversimplified, glossing over the nuanced interactions that could give rise to exotic properties like the observed noise decrease. The UCLA team’s findings emphasize the need for comprehensive quantum models embracing electron-phonon entanglement and collective charge behavior, which may reveal hidden phases and unexplored functionalities in materials science. This paradigm shift holds promise for discovering new materials tailored specifically to capitalize on these quantum coherence effects.

Looking toward the future, the UCLA team envisions leveraging strongly correlated materials as integrated circuit conductors, possibly transforming the conventional electronic landscape defined by silicon and copper interconnects. The potential to manipulate noise characteristics quantum-mechanically opens the possibility of fundamentally novel circuit architectures that transcend classical limitations, particularly relevant as computational demands surge with the rise of artificial intelligence and data-intensive applications.

Collaboration between multiple institutions underpinned this interdisciplinary effort, combining expertise in materials synthesis, characterization, theoretical modeling, and device engineering. The study was supported by prominent funding agencies, including the U.S. Office of Naval Research and the European Research Council, underscoring the strategic importance of mastering ultra-low-noise technologies for national and global technological leadership.

While tantalum- and niobium-based quasi-1D nanowires form the current benchmark, the search is ongoing for materials exhibiting even stronger charge density wave coherence and noise suppression at ambient conditions. The endeavor to identify and harness such materials paves the way toward a quieter, brighter future where electronic signals can be processed and transmitted with unprecedented fidelity, propelling the next wave of innovation in computing, communications, and sensor technology.

In summary, this breakthrough elucidates a remarkable new state of collective electronic conduction in quasi-1D charge density wave nanowires, where electron-phonon synchronization governs noise reduction in a manner previously unseen. The work not only advances fundamental quantum materials science but also points the way toward transformative applications that could redefine the performance envelope of modern electronics and quantum devices.

Subject of Research: Noise reduction in electronic conduction through quasi-1D charge density wave nanowires

Article Title: A quieter state of charge and ultra-low-noise of the collective current in quasi-1D charge-density-wave nanowires

News Publication Date: 31-Dec-2025

Web References:

• UCLA Samueli School of Engineering: https://samueli.ucla.edu
• Balandin Group at UCLA: https://balandin-group.ucla.edu
• California NanoSystems Institute at UCLA (CNSI): https://cnsi.ucla.edu
• Nature Communications article: https://www.nature.com/articles/s41467-025-67567-x

Image Credits: Balandin Lab/UCLA

Keywords: Semiconductors, Quantum computing, Electrical conductors, Strongly correlated materials, Charge density waves, Nanowires, Electron-phonon interaction, Noise reduction, Quantum transport

The primary challenge facing TWPAs has long been their apparent lack of true directionality. This limitation arises due to the potential for electromagnetic radiation to travel backward towards the input port. Such a phenomenon can lead to significant issues, including reflections that complicate signal processing. Researchers are continuously searching for solutions that can provide a built-in isolation mechanism along with amplification performance, which would mitigate the backward propagation of signals. The breakthrough presented by recent research focuses on achieving both goals through innovative design approaches employing Josephson junctions.

This novel design utilizes the physical properties of superconductors to achieve impressive results. By leveraging third-order nonlinearity for the amplification process, the researchers can effectively boost incoming microwave signals. In addition, second-order nonlinearity plays a crucial role in facilitating the frequency upconversion of any backward-propagating modes within the system. This dual approach not only enhances gain but also serves as a vital method for achieving reverse isolation, ensuring that reflected signals do not interfere with the primary input.

The efficacy of these parametric processes is significantly enhanced by incorporating a phase-matching mechanism. By optimizing the interaction between various modes within the amplifier, researchers can achieve substantial signal enhancements while limiting unwanted feedback from reverse traveling signals. The results reported in a recent study demonstrate a remarkable gain of up to 20 dB. This level of amplification is crucial for many applications, particularly in fields that require sensitive measurements or intricate quantum-state readouts.

In addition to amplification, the researchers have reported achieving up to 30 dB of reverse isolation. This impressive level of isolation allows for a more accurate retrieval of signals, as the device effectively eliminates noise from backward-traveling waves. This characteristic is increasingly vital in applications like quantum computing, where the clarity and integrity of signals can significantly impact overall system performance and reliability. Such advancements do not just offer theoretical improvements; they could spearhead practical solutions in designing next-generation quantum electronics.

The amplifier’s performance stretches across a static 3-dB bandwidth greater than 500 MHz. This wide operational bandwidth means that the device can accommodate a variety of microwave frequencies without losing effectiveness, making it incredibly versatile for various practical applications. The capability to maintain near-quantum-limited added noise during operation ensures that this device can be relied upon for high-precision experiments and applications within quantum optics and communication fields.

As researchers dive into the implications of these findings, the potential applications of such a device are numerous. From enhancing signal strength in quantum computers to refining measurements in experimental physics, the superconducting travelling-wave parametric amplifier isolator stands to benefit multiple technological horizons. Its ability to isolate and amplify simultaneously marks a significant step forward in the engineering of superconducting circuits. It creates newfound opportunities for complex experiments where control and precision are paramount.

Moreover, the implications of this research extend beyond just the realm of superconductors. The techniques and methods employed in the design of the amplifier are likely to inspire similar initiatives across various fields that require robust signal processing solutions. Engineers and scientists interested in the domains of telecommunications, quantum mechanics, and information processing may find valuable insights and practical implementations derived from this work.

While the frontier of superconducting technology continues to expand, developments such as the superconducting travelling-wave parametric amplifier isolator signify a leap toward realizing practical, high-efficiency quantum systems. Innovations like these serve not only to underline the vast potential of quantum electronic devices but also to remind us of the profound capabilities that superconductors carry. The research community is keenly observing as they unravel further advancements stemming from this significant study.

As the countdown to ubiquitous quantum technologies continues, breakthroughs like the superconducting travelling-wave parametric amplifier isolator serve to pique the interest of both academic researchers and private industry. The marriage of theory and engineering encapsulated in this innovative amplifier highlights the importance of addressing limitations inherent in current technologies. The path forward demands creativity, persistence, and a commitment to pushing boundaries, defining a future where quantum properties can be harnessed more effectively than ever before.

Gazing into the horizon of microwave technology and quantum computing, it becomes apparent that the journey of innovation is alive and active. Each advancement not only brings practicality closer but also constructs a narrative intertwined with scientific exploration and discovery. With superconducting devices like this amplifier isolator leading the way, the quest for operational excellence in quantum systems seems inevitable and incredibly promising.

For those who have been following the intricate developments in the field of quantum technology, the significance of this amplifier cannot be overstated. The implications for not just superconducting science but also a plethora of ancillary fields are immense. Time will reveal the long-term impact and possible adaptations of these findings in everyday applications, but the trajectory indicated by this research suggests an exciting landscape ahead.

As we stand on the threshold of the next generation of quantum technologies, superconducting travelling-wave parametric amplifiers could play a pivotal role in shaping the future of information processing and communication. The unique properties and capabilities of these devices will likely redefine methodologies across various sectors, establishing a foundation for robust advancements in the imminent evolution of quantum systems.

In summary, the development of the superconducting travelling-wave parametric amplifier isolator is a hallmark achievement that addresses longstanding challenges faced by microwave amplification systems. By leveraging the unique properties of superconducting materials, researchers have unlocked new potential for improved signal processing capabilities. This innovative work embodies the spirit of inquiry and showcases the potential of engineering solutions to overcome barriers in the burgeoning field of quantum technology.

Subject of Research: Superconducting travelling-wave parametric amplifiers

Article Title: A travelling-wave parametric amplifier isolator

Article References:

Ranadive, A., Fazliji, B., Le Gal, G. et al. A travelling-wave parametric amplifier isolator. Nat Electron (2025). https://doi.org/10.1038/s41928-025-01489-w

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41928-025-01489-w

Keywords: Superconducting devices, quantum technology, microwave amplification, parametric amplification, signal isolation, Josephson junctions, quantum computing, nonlinearity, phase matching, reverse isolation.

Central to quantum communication is the ability to reliably produce and transmit single photons, which serve as quantum carriers of information. These indivisible light quanta are pivotal for protocols such as quantum key distribution, offering theoretically unbreakable encryption. However, the efficiency of single-photon sources interfaced with optical fibers – the backbone of existing communication infrastructure – has been a persistent bottleneck. Conventional approaches involve placing photon emitters like quantum dots or rare-earth element ions outside the fiber, from where emitted photons must be coupled into the fiber. This coupling process is inherently inefficient, resulting in significant transmission loss that compromises communication fidelity over distances.

The innovative solution proposed by Associate Professor Kaoru Sanaka and his team at Tokyo University of Science circumvents this limitation by integrating single photon emitters directly inside the optical fiber itself. Their method selectively excites an individual rare-earth ion embedded within a tapered section of the fiber, enabling photon generation and waveguide transmission to occur simultaneously within the fiber. This closed-loop integration markedly reduces loss and elevates overall system efficiency – a vital advance for building practical quantum networks.

Rare-earth ions, particularly neodymium ions (Nd^3+), were judiciously chosen for this work due to their favorable emission properties across a broad spectral range. Crucially, Nd^3+ emits photons spanning wavelengths compatible with existing telecommunications standards, making these fibers directly adaptable to current fiber-optic infrastructure. The team created these novel light-emitting fibers by uniformly doping silica fibers with Nd^3+ ions before subjecting them to a precision heat-and-pull tapering process. This refined tapering reduces the fiber’s diameter and creates spatially resolvable individual ions within the tapered region, paving the way for selective excitation.

The physical mechanism relies on targeting a single isolated Nd^3+ ion with a pump laser while minimizing excitation of neighboring ions—thereby generating high-purity single photons directly into the fiber’s guided mode. The experimental setup involves collecting photons emitted at one end of the fiber and analyzing their statistical properties using the technique of photon autocorrelation. This approach confirms the hallmark quantum trait of single-photon emission: the anti-bunching effect, wherein photons are emitted one at a time rather than in clumps. This verification is essential, affirming that the device functions as a true single-photon emitter integrated within the fiber.

Importantly, the optical qualities of the Nd^3+ ions—such as emission wavelength and coherence—remain fundamentally unchanged by the tapering process. This preservation assures that the integration technique does not come at the cost of optical performance. Moreover, the team’s results demonstrate a significant increase in photon collection efficiency compared to previous methods where multiple ions were excited simultaneously, leading to a less controlled emission pattern and higher losses. Further efficiency gains are achievable by harvesting photons emitted from both ends of the tapered fiber section.

Operating at room temperature, this technology diverges from many quantum photonic systems that necessitate cumbersome and costly cryogenic cooling. The ability to function efficiently without refrigeration substantially simplifies real-world deployment and reduces associated operational costs. Additionally, since the platform uses commercially available silica fibers doped with rare-earth elements, it offers a cost-effective, scalable, and readily integratable solution for quantum communication networks.

Beyond secure communication, this fiber-embedded single-photon generation technique holds promise for advancing quantum computing architectures. By selectively controlling multiple isolated ions within a single fiber, the system could serve as a scalable quantum processor, enabling multi-qubit operations and sophisticated qubit encoding protocols. Such integrated photonic quantum processors are a key milestone towards practical quantum information processing devices.

Current and future research efforts are expected to focus on fine-tuning the emission wavelengths of single photons and enhancing their coherence properties to optimize system compatibility with various quantum technologies, including spectroscopy and biomedical imaging. These refinements will broaden the utility of this technique beyond communication, opening doors to new quantum applications across scientific disciplines.

The implications of this pioneering work are profound. By demonstrating highly efficient, room-temperature single-photon generation directly inside optical fibers, the researchers have established a practical and scalable platform poised to underpin next-generation quantum networks. This advancement brings us closer to realizing unhackable communication channels and versatile quantum computing systems seamlessly integrated with existing infrastructure.

As quantum information science continues to evolve, innovations like these highlight a transformative path where classical optical technologies and quantum physics converge. The universal adoption of such fiber-coupled quantum light sources will not only elevate data security but also accelerate progress towards a fully quantum-enabled information era, drastically reshaping the technological landscape in the decades to come.

Subject of Research: Not applicable

Article Title: Selective excitation of a single rare-earth ion in an optical fiber

News Publication Date: 22-Sep-2025

References: DOI: 10.1364/OE.570912

Image Credits: Dr. Kaoru Sanaka from Tokyo University of Science, Japan

Keywords

Quantum information science, Information science, Information technology, Quantum information, Computer science, Internet, Physics, Quantum optics, Quantum mechanics, Applied sciences and engineering, Physical sciences, Single photon sources, Quantum computing, Fiber optics

The scanning tunneling microscope stands at the heart of this achievement. With its atomically-sharp metallic needle, the STM can resolve individual atoms on surfaces by detecting currents generated from electrons tunneling between the tip and the sample. However, while it has been known that STM can sense electron spin states, directly accessing nuclear spins has posed a formidable challenge due to their relatively weak magnetic moments and the indirect nature of their interactions with the electrons. The Delft team ingeniously exploited the subtle hyperfine interactions—delicate quantum couplings between the nucleus and electron spins—to infer nuclear spin orientations by observing changes in the tunneling current.

Electron spins in atoms typically fluctuate on extremely short timescales, often mere nanoseconds, making real-time detection and control difficult. Nuclear spins, by contrast, can be far more stable, but their weak signals have long eluded rapid measurement. Surprisingly, the researchers found that the nuclear spin of the targeted atom remained stable for several seconds before flipping states. This timescale, orders of magnitude longer than electron spin lifetimes, allowed the team to monitor the nuclear spin transitions live on their computer screens, truly witnessing quantum behavior unfold in real time.

The real novelty of the experiment lies in the concept of single-shot readout—rapidly and reliably determining the nuclear spin state from a single measurement without averaging over multiple trials. Previous techniques often required repeated measurements to infer nuclear spin behavior, because the signal-to-noise level was prohibitively low or the measurement process itself disturbed the spin state. By tuning the STM setup and leveraging the hyperfine interaction, the Delft scientists detected fluctuations in the tunneling current that directly corresponded to the nuclear spin flipping between two distinct quantum states. This capability not only advances fundamental quantum measurement techniques but sets the stage for future quantum control schemes, where nuclear spins can serve as qubits or sensors.

This work reveals that nuclear spins, despite their small magnetic moment, have lifetimes suitable for quantum information tasks. While electron spins decohere within nanoseconds under typical conditions, nuclear spins act as robust quantum memories, persisting for seconds or longer. Capturing their dynamics on such timescales with an STM—an instrument traditionally used for imaging surfaces—reveals unprecedented atomic-scale information and control, which was previously thought impossible.

The implications for quantum sensing are profound. Nuclear spins tethered to surface atoms can function as ultra-sensitive probes of magnetic and electric fields, chemical environments, or even mechanical strains, all at the atomic scale. This capability surpasses traditional macroscopic sensors, promising advances in nanoscale materials science, condensed matter physics, and even the detection of elusive phenomena such as dark matter or novel quantum phases.

Achieving this feat required overcoming several technical hurdles. The STM tip must be exquisitely stable and sensitive to detect the minute current variations caused by nuclear spin flips, all while avoiding perturbation of the spin state. The research team employed rapid measurement protocols, coupled with sophisticated data analysis, to distinguish genuine nuclear spin signals from noise and other electronic fluctuations. Their success paves the way for the development of STM-based quantum sensors that can operate as scalable platforms for quantum simulation or computing.

The interplay of electron and nuclear spins within a single atom, long studied theoretically, now finds concrete expression through this experiment. The so-called hyperfine interaction, a quantum mechanical coupling arising from contact and dipolar effects between the electron cloud and the atomic nucleus, acts as the conduit transmitting nuclear spin information to the electron states detectable by STM. By harnessing this subtle yet fundamental interaction, researchers can now observe and manipulate nuclear spins with unprecedented precision.

Looking ahead, the researchers envision leveraging single-shot nuclear spin readout for quantum state preparation and error correction protocols, essential for robust quantum computing. On a practical level, this capability could enable the design of novel quantum devices where nuclear spins serve as stable information storage nodes or sensors integrated directly at the atomic scale. Furthermore, the experimental framework provides a testbed for exploring quantum coherence, decoherence mechanisms, and spin dynamics in complex materials.

This landmark study, conducted under the lead of Professor Sander Otte, marks a crucial step in the frontier of quantum measurement science. By illuminating the “silent” spins of atomic nuclei, the Delft team has expanded our toolkit for probing and harnessing the quantum world. As the field progresses, such techniques promise to transform our understanding of matter and underpin next-generation quantum technologies.

In summary, this research not only captures a fundamental quantum phenomenon—nuclear spin flips—in real time but also establishes STM as a versatile platform for quantum sensing and manipulation at the atomic scale. The ability to observe and control nuclear spins with such fidelity offers exciting possibilities in physics, materials science, and quantum engineering. As quantum technology races forward, these findings stand as a testament to the ingenuity and precision now achievable in experimental quantum science.

Subject of Research: Not applicable
Article Title: Single-shot readout of the nuclear spin of an on-surface atom
News Publication Date: 21-Aug-2025
Web References: https://www.nature.com/articles/s41467-025-63232-5
References: DOI: 10.5281/zenodo.15518772
Image Credits: Scixel

Keywords

Nuclear spin, quantum spin flipping, scanning tunneling microscope, single-shot readout, hyperfine interaction, quantum measurement, atomic scale sensing, quantum sensing, quantum information, electron spin, decoherence, quantum simulation

Traditional nuclear magnetic resonance spectroscopy, familiar to many through its medical imaging counterpart—magnetic resonance imaging (MRI)—has revolutionized our ability to visualize internal structures non-invasively. Yet, the inherently limited resolution of conventional NMR has imposed a boundary on examining molecular structures at the atomic scale. Diagnostic MRI and standard NMR methods require large ensembles of atoms to produce signals, preventing scientists from observing single molecules or even individual atoms. This limitation has been an enduring obstacle in both fundamental research and applications demanding unparalleled precision, such as quantum computing components and highly sensitive molecular sensors.

Li’s team has capitalized on the unique qualities of 2D materials, which form crystalline sheets just atoms thick. Hexagonal boron nitride, specifically, exhibits a lattice structure of alternating boron and nitrogen atoms arranged in hexagonal rings and hosts naturally occurring vacancies—missing atoms that create localized sites capable of trapping electrons or nuclear spins. By introducing carbon-13 isotopes into these vacancies, the researchers transformed these sites into controllable spin defects. Unlike its most abundant isotope, carbon-12, carbon-13 has a nuclear spin that interacts with magnetic fields, enabling it to be directly probed by magnetic resonance techniques.

The process of embedding carbon-13 isotopes into hBN involved a sophisticated technique where carbon-13-enriched carbon dioxide gas was accelerated toward the hBN crystal using an electric field, causing some atoms to replace boron or nitrogen atoms in the lattice. These substitutions created a new class of spin defects that serve as sensitive probes of their atomic surroundings. By exploiting optically detected NMR, a method that couples nuclear magnetic resonance with optical readout through emitted photons, Li’s group succeeded in achieving single-spin detection. This approach allows the direct observation of the quantum state of a single nuclear spin in a material only a few atoms thick—a feat never accomplished before.

One of the hallmark achievements of this study is the ability to classify the newly discovered spin defects into three distinct groups based on their characteristic spectroscopic signals. Collaborating with theorist Yuan Ping from the University of Wisconsin-Madison, the team combined experimental observations with advanced computational modeling to identify the specific atomic structures corresponding to two of these groups. These insights are crucial because understanding the precise defect geometry is fundamental for reproducible quantum device engineering and for tuning the coherence properties of spin qubits.

Coherence time, or how long a quantum state remains unperturbed, is a critical parameter for quantum technologies. Remarkably, the carbon-13 spin defects in hBN demonstrated long coherence times even at room temperature, an attribute that positions these defects as promising quantum memories. Quantum memories are the backbone of many quantum computing and communication schemes, storing quantum information reliably during processing and transmission. The discovery that these nuclear spins maintain coherence without requiring cryogenic cooling represents a major leap toward practical quantum devices operating under ambient conditions.

The implications of this advancement extend beyond the realm of quantum computing. Magnetic resonance microscopy enhanced with atom-scale resolution can revolutionize molecular analysis by enabling the direct detection and structural characterization of individual biological molecules. This capability opens up possibilities for unprecedented insight into protein folding, enzyme mechanisms, and pharmacological interactions at the ultimate level of detail, potentially transforming drug discovery and molecular diagnostics.

Historically, Li’s research group has pursued using the electron spins in boron vacancies within hBN as quantum sensors. While these electron spins emitted light to signal local magnetic environments, their optical emission was too weak for single-defect resolution. The pivot toward carbon-13 nuclear spins represents a strategic evolution, overcoming the sensitivity barrier by directly targeting nuclear rather than electronic spins, which are less prone to environmental noise and thus capable of longer coherence times.

The sophisticated interplay between nuclear and electron spins in these 2D materials allows for precise manipulation and readout of quantum states using combinations of magnetic resonance and optical techniques. Optically detected nuclear magnetic resonance uniquely enables this control by using laser excitation to polarize and detect nuclear spins indirectly via changes in emitted light, thus merging the strengths of optical measurement with the intrinsic information contained in nuclear spins.

This research was enabled by meticulous experimental craftsmanship combined with theoretical expertise, supported by funding from the Gordon and Betty Moore Foundation, the U.S. National Science Foundation, and the Department of Energy. By revealing the pathways to harness individual nuclear spins in scalable and accessible materials like hexagonal boron nitride, the study marks a transformative moment in quantum science, where the manipulation of matter at the smallest scales can translate into revolutionary technologies.

Looking forward, the ability to deterministically place and control carbon-13 spin defects promises the creation of quantum sensors of unparalleled sensitivity and spatial resolution. These detectors could transform a wide array of scientific disciplines, ranging from nanoscale magnetic resonance imaging to quantum-enhanced biological sensing. Moreover, the research enriches the toolbox for engineering novel qubits in 2D materials, essential for developing scalable quantum networks that integrate with existing semiconductor technology.

In summary, Purdue University’s recent demonstration of single nuclear spin detection and precise control in hexagonal boron nitride heralds a new era of quantum sensing and molecular microscopy. By weaving together the subtle intricacies of materials science, quantum physics, and cutting-edge spectroscopy, this work not only solves a longstanding challenge in NMR spectroscopy but also lays the groundwork for breakthroughs in quantum computing, communications, and biomedical research—ushering us ever closer to the long-envisioned realm of atomic-scale exploration and manipulation.

Subject of Research: Not applicable

Article Title: Single nuclear spin detection and control in a van der Waals material

News Publication Date: 9-Jul-2025

Web References:

• Article in Nature: https://www.nature.com/articles/s41586-025-09258-7
• Purdue Physics Faculty: https://www.physics.purdue.edu/people/faculty/tcli.php
• Purdue Quantum Science and Engineering Institute: https://quantum.research.purdue.edu/
• Purdue National Science Foundation’s Quantum Technologies Center: https://www.purdue.edu/cqt/
• Purdue Strategic Initiatives: https://www.purdue.edu/president/strategic-initiatives

References:
Li, T., et al. “Single nuclear spin detection and control in a van der Waals material.” Nature (2025). DOI: 10.1038/s41586-025-09258-7

Image Credits: Purdue University photo/Charles Jischke

Keywords:

• NMR spectroscopy
• Quantum information
• Qubits