Quantum Sensing & Metrology: Atomic Clocks & Quantum Sensors
Quantum sensing news: quantum metrology, atomic clocks, quantum gravimetry, magnetometers. Quantum imaging & positioning applications.
Quantum sensing exploits quantum superposition and entanglement to achieve measurement precision beyond classical limits, offering orders-of-magnitude improvements in timing, navigation, magnetic field detection, and gravitational sensing.
Core technologies include atomic clocks achieving precision of 10^-18 (losing 1 second over 30 billion years); quantum magnetometers detecting femtotesla magnetic fields; and quantum gravimeters measuring gravitational acceleration for underground infrastructure mapping.
India's Quantum Sensing and Metrology Initiatives
India's National Quantum Mission includes quantum sensing and metrology as one of four verticals with dedicated funding. The Qmet Tech Foundation at IIT Bombay serves as the Thematic Hub on Quantum Sensing, Imaging, and Metrology under NQM. Established as a Section-8 not-for-profit company, Qmet brings together 16 premier institutions and 40+ researchers across India.
Key Qmet technologies include the portable magnetometer and quantum diamond microscope developed at IIT Bombay's Photonics and Quantum Sensing Technology Lab (P-Quest Lab). The quantum diamond microscope uses nitrogen-vacancy (NV) centers in diamond as ultra-sensitive magnetic field sensors for applications including non-destructive testing of semiconductor chips and biological sensing of neuronal cultures.
The Physical Research Laboratory (PRL) in Ahmedabad develops atomic clocks for ISRO's navigation satellites (NavIC). The Defence Research and Development Organisation (DRDO) develops quantum sensors for defense applications including submarine detection and navigation in GPS-denied environments.
The NQM targets developing magnetometers with high sensitivity in atomic systems and atomic clocks for precision timing, communications, and navigation. The ₹720 crore quantum fabrication facility investment includes quantum sensing infrastructure at IIT Bombay and IIT Kanpur.
quantum-computingPrecision Measurement Now Underpins Industrial Technology Development
Scientists are addressing a critical need for standardised measurement techniques to facilitate the burgeoning field of quantum technologies. Nobu-Hisa Kaneko from the AIST, Global Research and Development Center for Business by Quantum-AI Technology (G-QuAT) and National Metrology Institute of Japan (NMIJ), alongside colleagues, present a strategic review charting a pathway towards metrological infrastructure for quantum hardware. This research is significant because it identifies the precision-measurement capabilities essential for the development, characterisation, and reliable operation of diverse quantum computing modalities, reversing the traditional direction of benefit where measurement now enables industrialisation. By surveying these needs and highlighting cross-cutting opportunities, the team proposes a framework that extends beyond computing into emerging quantum sensing applications, fostering greater integration and scalability within the sector. It reverses the traditional direction of benefit, where measurement now enables industrialisation. By surveying these needs and highlighting cross-cutting opportunities, the team proposes a framework that extends beyond computing into emerging quantum sensing applications, fostering greater integration and scalability within the sector. Establishing traceable standards for quantum component verification Electrical metrology, the science of accurate electrical measurement, now underpins the progression of quantum technologies through rigorous characterisation of components. It employs highly precise instruments to map electrical properties, ensuring each quantum device performs as expected, similar to quality control checks in a car factory. This process identifies and rectifies deviations from design specifications, but it isn’t simply about achieving accuracy. Establishing traceability, linking measurements back to internationally recognised standards defined by fundamental constants, guarantees consistency a
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quantum-computingAccurate Quantum Sensing Now Accounts for Real-World Limitations
Scientists are increasingly focused on optimising quantum sensing technologies, but assessing their true potential requires a comprehensive understanding of practical limitations. Zdeněk Hradil and Jaroslav Řeháček, from the Department of Optics at Palacký University, have established a new framework for evaluating quantum sensing performance under realistic resource constraints. Their work moves beyond the commonly used Fisher information, instead focusing on the complete inference process, encompassing state preparation, measurement, and data analysis, to provide a more operationally meaningful assessment of achievable precision. This research is significant because it clarifies when non-classical resources genuinely enhance sensing capabilities and offers a practical methodology for designing and evaluating future quantum sensing protocols, demonstrating, for example, that NOON states do not offer advantages over classical interferometry for global phase estimation when considering finite resources and prior information. Realistic precision limits in quantum sensing from full dataset analysis Calculations based on the Quantum Fisher Information (QFI), a commonly used benchmark, often overestimate achievable precision in quantum sensing by up to a factor of n, where n represents the number of measurements in the inference data set. Shifting the focus to the entire inference dataset as the fundamental unit of estimation enables a more realistic evaluation of quantum sensing protocols. Phase estimation using NOON states, a benchmark for quantum enhancement, offers no practical advantage over standard classical interferometry when accounting for total photon resources and prior knowledge of the signal. Analysis of Holland-Burnett interferometry and homodyne detection with squeezed states revealed that the number of repetitions in a measurement, alongside estimator construction, dictates achievable precision; the QFI is only a reliable indicator under specific conditi
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quantum-computingLight’s Subtle Shifts Measured with Unprecedented Precision
Scientists are continually striving to enhance the precision of phase estimation, a critical task in fields ranging from interferometry to quantum sensing. Mikhail S. Podoshvedov and Sergey A. Podoshvedov, from the Laboratory of quantum information processing and quantum computing at South Ural State University (SUSU), have demonstrated an ultra-precise phase estimation technique that uniquely bypasses the need for mode entanglement. Their research details the optical engineering of continuous-variable probe states using squeezed vacuum states and a beam splitter to achieve sub-Heisenberg precision, saturating the Cramer-Rao bound through simple intensity measurements. This innovative approach highlights that nonclassical photonic properties, rather than entanglement, are key to unlocking enhanced sensitivity in phase estimation protocols, potentially simplifying the implementation of high-precision quantum technologies. A new phase estimation technique achieves ultra-precise results without requiring mode entanglement. Mikhail S. The technique saturates the Cramer-Rao bound through simple intensity measurements. This approach highlights that nonclassical photonic properties, then entanglement, are key to unlocking enhanced sensitivity in phase estimation protocols, potentially simplifying the implementation of high-precision quantum technologies. Sub-Heisenberg precision attained via squeezed states and direct intensity measurements The quantum Fisher information of the squeezed vacuum state now reaches a value of FSMSV= 8(⟨nSMSV⟩2 + ⟨nSMSV⟩), representing a substantial improvement over previously attainable levels. Sub-Heisenberg precision, exceeding the limitations imposed by standard quantum mechanics, previously required intricate entangled states and precise measurement choices. Careful manipulation of continuous-variable states and simple intensity measurements now demonstrate that sub-Heisenberg precision is possible, bypassing the need for complex entanglem
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quantum-computingIs a quantum computer as a home PC possible?
Is it by the laws of physics possible to have a PC sized home computer using quantum mechanics? What break throughs is engineering and technology are required to make this a reality. If we had a room temperature superconductor needed? Materials to block outside noise? Spintronics, photons? Or a hybrid? Or the use of things like convention side? If your educated on the topic please feel free to post, or even better PM me! submitted by /u/Defiant-Travel8174 [link] [comments]
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quantum-computingNew federal funding set to reinforce Canadian quantum tech and innovation
National Research Council Canada to invest in quantum-related defence and security applicationsThe Institute for Quantum Computing (IQC) at the University of Waterloo welcomes the National Research Council Canada (NRC) investment of more than $161 million over five years to advance Canada’s leadership in quantum technology for defence and security applications. The funding is part of the federal government’s $900 million commitment for defence innovation announced this week in Ottawa.According to the announcement, in addition to NRC's ongoing quantum science and technology investments, the new funding is earmarked for industry, academia and government researchers that are developing breakthrough solutions in quantum sensing, quantum internetworking and quantum-safe communications. IQC researchers closely collaborate with NRC through its satellite office on Waterloo’s campus and many of NRC’s Challenge programs, which will be expanded with this new funding.The Honourable Stephen Fuhr (R), Canada's Secretary of State (Defence Procurement), met with Dr. Norbert Lütkenhaus (L), IQC executive director, and Siobhan Stables, IQC managing director, last month at the Mike & Ophelia Lazaridis Quantum-Nano Centre (QNC) — home to IQC.“Canada has long been forward-thinking in its investments in quantum research, and this reinforcement can propel IQC researchers to advance quantum technology and innovations even further together with our colleagues from NRC.”-Dr. Norbert Lütkenhaus, IQC’s executive director and professor in the Department of Physics and Astronomy at the University of Waterloo.At IQC, researchers are investigating core areas of quantum communication, computing and sensing, supported by materials and devices. This cutting-edge work from IQC research groups has direct implications for Canada’s national defence infrastructure and security capabilities. Many of the startups launched by our IQC members are involved with defence-related quantum projects and innovation.
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quantum-computingInfleqtion Appoints Chris O’Brien as Managing Director, Infleqtion Australia
Seasoned defense and industry leader with diverse experience in business development, systems engineering, and defense program acquisition LOUISVILLE, Colo. | March 12, 2026 | Infleqtion (NYSE: INFQ), a global leader in quantum computing and quantum sensing powered by neutral-atom technology, announced the appointment of Chris O’Brien as Managing Director of Infleqtion Australia effective immediately. In ... Read more The post Infleqtion Appoints Chris O’Brien as Managing Director, Infleqtion Australia appeared first on Infleqtion.
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quantum-computingRealistic Models Reveal Limits to Quantum Sensing Precision
Zdeněk Hradil and Jaroslav Řeháček, from the Department of Optics at Palacký University, have created a new framework for realistically evaluating quantum sensing technologies. The quantum Fisher information is commonly used to assess quantum sensing performance, but this metric lacks practical relevance without considering the complete sensing process, including state preparation and measurement limitations. The framework accounts for finite resources and data analysis, revealing that apparent advantages of certain quantum strategies, such as those employing NOON states, may stem from prior assumptions rather than genuine improvements in information gained. By revisiting established sensing techniques and focusing on estimator construction, the team provides a practical methodology for designing and assessing quantum sensors under realistic experimental conditions, clarifying when nonclassical resources truly deliver metrological benefits. Normalised resource accounting reveals negligible gains from NOON state quantum sensing Information gained from NOON states, a benchmark for quantum sensing, is operationally negligible when resources are normalized, a reduction of approximately 30% compared to previously assumed gains. Substantial precision improvements over classical methods require more than just maximising the quantum Fisher information (QFI), a standard metric in the field. Previously, the QFI was widely accepted as a reliable predictor of achievable precision, but it often misleads without a complete inference framework considering state preparation and measurement limitations. Bayesian framework analysis revealed that NOON states offer no practical advantage over standard classical interferometry when accounting for total photon resources. The apparent scaling benefits associated with these states stem primarily from pre-existing prior constraints, not from enhanced information gained during measurement. This extends to Holland-Burnett interferometry and s
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quantum-computingRice scientists unveil new tool to watch quantum physics behavior in action
Researchers at Rice University have confirmed broken symmetry within a kagome superconductor, a material exhibiting unusual electronic behavior, using a newly developed technique called magnetoARPES. Building upon angle-resolved photoemission spectroscopy, magnetoARPES incorporates a tunable magnetic field to probe the full electronic response of materials, a capability previously excluded from ARPES experiments. The team detected collective electron behavior consistent with theoretically predicted loop current orders, where electrons circle in opposite directions on the crystal lattice; this alignment was achieved by applying an external magnetic field. “Using magneto-ARPES allowed us to confirm that kagome’s electrons work together to break time-reversal symmetry,” explained Jianwei Huang, a former Rice postdoctoral researcher now at Sun Yat-Sen University and first author on the paper, offering the first direct experimental evidence of this behavior in momentum space. MagnetoARPES Technique Resolves Electronic Behavior with Tunable Magnetic Fields A newly refined technique called magnetoARPES is allowing physicists to observe quantum materials in ways previously impossible, revealing details about the collective behavior of electrons and potentially unlocking new avenues for superconductivity research. This addition enables scientists to probe the full electronic response to magnetic fields, offering crucial insights into the emergence of complex electronic behaviors. After years of simulations and experimentation, Ming Yi’s team discovered that a carefully calibrated magnetic field, generated by a coil, could preserve the quality of the momentum-resolved electronic spectral information. The team initially tested magnetoARPES on a kagome superconductor, a material known for its unusual electronic properties, which allowed them to detect collective electron behavior indicative of broken symmetry within the material. The observed symmetry breaking aligns with theor
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quantum-computingLearning from Radio using Variational Quantum RF Sensing
--> Quantum Physics arXiv:2603.10239 (quant-ph) [Submitted on 10 Mar 2026] Title:Learning from Radio using Variational Quantum RF Sensing Authors:Ivana Nikoloska View a PDF of the paper titled Learning from Radio using Variational Quantum RF Sensing, by Ivana Nikoloska View PDF HTML (experimental) Abstract:In modern wireless networks, radio channels serve a dual role. Whilst their primary function is to carry bits of information from a transmitter to a receiver, the intrinsic sensitivity of transmitted signals to the physical structure of the environment makes the channel a powerful source of knowledge about the world. In this paper, we consider an agent that learns about its environment using a quantum sensing probe, optimised using a quantum circuit, which interacts with the radio-frequency (RF) electromagnetic field. We use data obtained from a ray-tracer to train the quantum circuit and learning model and we provide extensive experiments under realistic conditions on a localisation task. We show that using quantum sensors to learn from radio signals can enable intelligent systems that require no channel measurements at deployment, remain sensitive to weak and obstructed RF signals, and can learn about the world despite operating with strictly less information than classical baselines. Comments: Subjects: Quantum Physics (quant-ph); Artificial Intelligence (cs.AI); Information Theory (cs.IT); Signal Processing (eess.SP) Cite as: arXiv:2603.10239 [quant-ph] (or arXiv:2603.10239v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.10239 Focus to learn more arXiv-issued DOI via DataCite Submission history From: Ivana Nikoloska [view email] [v1] Tue, 10 Mar 2026 21:26:43 UTC (10,222 KB) Full-text links: Access Paper: View a PDF of the paper titled Learning from Radio using Variational Quantum RF Sensing, by Ivana NikoloskaView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph < prev | next
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quantum-computingRemote engineering of particle-like topologies to visualise entanglement dynamics
--> Quantum Physics arXiv:2603.10491 (quant-ph) [Submitted on 11 Mar 2026] Title:Remote engineering of particle-like topologies to visualise entanglement dynamics Authors:Fazilah Nothlawala, Bereneice Sephton, Pedro Ornelas, Mwezi Koni, Bruno Piccirillo, Liang Feng, Isaac Nape, Vincenzo D'Ambrosio, Andrew Forbes View a PDF of the paper titled Remote engineering of particle-like topologies to visualise entanglement dynamics, by Fazilah Nothlawala and 8 other authors View PDF HTML (experimental) Abstract:Skyrmions are a particle-like topology with a quantised skyrmion number, realised across condensed matter and photonic platforms alike. In quantum photonics, they constitute an emerging resource, promising robust quantum information encoding, so far realised as single photon and bi-photon entangled states. Here we report the first visualisation of tripartite entanglement dynamics through topological structure using spin-skyrmion entangled states, where the topology of a single photon is remotely controlled through the spin of its entangled partner. We visualise our tripartite state theoretically by introducing the notion of a topological Bloch sphere that completely captures the entanglement and topolological features of the state. By leveraging this state, we realise the first quantum multiskyrmions, comprising multiple localised skyrmions within a single structure, that emulate signatures of their magnetic counterparts. We verify this experimentally and show that traversing our topological sphere reveals entanglement-driven particle-like motion of the localised topological structures. These dynamics unveil a physical manifestation of tripartite entanglement correlations which we illustrate by example of GHZ-like states, enabling a visualisation of multiple Bell states encoded within our system. Our work opens exciting possibilities for quantum sensing by mapping complex quantum channel features onto topological observables of multipartite states and offers a promisi
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quantum-computingTwo-Qubit Gate Performance Now Optimises Via Just Two Measured States
Scientists Alessandro Marcomini from the Peter Grünberg Institute – Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, and Philipp J. Vetter from Ulm University, with colleagues at the Peter Grünberg Institute – Quantum Control (PGI-8), Forschungszentrum Jülich GmbH, and the Institute for Quantum Optics, Ulm University, have developed a new method for optimising quantum gates using efficient two-qubit benchmarking. The research centres on nitrogen-vacancy centres in diamond and introduces a closed-loop optimisation technique that incorporates experimental feedback, a feature previously considered impractical due to the substantial demands placed on measurement resources. This innovative approach sharply reduces the number of measurements needed for gate optimisation by two orders of magnitude compared to conventional process tomography, thereby enabling faster and more practical quantum control experiments, as highlighted by Tommaso Calarco and Felix Motzoi. The development addresses a critical need in the field of quantum information processing, where achieving high-fidelity control over qubits is paramount for building functional quantum computers and advanced quantum sensors. Two-state evaluation delivers substantial gains in quantum gate fidelity Error rates were reduced to 0.6 percent, representing a reduction of two orders of magnitude compared to conventional optimisation techniques such as process tomography. Precise calibration of two-qubit gates previously demanded an extensive number of measurements, significantly hindering practical implementation and limiting the scalability of quantum systems. Achieving high-fidelity gate operation necessitates complex calculations involving the precise shaping of control pulses and exhaustive testing of their effects on the quantum system, thereby limiting the speed and scalability of quantum experiments. Process tomography, a standard method for characterising quantum gates, requires a complete mapping of the ga
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quantum-computingWorkshop on Gravitational Quantum Physics and Metrology
Workshop on Gravitational Quantum Physics and Metrology Acronym: Ljubljana RQI WorkshopDates: Monday, August 10, 2026 to Thursday, August 13, 2026Web page: Ljubljana RQIRegistration deadline: Wednesday, April 15, 2026Submission deadline: Wednesday, April 15, 2026Tags: Gravitational Quantum PhysicsQuantum Gravity (Weak-Field Regime)quantum informationquantum metrologyGravitational PhysicsQuantum States in GravityTests of Quantum GravityWeak-Field Quantum Gravity ExperimentsGravity-Induced EntanglementGravitational DecoherenceCollapse ModelsRelativistic Quantum SystemsEquivalence Principle (Quantum Regime)Quantum Effects of Acceleration and RotationQuantum Resources in Gravitational FieldsNear-Term Quantum Gravity ExperimentsSpace-Based Quantum ExperimentsQuantum Technologies in SpaceExperimental Quantum GravityQuantum Sensing for Gravitational EffectsGravitational MetrologyRelativistic Quantum InformationLaboratory Tests of Gravity and Quantum MechanicsEuropean Quantum Gravity ResearchRQI COST Action WG2Gravitational Quantum Physics Workshop 2026The field of gravitational quantum physics brings together ideas from quantum information, metrology, and gravitational physics to address questions such as how gravity affects quantum states, whether quantum properties of gravity can be tested in the weak field regime far below the Planck scale, how relativistic concepts extend to quantum systems, and how these effects can be tested experimentally. Many of these questions can now be explored with near-term laboratory experiments and with emerging space-based platforms. The workshop aims to provide a forum for exchange between theorists and experimentalists working on these topics. It focuses on recent results, open theoretical issues, and realistic experimental proposals, and seeks to strengthen coordination within the European research community active in gravitational quantum physics. Topics covered by the workshop include: Tests of quantum as
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quantum-computingDurham University to Lead UK Quantum Simulation Research Program
Insider Brief Researchers led by Simon Cornish at Durham University will lead a UK research program to develop advanced quantum simulators using ultracold polar molecules. The project will involve collaborations with University of Birmingham, Imperial College London, and King’s College London to study complex quantum many-body phenomena that are difficult for classical computers to model. The £9.99 million program will build experimental platforms including optical tweezer arrays, quantum-gas microscopy systems, and molecular Bose–Einstein condensate experiments to explore new quantum materials and interactions. PRESS RELEASE — The national programme, led by Professor Simon Cornish from the Department of Physics, will allow UK scientists to build some of the world’s most advanced quantum simulators. These devices will be capable of explaining some of the greatest mysteries in modern physics. Controlling quantum matter molecule by molecule Professor Cornish, working alongside fellow researchers at Durham and collaborators at Birmingham University, Imperial College London and King’s College London, will develop and study systems of ultracold polar molecules. These are a special type of quantum matter that exhibits long-range interactions between the constituents. They will build artificial materials by arranging the molecules into ordered arrays, controlling every single element of the experiment, including the quantum state of each molecule and how strongly molecules interact with one another. Using these materials, the researchers will study the novel quantum properties that emerge when many molecules are made to interact. Such quantum many-body phenomena play an important role in many areas of science, from materials and nuclear physics to chemistry and even biological processes. Yet they remain poorly understood because their behaviour is too complex for classical computers to model. A multi‑platform quantum research programme The funding will support several cutt
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quantum-computingDistributed g(2) Retrieval with Atomic Clocks: Eliminating Conventional Sync Protocols
--> Quantum Physics arXiv:2603.08768 (quant-ph) [Submitted on 9 Mar 2026] Title:Distributed g(2) Retrieval with Atomic Clocks: Eliminating Conventional Sync Protocols Authors:Md Mehdi Hassan, Jacob E. Humberd, Mohmad Junaid Ul Haq, Noah A. Crum, George Siopsis, Tian Li View a PDF of the paper titled Distributed g(2) Retrieval with Atomic Clocks: Eliminating Conventional Sync Protocols, by Md Mehdi Hassan and 4 other authors View PDF HTML (experimental) Abstract:We demonstrate a method to measure coincidences between polarization-entangled photons distributed to distant locations, eliminating traditional synchronization by employing a compact, chip-scale atomic clock for precise timing. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.08768 [quant-ph] (or arXiv:2603.08768v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.08768 Focus to learn more arXiv-issued DOI via DataCite Submission history From: Md Mehdi Hassan [view email] [v1] Mon, 9 Mar 2026 14:16:28 UTC (299 KB) Full-text links: Access Paper: View a PDF of the paper titled Distributed g(2) Retrieval with Atomic Clocks: Eliminating Conventional Sync Protocols, by Md Mehdi Hassan and 4 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph < prev | next > new | recent | 2026-03 References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv (What is alphaXiv?) Links to Code Toggle CatalyzeX Code
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quantum-computingLarge Language Model-Assisted Superconducting Qubit Experiments
--> Quantum Physics arXiv:2603.08801 (quant-ph) [Submitted on 9 Mar 2026] Title:Large Language Model-Assisted Superconducting Qubit Experiments Authors:Shiheng Li, Jacob M. Miller, Phoebe J. Lee, Gustav Andersson, Christopher R. Conner, Yash J. Joshi, Bayan Karimi, Amber M. King, Howard L. Malc, Harsh Mishra, Hong Qiao, Minseok Ryu, Xuntao Wu, Siyuan Xing, Haoxiong Yan, Jian Shi, Andrew N. Cleland View a PDF of the paper titled Large Language Model-Assisted Superconducting Qubit Experiments, by Shiheng Li and 16 other authors View PDF HTML (experimental) Abstract:Superconducting circuits have demonstrated significant potential in quantum information processing and quantum sensing. Implementing novel control and measurement sequences for superconducting qubits is often a complex and time-consuming process, requiring extensive expertise in both the underlying physics and the specific hardware and software. In this work, we introduce a framework that leverages a large language model (LLM) to automate qubit control and measurement. Specifically, our framework conducts experiments by generating and invoking schema-less tools on demand via a knowledge base on instrumental usage and experimental procedures. We showcase this framework with two experiments: an autonomous resonator characterization and a direct reproduction of a quantum non-demolition (QND) characterization of a superconducting qubit from literature. This framework enables rapid deployment of standard control-and-measurement protocols and facilitates implementation of novel experimental procedures, offering a more flexible and user-friendly paradigm for controlling complex quantum hardware. Comments: Subjects: Quantum Physics (quant-ph); Artificial Intelligence (cs.AI) Cite as: arXiv:2603.08801 [quant-ph] (or arXiv:2603.08801v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.08801 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: S
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quantum-computingQuantum Sensing of Birefringence Beyond the Classical Limit with a Hyper-Entangled SU(1,1) Interferometer
--> Quantum Physics arXiv:2603.08857 (quant-ph) [Submitted on 9 Mar 2026] Title:Quantum Sensing of Birefringence Beyond the Classical Limit with a Hyper-Entangled SU(1,1) Interferometer Authors:Samata Gokhale, Netanel P. Yaish, Michal Natan, Saar Levin, Yogesh Dandekar, Avi Pe'er View a PDF of the paper titled Quantum Sensing of Birefringence Beyond the Classical Limit with a Hyper-Entangled SU(1,1) Interferometer, by Samata Gokhale and 5 other authors View PDF HTML (experimental) Abstract:Quantum interferometric sensing plays a crucial role in a wide range of applications, including quantum metrology, quantum imaging, and quantum lithography, where minute phase shifts carry valuable physical information. The strength of quantum sensing lies in surpassing classical sensitivity limits, particularly through the use of quantum entanglement and squeezing to suppress optical shot noise. Birefringence sensing is crucial for various applications, as it provides detailed information about the material's structure, stress, composition, and environmental conditions. We present an interferometric scheme for detecting unknown small birefringence beyond the shot-noise limit of sensitivity that leverages the hyper-entanglement within a pair of polarized nonlinear SU(1,1) interferometers, coupled by the birefringence. Specifically, two pairs of crossed-polarization nonlinear media, both generate and measure two-mode quantum light that is squeezed and polarization-entangled. We present a complete theoretical analysis of the interferometer's sensitivity to small birefringence under realistic conditions of gain and internal loss, illuminating the potential for enhancement of the sensitivity by 3-15dB in practical, real-world experiments (the exact achievable enhancement is governed solely by the loss). Subjects: Quantum Physics (quant-ph); Optics (physics.optics) Cite as: arXiv:2603.08857 [quant-ph] (or arXiv:2603.08857v1 [quant-ph] for this version) https://doi.org/10.
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quantum-computingExperimental demonstration of optimal measurement for unambiguously discriminating asymmetric qudit states
--> Quantum Physics arXiv:2603.09026 (quant-ph) [Submitted on 9 Mar 2026] Title:Experimental demonstration of optimal measurement for unambiguously discriminating asymmetric qudit states Authors:Kang-Min Hu, Min Namkung, Myung-Hyun Sohn, Hyang-Tag Lim View a PDF of the paper titled Experimental demonstration of optimal measurement for unambiguously discriminating asymmetric qudit states, by Kang-Min Hu and 3 other authors View PDF HTML (experimental) Abstract:Identification of nonorthogonal quantum states without error is crucial for various applications in quantum information technology, as well as the foundations of quantum physics. Theoretical studies have proposed measurements that maximize the success probability of unambiguously discriminating quantum states. However, these methods are not always experimentally feasible, which has led most demonstrations to focus on equiprobable symmetric states. Here, we establish a projective measurement scheme that optimally discriminates multiple asymmetric qudit states. We experimentally demonstrate this optimal projective measurement using a photonic orbital angular momentum state, where asymmetric qudit states are encoded in the Laguerre-Gaussian modes of a heralded single-photon state. Our results have broad applications in high-dimensional quantum state-based quantum information processing, including quantum key distribution and quantum sensing. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2603.09026 [quant-ph] (or arXiv:2603.09026v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2603.09026 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Journal reference: Physical Review A 113, 032417 (2026) Related DOI: https://doi.org/10.1103/7qcr-znl2 Focus to learn more DOI(s) linking to related resources Submission history From: Hyang-Tag Lim Dr. [view email] [v1] Mon, 9 Mar 2026 23:45:32 UTC (2,782 KB) Full-text links: Access Paper: View a PDF of the pape
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quantum-computingMagnetic field-induced momentum-dependent symmetry breaking in a kagome superconductor
Nature Physics (2026)Cite this article When several degrees of freedom in quantum materials have similar energy scales, the intertwined electronic orders, which exhibit broken symmetries, are often strongly coupled. Recent studies on kagome superconductors, such as CsV3Sb5, report rotational and time-reversal symmetry breaking linked to a charge density wave. Here we observe a momentum-selective response of the electronic structure of CsV3Sb5 to an external magnetic field. By performing angle-resolved photoemission spectroscopy in a tunable magnetic field, we demonstrate that the response of the electronic structure is compatible with piezomagnetism along with strong orbital selectivity. Our results show that the origin of the time-reversal symmetry breaking is associated with the vanadium Van Hove singularities at the onset of the charge-density-wave order. We also demonstrate the presence of fluctuations beyond the charge ordering temperature. Our results reveal that magnetic fields can be used as tuning knobs for disentangling intertwined orders in the momentum space for quantum materials.This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any timeSubscribe to this journal Receive 12 print issues and online access $259.00 per yearonly $21.58 per issueBuy this articleUSD 39.95Prices may be subject to local taxes which are calculated during checkoutAll data needed to evaluate the conclusions are available from the corresponding authors upon reasonable request. Source data are provided with this paper.The band structure calculations used in this study are available from the corresponding authors upon reasonable request.Syozi, I. Statistics of kagome lattice. Prog. Theor. Phys. 6, 306–308 (1951).Article ADS MathSciNet Google Scholar Balents, L. Spin liquids in frustrated magnets. Nature 464, 199–208 (2010).
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quantum-computingScientists head underground to measure effects of gamma rays on superconducting qubits
Beneath Earth’s surface, shielded from the effects of most cosmic rays, is the Northwestern Experimental Underground Site, or NEXUS. Located about 350 feet underground at Fermi National Accelerator Laboratory, the research facility enables scientists to study the behavior of quantum devices in their quest to find evidence of dark matter. It’s here that a multi-institutional team of scientists took measurements of correlated charge noise in a chip comprised of multiple superconducting qubits for the first time. As reported in Nature Communications, their work will help inform the design of future quantum-based particle physics detectors, as well as develop noise reduction strategies to reduce qubit errors and decoherence. “Understanding whether a charge burst could affect multiple qubits as the charge moves through the chip … is crucial to scientists who use quantum sensors …” Daniel Bowring, Fermilab scientist Superconducting qubits are a leading option for building quantum computers. However, they are sensitive to disturbances from their environment and can make errors. By understanding how electrical fluctuations called charge noise affect superconducting qubits, scientists can find ways to reduce these errors and improve quantum computers. When an ionizing particle, like a cosmic ray or gamma ray passes through such a chip, it can create bursts of charge that can impact information stored in qubits. Scientists can directly measure these events because the qubits used in the study are incredibly sensitive to fluctuations in charge. “Understanding whether a charge burst could affect multiple qubits as the charge moves through the chip — what researchers call correlated charge noise — is crucial to scientists who use quantum sensors to detect very faint signals that are possibly from dark matter, and to computer scientists, who are interested in correcting errors,” said Daniel Bowring, a scientist at Fermilab and organizer of this study. Scientists use the Northwest
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quantum-computingInfleqtion to Showcase Quantum Accelerated Supercomputing with NVIDIA NVQLink at GTC 2026
Sqale Quantum Processing Unit (QPU) to be featured as part of the future of hybrid quantum workflows enabled by NVQLink LOUISVILLE, CO | March 10, 2026 | Infleqtion (NYSE: INFQ), a global leader in quantum computing and quantum sensing powered by neutral-atom technology, announced that it is showcasing accelerated quantum supercomputing integration into modern data centers through NVIDIA NVQLink at NVIDIA GTC 2026. GTC 2026 attendees can see Infleqtion’s Sqale QPU at the NVIDIA booth in a demonstration that showcases the future of a native integration of a neutral atom quantum processor into an NVIDIA accelerated HPC environment. Based on the ultra-low latency of NVQLink, Infleqtion hardware will work in concert with NVIDIA GPUs to handle the heavy computational demands of real-time quantum error correction and hybrid AI workloads. “The next era of high-performance computing will be accelerated by the seamless integration of quantum and classical resources into a single unified platform,” said Pranav Gokhale, Chief Technology Officer and General Manager, Quantum Computing at Infleqtion. “We are committed to NVQLink to accelerate the transition to commercial scale AI-Quantum factories. We believe neutral atom technology is the superior choice because of its inherent scalability, providing a strong foundation for this new HPC era.” Infleqtion’s inclusion in the NVQLink ecosystem highlights its growing role in hybrid quantum–classical workloads and a full stack system level approach required for the AI Quantum factory of the future. Meet with Infleqtion at GTC: NVIDIA booth #345: Live Sqale QPU demonstration as part of the NVQLink showcase. Infleqtion booth #438: Deep dive into the neutral atom advantage to quantum computing, including Infleqtion’s doubleMOT and Tiqker quantum clock. Software updates, including Infleqtion’s integration of contextual machine learning into the NVIDIA Jetson edge AI platform, will also be highlighted. For more information about Infleqtion
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