July 14, 2026

Optimal operating temperature for industry-compatible silicon spin quantum computing: colder is not necessarily better

Silicon spin qubits are a leading candidate for large-scale quantum computing owing to their compatibility with semiconductor manufacturing. However, scaling to useful fault-tolerant processors will likely generate thermal loads that exceed the cooling power available at millikelvin temperatures. Raising the operating temperature eases cooling requirements but reduces gate f...

Private Capacity of Quantum Channels Induced by Non-stabilizer Environmental States

We investigate the private capacity of quantum channels using the recently proposed quantum convolution theory for discrete-variable quantum systems. We focus on the role of the magic resource played in this framework. Firstly, for a large class of convolutional channels, we find that the private capacity is zero if the fixed environmental state is a stabilizer state. Moreov...

High-field Josephson effect enabled by a moiré Hofstadter spectrum

Magnetic fields generally suppress phase-coherent Josephson transport, limiting superconducting interferometry to relatively low fields. Here we show that moiré-engineered graphene Josephson junctions can overcome this constraint. Using ballistic graphene/hBN junctions, we establish phase-coherent Andreev transport through Fabry-Pérot oscillations and Fraunhofer interference...

Quantum Arithmetic Circuits in Public-Key Cryptography

Quantum computing has advanced rapidly in recent decades, driven by developments across the technology stack, including quantum error-correcting codes and efficient quantum algorithms. Among these, quantum arithmetic circuits serve as fundamental building blocks for various promising algorithms. Despite their crucial role, the design of quantum arithmetic circuits faces chal...

Multi-Stage Mamba-Based Architecture for Fast and Scalable Superconducting Qubit Readout

Reliable qubit readout is a critical bottleneck toward fault-tolerant quantum computing (FTQC). In superconducting quantum processors, readout operations are both error-prone and high-latency. These challenges become more severe in frequency-multiplexed architectures, where signal crosstalk among neighboring qubits significantly degrades readout fidelity. Existing machine le...

Moment-Structured Block Encodings of Periodic Finite-Difference Operators

Block encoding is the standard technique for accessing matrix data in quantum linear-algebra algorithms. Its implementation directly affects its subnormalization, which in turn controls the algorithm's success probability, simulation time, and downstream costs. Explicit construction of block encodings with provably optimal subnormalization exists for only a handful of operat...

Quantum Simulation of Strongly Correlated Fermion-Phonon Models in Circuit QED

Gate-based digital quantum simulations offer an exciting new paradigm for studying the many-body physics of strongly correlated systems. In this context, electron-phonon models are challenging for qubit-only quantum simulators, as bosonic degrees of freedom require costly finite-dimensional encodings. Here, we elaborate on an alternative approach based on a digital-analog ci...

States dressing analysis in a transmon-transmon-bus system

The multi-qubit gates fidelity of superconducting quantum processors can be limited due to the dressing of computational states by noncomputational ones. Here, we experimentally and analytically investigate a transmon-transmon-bus system where the computational states dressing is tunable over a broad range. We estimate the dressing using three methods: a full three-element m...

Input-Aware Dynamic Backdoor Attack Against Quantum Neural Networks

Quantum Neural Networks (QNNs) are a promising framework for quantum machine learning on near-term quantum devices, but their security risks remain insufficiently understood. Studies have shown that QNNs are vulnerable to backdoor attacks, yet existing quantum backdoors mostly rely on a fixed trigger shared by all poisoned inputs. This fixed-trigger design is a major weaknes...

Toward Quantum Utility in Correlated Topological Matter: Variational Preparation of Fractional Quantum Hall Manifolds

We investigate the use of variational quantum algorithms to prepare and characterize fractional quantum Hall states on near-term quantum processors. Focusing on the ν=1/3 Laughlin phase described by the V_1 Haldane pseudopotential, we formulate the lowest-Landau-level problem in second quantization, and implement particle-number-preserving variational circuits combined w...

nLighten and Arqit Demonstrate Sovereign Cloud Security Model Using Quantum-Safe Encryption

Multiparameter Quantum Metrology in Molecular Dimers

We investigate multiparameter quantum estimation in a molecular dimer composed of two dipole--dipole interacting two-level systems, focusing on the simultaneous estimation of temperature T and detuning Λ. By employing a vectorization approach to derive the quantum Fisher information matrix, we analyze the precision limits of both simultaneous and individual estimation st...

From Circuits to Hardware: Benchmarking Standard and Qubit-Efficient Quantum Optimization on Real Hardware

Despite rapid progress in quantum optimization, broad real-hardware benchmarks comparing multiple algorithmic families across diverse combinatorial problems under a common protocol remain limited. We benchmark gate-based quantum optimization on four NP-hard problems: multi-dimensional knapsack (MDKP), maximum independent set (MIS), quadratic assignment (QAP), and market-shar...

Fixed-Protocol Amortized MPS Tomography with Conformalized Predictive Uncertainty

Quantum state tomography is sample-starved, and the states one prepares live on a narrow, learnable manifold. A k=0 prior-only control shows that on concentrated families a prior estimate is already near-optimal, so ``high fidelity at few measurements'' can be family memorization rather than tomography; genuine measurement-efficiency needs a model that conditions on the...

Tennessee Allocates $3 Million to Incentivize Local Realocation of NSF X-Labs Quantum Teams

The State of Tennessee has announced a $3 million funding commitment to recruit National Science Foundation (NSF) X-Labs quantum research teams to establish operations within the state. Organized under the Tennessee Quantum X-Labs Challenge, the economic initiative aims to transition advanced quantum research into local commercial operations by leveraging the state's exis...

MIT and IBM Project Quantum Unity Operators into Language Model Latent Spaces for Multimodal Circuit Synthesis

Researchers from the MIT-IBM Computing Research Lab and IBM Quantum have developed a multimodal alignment framework that maps quantum unitary operators directly into the latent space of a large language model (LLM). Published as an IEEE QCE 2026 conference paper ("Aligning Quantum Operators with Large Language Models"), the architecture treats mathematical quantum operati...

EeroQ Validates CMOS-Controlled Electron Shuttling on Superfluid Helium for All-to-All Qubit Routing

Schematic rendering of EeroQ’s Wonder Lake chip stack. Quantum hardware developer EeroQ has published peer-reviewed experimental results demonstrating the selective, two-dimensional transport of electrons on superfluid helium using a commercial silicon control architecture. Published in Physical Review Applied ("Selective shuttling of electrons on helium using a CMOS cont...

Tennessee Announces $3 Million Commitment to Support NSF X-Labs Quantum Teams

Quantinuum, Rolls-Royce, Riverlane and University of Edinburgh Sign Agreement to Explore Quantum Computing For Industrial Design And Simulation

An efficient algorithm for approximate shadow Hamiltonian simulation

We propose an efficient algorithm based on shadow Hamiltonian simulation to approximately simulate the real-time dynamics of observables under time-independent Hamiltonians. Shadow Hamiltonian simulation works at the level of the operator algebra generated by the observables through commutators with the Hamiltonian. Exactly encoding the quantum state in this picture is gener...

Paraparticles intrinsically exhibit Hardy-space breakdown

The memory kernel of an open quantum system obeys Kramers--Kronig (KK) relations if and only if its Laplace transform is analytic in the upper half-plane -- a property known as Hardy-space analyticity. Here we show that non-unitary exchange statistics, the defining property of paraparticles, intrinsically breaks Hardy-space analyticity. The metric η that guarantees a real...

Noise Resilience of Quantum Key Distribution Protocols Secured Against Independent Attacks With One-Way Communication

We investigate the resilience to noise of single-qubit quantum key distribution (QKD) protocols in the scenario of security against independent eavesdropping attacks and key distillation based on one-way classical communication. To this end, we introduce a noise-based metric that quantifies the efficiency of QKD protocols. Within this framework, we analyze the maximal noise...

Trotter error compensation with polylogarithmic precision and nested-commutator scaling without ancillas

Product formulas are among the most practical approaches to Hamiltonian simulation, requiring no ancillary qubits and exhibiting error bounds governed by nested commutators rather than only by Hamiltonian norms. Their circuit size, however, scales polynomially with the inverse precision. We develop a high-order nested-commutator compensation (HNCC) algorithm that preserves t...

Bounding Kirkwood-Dirac negativity of Gaussian processes

The Kirkwood-Dirac quasiprobability provides an operational representation of a quantum state, whose negativity serves as a measure of nonclassicality. Despite its fundamental importance, the extremal values of the Kirkwood-Dirac negativity are still unknown in the general case. We investigate the Kirkwood-Dirac quasiprobability of an arbitrary quantum state under Gaussian p...

Optimal tomography of bosonic and fermionic Gaussian states

The sample complexity is the minimum number of copies required to learn an accurate classical description of a quantum state. Bosonic and fermionic Gaussian quantum states are families of quantum states that play a key role in quantum science and technology, from quantum optics and many-body physics to quantum chemistry, quantum computing, and quantum information theory. Des...

Quantum probe advantage in learning many-body systems

Which properties of a quantum many-body system are operationally accessible is a central question underlying spectroscopy, thermodynamics, and quantum information science. Conventional response theory answers this question within a system-only paradigm: one perturbs and measures the matter itself, obtaining susceptibility built from causally ordered nested commutators. Here...

Multiparameter Quantum Estimation in a Raman-Coupled Two-Qubit System

We investigate multiparameter quantum estimation in a Raman-coupled two-qubit system at thermal equilibrium. Analytical expressions for the quantum Fisher information matrix are derived to characterize the simultaneous estimation of the temperature and Raman coupling strength. The corresponding quantum Cramér--Rao bounds are obtained and compared with those of individual est...

A new class of pure non-Gaussian quantum states

We discuss a new class of pure non-Gaussian quantum states of light characterized by trigonal symmetry on the phase plane. We propose the term ``trigonal states'' for them and show that they can be generated using the standard non-degenerate four-wave process supplemented by the subsequent heralding measurement of the photon number in one of the two signal modes.

Spacer-Mediated Gold Nanocube Arrays for Edge-Localized Excitonic Enhancement in Monolayer MoS2

Plasmonic nanostructures offer an effective route for enhancing light-matter interaction in atomically thin semiconductors, whose optical response is intrinsically limited by their sub-nanometer active thickness. Here, we numerically investigate excitonic enhancement in monolayer (ML) Molybdenum Disulfide (MoS2) coupled to size-tuned gold (Au) nanocube arrays separated by th...

Operational Concealment of Measurement Incompatibility by Quantum Channels

Measurement incompatibility can remain intact at the operator level yet become operationally inaccessible when observations are restricted to the output of a quantum channel; we refer to this phenomenon as operational concealment. We develop a systematic adjoint-kernel framework for operational concealment in which observables are organized into operational equivalence class...

Higher-order covariance matrices for non-Gaussian quantum states

Covariance matrices lie at the heart of the powerful and well-established symplectic framework for describing continuous-variable Gaussian quantum states. However, since this framework only relies on first- and second-order moments, it is not sufficient for the analysis of non-Gaussian states because their higher-order moments are essential to capture some of their key prope...

Deploying and validating a metropolitan QKD secure network: architecture and field performance

The advent of cryptographically relevant quantum computers poses an existential threat to classical public-key infrastructure. Quantum Key Distribution (QKD) addresses this challenge by providing information-theoretic security for key establishment, independently of any computational hardness assumption. In this work, the deployment and experimental validation of a metropoli...

Interlocked Time Crystal in Coupled Spin-1/2 Ensembles under Local Dissipation

Multilevel dissipative systems can exploit multiple local transitions and coherence channels to generate nonstationary time-crystalline dynamics. Here we show that an analogous mechanism can be synthesized without enlarging the local Hilbert space by coupling two locally pumped and decaying spin-1/2 ensembles into a composite dissipative unit.Neither ensemble supports an aut...

Near-Optimal Mode Scaling for Finite-Dimensional Boson Sampling via Lie-Algebraic Leakage Bounds

Boson sampling demonstrates quantum advantage through the interference of indistinguishable particles, with output probabilities governed by matrix permanents. Realizing it on deterministic, matter-based platforms requires encoding the bosonic modes in finite-dimensional local Hilbert spaces, which introduces a leakage channel absent in linear optics: multi-particle bunching...

Q^2SAR: overcoming classical bottlenecks in drug discovery via quantum multiple kernel learning

Quantitative Structure-Activity Relationship (QSAR) modeling is a foundational computational methodology in early-stage drug discovery, heavily relied upon for predicting compound toxicity, bioavailability, and therapeutic potential. However, classical methods often struggle to effectively map the highly complex, non-linear, and high-dimensional interactions inher...

The Time-Space Complexity of Checking Multiple Assertions in Quantum Programs

Runtime assertions are a promising mechanism for testing and debugging quantum programs. But unlike the classical world, checking a quantum program that contains multiple assertions often requires using additional space or running the program additional times. For example, on current quantum hardware where mid-circuit measurement is restricted or costly, an assertion's pass/...

Anomalous Dissipation in Current Biased Josephson Systems

A new phase diffusive regime in a current biased Josephson junction is theoretically explored which originates from embedding the junction in a circuit environment with anomalous dissipation. This is realized by placing parallel to the junction a resistor in series with a capacitor such that electromagnetic fluctuations effectively couple also to the charge of the junction....

Holographic Timelike Entanglement and Subregion Complexity in Localized AdS3*S3*T4 Black Holes

We study timelike entanglement entropy and timelike subregion complexity in localized black holes with asymptotic AdS3*S3*T4 geometry, focusing on the black-pole solution. Unlike the BTZ solution, the black pole exhibits a nontrivial dependence on the internal sphere through the functions K_y(r,θ) and G(r,θ). Both observables are constructed from spacelike and timelike L...

Classical probabilistic realisation of quantum double-slit interference

We demonstrate how the interference effects for a quantum particle in the double-slit experiment can be described by classical probabilities. We investigate a classical field theory for a complex scalar field with probabilistic initial conditions. A central element are conserved charges leading to the concept of particles. These are statistical observables which describe pro...

Robust Spin Qubit Coupler via Minimal Kitaev Chain

While a minimal Kitaev chain is promised to host unprotected Majorana zero modes, its role for spin qubits is relatively underappreciated. Following recent breakthroughs in the fine control of transport behaviors, we propose to use minimal Kitaev chain as a robust coupling module between spin qubits. Long-distance, anisotropic exchange coupling can be mediated by the Andreev...

Strong Zero Modes in Supersymmetry-Inspired Quantum Circuits

We investigate discrete dynamics in quantum circuits with gates corresponding to the S-matrix of a supersymmetric 1+1D quantum field theory. We show that for a brick-wall configuration such circuits support both localized and delocalized dynamically conserved operators known as strong zero modes (SZM), the number of which depends on the parameter regime. We demonstrate that,...

Tunable non-Hermitian skin effect and topological phases in ladders with staggered nonreciprocal inter-leg hopping

We investigate the non-Hermitian skin effect (NHSE) and topological phases in a ladder model with staggered nonreciprocal inter-leg hopping, consisting of an Su-Schrieffer-Heeger (SSH) chain coupled to a normal tight-binding chain. By tuning the system parameters, we show that the direction of the NHSE under open boundary conditions can be reversed and can even become energy...

Quantum algorithms for second-order boundary value problems

Second-order boundary value problems are central to computational science, yet standard matrix-based numerical formulations can obscure the local geometric structure that quantum circuits may exploit. Here we introduce a framework for explicitly constructing finite-dimensional counterparts of continuous differential operators in a form compatible with quantum computation. St...

From Leaves to Clusters: Depth-Efficient SAT-Oracle Synthesis Based on the HRSE Model

Quantum oracles are a common building block of many quantum algorithms, where circuit depth is a primary cost that directly affects overall performance. Synthesizing oracles for SAT (CNF) formulas under a limited ancilla budget, however, tends to yield deep circuits, as existing methods underexploit clause-level parallelism. In this work, we present the Clustered Synthesis T...

Moment-based PPT criteria for random bipartite states

Moment-based relaxations of the positive partial transpose (PPT) criterion have been recently introduced, as a hierarchy of entanglement criteria involving only experimentally accessible quantities of a given bipartite state. The goal of this work is to study their typical detection performance on high-dimensional bipartite systems. Concretely, we investigate whether random...

Controlling the Inhomogeneous Broadening and Impedance Matching of a Spin Ensemble

We control the spectral distribution of a spin ensemble by applying a magnetic field gradient using an anti-Helmholtz coil inside a dilution refrigerator, and demonstrate impedance matching between the ensemble and a transmission line, achieving -50 dB absorption of incident radiation. This represents a first step toward a spin-ensemble-based quantum memory for itinerant mic...

Information geometric quantification of effective privacy in quantum metrology

Privacy of a quantum metrological protocol concerns the extent to which single parameters can be kept inaccessible to an observer or to other users of the network. In this work, an information geometric framework is developed to quantify privacy and accessibility of functions of parameters effectively, that is, up to a finite accuracy in state discrimination. Both quantities...

Experimental Observation of Anomalous Complementary Weak Values from Correlated Pairwise Two-State Vectors

Weak values (WVs) arise from weak measurements performed within a time-symmetric formulation of quantum mechanics, where a system is both pre- and post-selected. Anomalous WVs that lie far outside the eigenvalue spectrum of the observable hold both fundamental and practical significance. However, their generation typically relies on near-orthogonal pre- and post-selection, w...

Deployment of Entanglement-Based QKD in Financial Infrastructure

We demonstrate the feasibility of entanglement-based quantum key distribution (eQKD) in high-security financial infrastructure over a 22 km fiber link with 8 dB loss between two data centers using polarization entanglement. The fully automated system continuously generated secure keys for four months at an average rate of 63.8 kb/s, which were stored into a key management sy...

Which Classicality? Incidence, Simplex, and Product-Rule Tests in Finite Quantum Logics

Finite quantum-logical constructions can appear classical or nonclassical depending on which structure is retained. We distinguish incidence tests based on valuations, colorings, and partition representations; simplex-embedding tests for specified prepare-and-measure fragments; and operator-functional tests imposing spectral and product rules. We show that the collective GHZ...

Yaqumo Expands Seed Extension Round with Backing from Government-Funded JIC VGI and Toyota

Japanese hardware startup Yaqumo Inc. has secured an undisclosed capital expansion within its ongoing seed extension round, adding state-backed JIC Venture Growth Investments (JIC VGI) and Toyota Invention Partners (TIP) as new institutional shareholders. Executed via the streamlined J-KISS (Keep It Simple Security) convertible equity instrument, the deal bridges Japan’s...

SLAC Scientist Advances Research on Scalable Quantum Dot Qubits

US Must Pair Quantum Research With Industrial Strategy, UCLA Physicist Argues

Imec and Diraq Demonstrate Eight-Qubit Silicon Spin Array on CMOS-Compatible Platform