Quantum Computing
Quantum Computing news — Monday 05 October 2026
150 stories from 3 sources, every one in English. Each links to its publisher.
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planqc and LOGIQC Selected for Germany’s Quantum Computing Competition
The Quantum Insider
Insider Brief planqc and the LOGIQC consortium have been selected as one of six consortia competing in Germany’s Quantum Computing Competition to advance error-corrected quantum computing. LOGIQC, coordinated by planqc , will develop an…
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The AI Lab Launches Post-Quantum TIP Protocol for Content Verification
The Quantum Insider
Insider Brief The AI Lab has made its Trust Identity Protocol (TIP) publicly available as a post-quantum system for verifying content authorship, identity and whether digital works have been altered. The company argues that advances in…
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Quantinuum and The University of Western Australia Partner to Advance Australia’s Hybrid Quantum-AI-HPC Ecosystem
Quantum Computing Report
Quantinuum and The University of Western Australia (UWA) have partnered to advance Australia's quantum-AI-HPC ecosystem. This collaboration grants UWA access to Quantinuum's 98-qubit Helios trapped-ion system and focuses on co-designing…
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D-Wave Partners with University of Arkansas to Establish Quantum Supply Chain Initiative
Quantum Computing Report
D-Wave Quantum Inc. has partnered with the University of Arkansas's Supply Chain Management Research Center to create the Quantum Supply Chain Initiative Support Fund. This collaboration aims to advance quantum optimization tools for…
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AIDAQ 2026: AI is Now a staple of The Quantum story
The Quantum Insider
The Quantum Insider joined more than 2,500 participants in Berlin for Bitkom’s AI, Data & Quantum Summit, where AI kept turning up inside quantum. Berlin became the meeting point for Europe’s AI and quantum communities on 22 and 23…
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D-Wave and University of Arkansas Launch Quantum Supply Chain Initiative
The Quantum Insider
Insider Brief D-Wave and the University of Arkansas’ Supply Chain Management Research Center are collaborating on quantum computing research for complex supply chain problems. The collaboration establishes the Quantum Supply Chain…
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DecaQ Launches Cloud Beta 2 With Six Quantum Algorithm Families
The Quantum Insider
Insider Brief DecaQ announced Cloud Beta 2, which it says supports 400 logical digital qubits, six quantum algorithm families and up to 200,000 digital oracle gates on general-purpose hardware. The platform uses a Digital Quantum Oracle to…
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Quantinuum and The University of Western Australia Partner to Advance Australia’s Quantum Capability
The Quantum Insider
Insider Brief Quantinuum and the University of Western Australia signed an MOU to expand access to quantum computing, develop quantum talent and explore practical quantum applications in Australia. UWA researchers, students and…
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Germany Advances Key Consortia in €640 Million ($717.2 Million USD) Fault-Tolerant Quantum Computing Competition
Quantum Computing Report
Germany's Federal Ministry of Research, Technology and Space (BMFTR) is investing €640 million in a quantum computing competition to develop fault-tolerant quantum processing units by 2030. Six consortia, two each in neutral atoms, trapped…
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Second QDA Forum Focuses on Real-World Deployments And Progress of Quantum Computing
The Quantum Insider
Insider Brief Leaders from across classical and quantum computing met to accelerate the path to fault tolerant quantum computing and integration with high performance computing and AI infrastructures. The second QDA highlighted the fast…
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WISeSat.Space Completes Business Combination and Begins Nasdaq Trading
The Quantum Insider
Insider Brief WISeSat.Space, a sister company of SEALSQ , completed its business combination with Columbus Acquisition Corp. and began trading on Nasdaq under the ticker SAIQ on October 2, 2026. The transaction establishes WISeSat.Space as…
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Midwest Quantum Collaboratory Expands to Eight Universities with Addition of UIC, Northwestern, and Regional Partners
Quantum Computing Report
The Midwest Quantum Collaboratory (MQC) has expanded to include UIC, Northwestern, Indiana University, Washington University in St. Louis, and The Ohio State University, bringing its total to eight universities focused on quantum research…
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QNu Labs, BISAG-N, and IIT Gandhinagar Demonstrate India’s First 5.56 km Free-Space QKD Link
Quantum Computing Report
QNu Labs, BISAG-N, and IIT Gandhinagar successfully conducted India's first 5.56 km free-space Quantum Key Distribution (QKD) link. This trial, utilizing QNu Labs' PAT optical system, achieved a secure key rate of 230–260 bps and…
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SQMS Study Links Qubit Performance to Material and Fabrication Features
The Quantum Insider
Insider Brief Researchers from the Fermilab-led SQMS Center identified material and fabrication features associated with variations in superconducting qubit performance. The study examined 22 superconducting transmon qubits using seven…
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Unitary complexity in polynomial space
arXiv quant-ph
arXiv:2610.03705v1 Announce Type: new Abstract: We show that if quantum commitments exist, then either there is no polynomial-time solution to the unitary synthesis problem, or $\mathsf{BPP} \neq \mathsf{NEXP}$. Thus, showing…
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Entanglement Requires Fluctuations at Conformal Interfaces
arXiv quant-ph
arXiv:2610.02309v1 Announce Type: cross Abstract: We conjecture that the universal logarithmic coefficient for capacity of entanglement $c_{\mathrm{cap}}$ is bounded below by the corresponding entropy coefficient $c_{\mathrm{eff}}$ at…
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Quantum transmission in 1D disordered stealthy hyperuniform Kronig--Penney-like models
arXiv quant-ph
arXiv:2610.02501v1 Announce Type: cross Abstract: Disordered stealthy hyperuniform (SHU) systems are emerging as platforms for controlling classical and quantum transport due to vanishing single-scattering contributions in the stealthy…
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Beyond Pure Dephasing: Quantum Error Correction in Single Molecules Requires Multiple Spins
arXiv quant-ph
arXiv:2610.03318v1 Announce Type: cross Abstract: We propose multi-spin molecules as a viable architecture for fault-tolerant quantum computing. To this aim, we introduce a correction protocol handling both diagonal and off-diagonal…
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Non-Markovian two-time correlation functions for optomechanical systems
arXiv quant-ph
arXiv:2501.07678v4 Announce Type: replace Abstract: In this paper, we focus on the two-time correlation function (TTCF) of the cavity optomechanical system, which serves as the most popular tool in precision detection technologies. We…
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Coherence and decoherence in generalized Shor's algorithm
arXiv quant-ph
arXiv:2508.11962v3 Announce Type: replace Abstract: Quantum coherence constitutes a fundamental physical mechanism essential to the study of quantum algorithms. We study the coherence and decoherence in generalized Shor's algorithm where…
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Quantum advantages in multiparty communication
arXiv quant-ph
arXiv:2512.05538v2 Announce Type: replace Abstract: We investigate two senders and one receiver multiparty communication scenario. Following Phys.Rev.A83, 062112 and arXiv : 2506.07699, we study multiparty communication bounded by…
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Circuit Optimization for Universality Transformation
arXiv quant-ph
arXiv:2603.13169v3 Announce Type: replace Abstract: It is known that a computationally universal gate set $\{H,CCZ\}$ can be transformed to a strictly universal one $\{H, \Lambda(S)\}$ using one maximally imaginary state $|+i \rangle$ and…
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Quantum-Level Crosstalk Characterization of a 16x16 MEMS Optical Switch for Dynamic Quantum Communications
arXiv quant-ph
arXiv:2607.24299v2 Announce Type: replace Abstract: We present an all-to-all quantum-level crosstalk characterization of a commercial 16x16 MEMS optical switch for multi-user quantum communications using SNSPDs, correlating experimental…
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High-rate qLDPC processors
arXiv quant-ph
arXiv:2607.28795v2 Announce Type: replace Abstract: Despite significant progress on quantum low-density parity-check (qLDPC) codes, building qLDPC processors that are high-rate, high-throughput, hardware-friendly, and fast-to-decode…
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Fractal dimension predicts quantum kernel collapse in angle-encoded data
arXiv quant-ph
arXiv:2609.00475v2 Announce Type: replace Abstract: Angle-encoded quantum kernels on tabular data collapse when the feature map is wider than the intrinsic dimension of the data. We propose the correlation fractal dimension D2 as an a…
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WISER: Systematic Design-Space Exploration of Trapped Ions with Multiplexed Control
arXiv quant-ph
arXiv:2609.13546v2 Announce Type: replace Abstract: Trapped-ion Quantum Charge-Coupled Devices (QCCD) are a leading contender for quantum computing, but their scalability is constrained by control wiring and electronics. Wiring using…
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Captured weight and boundary leakage bound the error of sample-based spectral functions
arXiv quant-ph
arXiv:2608.16436v4 Announce Type: replace Abstract: Rayleigh-Ritz on a subspace from sample-based quantum diagonalization yields the spectral function of a probe state; we ask what bounds its error. The captured Born weight w does not do…
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Enhanced Dark Matter Quantum Sensing via Phase-Space Geometric Interferometry
arXiv quant-ph
arXiv:2603.23599v3 Announce Type: replace-cross Abstract: We propose a quantum sensing protocol for coupled qubit-oscillator systems that enhances the sensitivity by exploiting a geometric phase for dark matter searches. Instead of letting…
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A Controlled Study of Memory Hierarchy Transitions in Quantum Circuit Simulation on Apple M4 Pro Unified Memory Architecture
arXiv quant-ph
arXiv:2605.08792v3 Announce Type: replace-cross Abstract: State-vector quantum circuit simulation is memory-bandwidth bound, yet the interaction between memory hierarchy, access pattern, and hardware parallelism remains incompletely…
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Beyond transversality: structure of Clifford circuits for CSS codes
arXiv quant-ph
arXiv:2608.05688v2 Announce Type: replace Abstract: We characterize four groups of Clifford circuits for Calderbank--Shor--Steane (CSS) codes that are relevant to fault-tolerant logical operations. First, we show that every code-preserving…
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High-Rate Quantum Codes with Proven Distance and Low-Weight Measurements
arXiv quant-ph
arXiv:2610.02621v1 Announce Type: new Abstract: We study a family of quantum subsystem codes defined on rectangular coordinate grids of any dimension, with even side lengths of at least four. The directly measured operators act along…
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Counterdiabatic Quantum Circuits
arXiv quant-ph
arXiv:2610.02312v1 Announce Type: new Abstract: Counterdiabatic driving provides a universal route to fast quantum control, but its standard formulation presupposes a Hamiltonian generator. We develop a Hamiltonian-free theory of the…
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Singer-Difference-Set Qudit Stabilizer Codes from Non-Degenerate Quadrics in PG(d,q)PG(d,q): Construction, Structural Theorems, and Monte-Carlo Performance
arXiv quant-ph
arXiv:2610.02392v1 Announce Type: new Abstract: We propose Q(q,d), a family of q-ary non-CSS qudit stabilizer codes with prime power q and dimension d >= 2, constructed from Singer difference sets and non-degenerate quadrics in PG(d,q)…
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Determining the Number of Symmetry Sectors in Composite Quantum Spectra
arXiv quant-ph
arXiv:2610.03108v1 Announce Type: new Abstract: The spectral fluctuations in complex quantum systems are modeled in terms of spectra from random matrices. Quantitative agreement with random matrices holds only when the quantum spectrum is…
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Entanglement of purification for Werner states: canonical purification and nonadditivity
arXiv quant-ph
arXiv:2610.03630v1 Announce Type: new Abstract: We prove that the von Neumann entanglement of purification is nonadditive. For two-qubit Werner states $W(f)$ with singlet weight $1/64\le f\le1/4$, we show that canonical purification is…
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Scalable Passive QRAM
arXiv quant-ph
arXiv:2610.03700v1 Announce Type: new Abstract: We present a blueprint for implementing the physical QRAM operation in a scalable, passive manner, proving its feasibility in principle. Our construction is passive because for an $n$-qubit…
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Inverse Laplace and Mellin integral transforms modified for use in quantum communications
arXiv quant-ph
arXiv:2604.07787v2 Announce Type: replace Abstract: Integral transformations are useful mathematical tool to work out signals and wave-packets in electronic devices. They may be used in software protocols. Necessary knowledge may come from…
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Fermionic Genuine Multiparty Entanglement
arXiv quant-ph
arXiv:2607.20707v2 Announce Type: replace Abstract: Entanglement can show fundamentally different behavior in fermionic systems. However, while bipartite measures of fermionic entanglement have been established, genuine multiparty…
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Braid map definition of SLH-networks and the series product
arXiv quant-ph
arXiv:2609.13600v5 Announce Type: replace Abstract: This article investigates a cascade of quantum systems within an SLH-network. The original definition of an SLH-network depends on an open conjecture regarding the essential…
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Quantum Query Advantage Requires Space
arXiv quant-ph
arXiv:2609.29497v2 Announce Type: replace Abstract: Hao, Huang, and Liu (STOC'26) recently showed that optimal quantum query complexity may require large workspace even for short-output problems, and asked whether a quantum query advantage…
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Hawking-Page phase transition for pure Lovelock black holes
arXiv quant-ph
arXiv:2606.10647v2 Announce Type: replace-cross Abstract: We investigate the thermodynamic properties of static, spherically symmetric Anti-de Sitter (AdS) black holes, focusing on the interplay between characteristic temperatures, as well…
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The Power of Power-of-SWAP: Postselected Quantum Computation with the Exchange Interaction
arXiv quant-ph
arXiv:2603.28527v2 Announce Type: replace Abstract: We introduce Exchange Quantum Polynomial Time (XQP) circuits, which comprise quantum computation using only computational basis SPAM and the isotropic Heisenberg exchange interaction…
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Work fluctuation speed limit in boundary conformal field theories
arXiv quant-ph
arXiv:2610.01248v1 Announce Type: cross Abstract: We explore the fundamental limits on finite-time driving in quantum critical systems described by boundary conformal field theory. We show that stochastic work fluctuations arising from…
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Quantum approaches for particle-in-cell codes
arXiv quant-ph
arXiv:2610.03254v1 Announce Type: cross Abstract: Solving the high-dimensional, nonlinear partial differential equations that govern the rich physics of plasmas remains a major computational challenge. In fluid dynamics, quantum-inspired…
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Thermalization in a repeated-interaction model with memory effects
arXiv quant-ph
arXiv:2610.02854v1 Announce Type: new Abstract: We study how memory affects the thermalization of a qubit in a repeated-interaction model. In our model, a memory qubit interacts repeatedly with the system, while both qubits undergo…
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Emergent Dissipation from Fluctuating Quantum-Network Topology
arXiv quant-ph
arXiv:2610.03194v1 Announce Type: new Abstract: We investigate how dissipation can emerge in a quantum network from temporal fluctuations of the interaction topology. For a network whose graph is redrawn at short time intervals, the…
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Breaking the cubic barrier for the inverse-free Solovay-Kitaev algorithm
arXiv quant-ph
arXiv:2610.03655v1 Announce Type: new Abstract: The Solovay-Kitaev algorithm states that it is possible to efficiently compile unitaries to accuracy $\epsilon$ in $\text{polylog}(1/\epsilon)$ time using any universal gate set. While…
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An operational characterization of finite-dimensional quantum theory
arXiv quant-ph
arXiv:2610.03694v1 Announce Type: new Abstract: A key goal in the foundations of quantum mechanics is to identify operational constraints characterizing physical theories. Bell inequalities do so for classical probability theory, while…
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Evaluating Chern Topology in Discretized Brillouin Zones Using Bargmann Invariants
arXiv quant-ph
arXiv:2610.03104v1 Announce Type: cross Abstract: We develop a finite-state geometric framework based on third-order Bargmann invariants for evaluating Chern numbers and characterizing local quantum-state geometry. Using gauge-invariant…
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Universality of Stochastic Control of Quantum Chaos with Measurement and Feedback
arXiv quant-ph
arXiv:2506.10067v3 Announce Type: replace Abstract: We investigate universal features of measurement-and-feedback control of quantum chaotic dynamics by examining the quantum Arnold cat map, a paradigmatic model of quantum chaos. Inspired…
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Fault-Tolerant Quantum Error Correction for Constant-Excitation Stabilizer Codes under Coherent Noise
arXiv quant-ph
arXiv:2507.10395v2 Announce Type: replace Abstract: Collective coherent (CC) noise poses challenges for fault-tolerant error correction (FTEC), as it is not captured by conventional stochastic noise models. Constant-excitation (CE) codes…
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Decay of the survival probability of a local excitation in multi-qubit platforms
arXiv quant-ph
arXiv:2604.00625v2 Announce Type: replace Abstract: We present a theoretical study of the survival probability of a state initially prepared in the one-particle sector of a multi-qubit system. The motivation for our work is the ongoing…
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Object-relative ultraviolet weighting of electromagnetic modes and one-loop ultraviolet finiteness of internal photon lines in quantum electrodynamics
arXiv quant-ph
arXiv:2607.16096v2 Announce Type: replace Abstract: This work explores whether localized electromagnetic interactions can be modeled by a physically concluded object-relative ultraviolet weighting of photon modes. The proposal is motivated…
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From the Light Quantum to the Photon: The Evolution of a Physical Concept
arXiv quant-ph
arXiv:2609.04985v2 Announce Type: replace-cross Abstract: This work examines the physical and conceptual evolution of the light quantum from Planck's blackbody theory to the theoretical and experimental developments that led to the…
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Quantum--classical break-even in electronic dynamics of macrocyclic molecules
arXiv quant-ph
arXiv:2609.39693v2 Announce Type: replace Abstract: Here we demonstrate quantum--classical break-even for chemical dynamics applications, reaching useful accuracy with a quantum-hardware wall-clock time comparable to that estimated for…
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Phase-Altered Interleaved Randomized Benchmarking for Compiled Non-Clifford Gates
arXiv quant-ph
arXiv:2606.30327v2 Announce Type: replace Abstract: Interleaved randomized benchmarking (IRB) provides a scalable estimate of a gate's error rate, but its standard guarantees require the interleaved gate to be…
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Topological phase transition in a symmetric blockade structure
arXiv quant-ph
arXiv:2610.03186v1 Announce Type: new Abstract: We present a numerical study of a blockade Hamiltonian with a local $\mathbb{Z}_2$ symmetry. For such models, the existence of a topologically ordered ground state has been proven rigorously…
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Infrared Memory of a Majorana Shutter
arXiv quant-ph
arXiv:2610.03133v1 Announce Type: new Abstract: We study a finite-width Majorana shutter as a local, time-dependent scattering defect and determine which features of its infrared memory are insensitive to the microscopic spatial profile…
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Hamiltonian locality testing and certification do not achieve the Heisenberg limit
arXiv quant-ph
arXiv:2610.03205v1 Announce Type: new Abstract: We establish lower bounds for Hamiltonian property testing with access to the time-evolution operator but not its inverse. Each experiment may query the time-evolution operator multiple…
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Rate-Optimal Quantum Discrete Simulation Optimization
arXiv quant-ph
arXiv:2610.03360v1 Announce Type: new Abstract: Quantum computing has developed rapidly in recent years and has shown potential advantages over classical computing in various domains. In this paper, we study whether quantum computing can…
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Subdimensional linear-optical quantum computation: from qudit resource states to qubit quantum computation
arXiv quant-ph
arXiv:2610.03408v1 Announce Type: new Abstract: In this paper, we propose a linear-optical quantum computation scheme that starts from high-dimensionally entangled qudits but performs quantum computation on qubits defined in their…
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Quantum utility routing in continuous-variable QKD networks with trusted and untrusted relays
arXiv quant-ph
arXiv:2610.03382v1 Announce Type: new Abstract: Continuous-variable quantum key distribution (CV-QKD) networks require routing strategies that account simultaneously for secret key generation, relay trust and finite network resources. We…
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A graph-theoretic analysis of non-generic free-fermion solvability by Krylov decompositions
arXiv quant-ph
arXiv:2610.03557v1 Announce Type: new Abstract: Exactly solvable models are often identified from structural features of their interactions. For quantum spin Hamiltonians, these are captured by the frustration graph of anticommuting Pauli…
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Quantum simulation of wave optics in weakly inhomogeneous media using block-encoding
arXiv quant-ph
arXiv:2409.11020v3 Announce Type: replace Abstract: We propose a quantum algorithm that simulates the propagation of a light field through a weakly inhomogeneous medium. In the paraxial approximation, the wave equation in an inhomogeneous…
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Fragmentation is Efficiently Learnable by Quantum Neural Networks
arXiv quant-ph
arXiv:2512.00751v4 Announce Type: replace Abstract: In certain classes of physical quantum systems, the exponentially large state space "fragments" into many low-dimensional, dynamically disconnected subspaces. We introduce a learning…
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Hall viscosity of the Laughlin state on noisy quantum computers
arXiv quant-ph
arXiv:2512.09982v2 Announce Type: replace-cross Abstract: Hall viscosity is a quantized nondissipative stress response of a fractional quantum Hall (FQH) fluid to adiabatic geometric deformations. Despite strong theoretical interest, its…
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Classical Algorithms for Bipartite Quantum Max-Cut on Dense Expanders
arXiv quant-ph
arXiv:2610.03670v1 Announce Type: new Abstract: Quantum Max-Cut is a well-studied local Hamiltonian problem for which the classical complexity of the bipartite case remains open. We give a polynomial-time classical randomized algorithm for…
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Finding gflow on unlabelled open graphs
arXiv quant-ph
arXiv:2609.40099v2 Announce Type: replace Abstract: The one-way model of measurement-based quantum computing implements computations via successive adaptive single-qubit measurements on a resource graph state. This model has practical…
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Exponential quantum space advantage in random data streams
arXiv quant-ph
arXiv:2610.03645v1 Announce Type: new Abstract: We show two unconditional quantum space advantages in the random-order streaming model. First, we show the Yamakawa--Zhandry Code Intersection problem admits exponential quantum advantage in…
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Predicting properties of Scrooge ensembles with high accuracy and low sample complexity
arXiv quant-ph
arXiv:2609.39992v2 Announce Type: replace Abstract: The Scrooge ensemble associated with a density matrix $\rho$ is the maximally random ensemble whose average density matrix is $\rho$. It has attracted growing interest for its…
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Quantum Graph Theory by Example
arXiv quant-ph
arXiv:2603.23651v3 Announce Type: replace-cross Abstract: Quantum graphs have been introduced by Duan, Severini, and Winter to describe the zero-error behaviour of quantum channels. Since then, quantum graph theory has become a field of…
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Quantum parameter estimation with uncertainty quantification from continuous measurement data using neural network ensembles
arXiv quant-ph
arXiv:2509.10756v4 Announce Type: replace Abstract: We show that ensembles of deep neural networks, called deep ensembles, can be used to perform quantum parameter estimation while also providing a means for quantifying uncertainty in…
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Multivariate quantum signal processing with optimal query complexity
arXiv quant-ph
arXiv:2610.03393v1 Announce Type: new Abstract: Polynomial transformations of data encoded in quantum operations are a building block of quantum algorithms, and their query complexity measures how often those operations are used. For…
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SMP: A General Hyperedge-Based Framework for Circuit-Level Quantum Error Correction
arXiv quant-ph
arXiv:2610.02734v1 Announce Type: new Abstract: Hyperedge faults remain a major challenge in circuit-level quantum error correction. Accurately exploiting hyperedge correlations often requires substantial computational resources, which…
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Lifting Multiplicity in Randomized Benchmarking
arXiv quant-ph
arXiv:2610.03586v1 Announce Type: new Abstract: Randomized benchmarking comprises a suite of standard techniques for assessing the operational fidelity of quantum processors. These techniques can be reliably applied to groups with process…
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Quantum Simulation on Riemannian Manifolds
arXiv quant-ph
arXiv:2610.03673v1 Announce Type: new Abstract: We investigate algorithms for the quantum simulation of the Schr\"odinger equation on a Riemannian manifold, where the kinetic operator is defined by the Laplace--Beltrami operator…
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Interaction-induced period shift of the Kohn oscillation in a parity-time-symmetric harmonic trap
arXiv quant-ph
arXiv:2610.02984v1 Announce Type: cross Abstract: The center of mass of a Bose--Einstein condensate in a harmonic trap oscillates at the trap frequency independently of the interactions. Without interactions a parity-time-symmetric…
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Decohering Kitaev's Sixteenfold Way: A Holographic Approach
arXiv quant-ph
arXiv:2610.03610v1 Announce Type: cross Abstract: We study anyon decoherence in 2D topological order, with the fermion decoherence in Kitaev's sixteenfold way as explicit examples. The sixteenfold way includes chiral topological phases…
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Optimal Quantum Speedups for Repeatedly Nested Expectation Estimation
arXiv quant-ph
arXiv:2602.08120v2 Announce Type: replace Abstract: We study the estimation of repeatedly nested expectations (RNEs) with a constant horizon (number of nestings) using quantum computing. We propose a quantum algorithm that achieves…
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Emergent-Coupling-Based Ansatz Evaluated on a Superconducting Quantum Processor
arXiv quant-ph
arXiv:2603.28486v2 Announce Type: replace Abstract: The performance of the variational quantum eigensolver depends critically on the choice of ansatz. In this work, we experimentally evaluate the emergent-coupling-based ansatz (ECBA), a…
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No Free Compression in Quantum Relaxations for Optimization
arXiv quant-ph
arXiv:2608.25151v2 Announce Type: replace Abstract: Qubit-efficient quantum relaxations compress classical decision variables into expectation values on substantially fewer qubits. We ask what resource tradeoffs this compression entails…
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Tight Time-Space Lower Bounds for Collision Finding and Element Distinctness under Label Symmetry
arXiv quant-ph
arXiv:2609.10808v2 Announce Type: replace Abstract: How much memory is needed to retain the quantum speedup for collision finding? For a uniformly random function $f:[N]\to [N]$, the BHT algorithm finds a collision using $O(N^{1/3})$…
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A provable quantum advantage for approximate optimization via decoded quantum interferometry
arXiv quant-ph
arXiv:2610.02145v2 Announce Type: replace Abstract: Decoded quantum interferometry (DQI) is a novel paradigm for tackling approximate optimization problems on quantum computers. This framework comes with strong performance guarantees and…
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Nanoscale sensing of spatial correlations in nonequilibrium current noise
arXiv quant-ph
arXiv:2404.15398v2 Announce Type: replace-cross Abstract: Nitrogen-vacancy centers are spatially resolved probes of current noise. So far, current noise sensing with NV centers has primarily been used as a way to probe equilibrium…
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Discriminating Lindbladian Dynamics
arXiv quant-ph
arXiv:2610.03629v1 Announce Type: new Abstract: The fundamental task of quantum hypothesis testing, which consists in discriminating quantum objects, has been extensively studied for quantum states and channels. Here, we investigate the…
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Breaking the chain: geometry-native state preparation with ASPIRE
arXiv quant-ph
arXiv:2610.03528v1 Announce Type: new Abstract: Loading data into quantum computers is a key bottleneck that threatens end-to-end quantum advantage. Quantum-circuit compilers for structured states like matrix product states (MPS) are a…
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BARC codes: general polynomial framework for coherent-state superposition codes
arXiv quant-ph
arXiv:2610.03663v1 Announce Type: new Abstract: We introduce an algebraic framework for constructing a new class of quantum error-correcting codes, bosonic algebraically-restricted constellation (BARC) codes. The code states are finite…
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Analysis of Quartic Potential Problems Using Fredholm Integral Operators with Airy Functions
arXiv quant-ph
arXiv:2603.02374v5 Announce Type: replace-cross Abstract: Fredholm integral operators that commute with the Hamiltonians of certain quantum mechanical systems with quartic potentials are introduced in closed analytical form. The operators…
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Self-organized Layered Structures of Nitrogen-Vacancy Centers with Preferential Orientation in Heteroepitaxial Diamond Films
arXiv quant-ph
arXiv:2610.03150v1 Announce Type: new Abstract: Here, we report the fabrication and characterization of single crystal diamond films on a two-inch wafer-scale containing three-dimensional layered structures of negatively charged…
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Distance-Independent Universality of Clifford+T
arXiv quant-ph
arXiv:2610.03364v1 Announce Type: new Abstract: A well-known theorem states that the Clifford+T gate set is universal for quantum computing. The theorem combines approximation using a distance measure on unitary matrices with equality up…
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A note on tomography of states with low stabilizer rank
arXiv quant-ph
arXiv:2610.03658v1 Announce Type: new Abstract: In this note, we consider tomography of $n$-qubit quantum states $|\psi \rangle$ that are promised to have stabilizer rank $k$ i.e., admit a stabilizer decomposition of $|\psi\rangle =…
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Quantum estimation, channel orders, and private capacity
arXiv quant-ph
arXiv:2610.03706v1 Announce Type: new Abstract: Recent examples have shown that zero private capacity need not imply antidegradability and that two channels with zero private capacity can nevertheless transmit private information together…
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Single-Shot Decoding and Fault-tolerant Gates with Trivariate Tricycle Codes
arXiv quant-ph
arXiv:2508.08191v3 Announce Type: replace Abstract: While quantum low-density parity check (qLDPC) codes are a low-overhead means of quantum information storage, it is valuable for quantum codes to possess fault-tolerant features beyond…
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An entropic characterization of Haag duality
arXiv quant-ph
arXiv:2609.13550v2 Announce Type: replace Abstract: Motivated by Haag duality in quantum spin systems, we show that Haag duality for a pair of commuting factors generated by increasing sequences of finite-dimensional matrix algebras is…
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QuLoC: Photonic Quantum-Assisted Low-Rank LLM Compression
arXiv quant-ph
arXiv:2609.40146v2 Announce Type: replace Abstract: As LLMs grow in size, compression becomes increasingly important for efficient deployment. SVD-based low-rank compression reduces parameter counts but can degrade downstream performance…
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Compatibility of quantum instruments
arXiv quant-ph
arXiv:2609.40266v2 Announce Type: replace Abstract: Measurement compatibility asks whether a family of quantum measurements can be simulated by one parent measurement followed by classical post-processing. We extend this measurement…
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Real-Time Adaptive Filtering and the Boxcar Limit in Superconducting Qubit Readout
arXiv quant-ph
arXiv:2610.00783v2 Announce Type: replace Abstract: Control and readout systems for superconducting quantum computing support real-time control and high-fidelity qubit-state discrimination. We examine when additional digital processing…
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Toward Optimal Circuit Depth for Geometrically Local Hamiltonian Simulation
arXiv quant-ph
arXiv:2610.01839v2 Announce Type: replace Abstract: Understanding the dynamics of interacting quantum systems is a central goal of quantum simulation. For geometrically local Hamiltonians, locality suggests that digital simulation should…
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Two-center Dirac equation in a Gaussian basis set
arXiv quant-ph
arXiv:2610.03217v1 Announce Type: new Abstract: A method for solving the two-center Dirac equation using a Gaussian-product basis set tailored to the axial symmetry of diatomic systems is presented. For the ground state of H$_2^+$ at an…
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Robust constrained optimization of nonequilibrium Casimir repulsion in a biased-semiconductor cavity
arXiv quant-ph
arXiv:2610.02471v1 Announce Type: new Abstract: Nonequilibrium electromagnetic fluctuations offer a route to repulsive Casimir--Lifshitz forces. However, designs optimized only at nominal conditions may be fragile. We formulate repulsion…
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Single-photon addition to multimode quantum fields at telecom wavelengths using lithium niobate and its doped variants
arXiv quant-ph
arXiv:2610.02473v1 Announce Type: new Abstract: Multimode spectro-temporal non-Gaussian quantum states of light play a crucial role in continuous-variable quantum information processing. In particular, the non-Gaussian quantum states…
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Optimal state detection without likelihood estimation
arXiv quant-ph
arXiv:2610.02644v1 Announce Type: new Abstract: We show that adaptive Bayesian estimation in fluorescence state detection reduces to a comparison of elapsed time with two arithmetic time sequences fixed by the bright and dark count rates…
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Stimulated Parametric Down-Conversion: From Foundational Coherence to Structured Light Applications
arXiv quant-ph
arXiv:2610.03241v1 Announce Type: new Abstract: Stimulated parametric down-conversion (StimPDC) is the seeded version of the process that underlies much of photonic quantum information. Replacing the vacuum at one input port with a…
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Composable logical gate error in approximate quantum error correction: reexamining gate implementations in Gottesman-Kitaev-Preskill codes
arXiv quant-ph
arXiv:2509.14658v4 Announce Type: replace Abstract: Quantifying the accuracy of logical gates is paramount in approximate error correction, where perfect implementations are often unachievable with the available set of physical operations…
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Benchmarking Gaussian and non-Gaussian input states with a hybrid sampling platform
arXiv quant-ph
arXiv:2512.08433v3 Announce Type: replace Abstract: The original boson sampling paradigm-consisting of multiple single-photon input states, a large interferometer, and multi-channel click detection-was originally proposed as a photonic…
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Post-selected Criticality in Measurement-induced Phase Transitions
arXiv quant-ph
arXiv:2603.15744v2 Announce Type: replace Abstract: Information-theoretic phase transitions, such as the measurement-induced phase transition (MIPT), characterize the robustness of quantum dynamics to local monitoring and are naturally…
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Faster quantum linear system solver beyond the condition number
arXiv quant-ph
arXiv:2607.07691v2 Announce Type: replace Abstract: The spectral condition number is a widely adopted measure of worst-case cost for quantum linear system solvers. Yet it can significantly overestimate the actual runtime for a typical…
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Keyless secrecy against bounded adversaries
arXiv quant-ph
arXiv:2609.12251v2 Announce Type: replace Abstract: We introduce a keyless coding/cryptographic primitive that asks for two guarantees at once: the receiver is never fooled into accepting a message other than the one sent, and the…
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Clarifications on the Experimental Status of Real Quantum Theory
arXiv quant-ph
arXiv:2610.03644v1 Announce Type: new Abstract: In our previous paper on the matter, we proved that real quantum theory (RQT) cannot be experimentally falsified without the experiment falsifying quantum theory (QT) as well. Our result is…
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Learning Noise-Robust Stabilizer Structure via Bell Sampling
arXiv quant-ph
arXiv:2610.03307v1 Announce Type: new Abstract: Bell sampling efficiently learns the stabilizer group, and hence the stabilizer nullity, of pure states with little magic, a primitive underlying tomography and certification of low-magic…
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Quantum code parameters, checkable by a certificate of provable size
arXiv quant-ph
arXiv:2610.03214v1 Announce Type: new Abstract: A code is described by three numbers: its physical qubits, its logical qubits, and the smallest error it cannot detect, counted in qubits. The first two are linear algebra. The third, the…
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SpiderCSS: Scalable Fault-Tolerant CSS State Preparation
arXiv quant-ph
arXiv:2610.03714v1 Announce Type: new Abstract: Fault-tolerant preparation of logical states is a critical primitive for the realization of large-scale fault-tolerant quantum computing. This paper introduces SpiderCSS, a scalable…
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Gap-Protected Heisenberg-Limited Squeezing with Locally Interacting Multi-Level Spins
arXiv quant-ph
arXiv:2610.02314v1 Announce Type: new Abstract: We demonstrate a general mechanism to generate scalable, metrologically useful entanglement in the form of generalized spin squeezing in multi-level (qudit) spin systems with power-law…
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Investigating entanglement dynamics with dynamical decoupling together with initial qubit-reservoir correlations
arXiv quant-ph
arXiv:2610.02453v1 Announce Type: new Abstract: We study the exact entanglement dynamics of two qubits coupled to a common bosonic reservoir through a pure dephasing interaction. We ask how this dynamics changes when the qubits and the…
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Root-sparsity scaling for Hamiltonian simulation, differential equations and linear-system solvers
arXiv quant-ph
arXiv:2610.02939v1 Announce Type: new Abstract: We give quantum algorithms for Hamiltonian simulation, linear differential equations, and linear systems with square-root dependence on sparsity. For an $s$-sparse Hermitian matrix with row…
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Pulse-resolved post-generation phase control of squeezed light at 93 MHz with a bulk lithium-niobate modulator
arXiv quant-ph
arXiv:2610.03257v1 Announce Type: new Abstract: Time-domain multiplexing of continuous-variable quantum states provides a scalable approach to photonic quantum information processing, in which individual temporal modes can be sequentially…
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No Size-Preserving Amplification with Quantum Advice
arXiv quant-ph
arXiv:2610.03377v1 Announce Type: new Abstract: Marriott and Watrous showed that quantum Merlin--Arthur games admit generic error reduction without increasing witness size [Computational Complexity, 2005]. In this work, we show that this…
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Opportunistic full reconstruction of 100-dimensional frequency-bin quantum states
arXiv quant-ph
arXiv:2610.03496v1 Announce Type: new Abstract: Frequency-bin encoding provides a scalable platform for photonic quantum information processing by enabling high-dimensional qudit states compatible with the telecommunications…
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Robustness of quantum spectrum estimation: weak Schur sampling under noisy inputs
arXiv quant-ph
arXiv:2610.03582v1 Announce Type: new Abstract: We initiate the study of weak Schur sampling (WSS) under noisy input. Many optimal quantum learning algorithms rely on this measurement, for instance in such fundamental tasks as quantum…
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A Complete Proof of $\mathsf{QMA}_1$-Hardness for Weighted Gapped Clique Homology
arXiv quant-ph
arXiv:2610.03584v1 Announce Type: new Abstract: The computational complexity of simplicial homology has been studied since the question was raised by Kaibel and Pfetsch, and clique homology was later shown to be $\mathsf{QMA}_1$-hard by…
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Experimental Asynchronous Measurement-Device-Independent Quantum Cryptographic Conferencing
arXiv quant-ph
arXiv:2602.20927v2 Announce Type: replace Abstract: The quantum cryptographic conferencing (QCC) protocol, which distributes identical secure keys to user groups, is a crucial component of the quantum network. Previous experimental works…
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Majorana-Pauli stabilizer codes and duality webs of fermionic topological phases
arXiv quant-ph
arXiv:2606.25048v2 Announce Type: replace Abstract: Stabilizer codes provide exact lattice realizations of bosonic topological orders. In contrast, systematic stabilizer descriptions of intrinsically fermionic topological phases remain…
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Analytical controls for dispersive multi-qubit interactions in mediator-coupled quantum registers
arXiv quant-ph
arXiv:2610.03064v1 Announce Type: new Abstract: Fast control of long-lived quantum registers often relies on an auxiliary degree of freedom, a mediator, but real mediator excitation can introduce decoherence, leakage, or loss when the…
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Certification of high-dimensional entanglement in continuous-variable systems
arXiv quant-ph
arXiv:2610.03113v1 Announce Type: new Abstract: The dimensionality of entanglement in high-dimensional quantum systems is quantified by the Schmidt number, whose large value signals potential advantages for quantum communication and…
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Efficiently and Reliably Measuring Information Processing Capacity in Dynamical Systems via Kernels
arXiv quant-ph
arXiv:2610.03281v1 Announce Type: new Abstract: Information Processing Capacity (IPC) is a powerful system-agnostic metric for quantifying a dynamical system's computational capability and is widely used in quantum reservoir computing…
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Optimizing quantum error correction through error attribution
arXiv quant-ph
arXiv:2610.03399v1 Announce Type: new Abstract: Logical error rate is a standard benchmark for quantum error correction, providing an aggregate measure of the overall effect of physical noise. In actual QEC architectures, errors at…
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An exact semidefinite characterization of the stoquasticity cone of permutationally invariant Bell operators
arXiv quant-ph
arXiv:2610.03438v1 Announce Type: new Abstract: Bell correlations have been detected in atomic ensembles ranging from hundreds to hundreds of thousands of particles, witnessed by the permutationally invariant (PI) Bell operators. For all…
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Geometric Aspects of Entanglement
arXiv quant-ph
arXiv:2610.03446v1 Announce Type: new Abstract: Quantum entanglement is a fundamental resource in quantum information theory, yet its general characterization and quantification remain challenging, especially in multipartite systems. In…
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Efficient Sampling for Many-Body Fermionic Non-Gaussianity
arXiv quant-ph
arXiv:2610.03492v1 Announce Type: new Abstract: Fermionic non-Gaussianity is a key resource for universal quantum computation, and its behavior in quantum many-body systems has attracted growing interest. Recently, a convolution-based…
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Quantum Fire with Delegated Cloning
arXiv quant-ph
arXiv:2610.03593v1 Announce Type: new Abstract: Quantum fire is a recently introduced cryptographic primitive consisting of efficiently preparable quantum states, called \emph{flames}, that admit efficient cloning but resist efficient…
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Evolving Hybrid Quantum-Classical Architectures for Image Classification
arXiv quant-ph
arXiv:2610.03220v1 Announce Type: cross Abstract: Hybrid quantum classical neural networks integrate parameterized quantum circuits (PQCs) with established deep learning architectures, but their performance depends strongly on the choice…
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Schr\"odingerization for quantum linear systems problems
arXiv quant-ph
arXiv:2609.25660v2 Announce Type: replace Abstract: We develop a Schr\"odingerization algorithm for quantum linear systems problems in two higher dimensions. The earlier LC-Schr\"odingerization approach represents the solution as a time…
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Inverse-Designed Photonic Crystal Cavities with Controllable Far-Field Numerical Aperture
arXiv quant-ph
arXiv:2509.16827v2 Announce Type: replace-cross Abstract: Photonic crystal cavities confine light to subwavelength volumes, enabling strong light-matter interactions for applications in low-power photonics, optoelectronics, nonlinear…
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Cooperative Quantum Optical Effects of Moir\'e Exciton Superlattices
arXiv quant-ph
arXiv:2603.06998v2 Announce Type: replace-cross Abstract: The unique properties of two-dimensional moir\'e systems have been widely studied from many perspectives. However, relatively little work has investigated how the real-space…
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Asymptotic Quantum Dynamics of Ghost Fields
arXiv quant-ph
arXiv:2605.29047v2 Announce Type: replace-cross Abstract: The dressed propagator of a ghost coupled to ordinary fields develops a pair of complex conjugate poles in the first Riemann sheet above the multi-particle threshold. We study the…
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Scaling equations for Bose-Einstein condensate dynamics across all interaction regimes
arXiv quant-ph
arXiv:2609.13497v2 Announce Type: replace-cross Abstract: We derive a unified set of scaling equations for Bose-Einstein condensates in time-dependent harmonic traps, connecting the weakly interacting Gaussian regime to the strongly…
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Quantum Bipolar Thermoelectricity
arXiv quant-ph
arXiv:2508.03219v3 Announce Type: replace-cross Abstract: Thermoelectricity is generally understood as a classical effect emerging from energy-dependent transport asymmetries. Here, we uncover a purely quantum mechanism, where a…
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The complexity of entangled graph colouring via polymorphisms
arXiv quant-ph
arXiv:2610.02565v1 Announce Type: new Abstract: Constraint satisfaction problems (CSPs) with operator assignments to the variables provide a well-structured setting to study the decision complexity of the entangled value of classes of…
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Fault tolerance of quantum circuits with tensor networks and symplectic geometry
arXiv quant-ph
arXiv:2610.03429v1 Announce Type: new Abstract: We develop an operator-algebraic framework for analyzing fault tolerance in quantum circuits and establish necessary and sufficient conditions for fault tolerance under any given noise model…
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Quantum Codeword Sensing
arXiv quant-ph
arXiv:2610.03659v1 Announce Type: new Abstract: Consider the task of identifying an unknown classical codeword delivered to a register of quantum sensor qubits through a sequence of weak phase interactions that each encode one bit. Suppose…
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Efficient capacity-achieving entanglement generation with application to pure-loss Bosonic channels
arXiv quant-ph
arXiv:2610.03674v1 Announce Type: new Abstract: While the ultimate limits on the rate of quantum communication over noisy channels are well-established, very few efficient coding schemes achieving these limits are known. This contrasts…
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On The Complexity of Redundancy-Free Quantum Hamiltonians
arXiv quant-ph
arXiv:2610.03697v1 Announce Type: new Abstract: We consider a class of redudancy-free Hamiltonians, which are those where the trace vanishes for any product of Hamiltonian terms in which at least one term appears an odd number of times…
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How to Build Pseudorandom Unitaries in Microcrypt
arXiv quant-ph
arXiv:2610.03711v1 Announce Type: new Abstract: We provide the first evidence relative to a classical oracle that pseudorandom unitaries (PRUs) can exist without quantum-computable one-way functions. To obtain this result, we first prove…
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A Unified Error Correction Code for Universal Quantum Computing with Identical Particles
arXiv quant-ph
arXiv:2602.20452v3 Announce Type: replace Abstract: We present a universal fault-tolerant quantum computing architecture based on identical particle qubits (IPQs), where we find that the first-order IPQ - bath interaction fundamentally…
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Entanglement between quantum dots transmitted via Majorana wire: Insights from the fermionic negativity, concurrence and quantum mutual information
arXiv quant-ph
arXiv:2603.04108v2 Announce Type: replace Abstract: We study quantum entanglement in a system comprising two quantum dots interconnected through the short topological superconducting nanowire, which hosts overlapping boundary Majorana…
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Uniqueness of imaginarity-assisted exact transformation from real orthogonal operations to arbitrary unitary operations
arXiv quant-ph
arXiv:2603.11812v2 Announce Type: replace Abstract: The computational universality with an elementary gate set $\{H,CCZ\}$ can be transformed to the strict universality by using a maximally imaginary state $|+i \rangle$ and some…
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Dimension Reduction for Quantum Adaptive Agents
arXiv quant-ph
arXiv:2607.19156v2 Announce Type: replace Abstract: Adaptive agents realise complex reactive behaviours by using a memory of past input stimuli and output actions to guide structured future responses. Quantum adaptive agents can operate…
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Quantum Error-Corrected Memories Keep Proper Time
arXiv quant-ph
arXiv:2610.02786v1 Announce Type: new Abstract: What does quantum error correction do to relativistic proper time? We show that when two error-corrected quantum memories follow distinct worldlines and are controlled by local references…
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Quantum Channel Polynomial Processing
arXiv quant-ph
arXiv:2607.06557v2 Announce Type: replace Abstract: We introduce a quantum algorithmic framework based on probabilistic mixtures of unitary channels that, similar to the framework of quantum singular value transformations, enables the…
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Quasiparticle quantum simulation of materials with the Bethe-Salpeter equation
arXiv quant-ph
arXiv:2610.02916v1 Announce Type: new Abstract: The first-principles quantum simulation of the full electronic Hamiltonian of a material model of realistic size appears daunting even in a future era of fully fault-tolerant quantum…