Quantum Computing
Quantum Computing news — Thursday 15 October 2026
150 stories from 3 sources, every one in English. Each links to its publisher.
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Google Quantum AI ＆ DeepMind Demonstrate Modular Hyperbolic Codes for Over 30x QEC Overhead Reduction
Quantum Computing Report
Researchers from Google Quantum AI, Google DeepMind, and MIT have developed a modular quantum error correction (QEC) architecture that significantly reduces the physical qubit overhead required for quantum computing. This new approach…
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Germany Issues Joint Federal PQC Migration Guidelines to Align with EU Post-Quantum Roadmap
Quantum Computing Report
Germany has released national guidelines for migrating to Post-Quantum Cryptography (PQC), aligning with the EU's roadmap. The strategy, driven by advancements in AI and threats to classical encryption, outlines a three-phase migration…
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IBM Research Automates QEC Decoder Chip Design Using Open AI Agent Factories at 11.5x Lower Inference Cost
Quantum Computing Report
IBM Research has developed an AI agent factory to automate the design of QEC decoder chips, achieving up to 204x hardware speedup and 11.5x lower AI inference costs. This system utilizes autonomous multi-agent search and open-weight…
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FirstQFM Foundation Model Cuts Quantum Gate Times by 33% on QuantWare QPU via NVIDIA Computing
Quantum Computing Report
FirstQFM AB has achieved a 33% reduction in single-qubit gate execution times on QuantWare’s 21-qubit Contralto-D21 superconducting quantum processor, without compromising gate fidelity. This was accomplished using their patented quantum…
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Classiq Partners with FreeYa Mind Campus to Launch Quantum Applications Hub in Romania
Quantum Computing Report
Classiq has partnered with FreeYa Mind Campus to open a Quantum Applications Hub in Iași, Romania, which will serve as Classiq's regional headquarters. This hub integrates Classiq's quantum software platform with the campus's IBM Quantum…
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Stony Brook Quantum Memory Named to TIME’s Best Inventions of 2026
The Quantum Insider
Insider Brief Stony Brook University ‘s patented quantum memory technology, commercialized by Qunnect as Qu-MEM, has been named to TIME’s Best Inventions of 2026 list in the Experimental category. Qu-MEM is a room-temperature quantum…
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Anderon Releases First Superconducting Quantum PDK for 300mm Wafer Fabrication
Quantum Computing Report
Anderon, a quantum foundry operator, has released its first Superconducting Quantum Process Design Kit (PDK) for 300mm wafer fabrication. This PDK provides standardized design rules and building blocks for manufacturing superconducting…
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ORCA Computing Launches PT-3 Photonic Quantum System in London for Hybrid AI and Industrial Optimization
Quantum Computing Report
ORCA Computing has launched its PT-3 photonic quantum system in London, integrating it with NVIDIA GPU-accelerated computing infrastructure. This room-temperature system, consuming 6 kW, uses 64 photons across 128 qumodes to enhance…
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DOE ARPA-E Launches $37 Million QC3 Program Across Ten Quantum Chemistry Performers
Quantum Computing Report
The U.S. Department of Energy’s ARPA-E has launched the $37 million Quantum Computing for Computational Chemistry (QC3) program, funding ten research teams for three years. This initiative aims to achieve a 100-fold speedup over classical…
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Terra Quantum Publishes White Paper Detailing Post-Quantum Cryptography Migration Paths for Blockchain Ecosystems
Quantum Computing Report
A white paper by Terra Quantum AG analyzes the vulnerability of major blockchain platforms like Bitcoin, Ethereum, and Solana to post-quantum cryptography (PQC) threats, highlighting the risks posed by Shor's algorithm to digital signature…
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Terra Quantum and Schaeffler Publish Peer-Reviewed Study on Hybrid Quantum Machine Learning for Materials Modeling
Quantum Computing Report
Terra Quantum and Schaeffler have published a peer-reviewed study in Computational Materials Science on hybrid quantum machine learning for materials modeling. Their research demonstrates that a hybrid quantum-classical Allegro model…
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Terra Quantum Joins QuEra Quantum Alliance to Expand Neutral-Atom Software Layer
Quantum Computing Report
Terra Quantum has joined the QuEra Quantum Alliance to advance neutral-atom quantum computing. Terra Quantum, a quantum software and algorithm developer, will contribute its TQ42 platform to the alliance, offering a Python SDK, APIs, and…
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Argonne and UIUC Demonstrate First On-Chip Coupling of Propagating Spin Waves to Superconducting Circuits
Quantum Computing Report
Scientists from Argonne National Laboratory and UIUC have developed the first-of-its-kind hybrid circuit, integrating propagating spin waves with a superconducting resonator on a single chip. This innovation allows for strong coupling…
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IonQ and the University of Cambridge Open Quantum Innovation Centre at Cavendish Laboratory
Quantum Computing Report
IonQ and the University of Cambridge have opened the IonQ Quantum Innovation Centre at the Cavendish Laboratory, deploying a 256-qubit Superion quantum computer and a quantum network. This initiative, supported by Innovate UK and aligning…
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D-Wave Delivers Italy’s First Annealing Quantum Computer to Lombardy Infrastructure Hub
Quantum Computing Report
D-Wave has installed Italy's first on-premises Advantage2 annealing quantum computer at Villa Saporiti in Como. Funded by Swiss Quantum Technology SA (SQT) with a €10 million agreement, this 4,400+ qubit system will be accessible to…
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Dirac Labs Joins Wisconsin Security Research Consortium to Advance Quantum PNT for Autonomous Defense Platforms
Quantum Computing Report
Dirac Labs has joined the Wisconsin Security Research Consortium (WSRC) to advance quantum-enabled Positioning, Navigation, and Timing (PNT) systems. They are developing a quantum universal positioning system using diamond-based quantum…
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Sweden Joins European Quantum and AI Skills Academies
The Quantum Insider
Insider Brief Sweden is joining European Skills Academies for Quantum and AI, with Nordita supporting the Nordic-Baltic Quantum Academy and Swedish organizations contributing to AI skills development. The European Quantum Skills Academy…
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IonQ and University of Cambridge Open Quantum Innovation Centre
The Quantum Insider
Insider Brief IonQ and the University of Cambridge have opened the IonQ Quantum Innovation Centre at the Ray Dolby Centre, establishing the company’s first university-based centre of this kind. The centre’s nine initial research projects…
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SEALSQ Reports 65% Revenue Growth in First Nine Months of 2026
The Quantum Insider
Insider Brief SEALSQ reported preliminary nine-month 2026 revenue of $16.3 million, up 65% year over year, and reaffirmed its full-year revenue guidance of $27 million to $36 million. The company reported approximately $463 million in…
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Quantum Alliance Launches to Set Post-Quantum Standards for Blockchains
The Quantum Insider
Insider Brief Leaders from nine blockchain organizations have launched the Quantum Alliance , an open standards initiative to define and verify post-quantum readiness across blockchain networks, wallets and infrastructure. The Alliance…
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D-Wave Delivers Advantage2 Annealing Quantum Computer to Italy
The Quantum Insider
Insider Brief D-Wave has delivered its Advantage2 annealing quantum computer to Villa Saporiti in Como, Lombardy, Italy, with installation planned to provide European researchers, universities and businesses with access to the system…
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Photonics Simulation Software Startup EMode Photonix Raises $1 Million Pre-Seed
The Quantum Insider
Insider Brief EMode Photonix raised $1 million in pre-seed funding led by Ground State Ventures , with participation from Harlow Capital Management, to expand its photonics simulation software business. The company says its software…
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Dirac Labs joins Wisconsin Security Research Consortium
The Quantum Insider
Insider Brief Dirac Labs has joined the Wisconsin Security Research Consortium as an industry affiliate to advance GPS-independent quantum navigation for autonomous maritime missions. The Madison-based company is developing diamond-based…
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Argonne Researchers Couple Spin Waves With Superconducting Circuits
The Quantum Insider
Insider Brief Researchers from Argonne National Laboratory and the University of Illinois Urbana-Champaign demonstrated a hybrid system that couples magnetic spin waves with superconducting circuits for quantum information processing. The…
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Riverlane and NVIDIA Use AI to Speed Up Quantum Decoder Calibration
The Quantum Insider
Insider Brief Riverlane and NVIDIA are exploring how AI and GPU-accelerated computing can speed up decoder calibration for quantum error correction as quantum hardware behaviour changes. Using Riverlane ’s Local Clustering De
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FirstQFM Model Cuts Single-Qubit Gate Times by 33% on QuantWare Processor
The Quantum Insider
Insider Brief FirstQFM applied its quantum foundation model to a 21-qubit QuantWare superconducting processor at the Israeli Quantum Computing Center, reducing single-qubit gate execution time by 33% without reducing gate fidelity. The…
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SEALSQ to Showcase Post-Quantum Security Products at electronica 2026
The Quantum Insider
Insider Brief SEALSQ and its subsidiary IC’Alps will showcase post-quantum security products and custom chip design services at electronica 2026 in Munich, Germany, from November 10–13. The company plans to demonstrate the VaultIC409…
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ZeroTier Releases RC3 of Quantum-Secure Networking Platform
The Quantum Insider
Insider Brief ZeroTier has released Release Candidate 3 (RC3) of ZeroTier Quantum, a networking platform designed to provide post-quantum cryptographic protection across managed, sovereign, self-hosted and air-gapped deployments. The…
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Guest Post — Seeing Underground: Quantum Sensing in Mineral Exploration
The Quantum Insider
By Zeynep Koruturk , Dr. Kris Naudts , and Donald Harmitt @ Firgun Ventures . Firgun Ventures is a VC firm investing in Series A/B quantum scale-ups globally. Demand for critical minerals is rising just as copper exploration is becoming…
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ORCA Computing Launches PT-3, The Latest Generation of Its Photonic Quantum Computers
The Quantum Insider
Insider Brief ORCA Computing launched its PT-3 photonic quantum computer at Digital Realty’s London innovation lab, pairing it with NVIDIA accelerated computing for scientific AI and industrial optimization. ORCA reported that a…
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Competitive scaling of small-subsystem-optimization heuristics for LABS
arXiv quant-ph
arXiv:2610.14361v2 Announce Type: replace-cross Abstract: The low autocorrelation binary sequences (LABS) problem, often formulated as a spin-lattice energy-minimization problem, is a combinatorial optimization problem with a very rugged…
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Geometric-resource bounds and permutation-averaged success probabilities for the WZP algorithm
arXiv quant-ph
arXiv:2610.20198v1 Announce Type: new Abstract: Solving linear systems of equations is a fundamental task in machine learning and optimization. In this work, we extend the original WZP algorithm from real symmetric linear systems to…
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Rare Event Simulation of Quantum Error-Correcting Circuits
arXiv quant-ph
arXiv:2509.13678v4 Announce Type: replace Abstract: We describe a practical approach for accessing the logical failure rates of quantum error-correcting (QEC) circuits under low physical (component) failure rate regimes. Standard Monte…
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Gap-Priced $|T\rangle$-States: Dynamic $|T\rangle$ Post-Selection and Budget-Aware Factory Provisioning
arXiv quant-ph
arXiv:2610.19299v1 Announce Type: new Abstract: Magic $|T\rangle$-state preparation dominates the cost of fault-tolerant quantum computation on surface codes, yet cultivation and distillation are typically provisioned statically, leaving…
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Coherent-State Integrals Beyond the Domain of Operator Products
arXiv quant-ph
arXiv:2610.19702v1 Announce Type: cross Abstract: Inserting a resolution of the identity between two operators turns a matrix element of their product into a phase-space integral. For unbounded operators the product need not exist on the…
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Preservation of photon statistics upon selective molecular modulation in hollow-core fibers
arXiv quant-ph
arXiv:2610.19964v1 Announce Type: cross Abstract: Preserving the underlying statistical properties of light during frequency transduction is essential for interfacing spectrally disparate quantum systems. To do this successfully, the…
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A quantum annealing approach to the minimum distance problem of quantum codes
arXiv quant-ph
arXiv:2404.17703v4 Announce Type: replace Abstract: Quantum error-correcting codes (QECCs) are at the heart of fault-tolerant quantum computing. As the size of quantum platforms is expected to grow, one of the open questions is to design…
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Autonomous optomechanical Maxwell Demon engine
arXiv quant-ph
arXiv:2610.18237v2 Announce Type: replace Abstract: We present a fully autonomous model of a mechanical Maxwell demon engine that converts heat absorbed by a qubit into population inversion in an attached quantum battery. A damped…
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Selective Control and Imaging of Higgs and Goldstone Modes with a Quantum Simulator
arXiv quant-ph
arXiv:2610.19219v1 Announce Type: new Abstract: We realize the mesoscopic Bose-Hubbard model at unit-filling on a two-dimensional array of transmon qubits and selectively excite collective modes associated with amplitude or phase…
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Hyperentanglement in intermediate phase-space planes: benchmarking a photon-pair source for quantum key distribution
arXiv quant-ph
arXiv:2610.20005v1 Announce Type: new Abstract: We characterize a source of photon pairs simultaneously entangled in polarization and in the transverse spatial degree of freedom, with the spatial measurements performed in intermediate…
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Instability of Markov chains under infinitesimal coherent dissipation
arXiv quant-ph
arXiv:2610.18983v1 Announce Type: new Abstract: Under local Lindbladian evolution, the growth of conditional mutual information and its associated Markov length scale is not limited by Lieb-Robinson bounds, yet it has been unclear how…
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Logical gate set tomography
arXiv quant-ph
arXiv:2610.19034v1 Announce Type: new Abstract: Quantum error correction (QEC) can strongly suppress noise, but predicting whether a computation succeeds requires understanding not only how much effective noise persists after QEC, but what…
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Cavity-assisted dynamic nuclear polarisation
arXiv quant-ph
arXiv:2610.19180v1 Announce Type: new Abstract: Dynamic nuclear polarisation transfers polarisation from electron to nuclear spins by relying on a dissipative channel. Here we introduce a cavity-based DNP mechanism which uses the radiative…
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Quantum-classical algorithm interpolation for spatial search
arXiv quant-ph
arXiv:2610.19255v1 Announce Type: new Abstract: Quantum-walk algorithms can quadratically reduce the dependence of spatial search on the classical hitting time $\mathrm{HT}$. Realising this speedup using standard quantum-walk algorithms…
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Leakage benchmarking with decohering subgroups in the presence of preparation and measurement errors
arXiv quant-ph
arXiv:2610.19304v1 Announce Type: new Abstract: A common problem with physical qubits is that the state can leak outside the computational subspace. To characterize the problem, it is desirable to measure both the leakage probability and…
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Cryogenic Multiplexing Control Chip for Superconducting Quantum Processor
arXiv quant-ph
arXiv:2610.19599v1 Announce Type: new Abstract: This paper proposes a scheme and design of cryogenic multiplexing control chip (MCC) which enables one microwave cable to control many superconducting qubits. Designed based on adjustable…
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Transport Information Beyond Strong Eigenstate Thermalization
arXiv quant-ph
arXiv:2610.19675v1 Announce Type: new Abstract: Strong eigenstate thermalization (ETH) in operationally mean-ergodic, non-chaotic systems provides an opportunity to investigate whether Floquet eigenstates retain information about classical…
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Tomography for coherent noise
arXiv quant-ph
arXiv:2610.19779v1 Announce Type: new Abstract: Coherent noise poses a fundamentally greater challenge to quantum error correction than independent s- tochastic Pauli errors, because unitary errors preserve interference between error…
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Acoustic scattering from quantum dynamics
arXiv quant-ph
arXiv:2610.19873v1 Announce Type: new Abstract: Scattering of sound waves propagating in a compressible fluid is linked to the quantum dynamics generated by a class of non-Hermitian Hamiltonian operators. The scattering amplitude is…
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Photon Demultiplexing Using Spatial Routing
arXiv quant-ph
arXiv:2610.19933v1 Announce Type: new Abstract: Spatial sectioning of the far-field noncollinear field from spontaneous parametric down-conversion (SPDC) is a promising approach for multiparty quantum communication. Although demonstrations…
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Metric-Changing Quasi-Hermitian Quenches: Normalized Loschmidt Amplitude and Complex-Time Zeros
arXiv quant-ph
arXiv:2610.20016v1 Announce Type: new Abstract: In quasi-Hermitian mixed-state quenches, the initial and final Hamiltonians generally possess different positive-definite metrics, so post-quench evolution is not quasi-unitary in the initial…
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Loss-Tolerant Measurement-Device-Independent QKD over Untrusted Repeaters via High-Dimensional Time-Bin Multiplexing
arXiv quant-ph
arXiv:2610.20148v1 Announce Type: new Abstract: We propose a loss-tolerant measurement-device-independent quantum key distribution (MDI-QKD) protocol using time-bin-multiplexed single photons entangled with local qubits stored in…
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Quantum Spectral Estimation with Multiple Initial States: Improved Error and Cost Scaling
arXiv quant-ph
arXiv:2610.20482v1 Announce Type: new Abstract: We study quantum spectrum and eigenstate property estimation using multiple initial states and generalized Hadamard tests. Building on the QFAMES (quantum filtering and analysis of…
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Demonstration of a mobile ion-trap quantum device
arXiv quant-ph
arXiv:2610.20487v1 Announce Type: new Abstract: Trapped-ion devices are being investigated for transportable applications, including the transfer of exotic charged particles between laboratories and the development of portable quantum…
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Petz Recovery through a Single Polar Transformation for Approximate Quantum Error Correction
arXiv quant-ph
arXiv:2610.20515v1 Announce Type: new Abstract: The Petz recovery map provides a near optimal decoder for approximate quantum error correction, but its inverse square-root normalization complicates circuit implementation. We use the polar…
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Quantum Work Statistics from Entanglement-Assisted Invariance
arXiv quant-ph
arXiv:2610.20528v1 Announce Type: new Abstract: We demonstrate that the one-time measurement scheme is more consistent than the standard two-time measurement scheme with respect to the fundamental symmetry of entanglement, namely…
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Measurement-induced criticality for non-Abelian anyons: The monitored golden chain
arXiv quant-ph
arXiv:2610.18965v1 Announce Type: cross Abstract: Non-Abelian anyon chains whose interactions favor a single fusion channel host quantum critical ground states described by minimal-model conformal field theories (CFTs) protected by a…
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Viscous hydrodynamics from correlated losses
arXiv quant-ph
arXiv:2610.19083v1 Announce Type: cross Abstract: Interactions turn a gas into a fluid. We show that two-body loss can take their place. Correlated loss induces elastic scattering, as required by the optical theorem, which dominates at…
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Beyond the lemon: Spectra of random Lindblad operators with a Hamiltonian component
arXiv quant-ph
arXiv:2610.19261v1 Announce Type: cross Abstract: Generators of continuous-time quantum Markovian evolution, known as Lindblad operators, play a key role in the theory of open quantum systems. The question of how to define and characterize…
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Mutual Information of Measurement in Conformal Field Theories
arXiv quant-ph
arXiv:2610.19286v1 Announce Type: cross Abstract: The mutual information of measurement of a local operator between two spatial regions characterizes the reduction in the uncertainty of measurement outcomes in one region given the outcome…
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A low-cost compact muon detector for millikelvin operation
arXiv quant-ph
arXiv:2610.20132v1 Announce Type: cross Abstract: Ionizing radiation produces correlated errors in superconducting qubits, posing some challenges to quantum error correction. In addition, it causes background events in other…
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Directional effects of the Unruh effect on steering harvesting
arXiv quant-ph
arXiv:2610.20151v1 Announce Type: cross Abstract: We investigate directional quantum steering harvesting by two uniformly accelerated non-identical Unruh-DeWitt detectors coupled to a massless scalar field in the Minkowski vacuum. We show…
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Universal enhancement of the pairing gap in a dilute Fermi superfluid
arXiv quant-ph
arXiv:2610.20434v1 Announce Type: cross Abstract: At zero temperature, a dilute Fermi gas with an attractive contact interaction forms a superfluid with gapped fermionic excitations. We show that the gap at weak coupling can be organized…
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All you need is Trotter
arXiv quant-ph
arXiv:2311.01533v5 Announce Type: replace Abstract: The work here enables a cost scaling of $\tilde{O}\left( \frac{T ^{1+o(1)}\,{\rm log}^2 (1/\epsilon)}{\varepsilon}\right)$ and maximum depth $\tilde{O}\left( \frac{T^{1+o(1)}\,{\rm log}…
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Renormalisation of Quantum Cellular Automata
arXiv quant-ph
arXiv:2407.12652v3 Announce Type: replace Abstract: We study a coarse-graining procedure for quantum cellular automata on hypercubic lattices that consists in grouping neighboring cells into tiles and selecting a subspace within each tile…
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Solving the traveling salesman problem on $\lceil \log_2 (N-1)! \rceil$ qubits with a variational quantum Kolmogorov--Arnold network: exact-gradient CVaR training and generalization over time-dependent graphs
arXiv quant-ph
arXiv:2509.22752v2 Announce Type: replace Abstract: The one-hot encoding of the traveling salesman problem (TSP) on quantum hardware needs $(N-1)^2$ qubits for $N$ sites and penalty terms that dominate the cost landscape. Permutation…
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Unconditional full vector magnetometry using spin selectivity in Nitrogen Vacancy centers in diamond
arXiv quant-ph
arXiv:2602.12090v2 Announce Type: replace Abstract: Quantum sensors based on nitrogen vacancy (NV) centers in diamond have been a central topic in the sensing community for more than a decade. The extraordinary properties at room…
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Learning Quantum Operator Dynamics from Short-Time Data
arXiv quant-ph
arXiv:2603.14699v2 Announce Type: replace Abstract: Real-time dynamics of quantum observables provide direct access to excitation spectra and correlation functions in quantum many-body systems, but currently available quantum devices are…
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Classical shadows with arbitrary group representations
arXiv quant-ph
arXiv:2604.01429v2 Announce Type: replace Abstract: Classical shadows (CS) has recently emerged as an important framework to efficiently predict properties of an unknown quantum state. A common strategy in CS protocols is to parametrize…
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Magnetic domains stabilized by symmetry-protected zero modes
arXiv quant-ph
arXiv:2604.15510v2 Announce Type: replace Abstract: Understanding mechanisms for the breakdown of thermalization in closed quantum systems is a central problem in quantum many-body physics. We demonstrate strong nonergodic behavior in the…
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The power of unentanglement without destructive interference
arXiv quant-ph
arXiv:2604.27886v3 Announce Type: replace Abstract: Stoquasticity, originating in sign-problem-free physical systems, gives rise to $\sf StoqMA$, introduced by Bravyi, Bessen, and Terhal (2006), a quantum-inspired intermediate class…
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On Constructing and Decoding Quantum Triorthogonal Codes
arXiv quant-ph
arXiv:2605.24519v3 Announce Type: replace Abstract: Triorthogonal codes are a basic ingredient in magic-state distillation, as they enable transversal implementation of logical $\mathsf{T}$ gates. As a non-Clifford operation, the…
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A quantum algorithm for one-shot signatures
arXiv quant-ph
arXiv:2606.23612v2 Announce Type: replace Abstract: We provide a pre-obfuscation circuit-level implementation of an efficient one shot signature scheme, which has known applications to delegated signatures, secure token transfer, and…
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Compact deterministic liquid-crystal polarization controller with single-measurement direct control
arXiv quant-ph
arXiv:2607.20987v2 Announce Type: replace Abstract: Polarization controllers (PCs) and their control algorithms are critical for compensating environmental disturbances and maintaining signal fidelity in polarization-sensitive photonic…
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The cost of direction in quantum Bell certification
arXiv quant-ph
arXiv:2609.10162v3 Announce Type: replace Abstract: Certifying a quantum bound can require more information than realizing the correlations that attain it. We show that this distinction becomes unbounded when a proof must condition on one…
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Classical Cellular Automaton for Measurement-Only Entanglement Transitions
arXiv quant-ph
arXiv:2609.28743v2 Announce Type: replace Abstract: We introduce a generalized classical long-range stochastic cellular automaton that exactly captures the entanglement dynamics and transitions of a measurement-only monitored quantum…
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Invertible subalgebras for chiral semion topological order
arXiv quant-ph
arXiv:2610.18953v1 Announce Type: new Abstract: Chiral topological order is incompatible with strictly two-dimensional local commuting-projector Hamiltonians on finite-dimensional tensor-product Hilbert spaces. Invertible subalgebras…
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On the structure of low-rank PPT entangled states violating Peres conjecture
arXiv quant-ph
arXiv:2610.19905v1 Announce Type: new Abstract: Bound-entangled states with positive partial transpose (PPT) can exhibit quantum steering and Bell nonlocality, disproving the long-standing Peres conjecture and its stronger steering…
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Gravity from generalized entropy
arXiv quant-ph
arXiv:2610.19106v1 Announce Type: cross Abstract: Gravity from entropy (GfE) identifies its Lagrangian with the geometric quantum relative entropy (GQRE) between the spacetime metric and a metric induced by matter and curvature, treating…
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Preparing multi-qudit states in a definite-weight subspace
arXiv quant-ph
arXiv:2606.24659v3 Announce Type: replace Abstract: We formulate a deterministic algorithm for preparing arbitrary multi-qudit states in a definite-weight subspace. By ordering the corresponding computational basis states according to a…
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SQD-Agent: LLM-driven agentic framework for Quantum Chemistry workflows
arXiv quant-ph
arXiv:2609.39302v2 Announce Type: replace Abstract: Quantum algorithms and quantum hardware are advancing towards a promising paradigm for scientific applications. However, translating domain-specific problems into executable hybrid…
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QMA(2) with Limited Shared Entanglement
arXiv quant-ph
arXiv:2609.39668v3 Announce Type: replace Abstract: In $\mathsf{QMA}(2)$, two computationally unbounded provers submit unentangled quantum witnesses to a polynomial-time quantum verifier. We ask whether allowing limited shared entanglement…
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The quantum-classical bipartite universe and the logical emergence of $\hbar$ from classical temporality
arXiv quant-ph
arXiv:2610.05083v2 Announce Type: replace Abstract: We present a foundational reinterpretation of quantum dynamics based on the standard von Neumann formalism, positing a structural logical bipartition between a classical observational…
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The Mermin-Peres Magic Square Game With Three or More Players
arXiv quant-ph
arXiv:2610.06534v2 Announce Type: replace Abstract: We present a generalization of the Mermin-Peres magic square game to $N$ players, in which the square is replaced by an $N$-dimensional hypercube. We show that the winning probability of…
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Green's functions for magnetic Dirac operators and bulk-edge correspondence
arXiv quant-ph
arXiv:2509.17151v2 Announce Type: replace-cross Abstract: We study the resolvent kernel (Green's function) of magnetic Dirac operators on a half-plane with boundary conditions interpolating between infinite mass and zigzag cases, excluding…
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Quantum speed limit time for bipartite entanglement in neutrino oscillations in matter with nonstandard interactions
arXiv quant-ph
arXiv:2602.03748v2 Announce Type: replace-cross Abstract: In the three-flavor neutrino oscillation framework, we investigate the transition probabilities of an initial muon neutrino flavor state in the presence of nonstandard interactions…
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A Versatile Variational Quantum Kernel Framework for Non-Trivial Classification
arXiv quant-ph
arXiv:2511.10831v3 Announce Type: replace-cross Abstract: Quantum kernel methods are a promising branch of quantum machine learning, but their per- formance across data types and encoding choices remains incompletely understood. To address…
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Soft-Radiation-Induced Decoherence of Heavy-Quark Spin Entanglement at the Electron-Ion Collider
arXiv quant-ph
arXiv:2606.29944v3 Announce Type: replace-cross Abstract: Using the soft-gluon theorem, we identify a soft-recoil mechanism by which unresolved gluon radiation induces decoherence in the spin correlations of heavy quark-antiquark pairs…
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Hermitian Hulls of Cyclic Codes and Exact Dual Distances of Extended Linear Codes
arXiv quant-ph
arXiv:2607.12242v3 Announce Type: replace-cross Abstract: Let $\mathcal{C}$ be an $[n,k,d]$ linear code over $\F_{q^2}$ with parity-check matrix $H$. The rank $r=\Rank(HH^{\dagger})$ measures how far the Hermitian dual…
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An Aubry-Andr\'e localized optical lattice clock
arXiv quant-ph
arXiv:2610.17499v2 Announce Type: replace-cross Abstract: Optical lattice clocks in space could improve satellite navigation systems and enable new tests of fundamental physics, including gravitational-wave detection and tests of…
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Intermediate memory costs of quantum channel synthesis with a protected subsystem
arXiv quant-ph
arXiv:2610.20536v1 Announce Type: new Abstract: A quantum memory can preserve a subsystem perfectly while discarding information needed by a later operation. We study the total intermediate dimension required for channel synthesis when the…
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Sharp Asymptotics for $k$-Positivity Shifts under Singular Perturbations
arXiv quant-ph
arXiv:2506.03773v3 Announce Type: replace Abstract: We show that, as the Choi matrix of a completely positive perturbation direction approaches a singular limit, the shift required for $k$-positivity can diverge more slowly than that…
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Fundamental Limitations of QAOA on Constrained Problems and a Route to Exponential Enhancement
arXiv quant-ph
arXiv:2511.17259v5 Announce Type: replace Abstract: We study the feasibility limitations of generic QAOA for permutation-constrained optimization, where valid configurations occupy an exponentially small fraction of the Boolean hypercube…
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Spatial Phase Control of Energy and Ergotropy in Quantum Batteries
arXiv quant-ph
arXiv:2602.18192v3 Announce Type: replace Abstract: We investigate the role of spatial geometry in controlling energy storage and work extraction in a non-Markovian quantum battery. The system consists of two identical two-level systems…
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Causal memory and structural complexity of correlated quantum sequences
arXiv quant-ph
arXiv:2610.06519v2 Announce Type: replace Abstract: What makes one quantum process more complex than another? We adopt an operational approach inspired by classical complexity science, which characterises structure through the memory…
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PULSUS: Direct Frequency-Domain Multidimensional Spectroscopy Beyond the Impulsive Rotating-Wave Approximation
arXiv quant-ph
arXiv:2610.18712v2 Announce Type: replace Abstract: We introduce PULSUS, a direct frequency-domain framework for multidimensional spectroscopy of open quantum systems beyond the impulsive rotating-wave approximation. Coherence-frequency…
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Regularized barycentric R\'enyi divergences
arXiv quant-ph
arXiv:2609.17517v5 Announce Type: replace Abstract: Barycentric R\'enyi divergences were introduced in [Mosonyi, Bunth, Vrana, Linear Algebra and its Applications, 2024] as an alternative to standard Kubo-Ando constructions to define…
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Testing graph isomorphism using simple quantum circuits
arXiv quant-ph
arXiv:2610.19962v1 Announce Type: new Abstract: The graph isomorphism problem asks whether two graphs are equivalent up to a permutation of their vertices. Its precise computational complexity remains unresolved, and it is still unknown…
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A modular quantum computer based on Cornucopia codes
arXiv quant-ph
arXiv:2610.19073v1 Announce Type: new Abstract: Ultra-high-rate quantum error correction codes can store many logical qubits in a single code block with few physical qubits. A fault-tolerant quantum computer, however, also requires a…
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Energy-constrained two-way capacities of pure-loss and quantum-limited amplifier channels
arXiv quant-ph
arXiv:2610.06832v3 Announce Type: replace Abstract: We determine the two-way quantum, entanglement-distribution, private, and secret-key capacities of the pure-loss bosonic channel under an unconditional mean transmitted-photon-number…
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Federated Unlearning of Quantum Data via Classical Shadows
arXiv quant-ph
arXiv:2610.19077v1 Announce Type: new Abstract: Quantum federated learning trains a quantum neural network (QNN) across nodes that hold quantum data, such as the states of quantum sensors. To forget data, unlearning methods for quantum…
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Expanding quantum magnetic field
arXiv quant-ph
arXiv:2605.27426v2 Announce Type: replace Abstract: We develop the quantum theory of the causal formation of a long-range magnetic field generated by an external current that is instantaneously switched on and subsequently kept constant in…
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Post-Optimization Subspace Corrections to Quantum Ans\"atze
arXiv quant-ph
arXiv:2610.19109v1 Announce Type: new Abstract: Circuit depth and measurement count are the main limitations for chemical applications of the leading variational quantum algorithms on quantum computers. We show that both resource…
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Quantum LDPC Codes from Polynomial Minors
arXiv quant-ph
arXiv:2610.19459v1 Announce Type: new Abstract: We construct quantum codes from codewords of a cyclic code and the minors of a polynomial matrix. The construction uses a two-row, three-column matrix whose minors yield a second matrix…
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Majorana Edge Modes Reshape Kibble-Zurek Scaling in Kitaev Honeycomb Ribbons
arXiv quant-ph
arXiv:2610.19923v1 Announce Type: new Abstract: Recent progress in programmable quantum simulators motivates exact benchmarks for nonequilibrium dynamics in topological quantum matter. We study the Kitaev honeycomb model driven through its…
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Joint-measurement advantage and finite-time transitions in accelerated detector registers
arXiv quant-ph
arXiv:2610.19941v1 Announce Type: new Abstract: The Unruh response thermalizes accelerated detectors, but the entanglement remaining in a register does not by itself specify what distributed measurements can recover. We study this…
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Q-Edge: Symmetry-Reduced Quantum Simulation of Structured Extreme Dependence
arXiv quant-ph
arXiv:2609.03706v3 Announce Type: replace Abstract: High-dimensional simulation of multivariate extremes is fundamentally limited by the combinatorial complexity of dependence, often more than by the scarcity of extreme observations. We…
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A Reconstruction of Michelson Interference from On--Off Detection Statistics
arXiv quant-ph
arXiv:2610.19569v1 Announce Type: new Abstract: This paper reconstructs the Michelson interference phenomenon based solely on the binary (on-off) statistics of a single-photon counter and macroscopic path-difference data, without the a…
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Programmable Polaron Models and Tomography in Trapped-Ion Quantum Simulators
arXiv quant-ph
arXiv:2610.18970v1 Announce Type: new Abstract: Strong coupling between mobile charge carriers or excitons and lattice vibrations gives rise to polarons: quasiparticles formed by charge carriers dressed by a cloud of phonon excitations…
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Dynamical Decoupling of Nonclassical States in a Biased-Noise Spin Qudit
arXiv quant-ph
arXiv:2610.19676v1 Announce Type: new Abstract: Encoding quantum information in $d$-dimensional systems (qudits) with $d>2$ offers appealing new directions for resource-efficient quantum computing. However, protecting the coherence of…
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Trading energy for coherence in mode discrimination
arXiv quant-ph
arXiv:2610.19897v1 Announce Type: new Abstract: Energy is arguably the main resource in classical physics; coherence is the prototypical quantum resource. In this paper, we study the interplay between these two resources in the task of…
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Phase-preserving steady-state operations beyond Lindblad master equations
arXiv quant-ph
arXiv:2510.10394v4 Announce Type: replace Abstract: We consider a class of nonunitary operations that is naturally implemented via a combination of projective measurement and unitary operators. We implement these operations without using…
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Bimodal non-Gaussian photonic states from a single quantum emitter in a waveguide
arXiv quant-ph
arXiv:2608.03658v2 Announce Type: replace Abstract: We investigate the generation of deterministic and heralded non-Gaussian states of light, using a single two-level system coupled to a chiral waveguide. We study the case of a single two…
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Exact quantum circuits for a Heisenberg triangle with Dzyaloshinskii-Moriya interaction
arXiv quant-ph
arXiv:2609.15411v2 Announce Type: replace Abstract: We construct short analytical quantum circuits for the exact evolution of a spin triangle with Dzyaloshinskii--Moriya (DM) interaction. We consider pure DM interaction with arbitrary real…
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The cost of classically simulating quantum communication is as high as it could be
arXiv quant-ph
arXiv:2610.19060v1 Announce Type: new Abstract: A long-standing open question is to characterize the classical communication cost of simulating the correlations arising from measurements on finite-dimensional quantum systems. We consider…
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Quantized six-vertex realizations of frustration graphs
arXiv quant-ph
arXiv:2610.20166v1 Announce Type: cross Abstract: A recent graph-theoretic criterion for a Hamiltonian to exhibit a free-parafermion spectrum is that its frustration graph be an indifference graph. We show that an arbitrary finite…
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Heterogeneous entanglement between a trapped ion and a solid-state quantum memory
arXiv quant-ph
arXiv:2603.05836v2 Announce Type: replace Abstract: Hybrid quantum networks offer a promising architecture for scalable quantum information processing and a future quantum internet, as they can combine the complementary strengths of…
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Why does the wavefunction 'collapse' in relational approaches to quantum mechanics?
arXiv quant-ph
arXiv:2604.12094v2 Announce Type: replace Abstract: I argue that there is a straightforward way to understand the occurrence of wavefunction collapses or 'quantum events' in relational approaches to quantum mechanics: we necessarily…
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Theory of spacetime quantum fault tolerance
arXiv quant-ph
arXiv:2609.39758v2 Announce Type: replace Abstract: We present a unified algebraic theory of Clifford spacetime quantum fault tolerance, which underpins universal fault-tolerant quantum computation. We construct a spacetime chain complex…
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Compound beams for direct experimental comparison of quantum operations
arXiv quant-ph
arXiv:2608.09518v2 Announce Type: replace Abstract: Compound beams composed of simple experimental blocks (detected in simultaneous detection windows) that form specific quantum-correlated structures are suggested for simulating the…
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Probing critical phases in quasiperiodic systems via subsystem information capacity
arXiv quant-ph
arXiv:2605.06075v3 Announce Type: replace-cross Abstract: We systematically investigate the entanglement and information dynamics of quasiperiodic systems across their extended, critical, and localized phases, aiming to identify dynamical…
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Void-Free Through-Glass Vias for Multilayer Surface-Electrode Ion Traps
arXiv quant-ph
arXiv:2610.19736v1 Announce Type: new Abstract: Through-substrate interconnects are a key technology for scaling surface-electrode ion traps (SEITs) toward large electrode counts and complex architectures. Dielectric substrates such as…
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Quantum-enhanced phase interrogation of a fiber-optic strain sensor
arXiv quant-ph
arXiv:2610.19752v1 Announce Type: new Abstract: Fiber-optic sensors enable high-sensitivity measurements of various physical parameters. Here, we demonstrate a quantum-enhanced interrogation of an all-fiber-optic Fabry-Perot resonator…
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Advances in quantum optomechanical control based on cavity cold-atom systems
arXiv quant-ph
arXiv:2610.20040v1 Announce Type: new Abstract: Cavity optomechanics represents a frontier research direction in quantum science and technology, centered on the control and exploration of interactions between electromagnetic fields and…
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A compact six-beam 3D magneto-optical trap based on multifunctional metasurface chips
arXiv quant-ph
arXiv:2610.19504v1 Announce Type: cross Abstract: Magneto-optical traps (MOTs), indispensable to cold-atom-based quantum computing and quantum precision measurement, are increasingly desired in compact and stable form. Particularly, the…
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Computational Aspects of the Trace Norm Contraction Coefficient
arXiv quant-ph
arXiv:2507.16737v3 Announce Type: replace Abstract: We show that approximating the trace norm contraction coefficient of a quantum channel within a constant factor is NP-hard. Equivalently, this shows that determining the optimal success…
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Riemannian Formulation of Sample-Based Quantum Krylov Solvers for Elliptic Problems: Energy-Norm Guarantees and Duct-Flow Applications
arXiv quant-ph
arXiv:2610.15586v2 Announce Type: replace Abstract: Sample-based quantum linear solvers measure quantum Krylov states $e^{-iAT}|b\rangle$ and reconstruct the solution of $Ax=b$ classically on the observed basis states. We develop this…
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Photon localization: a comparative study
arXiv quant-ph
arXiv:2608.04134v2 Announce Type: replace Abstract: We compare different measures for photon localization in terms of two-dimensional Gaussian wave packets of width Delta k. We find that all measures start to coalesce if the wave packet…
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Deterministic and Programmable Fusion for Scalable Generation of Photonic Graph States
arXiv quant-ph
arXiv:2610.19927v1 Announce Type: new Abstract: Entanglement in multiphoton graph states is an important resource with various applications, such as measurement-based quantum computing and memory-less quantum repeaters. While some…
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Quantum models of interaction Hamiltonians and their paradoxes
arXiv quant-ph
arXiv:2609.11618v2 Announce Type: replace Abstract: In quantum physics it is commonplace to model the interaction of remote systems with a many-body Hamiltonian. Taking such an action-at-a-distance description {\it \`a la lettre} leads to…
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Objectivity, basis ambiguity, and the classical simulability of concordant quantum computation
arXiv quant-ph
arXiv:2510.03225v2 Announce Type: replace Abstract: Concordant quantum computations, in which circuits whose register carries zero quantum discord with respect to every subsystem at every step, contain neither entanglement nor any other…
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The Generalized BEADS Representation: An Informationally Complete Visualization of Mixed Quantum States
arXiv quant-ph
arXiv:2610.19054v1 Announce Type: new Abstract: A deep understanding of quantum information theory is essential for quantum science and technology. However, quantum mechanics and particularly quantum information theory suffer from a lack…
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Gaussian and Qubit Semigroup Dynamics beyond GKSL
arXiv quant-ph
arXiv:2610.20258v1 Announce Type: new Abstract: A well established approach to describe open quantum system dynamics is the celebrated Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation. In this article we aim to shed light on…
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Searching for Ultra-Light Axions with Twisted Cavity Resonators of Anyon Rotational Symmetry with Bulk Modes of Non-Zero Helicity
arXiv quant-ph
arXiv:2208.01640v4 Announce Type: replace-cross Abstract: M\"obius-ring resonators stem from a well-studied geometrical structure with a one-sided topology, the M\"obius strip, and have been shown to exhibit fermion rotational symmetry…
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Retrieving Metrological Information from Noisy Squeezed Spin States via Bayesian Optimization
arXiv quant-ph
arXiv:2610.19471v1 Announce Type: new Abstract: Frequency inhomogeneity can obscure the metrological advantage of squeezed spin states, making the choice of readout crucial. We study interacting spin-1/2 ensembles with static local…
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Shot- and Noise-Aware Pauli Correlation Encoding for Max-Cut Experiments on IBM Heron Quantum Processor
arXiv quant-ph
arXiv:2610.19544v1 Announce Type: new Abstract: Pauli correlation encoding (PCE) encodes $m$ binary variables in the signs of $k$-body Pauli correlators of $n=O(m^{1/k})$ qubits, and trains a parameterized circuit on a relaxed loss of…
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Semiclassical state on algebra of observables for de Sitter space and time reversal symmetry
arXiv quant-ph
arXiv:2610.14175v1 Announce Type: cross Abstract: In de Sitter static patch holography, coupling bulk quantum fields to an observer's dynamical clock yields a type II$_1$ von Neumann algebra $\mathcal{M}_+$ of gauge-invariant observables…
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Sequential vs. Synchronized Entanglement Swapping: QKD Secret-Key Rate under Optimized Link-Layer Control
arXiv quant-ph
arXiv:2605.04047v2 Announce Type: replace Abstract: Quantum repeater chains build long-distance entanglement for quantum key distribution (QKD) by creating pairs on short links and joining them through entanglement swapping. Because stored…
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State-resolved quantum-information fingerprints of partial dynamical symmetry in the interacting boson model
arXiv quant-ph
arXiv:2608.04486v3 Announce Type: replace Abstract: Partial dynamical symmetry (PDS) is an algebraic structure in which a symmetry is neither exact nor fully broken: a subset of eigenstates keeps good quantum numbers and stays solvable…
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Fundamental Limits on QBER and Distance in Quantum Key Distribution
arXiv quant-ph
arXiv:2602.22319v2 Announce Type: replace Abstract: Quantum key distribution (QKD) enables information-theoretic secure communication, yet its ultimate tolerance to noise and achievable transmission distance remain fundamentally…
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Structured-Light Magnetometry in a Coherently Controlled Atomic Medium
arXiv quant-ph
arXiv:2603.25781v3 Announce Type: replace-cross Abstract: A structured-light-based approach to magneto-optical rotation (MOR) magnetometry is proposed, in which magnetically induced polarization rotation is converted into a directly…
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Tripartite Form Universality in Holographic Entropy Inequalities
arXiv quant-ph
arXiv:2609.22504v2 Announce Type: replace-cross Abstract: To elucidate the meaning of holographic entropy inequalities (beyond subadditivity) which characterize the entanglement structure of geometric states in holography, arXiv:2309.06296…
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Improved Quantum Algorithms for R\'enyi Entropies Estimation
arXiv quant-ph
arXiv:2610.19936v1 Announce Type: new Abstract: Entropy estimation of discrete probability distributions is a fundamental problem in statistical inference and quantum property estimation. In this paper, we study the problem of estimating…
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Dicke model of open-shell atoms with tensor polarizability
arXiv quant-ph
arXiv:2610.20043v1 Announce Type: cross Abstract: We study the extended Dicke model obtained from the scalar--vector--tensor polarizability of open-shell atoms coupled to a shared cavity mode. For a single electric-dipole channel…
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Degeneracy graph determinants and higher-dimensional Young diagrams
arXiv quant-ph
arXiv:2610.20368v1 Announce Type: cross Abstract: Kemp and Ramgoolam proposed a basis of monomials for a commutative semisimple algebra with generators \(C_1,\ldots, C_L\), constructed from a degeneracy graph which records how the…
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Single and coupled quantum van der Pol oscillators: Wigner-function dynamics, exact qutrit solutions, and synchronization
arXiv quant-ph
arXiv:2610.19904v1 Announce Type: new Abstract: We study quantum van der Pol oscillator in which single-photon pumping competes with a nonlinear two-photon dissipative channel to produce a quantum limit cycle, and the question of how two…
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Stabilizer entropy cones as self-dual slices of linear rank cones: a five-party gap and dependence on the local dimension
arXiv quant-ph
arXiv:2610.18905v1 Announce Type: cross Abstract: Entanglement entropies of multipartite pure states satisfy linear inequalities; for stabilizer states, the backbone of quantum error correction, the achievable entropy vectors generate a…
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Optimal Disorder Strength for Approximate Unitary $k$-Designs in Spin Chains
arXiv quant-ph
arXiv:2610.18954v1 Announce Type: new Abstract: Quantum simulators with disordered spin Hamiltonians offer a natural route to Haar-like unitary ensembles, but face a competition. Disorder enhances randomness, yet strong disorder suppresses…
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Finite-size quantum key distribution rates from R\'enyi entropies using conic optimization
arXiv quant-ph
arXiv:2511.10584v4 Announce Type: replace Abstract: Finite-size general security proofs for quantum key distribution based on R\'enyi entropies have recently been introduced. These approaches are more flexible and provide tighter bounds on…
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Mirror subspace diagonalization: A real-time quantum Krylov algorithm with near-optimal sampling cost
arXiv quant-ph
arXiv:2511.20998v3 Announce Type: replace Abstract: Quantum Krylov algorithms are a promising approach for ground-state energy estimation on near-term quantum computers. However, their sampling cost is inherently high because each…