September 24, 2026

Purely-logarithmic-time- and constant-space-overhead fault-tolerant quantum computationTier 3

We prove that constant-space-overhead fault-tolerant quantum computation can be achieved with provably strictly logarithmic time overhead, improving over the best known results with additional subpolylogarithmic factors. Our main construction uses polynomial-subrank transversal logical CCZ gates on good quantum locally testable codes to implement addressable universal com...

Photonic Inc. and Microsoft Collaborate on Quantum Resource EstimationTier 2

Insider Brief PRESS RELEASE — Photonic Inc. and Microsoft are collaborating on quantum resource estimation for distributed, large-scale quantum computing systems and advanced error-correction approaches. The companies are exploring how architecture, quantum networking requirements and error-correction methods affect physical qubit counts, runtime and system overhead. P...

Previously: 2026-09-23

Analog neutral-atom for in-memory processing in quantum reservoir computingTier 3

Quantum Reservoir Computing (QRC) exploits the rich dynamics of quantum many-body systems to process time-dependent information with high-dimensional state spaces. While neutral atom arrays offer a scalable platform for this paradigm, realizing intrinsic temporal memory without relying on external classical buffering requires precise control over the relaxation dynamics of t...

A photonic integrated comb engine for ultracold quantum gasesTier 3

Cold atoms underpin quantum sensing, simulation and computation, but their coherent control demands highly stable optical fields whose generation, referencing and power scaling remain formidable integration challenges. While photonic integrated circuits have yielded compact visible lasers and high-Q microresonators have enabled chip-scale optical frequency combs, these cru...

Beyond Antibunching: Photon Correlation Analysis Reveals Blinking OriginTier 3

A variety of quantum emitters compete in the quest for the best single-photon source for photonic quantum technologies. Consequently, only a consistent approach to analyze the second-order auto correlation function allows comparison of the multi-photon contribution (g^((2))(0)) of different sources. However, the community employs different and inconsistent methods for blin...

Sub-Doppler cooling of trapped ions using optical tweezersTier 3

We propose a sub-Doppler cooling scheme for trapped-ion crystals in Paul traps. The combination of a hollow tweezer and microwave drive creates an effective two-level system which is cooled through attractive Sisyphus cooling. For ^(171)rmYb^+ ions, we numerically identify optimal parameters for one- and two-ion crystals, and investigate the cooling rate in ion crysta...

Non-Hermitian Purcell Physics in Dissipatively Coupled Planar Photon-Magnon SystemsTier 3

The Purcell effect has emerged as a powerful mechanism for controlling spontaneous emission and dissipation in cavity and nanophotonic systems; however, its realization in dissipative non-Hermitian hybrid platforms remains largely unexplored. In this work, we investigate the Purcell effect in a dissipatively coupled photon-magnon hybrid quantum system consisting of a yttrium...

Optical Schrödinger cat states generated using cavity Rydberg quantum photonicsTier 3

We introduce cavity Rydberg quantum photonics as a novel platform for generating hybrid entangled states of optical photons. The system achieves world-record sizes of these states and has the potential to produce yet larger states in the future. In the hybrid entangled state produced here, a superposition of two coherent states is entangled with a polarization qubit carried...

Repairability of Inexact Solvers in Recursive State Estimation with Machine LearningTier 3

Recursive state estimation often executes approximate numerical solutions inside a feedback loop, where highly accurate local steps do not guarantee better overall results. For a fixed linear Kalman model, we characterize when a correction within a prescribed subspace and norm budget can meet a local admissibility tolerance, and how the defects actually executed affect the f...

The winner's curse in hardware VQE: drift-differenced remeasurement of finite-shot selection biasTier 3

Finite-shot optimization can make noisy variational quantum eigensolver energies look artificially accurate. We studied six molecules on two IBM Heron r3 processors in eight replicated cells. Seven optimizer-selected values fell below the exact active-space eigenvalue by up to mHa. Independent later evaluation of the selected and final parameter points, differenced to remove...

Image Compression Using Quantum Wavelet Transform and Quantum Convolutional NetworksTier 3

This paper presents a hybrid quantum-classical framework for grayscale image compression and decompression, leveraging the strengths of quantum computing and deep learning. The compression pipeline integrates a Variational Quantum Daubechies Wavelet Transform (V-QDWT) and a trainable Quantum Convolutional Neural Network (QCNN) optimized end-to-end to achieve efficient, image...

Scalable simulation of non-Markovian quantum transport by stochastic-phase bath reductionTier 3

Accurate simulations of non-Markovian quantum transport remain limited to small systems, and a key bottleneck is that each system site requires an independent set of quantum bath orbitals. We introduce the Stochastic Phase Algorithm (SPA), which replaces the independent local Gaussian baths in single-quasiparticle Holstein models by R shared quantum baths with stochastic s...

Distilling Datasets into Shallow Circuits for Quantum Machine LearningTier 3

In quantum machine learning, training a quantum model requires each sample to be prepared as a quantum state by a loading circuit that must be re-executed for every shot at every training step. The total burden therefore scales with both the number of samples and the cost of preparation. Existing approaches reduce the loading cost of individual inputs or distill data and com...

Response of Hellinger-distance based coherence to weak decoherence in two-flavor neutrino oscillationsTier 3

We evaluate the Hellinger-distance coherence of the two-flavor neutrino state subject to Lindblad damping of the mass-eigenstate interference term, and obtain a closed expression in terms of the flavor-basis density-matrix elements. In the two-flavor vacuum treatment with negligible wave-packet separation, the undamped state is pure, and the smallest eigenvalue of the damped...

Quantum Simulation of Si/SiGe Devices with Experimentally Calibrated Micromagnet EffectsTier 3

Silicon-based spin qubits in Si/SiGe heterostructures are a leading platform for scalable quantum computing, yet bridging the gap between theoretical computer-aided design(CAD) models and experimental reality remains a significant challenge. Standard simulations often fail to capture critical physical phenomena, such as interface dipoles, parasitic charge accumulation, and t...

Q.ANT Launches Open-Source SDK for Photonic ComputingTier 2

Insider Brief PRESS RELEASE — Q.ANT, the pioneer in commercial photonic computing, today debuted its open-source software development kit for photonic computing, making the programming tools for a photonic processor publicly available for the first time. Programmers now have everything they need to develop applications for Q.ANT‘s Native Processing Units (NPUs),...

Quantum score matching with applications to learning thermal statesTier 3

Score matching has driven major advances in classical generative learning by enabling models to learn from data without evaluating intractable normalization constants, or partition functions. Yet, extending this principle to quantum learning requires rethinking its foundations, as quantum states are described by noncommuting density operators rather than scalar probabilities...

CP asymmetry and visible decay in 3+1 neutrino oscillations on a quantum computerTier 3

We use quantum simulation to study how visible neutrino decay modifies the vacuum CP asymmetry in muon-to-electron oscillations within a 3+1 neutrino scenario. The decay channel preserves CP symmetry, with CP violation arising from phases in the mixing matrix. We track the energy redistribution from visible decay and distinguish how parent attenuation and daughter regenera...

Chattanooga Schools Begin K–12 Quantum Technology CurriculumTier 2

Insider Brief PRESS RELEASE — As EPB launches its quantum computer, the TN QuantumWorks K–12 quantum technology and career awareness curriculum is now being implemented in Hamilton County classrooms. Announced earlier this year, the curriculum includes programs for four age groups: grades K–2, grades 3–5, middle school, and high school. TN QuantumWorks is designed to [...

Classiq, INGL and IonQ Test Quantum Optimization for Natural Gas NetworksTier 2

Insider Brief PRESS RELEASE — Classiq and Israel Natural Gas Lines Ltd. (INGL) announced results from research applying quantum optimization to natural gas transmission planning, including execution of a reduced version of the problem on the IonQ Forte-1 quantum computer. The collaboration focused on a familiar challenge for pipeline operators: moving gas from supplier...

Qunnect Publishes Research on Quantum Security Beyond QKDTier 2

Insider Brief PRESS RELEASE — Qunnect, the leading quantum networking company with more quantum networks deployed than any other company, today announced its work with U.S. government agencies and national security partners. That work, together with Qunnect’s commercial deployments and new research, provides a foundation for security applications that will protec...

CGI And D-Wave Quantum Partner to Advance Enterprise Quantum AdoptionTier 2

Insider brief PRESS RELEASE — CGI (NYSE: GIB) (TSX: GIB.A), one of the largest independent IT and business consulting services firms in the world, today announced a strategic partnership with D-Wave Quantum Inc. (NASDAQ: QBTS) (“D-Wave“), the only dual-platform quantum computing company providing both annealing and gate-model systems, software and...

Broadband Quantum Optical Storage with Chemically Engineered Molecular Eu^3+ ComplexTier 3

Broadband quantum memory devices are essential elements for future quantum networks. Here we propose a broadband quantum memory scheme called Hole Anti-hole Grating Echo Memory (HAGEM) for rare-earth ions in solids. We provide a Eu^3+ molecular complex with special hyperfine level structures of which the hyperfine level separations are in a specific mathematical cor...

Compressed Permutation Oracles RevisitedTier 3

The compressed permutation oracle has been used to analyze the quantum security of a number of cryptographic constructions which resisted prior techniques. However, these analyses were fundamentally limited by the poor soundness of the method: the technique was proven sound only up to O(N^(1/12)) queries to permutations on N elements. We revisit this analysis, improving...

Sharp pairwise reduction for quantum hypothesis testingTier 3

We determine the optimal universal coefficient in a reduction of multiple to binary quantum hypothesis testing. Specifically, for every finite ensemble in any Hilbert space dimension (finite or infinite), we prove that the error probability of the global pretty good measurement (PGM) is at most four times the sum of the optimal binary error probabilities. By constructing a f...

Simulation of a Battery Cell on Quantum Computers: Reactions & TransportTier 3

Simulations of electrochemical materials and systems accelerate technological progress, but are still limited by computational power. In particular, quantum computing offers prospects for higher resolutions, due to the exponential amount of data that can be stored in a quantum state. As current quantum computers are still noisy, we consider a hybrid quantum-classical algorit...

The Minimal Dimension of Entangled-Noise AdvantageTier 3

Can entangled noise erase entanglement more efficiently than separable noise? Standard robustness restricts the added noise to separable states; generalized robustness allows any state. We prove that the two costs coincide for every two-qubit state and give an explicit full-rank qubit--qutrit state with a strict gap. Positivity under partial transpose (PPT) characterizes sep...

Multipartite GHZ diagonal states and their entanglement propertiesTier 3

In this paper, we investigate the family of GHZ diagonal states, which are mixed multipartite quantum states that are diagonal in a GHZ type basis. We show that the class of GHZ diagonal states is highly symmetric and exhibits rich entanglement properties, making it relevant for applications in multipartite quantum key distribution.

Bridging two families of non-Hermiticity: from non-reciprocal couplings to an imaginary potential using the Lanczos transformationTier 3

Two types of non-Hermiticity found in physical systems, i.e., non-reciprocal couplings and complex potentials, have gained considerable interest recently. The former leads to the non-Hermitian skin effect, while the latter gives rise to a range of non-Hermitian symmetries such as parity-time (PT) and particle-hole symmetries. Although these two non-Hermitian forms have bee...

Improved convergence radius of the Fer expansion for Hermitian generatorsTier 3

The Dyson series expands the propagator of a time-dependent Hamiltonian in powers of the Hamiltonian, but its truncations are in general not unitary. The Fer expansion writes the same propagator as an infinite product of matrix exponentials, each of them unitary, and its remainder decays doubly exponentially with the number of factors. Convergence, however, is guaranteed onl...

Decoherence Tuning in Voltage-Driven Plasmonic CavitiesTier 3

Strong light-matter coupling offers a powerful framework for modifying molecular structure, dynamics, and optical response, yet achieving this regime at the single-molecule level remains a central challenge. Scanning Tunneling Microscope Break Junctions (STM-BJ) provide a promising route by combining single-molecule addressability with extreme nanoscale field confinement. Ho...

Beyond Maximal Entanglement: Exact Resources for Multiparty Encrypted Quantum CloningTier 3

Encrypted quantum cloning distributes an unknown k-qubit state among m encrypted clones so that no individual clone reveals the input, yet the state can be recovered from any one clone together with a common quantum key. We ask the inverse question: for a fixed encoding architecture, which multipartite pure states can serve as exact resources for this task? For m≥2,...

Optimal limits on weak integrability breaking and protected thermal memory near qutrit exchangeTier 3

Although integrability does not universally require a continuous one-site symmetry, we rigorously prove that every jointly analytic, regular Yang-Baxter deformation of the qutrit exchange interaction necessarily retains a nontrivial, analytically varying one-site charge. Breaking this local symmetry imposes a fundamental physical constraint on approximate conservation, gover...

Certifying fermionic Gaussian states (and a little more) with optimal precision dependenceTier 3

Fermionic Gaussian states are the workhorse reference states for qubit-based quantum simulation of fermionic systems, yet existing certification protocols either proceed via fidelity estimation, leading to suboptimal sample complexity in the target precision ε, only apply to Haar-typical states, or require adaptive measurements on a large fraction of qubits. We give an ada...

Unbounded Operators, Physicality, and Modality in Quantum TheoriesTier 3

In this paper, I address the problem regarding the physicality of Hilbert space in quantum mechanics, a topic brought into focus by Carcassi et al.'s paper "The unphysicality of Hilbert spaces" recently. I argue for the physicality of the Hilbert space in quantum mechanics, and demonstrate that there are inevitable ambiguity and arbitrariness if we want to identify the set o...

Optimal local oscillators for the homodyne detection of multiphoton statesTier 3

We propose a framework for optimizing pulsed local oscillators (LO) for homodyne detection of multiphoton-number states by exploiting the tensor structure of their joint-spectral amplitude (JSA). We show that finding the optimal LO is equivalent to computing the JSA tensor's leading unitary eigenpair and that the factor matrices of the JSA's Tucker higher-order singular valu...

Quantum Topological Data Analysis Beyond Betti Numbers: Complexity Hardness & An Algorithm for Torsion WitnessTier 3

Recent advances have revealed an interplay between quantum computing and topological data analysis (TDA). Most quantum TDA has focused on Betti numbers, which characterize the connectivity and ``holes'' of a dataset. Homology, however, contains additional information in the form of torsion: a nontrivial cycle can become trivial after being repeated finitely, revealing global...

Quantum Metrology for Signals with an Unknown Causal StructureTier 3

Quantum sensing protocols usually presuppose where and when each signal acts, yet this information is unavailable beforehand in experiments such as scattering and radar. We show that causal agnosticity forces a measurement scheme to be interferometric even when only discrete interactions are allowed. Describing the sensing events in the recently developed quantum state over...

Quantum Advantage in Topological Data Analysis via Mayer HomologyTier 3

Prior work has explored quantum algorithms for topological data analysis (TDA), revealing the possibility of exponential quantum speedups in estimating the ratios of Betti numbers to the dimension of the combinatorial Laplacian. However, this quantity is only non-vanishing and efficient-to-quantumly-estimate when Betti numbers are exponentially large, a case for which concre...

Theory of Airy-Beam Wavefront SensingTier 3

A new wavefront sensing framework based on the interference of counter-accelerating Airy beams is presented. An engineered cubic phase function transforms a single Gaussian beam into two coherent Airy beams with opposite transverse accelerations, which self-recombine during free-space propagation to form an interference pattern encoding the aberrated incident wavefront. Nume...

Cubical Sheaf Complexes with Constant Expansion with Applications to Asymptotically Good qLTCsTier 3

For every fixed integers r ≥4 and 2 ≤k ≤r-2, we construct r-dimensional cubical sheaf complexes whose degree-k CSS codes have positive constant rate, linear distance, and constant soundness, with bounded row and column weights. Taking r=4 and k=2 gives a family of asymptotically good binary qLTCs. At the core of our construction is a uniform product-expa...

Spectral Gap of the Hexagonal AKLT Model via Boundary-State FactorizationTier 3

We establish a sufficient condition under which overlapping PEPS boundary states satisfy the approximate factorization criterion for a spectral gap. The condition is formulated in terms of the boundary response induced by cutting bonds through the center of a rectangular region. We decompose this response into a contribution common to all four associated regions and a remain...

Refuting the QAOA fixed-angle conjectureTier 3

The fixed-angle conjecture for the quantum approximate optimisation algorithm (QAOA) is shown to be false for depth-2 QAOA on 9-regular graphs, and proven to be correct for depth-1 on any regular graph, as well, as for any depth on all 2-regular graphs.

Geometric perspective on quantum Rabi model: Super adiabatic universality and curvature non-adiabatic effectsTier 3

Quantum Rabi model (QRM) is a fundamental model in light-matter interactions (LMIs), whereas this finite-component system manifests infinite physics to be explored and a full understanding has not yet been reached after a hundred years since it was proposed. In the present work we create a geometric perspective for the QRM by mapping to a curved nanowire system, with curvatu...

Charge and spin qubits in interacting quantum dots coupled to Rashba-active leadsTier 3

We present a unified study of charge and spin qubits encoded in a single interacting quantum dot tunnel-coupled to Rashba fermionic leads. The dot is described by an Anderson impurity Hamiltonian with either repulsive or attractive local interactions and a magnetic field of arbitrary orientation. In the repulsive regime, a spin qubit is encoded in the singly occupied spin se...

The refractive index of the medium within the volume of deep inelastic ep scattering: I. Group velocity of interaction carriersTier 3

We propose a new method for measuring several characteristics of a fermion-boson medium formed during deep inelastic particle scattering. This method involves measuring the group and phase velocities of the accompanying wave process. The phase and group velocities of a wave process are related by the Rayleigh differential condition. The refractive index of a medium is determ...

Singapore Scientists Claim They Built The World’s Most Accurate Atomic ClockTier 2

Insider Brief PRESS RELEASE — Take a second and turn it into trillions of moments. Measure each one. That’s how precisely an atomic clock at Singapore’s Centre for Quantum Technologies (CQT) keeps time – and with record-making accuracy, according to results published in Nature on 23 September. “I am confident that what we have now is the […]

German Government Selects QUDORA-Led Consortium For €122 Million ProjectTier 2

Insider Brief PRESS RELEASE — QUDORA will lead a seven-member consortium of research institutions and industry partners in a bid to build one of Europe’s most advanced quantum computers. The project, named NFQC-1k, is being selected under the Quantum Computing Competition of Germany’s Federal Ministry of Research, Technology and Space (BMFTR), with a total volume ...

Global Study Finds Quantum Industry Dependent on Cross-Border Supply ChainsTier 2

Insider Brief PRESS RELEASE — A new international survey of the quantum industry finds that the supply chains supporting quantum technologies are deeply global, with companies of every size relying on suppliers and customers across national borders. The survey included responses from 160 companies headquartered in 15 countries that reported suppliers in 36 countries, c...

Azulene Labs Secures $3.4 Million Pre-Seed Round For Drug And Materials SimulationTier 2

Insider Brief PRESS RELEASE — Azulene Labs, a startup creating the future of drug and materials development, has raised a $3.4 million pre-seed round. The round was led by Ground State Ventures, with participation from existing Azulene investor Entrada Ventures and angels. While mechanical and civil engineers design new products with high-precision software, chemistry...

Optimal low-rank compression of quantum dynamicsTier 3

Local quantum interactions generate dynamics in an exponentially large Hilbert space, yet locality and entanglement restrict the information that can spread and accumulate. Bounds on propagation and entanglement growth, together with tensor networks, exploit these restrictions to discard information unnecessary for describing the evolution. This leads to a sharper question:...

A Proof of Shor's Orthogonal-Measurement Conjecture and the Structure of Information-Optimal Quantum MeasurementsTier 3

Which quantum measurement extracts the most classical information from an ensemble? We introduce the posterior algebra, a new canonical operator algebra selected by mutual information. For faithful ensembles, an affine information bound is exact precisely when this algebra is commutative; its joint spectral measurement is then optimal, and every optimal finite POVM refines i...