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• Spin Injection Linked to Two-Photon Fluctuations in Quantum Dots

  A study of electrically driven quantum dots found that two-photon emission statistics fluctuated during excitation pulses when spin injection was active, while single-photon counts followed a smoother profile. The authors say cooperative emission is a plausible explanation, but the microscopic mechanism remains unidentified.

• Harvard Team Uses Tension to Boost SiV–Phonon Coupling

  Harvard researchers report that tensioned diamond nanobeams can improve mechanical coherence while increasing coupling to silicon-vacancy centers near the beams’ clamps. Their experiments show a tenfold clamp-to-center coupling increase, but the demonstrated device couples mechanical motion to SiV orbital states, not yet to spin states.

• Quantum Errors Pick the Late-Time Mixed-State Ensemble

  A theoretical study finds that, after sufficient scrambling, dilute local quantum errors determine the late-time distribution of measurement-conditioned mixed states through the errors’ normalized Choi state. The authors derive the result for several circuit models and report numerical tests in qubit circuits and kicked Ising dynamics.

• Princeton Team Uses Rydberg Blockade to Speed Ytterbium Loading

  A Princeton-led team reports a Rydberg-blockade method that prepares single ytterbium atoms in optical tweezers in tens of microseconds. The faster protocol matches conventional loading’s filling fraction, while a metastable-state version reaches 74.8% but adds preparation time.

• PRX Quantum Paper Automates Boundaries for Planar Quantum Codes

  A paper published in PRX Quantum on October 23 presents algorithms for constructing gapped boundaries and defects in two-dimensional topological stabilizer codes. Its bivariate bicycle code examples include a proposed planar family encoding eight logical qubits on a 12L × 12L lattice.

• Blue Light Can Make CV-QKD Estimate a Positive Key Rate When the Correct Rate Is Nonpositive

  Researchers found that 405-nanometer light can temporarily reduce a quantum transmitter’s modulation variance, creating a calibration mismatch after the variance recovers. Their calculations show the mismatch can produce a falsely positive estimated key rate, not demonstrated secret-key generation.

• HRL’s SpinQICK Runs a Fully Connected Spin Qubit

  A paper by HRL Laboratories researchers reports coherent control, state preparation and readout of a fully connected triangular spin-qubit device using SpinQICK. The authors also use dynamical-decoupling measurements to examine noise and drift in the setup.

• Quantinuum and Oracle Open Helios Beta to Selected Cloud Users

  Quantinuum says Oracle’s Quantum AI Compute beta is accepting applications from selected organizations seeking cloud access to its Helios quantum computer. The free preview is for evaluation, not production, and Oracle says places are limited.

• Monarch Supplies Photonics for NASA’s Quantum Gravity Pathfinder

  Monarch Quantum says it is supplying integrated photonics hardware for Infleqtion’s work on NASA’s Quantum Gravity Gradiometer Pathfinder. The space-based sensor is designed to measure tiny variations in Earth’s gravity, with a flight demonstration expected in 2030.

• SQD Recovers FeO Model Ground States from IBM Quantum Samples

  A preprint reports that sample-based quantum diagonalization recovered ground-state energies for two iron-oxide molecular models using samples from IBM Quantum hardware. For FeO, the method recovered the ground-state doublet to machine precision in a 184-determinant subspace.

• JPMorgan Researchers Combine QKD Authentication and Key Expansion

  JPMorganChase researchers tested a quantum authenticated key expansion protocol that combines authentication and key generation, with each of three runs producing between 177,000 and 213,000 key bits. The demonstration used QKD hardware with post-selection and offline software processing, rather than a complete real-time system.

• Franco-Rubio, Bochniak and Cirac Map Defects in Matrix-Product States

  Adrián Franco-Rubio, Arkadiusz Bochniak and J. Ignacio Cirac develop a framework for symmetry defects in matrix-product states with matrix-product unitary symmetries. Their gauging method preserves bond dimension when block independence holds, while a state-level alternative accommodates cases where it does not.

• Floquet-ADAPT-VQE Targets Quasienergies in Driven Systems

  Floquet-ADAPT-VQE recasts periodically driven quantum systems as a static problem to calculate quasienergies and Floquet states. The paper reports classical simulations on driven XYZ spin chains and describes fixed-depth circuits for evaluating time-dependent observables.

• Peixue Wu Finds No Entanglement Advantage for Phase-Covariant Channels

  A paper posted by Peixue Wu on October 29, 2026, proves that entangling codewords does not increase classical communication rates for phase-covariant channels in any dimension. It also establishes strong additivity for qubit-to-qubit channels and identifies questions that remain open for other channel classes.

• A Tryptophan Twist Could Sharpen Cryptochrome’s Magnetic Compass

  A Kobe University-led team links motion in cryptochrome to spin selectivity in light-triggered reactions. Its model predicts a rise in directional signal from 0.3% to 1.6%, but the work does not show magnetic navigation in living animals.

• Mamba Decoder Cuts QEC Scaling to O(d²) in Real-Time Simulations

  Changwon Lee, Tak Hur and Daniel K. Park report a Mamba-based quantum error-correction decoder with O(d²) computational scaling, compared with O(d⁴) for the Transformer decoder they studied. Tests on Google Sycamore memory data matched the Transformer’s performance, while simulations that model decoder latency gave Mamba a higher effective error threshold.

• Yang Team Identifies Quantum Transitions That Require Open Chains

  A study describes dynamical quantum phase transitions that occur in open chains but not under periodic boundary conditions. The authors connect the effect to memory, complex momenta and a winding number, and propose a particle-counting test.

• NIST Team Reads a Superconducting Qubit at 99.2% with Millimeter Waves

  A NIST-led team measured a superconducting transmon with a 34.7 GHz resonator and reported 99.2% readout fidelity using 109 resonator photons. The experiment also found just 1.74% measurement efficiency, leaving substantial room to improve the readout chain.

• Researchers Map Trapped-Ion Ramsey Data to Feynman Diagrams

  A paper in Quantum describes a statistical method for estimating Feynman-diagram contributions from qubit measurements of an oscillator. Its results come from simulations, not a reconstruction using newly collected experimental data.

• BTQ Brings MIMIQ to qBraid’s 35,000 Developers

  BTQ Technologies has made QPerfect’s MIMIQ quantum emulator available through qBraid’s managed API, reaching a community of more than 35,000 developers. The integration supports large-circuit testing with Matrix Product State methods, subject to circuit structure and entanglement.

• SoftBank and Five Firms Begin Quantum Materials R&D

  SoftBank, TOPPAN Holdings, AISIN, Asahi Kasei, AGC and DIC have agreed to develop a materials research platform combining quantum-computing calculations with AI. The NEDO-backed project will test materials applications from next-generation batteries to optical materials and superconductors through fiscal 2028.

• QSolid Tests Its 30-Qubit Processor as 10-Qubit System Opens Access

  Germany’s QSolid consortium says it is testing a 30-qubit quantum processor, while its previously tested 10-qubit system has already been made available to users. The €76.3 million project reports fast-gate and hardware-integration advances but gives no error-rate or benchmark figures for the larger processor.

• Quantum Dots Outpace Laser Pulses in an MDI-QKD Model

  A theoretical comparison finds that quantum-dot sources can outperform optimized weak coherent laser pulses in modeled MDI-QKD key rates, assuming perfect photon indistinguishability for that comparison. A separate analysis finds that imperfect indistinguishability sharply limits the modeled transmission range for both source types.

• Shaghaghi Sets Out Six-Step Z-Rotation Protocol for Bosonic Qubits

  A six-step protocol in a new paper proposes a shared way to implement arbitrary Z rotations across a class of bosonic circuit-QED qubits. The paper’s examples include encodings that meet its mathematical condition and a two-mode Fock-state example that does not.

• Rhenium Transmon Reaches 407 Microseconds, but Surface Loss Persists

  A rhenium transmon reached a time-averaged relaxation time of 407 ± 34 microseconds, while measured surface losses were comparable to tantalum’s. The researchers report no observable native oxide layer on the rhenium at the nanometer scale.

• Southeast University Team Demonstrates Quantum Mpemba Effect in a Qubit

  A team at Southeast University used a controllable optical experiment to simulate a quantum thermal-relaxation map and demonstrate a strong Mpemba effect in a single qubit. Their approach removes coherence from the initial state to bypass the map’s degenerate, slowest-decaying modes.

• QuantrolOx Raises €12 Million to Scale Quantum-Control Software

  The Oxford spinout raised a €12 million Series A led by IW Capital, with the EIC Fund and Transpose Capital also investing. QuantrolOx says it will use the funding to accelerate commercial growth and expand in North America.

• qBraid Launches OS for Quantum Hardware Operators

  qBraid introduced qBraid OS on October 21, 2026, to manage access, scheduling and billing for quantum computers alongside NVIDIA accelerated computing. Seven organizations, including IBM, IonQ and Diraq, are early-access partners.

• A Parametric Cavity Synchronizes Two Spin Ensembles Without Breaking Parity

  A theoretical study describes two spin ensembles synchronizing through a shared, parametrically amplified cavity while the system’s steady state remains symmetric and time independent. The authors identify the oscillation in two-time correlations and a slow Liouvillian mode, rather than in one-time averages.

• Treasury Proposes Wider Controls on Quantum Investment

  Treasury has proposed expanding outbound investment restrictions to cover software and algorithms for quantum technologies, alongside controls on quantum hardware and related systems. The proposal is open for public comment through December 7, 2026, while existing rules remain in effect.

• Shmueli Ties Indefinite Causal Order to Computation Beyond BQP

  Omri Shmueli’s paper studies whether quantum operations without a fixed causal order can solve problems beyond ordinary polynomial-time quantum computation. It presents a polynomial-time method for a unique-sink orientation problem, with the claim of exceeding BQP conditional on that problem having no quantum polynomial-time algorithm.

• IBM VQE Tests Find Error Bars Missed Energy Residuals by Up to 32×

  A study of molecular energy evaluations on IBM’s Aachen and Pittsburgh quantum processors found raw VQE residuals for oxygen and beryllium hydride reached 12 to 32 times the reported statistical uncertainty. The 110-job study also found that error mitigation’s effect varied by molecule and processor, while repeated runs exposed variation hidden by per-job error bars.

• Fraunhofer Team Switches Off NV Laser for 100% Magnetic Contrast

  A Nature Communications study reports an NV-diamond magnetometer inside a laser cavity that reaches 100% optical contrast. The team calculates photon-shot-noise sensitivity limits below 400 fT/√Hz for all vector components, but has not achieved those limits in actual measurements.

• IDEMIA Wins First EMVCo Certification for PQC Payment Cards

  IDEMIA Secure Transactions says EMVCo has certified its first payment-card platform to provide access to post-quantum cryptography and crypto-agility services. The Java Card platform combines a hardware accelerator with IDEMIA’s Sphere PQC library while supporting existing payment applications.

• Neural Triage Posts 28×–343× qLDPC Speedups in Benchmark

  A neural decoder called Triage cuts reported decoding time for two high-rate quantum LDPC codes in simulations. The October 29 preprint reports speedups of 28× and 343×, but compares GPU batch processing with CPU baselines.

• Park, Kwak and Kim’s Transformer Posts an 18.1% Code-Capacity Threshold

  Seong-Joon Park, Hee-Youl Kwak and Yongjune Kim report an 18.1% decoding threshold for surface codes under a code-capacity noise model. Their qubit-centric transformer also shows scalable error suppression in circuit-level tests, where the abstract describes performance rather than a threshold percentage.

• Wang et al.’s Dynamic Architecture Cuts Lattice-Surgery Compilation Time 75.5×

  A lattice-surgery compiler reallocates routing space as a quantum circuit runs, reporting lower space–time volume and faster compilation than DasCot. The paper’s evaluation also describes the benchmark set, modeling assumptions and tradeoffs behind those results.

• BIRD Funds Qarakal–Quantum Elements Catalysis MVP

  BIRD approved $7.4 million in conditional grants for seven U.S.-Israel R&D projects, including a quantum-chemistry MVP by Qarakal Quantum and Quantum Elements. The companies plan to use quantum computing to map complex surface-catalysis reactions.

• Silicon Cavity Records 1.29 Million Photon Counts per Second

  A silicon-based source produced near-infrared single photons at 1217 nanometers, with a saturated count rate of 1.29 million per second. The study reports separate measurements of photon antibunching and purity under different excitation conditions.

• IBM Connects Two 120-Qubit Chips With 99% State Transfer

  IBM researchers link two 120-qubit Nighthawk R1 processors with four superconducting coaxial cables and report 99.00% mean fidelity for quantum state transfer. The links also support distant gates and entangled states, though controlled-Z gates across the processors average 94.75% fidelity.