September 7, 2026

Sparrow Quantum Sets Record With 500 Million Usable Photons Per SecondTier 2

Efficient Quantum Error Correction from Three Dimensional Qubit ControlTier 3

High-rate quantum low-density parity-check (qLDPC) codes can substantially reduce qubit overhead relative to surface codes, but their advantage depends on efficiently realizing nonlocal syndrome extraction. We study the [[144,12,12]] bivariate bicycle code on a neutral-atom architecture with native three-dimensional (3D) geometry, comparing planar and 3D embeddings while...

TETRIS-Q: Tiling-based Effective Transient-fault Reduction on Interleaved Superconducting QubitsTier 3

The struggle of the hour in quantum computing research is achieving effective suppression of the error mechanisms induced by the interaction of external radiation with superconducting quantum devices. Despite the rapid advancements in quantum error correction (QEC) of recent years, radiation-induced faults are yet to be fully addressed. These events are known to be the cause...

Learning unknown stabilizer codes using product measurementsTier 3

Efficiently characterizing quantum error correcting codes is a key challenge on the path to fault-tolerant quantum computation. Stabilizer codes, a central class of such codes, are defined by a set of stabilizer generators. Here, we present an algorithm that uses random single-qubit measurements to learn the stabilizer generators of any stabilizer code from N copies of sta...

Research and simulation of analytical polarization control enabled by optical computing on an integrated photonics chipTier 3

Dynamic polarization controllers are key devices with broad applications in many fields. However, most on-chip polarization controllers still rely on traditional blind-search methods, whereas analytical optical-computing approaches remain insufficiently explored, particularly with respect to calibration and endless polarization control. With the accurate relative phase of Ma...

A photonic source with half-a-GHz single-photon fluxTier 3

Advanced optical quantum technologies demands high quality quantum light generation at very high rates. Here, we report on a deterministic single-photon source that simultaneously combines high excitation rates with high system efficiency to reach over 500 MHz of in-fibre single-photon flux. The source delivers optical power of over 100 pW, as is measured with an off-the-she...

Compiling the 2D Fermi-Hubbard ground-state energy estimation algorithm for active volume quantum architecturesTier 3

As quantum computing enters the early fault-tolerant era, circuit compilation choices will increasingly depend on details of the underlying architecture rather than solely optimizing for generic proxies such as non-Clifford count. We present an active-volume-aware compilation of the ground-state energy estimation algorithm for the two-dimensional Fermi-Hubbard model using qu...

A double-resonator coupler for high-fidelity two-qubit gates between superconducting qubitsTier 3

Tunable couplers have enabled two-qubit gate fidelities in superconducting quantum processors to approach 99.9%, yet simultaneously suppressing residual interactions and maintaining flexible qubit-frequency allocation remain central challenges for scaling. Here, we propose a double-resonator coupler (DRC) consisting of two resonators interconnected by a single Josephson j...

How dipolar interactions structure molecular dropletsTier 3

We investigate how dipolar interactions between microwave-shielded polar molecules structure the self-bound droplets formed under variation of the interaction strength. We identify the transition from droplets to crystals as a finite-size first order transition. With droplet-ring states and transitional supersolid states we predict additional structure in the crystal and dro...

QMClaw: A Scalable General-purpose Framework for Quantum Measurement and ControlTier 3

As quantum computing continues to scale, quantum measurement and control (QMC) are increasingly constrained by calibration workflow complexity and by requirements for low-latency execution, robust exception handling, and traceable workflow governance. Existing frameworks for QMC are specialized and task-specific, while language-model-based agents for QMC suffer from excessiv...

SAR and InSAR Change Detection with Quantum Generative ModelsTier 3

Change detection in synthetic aperture radar (SAR) and interferometric synthetic aperture radar (InSAR) underpins disaster response, infrastructure monitoring and land-use enforcement. Detection is limited by the background estimator, which conventionally forms a conditional expectation directly from observed pixel statistics and degrades where those statistics are sparse, i...

Impact of Data Loss in Postprocessing on Training and Inference of Quantum Neural NetworksTier 3

As quantum hardware scales to larger devices, the classical software layers that interface with it must evolve in step. Postprocessing routines developed and tested primarily in simulator settings can encode assumptions that no longer hold on utility-scale devices, leading to data loss that can be difficult to detect from high-level model outputs alone. We present a case stu...

Neural networks learn to reconstruct multipartite entanglement from quantum marginalsTier 3

Different sets of local correlations are not equivalent: some fragments of reduced data uniquely determine a global quantum state, while others leave it ambiguous. The quantum marginal problem asks whether a collection of reduced density matrices uniquely determines a compatible global quantum state. Although generic quantum states are uniquely specified by suitable sets of...

A Representation-Theoretic Framework for Characterizing Barren PlateausTier 3

The scalability of variational quantum algorithms is fundamentally limited by the barren plateau effect, where the cost-function variance vanishes with system size, rendering optimization impractical. Recent Lie-algebraic approaches for deep parameterized have enabled a unified analytical understanding of this challenge but require either the initial state or the measurement...

Ancilla mediated steady-state engineering in open quantum systemsTier 3

Engineering the properties of a reservoir and its coupling to a quantum system is a powerful tool for simulating quantum thermodynamic processes and for generating otherwise inaccessible steady states. Yet tailoring both the reservoir and its coupling within a single platform remains challenging. Here we introduce a platform, in which an ancilla qubit mediates the coupling o...

One-Shot and Concurrent Hitting Times for Grover-Coined Quantum Walks on Cubelike GraphsTier 3

We study the one-shot and concurrent hitting for the discrete-time Grover-coined quantum walk on cubelike graphs G=Cay(Z_2^d,Ω) of degree Δ=|Ω|. Starting from the vertex labeled $0$, we identify σ=bigoplus_(ω∈Ω)ω as a natural target vertex; for the hypercube, σ is precisely the antipodal vertex. For families with Δ→∞, let T be an integer...

Quantum Foundry Copenhagen and Novo Nordisk Foundation Announce 5,300 m² Fabrication Facility for Quantum ChipsTier 2

Technology firm Quantum Foundry Copenhagen and the Novo Nordisk Foundation have announced plans to construct a 5,300 m² commercial quantum chip fabrication facility in Copenhagen, Denmark. Operational by 2027, the infrastructure is engineered to bridge academic research with industrial manufacturing, offering commercial wafer fabrication, characterization, assembly, and p...

Lindblad Multiproduct FormulasTier 3

We introduce Lindblad Multiproduct Formulas: a quantum error mitigation technique that uses two-dimensional tensor networks contracted with loop-corrected belief propagation. The quantities required to implement the error mitigation scheme that are evaluated with tensor networks can be less computationally expensive to calculate than the expectation values themselves, thus a...

NEC Halts Development of Quantum Computer HardwareTier 2

RIKEN Integrates QunaSys QURI SDK Enterprise into Japan’s JHPC-quantum PlatformTier 2

The RIKEN Center for Computational Science (R-CCS) has officially adopted the enterprise quantum software development kit QURI SDK Enterprise from Tokyo-based algorithm developer QunaSys Inc. as the primary software layer for Japan’s national JHPC-quantum project. Funded by the New Energy and Industrial Technology Development Organization (NEDO) under the Ministry of Econ...

Forschungszentrum Jülich Operates eleQtron’s JION Trapped-Ion QPU via JUNIQ InfrastructureTier 2

Research center Forschungszentrum Jülich and University of Siegen spin-off eleQtron GmbH have officially brought the JION (Jülich trapped-ION) quantum computer into operation at the Jülich Supercomputing Centre (JSC). Integrated into the JUNIQ (Jülich UNified Infrastructure for Quantum computing) platform, the gate-based trapped-ion processor is linked directly to JSC's H...

Towards Scaling Quantum Fine-Tuning of Foundational Time Series Models for ClassificationTier 3

Time-series foundation models produce rich embeddings, but whether quantum models can exploit them, and how far hybrid classical-quantum architectures scale, remains unclear. We address this by fine-tuning Chronos for power-grid event classification (PSML-5) with a quantum head on the model's embeddings. Grouping embeddings by physical sensor type before summarization alread...

Parametric and feedback-controlled multiparameter quantum estimation in a double cavity optomechanics: steady and dynamical stateTier 3

Multiparameter quantum estimation in open optomechanical systems is fundamentally constrained by dissipation, thermal fluctuations, and measurement incompatibility. In this work, we investigate a coupled-cavity optomechanical platform in which two mechanical modes interact with driven optical cavities, two-mode squeezed vacuum, intracavity degenerate parametric amplification...

Non-reciprocally interacting Ornstein-Uhlenbeck processes: Exceptional points, Anomalous relaxation, Pseudo-equilibrium and Boundary refrigerationTier 3

Non-reciprocal interactions are ubiquitous in active, biological, and disordered systems, generically driving them out of equilibrium. Here, we introduce a hierarchy of non-reciprocally interacting Ornstein-Uhlenbeck (NROU) models governed by a tunable non-reciprocity parameter g. At a special point g=g^*, the drift matrix becomes non-diagonalizable, realizing exceptiona...

Coincidence-based spectral engineering for spectral matching in cascaded downconversionTier 3

Three-photon states generated via cascaded spontaneous parametric downconversion provide a direct route to multipartite entanglement. However, current implementations require careful spectral matching between successive nonlinear stages, which constrains the choice of downconversion sources. In this work, we show that coincidence-based spectral filtering relaxes this require...

Fundamental Limits of Quantum Metrology Beyond Fixed Causal OrderTier 3

Quantum metrology with indefinite causal order (ICO) has attracted intense interest due to its potential to surpass the limitations of conventional fixed-order strategies. A key open question is whether ICO can fundamentally enhance asymptotic precision scaling. In this work, we bridge this gap for the estimation of a single parameter encoded in N identical uses of a finit...

Restricting the effects hides a nonphysical symmetry from every causal structureTier 3

Real-amplitude quantum theory is the subtheory of quantum theory invariant under complex conjugation, and experiments in a network of independent sources have measured correlations above the real bound. A theory can nevertheless carry the same conjugation without complete positivity and still have exactly the correlations of its own conjugation-invariant subtheory in every c...

Memory-Optimal Sequential Synthesis of Multimode Gaussian TransformationsTier 3

In modular quantum computing architectures, communication between hardware modules is mediated by traveling qumodes sent through transmission lines. Each output qumode interacts with the emitting module only once through a beam-splitter-type interaction and becomes inaccessible to that module after emission. Information required for subsequent outputs must therefore remain i...

Quantum-State Texture Dynamics: Theory and ExperimentTier 3

Quantum-state texture (QST) has found applications in several fields from quantum foundations and computation to quantum criticality. However, a general theory of QST dynamics under arbitrary physical processes remains unavailable, limiting both its practical application and experimental exploration. Here, we demonstrate that the QST response to an arbitrary finite-dimension...

Quantum Optimisation for Protein-Protein Interaction Network AlignmentTier 3

Protein-protein interaction (PPI) network alignment combines topological and sequence information to identify conserved modules across species, but global alignment remains challenging: heuristics sacrifice optimality, while exact methods lack scalability. We model the alignment as a weighted maximum common induced subgraph problem and reformulate it through the modular prod...

The marginal is pretty goodTier 3

One-shot information theory measures often require an optimization over states, but the form of these optimizers can be complicated or depend on the initial problem in nonlinear ways. In this note, we show that in many instances using the marginal instead of the optimal state is sufficiently good and only changes the result by a small factor. We prove that for the Petz-Rényi...

Optimal inequalities for completely bounded polynomials and the limitations of quantum query algorithmsTier 3

We consider the problem of establishing limitations on the power of quantum query algorithms via the completely bounded polynomial method. In particular, we prove several optimal functional inequalities involving different notions of completely bounded polynomials. These inequalities lead to limiting theorems for the power of quantum query algorithms that improve on prior wo...

AxQM: A Textbook-Scale Benchmark for Formal Proof Synthesis in a Library of Finite-Dimensional Quantum MechanicsTier 3

Formalizing mathematics in a proof assistant, where a machine checks every definition, statement and proof, has set a new standard of rigor. Large language models are now capable of formalizing autonomously, even at the scale of whole textbooks. We bring this standard of rigor to physics, where theoretical arguments carry idealizations that are rarely stated fully, and any l...

Fanout Complexity of Symmetric Boolean Functions in QAC^0Tier 3

Whether QAC^0 can compute PARITY_n remains open. Computing PARITY_n is equivalent to implementing FANOUT_n under QAC^0 reductions. This raises a more general question: for an arbitrary symmetric Boolean function f:{0,1}^n→{0,1}, what fanout size is necessary and sufficient for computing f in QAC^0? W...

Environment-assisted transport in a strongly correlated boundary-driven Fermi-Hubbard chainTier 3

We study steady-state transport in a one-dimensional Fermi-Hubbard chain coupled to particle reservoirs at the boundaries and to local dephasing baths at each site, using the time-evolving block decimation (TEBD) method to solve the Lindblad master equation. In the absence of dephasing, the current exhibits two well-separated maxima as a function of the boundary driving rate...

On the growth of operator entanglement in brickwork circuits with Yang--Baxter gatesTier 3

We study the operator entanglement of local operators in one-dimensional brickwork circuits whose two-site gate satisfies the braid relation; throughout this work, we call such a gate a Yang--Baxter gate. We establish upper bounds for several structured, overlapping classes of Yang--Baxter gates. We show that the operator Schmidt rank remains uniformly bounded in time for al...

Operational Roles of QRNG-Derived Quantum Entropy in Bitcoin Proof-of-Work ArchitecturesTier 3

Replacing classical entropy with QRNG output does not change honest Bitcoin PoW success probability when candidate headers remain distinct. The original contribution of this paper is a reproducible benchmark that locates and measures the operational value of quantum entropy in hybrid quantum-classical mining infrastructure through two scheduler-level observables, the entropy...

Qlippy: A Retrieval-Augmented GenAI Assistant for Reproducible Quantum Workflows and Experiment TrackingTier 3

Quantum software development is iterative and error-prone. Noisy hardware and repeated re-execution make experiment tracking, provenance, and reproducibility essential, yet these practices are hard to adopt because of tooling complexity and the specialized knowledge they demand. General-purpose language models can help but tend to hallucinate and lack grounding in domain-spe...

Hadamard Rigidity of Positive Sojourn Time Distributions for Rotation CoinsTier 3

We study the distribution of the positive sojourn time for a one-dimensional two state quantum walk, conditioned on return to the origin. Konno showed that, for the Hadamard walk, this conditional distribution is exactly uniform at times divisible by $4$. In this paper, we investigate whether this finite time exact uniformity characterizes the Hadamard coin within the family...

From the Light Quantum to the Photon: The Evolution of a Physical ConceptTier 3

This work examines the physical and conceptual evolution of the light quantum from Planck's blackbody theory to the theoretical and experimental developments that led to the quantization of the electromagnetic field. The present study shows that the decisive transition occurred in Einstein's quantum theory of radiation (1916-1917). Absorption, stimulated emission, and sponta...

Microkelvin resolution thermometry at the nanometre scaleTier 3

Accurate temperature readings of transient events at the nanometer scale are challenging due to the low sensitivity of available sensors. Nanodiamonds containing nitrogen-vacancy (NV) centers have been used for nanoscale thermometry in complex environments, including inside living cells. However, their performance has been limited by short coherence times and low photon coun...

Transition between weak and strong measurements in the presence of post-selectionTier 3

In the weak measurement regime, post-selection can result in the observation of anomalous weak values, seemingly contradicting the eigenvalue statistics observed when the measurement interaction is strong. Here, we investigate the dependence of meter statistics on measurement strength in a post-selected measurement. We find that the meter statistics in the intermediate regim...

Shapley Valuation of Finite-Copy Quantum Data Depends on Physical AccessTier 3

Data valuation asks how learning utility should be attributed to training data contributors. Most classical formulations begin after data have become reusable records, so the physical readout of the data is effectively fixed. Finite-copy quantum data are different: unknown states are consumable physical systems, and the same supplied states and downstream task can yield diff...

Analytical model for polarization transfer during gas-phase collision events in spin-exchange optical pumping: Spin-1/2 ^(129)Xe versus spin-3/2 ^(131)XeTier 3

Spin-exchange optical pumping (SEOP) is a method for producing spin-hyperpolarized noble gas nuclei, such as 129Xe and 131Xe, which are used in various magnetic resonance applications from fundamental physics to quantum sensing and medical imaging. In SEOP, optically polarized alkali-metal atoms transfer their spin polarization to the noble gas nuclei in gas-phase collision...

One Bit of Collective Information Is Worth N ln 2 Bits of Local Information in a Many-Body Quantum BatteryTier 3

Charging a quantum battery through a collective non-adiabatic stroke stores energy in a shared bosonic mode, but part remains locked in correlations with the collective spin and is inaccessible to cyclic unitaries acting on the mode alone. A demon holding one bit can unlock this energy, quantified by the daemonic ergotropy. We investigate the value of one bit and its depende...

Qmes: Quantum Meta-Learning for Encoding Selection in Quantum Kernel MethodsTier 3

Selecting an effective encoding quantum circuit is a key challenge in quantum kernel methods because different feature maps can lead to different performance. Conventional methods require constructing and evaluating every circuit for each new dataset, making it computationally expensive. We present Qmes, an open-source Python package that automatically recommends circuits th...

Residual detuning in the laboratory-frame anti-Jaynes--Cummings model with a squeezed vacuumTier 3

The laboratory-frame anti-Jaynes--Cummings (AJC) interaction retains a residual detuning 2fλ that is absent from the rotating-frame model. We map two proposed remedies---a Kerr shift χ(a^†a)^2 and collective Dicke coupling of N two-level emitters---for a squeezed vacuum on that ladder (r=1, ⟨n⟩=sinh^2 r≃1.38). All quoted contrast...

DPRQ: A Dynamic Programming-based Qubit Routing Algorithm for Collective Communication in Distributed Quantum ComputingTier 3

Distributed quantum computing (DQC) offers a promising approach to scale quantum computing by overcoming the resource limitations of a single quantum processor. However, inter-node communication remains a major bottleneck of DQC due to inefficient and error-prone entanglement distribution. Optimizing inter-node communication can not only reduce the amount of entanglement res...

Calculation of DFT Spin-Orbit Spillage with Quantum ESPRESSOTier 3

This work describes the calculation of spin-orbit spillage from a crystal structure. Spin-orbit spillage provides a measure of the likelihood that a material has topological character. The spillage also provides the reference quantity for the machine-learning classifier of Choudhary et al., which predicts whether the spillage exceeds a specified threshold rather than the cal...

State-Based Quantum Operations: Chameleon GatesTier 3

We introduce chameleon gates as a natural generalization of conventional quantum controlled-gates. Chameleon gates are state-based quantum controlled-operations that retain standard elements such as control and target systems, while introducing a new feature: the quantum knob. This knob is a quantum signal (state) that determines the operation performed by the gate. Conseque...

Gradient-based optimal control of the non-Hermitian skin effect in optomechanical arraysTier 3

In single-port non-Hermitian sensors the Petermann factor offsets susceptibility gains, imposing a strict resource bound on metrological precision. We test whether a multi-port geometry can evade this bound: a double-chain optomechanical ladder with opposing non-reciprocal hoppings spatially separates signal amplification from quantum-noise drainage, and gradient-based diffe...

Who’s News: Strategic Appointments at QuIC, Atom Computing, and Qilimanjaro Quantum TechTier 2

Cécile Perrault is the new Executive Director of QuIC, Kevin Messerle is the new CFO of Atom Computing, and Albert Solana is the new Chief of Staff at Qilimanjaro Quantum Tech, all bringing their expertise to advance quantum technologies.