July 13, 2026

A Quantum Path to Partial Differential Equations

Partial differential equations are a promising application area for fault-tolerant quantum algorithms, but the subject lies between two communities with different languages: numerical analysis and quantum computation. These lecture notes provide a numerically grounded introduction for readers entering from either field. Block encoding is the organizing principle: once a disc...

Lean-QIT: Towards a Formal Infrastructure for Quantum Information Theory

Quantum information theory (QIT) characterizes the capabilities and fundamental limits of quantum information processing, underpinning quantum communication, computation, and error correction. Formalizing its coding theorems requires connecting finite-block protocols, analytic inequalities, and asymptotic limits within a unified machine-checked framework. Existing developmen...

Majorana parity qubit in coupled minimal Kitaev chains

Majorana zero modes provide a route to fault-tolerant qubits by encoding information non-locally in fermion parity. Their sensitivity to noise is expected to decrease exponentially with increasing separation between the Majoranas, a suppression known as topological protection. Kitaev chains engineered in quantum dot-superconductor arrays provide a tunable platform in which s...

Superconducting singlet-triplet qubits

Hybrid devices integrating quantum dots with Josephson junctions are gaining interest because they combine spin-based quantum computing with circuit quantum electrodynamics (circuit QED) methods. In particular, Andreev spin qubits have shown significant experimental progress including strong two-qubit coupling, and are predicted to exhibit all-to-all connectivity. Here we pr...

Speckle-based feedback control of optical dipole trap axial waist position

Cold neutral atoms is a powerful tool for many experiments ranging from frequency standards and sensing to quantum simulations. Sensitive experiments often demand transferring cold atoms from one vacuum chamber to the other with better optical access and vacuum. In case the transfer is done with a beam waist controlled by a focus-tunable lens, repeatability of the transfer a...

Deterministic Generation of Linear Photonic Cluster States with Semiconductor Quantum Dots: A Detailed Comparison of Different Schemes

Photonic graph states are key resource states for measurement based quantum information processing. As semiconductor quantum dots are excellent deterministic photon emitters, several protocols using them for the generation of linear cluster states have been proposed, either based on constant precession of a hole or electron spin in a weak magnetic field, or based on optical...

Quantum Scattering Model of Dual Parallel Mach Zehnder Electro Optic Modulators: General Formalism, Impairments, and Applications to Frequency-Bin Photonic Quantum States

We present a quantum mechanical model of dual parallel Mach Zehnder electro-optic modulators (DPMZMs), derived using the quantum scattering formalism [1,2]. We obtain the complete, unrestricted transformation of single-photon and coherent input states through the DPMZM architecture, including independent radiofrequency drive conditions on each internal modulator, and recover...

Shadow-Based Noise Fingerprinting of Simulated Quantum Noise Models

Accurate noise classification is essential for operating near-term quantum processors, yet existing approaches, such as quantum process tomography, scale exponentially with system size, limiting their practicality for routine calibration. We propose a scalable noise fingerprinting pipeline that combines structured classical shadow tomography with physics-informed feature eng...

Local Determinacy of Quantum Master Equations and a Mechanical Interpretation of the Multi-Mode Jaynes-Cummings and Central Spin Models

We propose a novel formulation of master equations for open systems wherein the evolution of a state is determined solely by its local behaviour at any point of time. Specifically, our formulation allows for a local interpretation of the workings of beyond-Markovian dynamics as opposed to the more common conception that non-Markovian state evolution is affected by its cumula...

Generalized Nonlinear Imaginary-Time Evolution

Imaginary-time evolution (ITE) is a powerful method for ground-state preparation of a given Hamiltonian. The normalized ITE can be viewed as a gradient flow of the energy expectation value with respect to the Fubini--Study metric. In this work, we propose a generalized nonlinear imaginary-time evolution (NITE) for more general quantum state-preparation tasks. We further pres...

A Semiclassical Gaussian Wavepacket Method for Non-Adiabatic Molecular Dynamics

We introduce two non-adiabatic semiclassical methods that employ two coupled Gaussian wavepackets, each one traveling on a separate diabatic potential energy surface. The wavepackets take the form of thawed Gaussians and are driven by classical equations of motion which account for the diabatic coupling. The classical equations of motion are derived in one case by enforcing...

Qubit-Boson Hybrid Beam-Splitter Gate with Kerr Nonlinearity in Circuit QED for Many-Body Dynamics

We introduce a hybrid qubit-boson beam-splitter gate in which a microwave cavity mode couples to an exchange-dressed two-level subsystem of an interacting two-qubit system in the presence of Kerr nonlinearity. Starting from a general circuit quantum electrodynamics (cQED) model, we derive the corresponding hybrid qubit-cavity interaction, develop its open-system description...

A combinatorial framework for clustering graph states: Algorithms and hardness for rank-integrity

We introduce a new notion of distance between two graph states |G⟩ and |G'⟩ on the same set of qubits. This distance is the minimum number of ancilla qubits in a graph state |G⟩ from which both |G⟩ and |G'⟩ can be ``easily prepared''. (When preparing graph states, we are only allowed to use one-qubit Clifford gates, one-qubit...

Diagnosing quantum reservoirs at scale based on expressivity and coverage

Quantum reservoirs offer a hardware-friendly route to quantum machine learning, replacing trainable circuits with fixed random dynamics and a classical readout. Because the reservoir is not optimized, performance depends entirely on the choice of reservoir family, yet existing diagnostics demand resources that grow exponentially with system size. We introduce a scalable, har...

Operational Shadows of Hilbert-Space Probabilities

At one frozen setting, the probabilities observed in a sharp quantum context are indistinguishable, as detector-click statistics, from ordinary probabilities on the atoms of a classical partition. But an actual analyzer usually comes with a calibrated knob: a tangible handle on the apparatus. If the measurement configuration is co-varied continuously through this physical pa...

Constraint-Preserving QAOA for Personnel Rostering: Coverage-Preserving and Guarded-XY Mixer Constructions

The Quantum Approximate Optimization Algorithm (QAOA) is a promising framework for combinatorial optimization, but constrained problems are commonly handled using energetic penalty terms that require calibration and allow infeasible configurations to remain dynamically accessible. We develop a constraint-preserving QAOA framework for personnel rostering in which hard schedul...

Hybrid Quantum and Classical Workload Management with Graph-based Scheduling

High Performance Computing (HPC) centers are expanding to encompass resources that extend beyond traditional computing. By extending resources to quantum computing, hybrid quantum-classical workflows tackle complex optimization problems that have never before been possible. However, integrating quantum processing units (QPUs) into cloud-native and scientific workload manager...

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...

NordLocker Deploys “Project Renaissance” Architecture to Implement Atomic-Journaling Encrypted Cloud Platform

Zero-knowledge data security provider NordLocker has launched a structural overhaul of its primary private storage architecture, transitioning from a rigid, locker-centric file system to a decentralized, append-only journaling engine. Codenamed "Project Renaissance," the platform rebuild replaces the company's legacy monolithic file trees with an atomic metadata logging m...

SEALSQ and Quobly Execute $5M Commercial Accord to Embed Post-Quantum Cryptography in Silicon Quantum Processors

Post-quantum semiconductor developer SEALSQ Corp (NASDAQ: LAES) has signed a $5 million commercial agreement with French silicon-based quantum hardware pioneer Quobly. The contract signals the deployment phase of a technology partnership initiated in November 2025 following SEALSQ's direct equity investment in the firm. The contract tracks Quobly's massive €115 million Se...

JIC Venture Growth Investments And Toyota Invention Partners Join Yaqumo Seed Extension Round

NordLocker Prepares Encrypted Cloud Storage for the Post-Quantum Era

SEALSQ and Quobly Sign $5 Million Agreement to Secure Silicon Quantum Computers

Phase-switchable nonreciprocal entanglement via magnon squeezing in ring-cavity optomagnomechanics

Cavity optomagnomechanics provides a versatile platform to explore macroscopic quantum correlations, particularly nonreciprocal entanglement. In this work, we propose a theoretical scheme to generate switchable bipartite and tripartite entanglement in an optomagnomechanical ring cavity by exploiting phase-controlled magnon squeezing. Indeed, two spatially separated ferrimagn...

Nonlinear particle detectors across the Rindler firewall

We investigate Unruh-DeWitt detectors coupled to composite observables of a quantum scalar field, including quadratic coupling to the field momentum and coupling to the local energy density. We develop a distributional framework for evaluating the corresponding detector response functions and apply it to detectors crossing the Rindler firewall. While we recover the finite re...

Silicon-Germanium Heterostructures with Enhanced Valley Splitting for Spin Qubits

Achieving valley splittings well in excess of the thermal energy of electrons and avoiding valley excitations is essential for the consistent initialization, operation and readout of gate-defined Si spin qubits. In this work, we present a device-level optimization strategy for pushing valley splittings to between 1 and 5 meV, well beyond values reported in nearly all previou...

Optimality of the free quantum evolution: the general case with nodes

Extending and refining a preceding work, the free evolution of a quantum wave function, with fixed initial and final modulus, is considered in the general case where nodes are allowed. The method is based on considering a suitable simple functional related to the quadratic optimal transport cost in discrete time. Under reasonable assumptions it is shown that, if nodes are pr...

Complete measurement of tunnel- and valley-coupling parameters in a silicon double quantum dot

Tunneling is essential in the initialization, measurement, and control of quantum dot qubits. In silicon, such tunneling connects not only the qubit states but also valley minima in the conduction band on opposite sides of the Brillouin zone, with large consequences for the quantum dot behavior. Here we present a full characterization of the intravalley and intervalley tunne...

A complete ultrametric on von Neumann's incomplete tensor products

We revisit von Neumann's theory of infinite tensor products of Hilbert spaces. On the set Γ of equivalence classes of C_0-sequences, which labels the incomplete tensor products inside the complete tensor product, we introduce a natural pseudo-ultrametric d: the distance between two classes is the convergence exponent of the series Σ_j|⟨φ_j,ψ_j⟩-1|...

Fluctuation theorems for thermally isolated driven quantum systems: nonadiabaticity, excess work and strong inequalities

We expand on the ideas developed by C. Jarzynski in Physica A 552, 122077 (2020), where an integral fluctuation theorem was derived with the aim of obtaining thermodynamic inequalities stronger than those implied by the Jarzynski equality. Restricting ourselves to the quantum setting, we derive the corresponding detailed fluctuation theorem and additional detailed and integr...

Quantum Orchestras: a Concrete Semantics for Recursive Hybrid Programs

Many production quantum programming languages represent hybrid quantum computations by extending a classical base language with a quantum effect, where qubits are addressed by reference, and quantum operations are understood to mutate some external quantum state. However, the semantics of this view of quantum computation remains underdeveloped, especially when the language a...

GHz-rate all-fiber active polarization state analyzer for quantum protocols

Active selection of the measurement basis underpins quantum protocols including device-independent quantum key distribution, quantum teleportation with active feed-forward, and Bell tests. High-speed operation is crucial to minimize the latency between consecutive measurement choices, enabling faster protocol execution and higher achievable communication rates. Here, we demo...

Confinement drives valley splitting above 4K in buried silicon quantum wells

Controlling the energy scales of a quantum system is essential for defining robust qubits. In silicon spin qubits, the nearly degenerate conduction-band valleys create a leakage channel from the single-spin computational basis, posing a challenge to scaling and to shuttling-based architectures. Here, we measure the relevant energy scales of single-electron spin qubits in bur...

Higher-Order Programs with Indefinite Causal Orders: a Linear Approach to Coherent Control of Quantum Processes

Processes with indefinite causal orders (ICOs), such as the quantum switch, are higher-order quantum processes that superpose the order in which quantum operations are performed. Such coherent control yields computational advantages but is not faithfully captured by existing quantum programming languages: either they are restricted to the unitary case, and thus cannot combin...

Playing Bayesian games better with separable quantum states than with any classical correlation

Bayesian games, also known as games of incomplete information, are a fruitful arena for exploring the impact of correlations on a set of independent agents (players) via the game equilibria to which they give rise. It was realised some time ago that quantum states shared between the players can lead to new and beneficial equilibria, compared to classical correlation. While u...

Orthogonal Quantum Krylov Diagonalisation

Quantum subspace-diagonalization methods, particularly Quantum Krylov Diagonalization (QKD), provide a promising route for computing low-energy spectra of quantum many-body Hamiltonians. However, existing quantum Krylov approaches rely on non-orthogonal Krylov bases, requiring overlap-matrix regularization that limits numerical stability and accuracy. In this work, we introd...

COSMA: Communication-aware Optimization of Fermionic Simulation Kernels for Modular Quantum Architectures

Quantum simulation is a leading application of quantum computing, but scaling to chemically relevant problems requires modular architectures composed of interconnected quantum processing units. In such systems, inter-core quantum communication becomes a major performance bottleneck. In this work, we present COSMA, a communication-aware compilation framework for fermionic sim...

When Routes Run Out: Adversarial Co-Learning and Explainable Robustness in Quantum Repeater Networks

We study an adversarial bandit problem for entanglement-based quantum-network routing over a modest graph corpus. Alice selects an end-to-end repeater route for an Ekert-91 protocol (E91) representing her move, while Eve selects an attack surface, either edge intercept--resend or repeater memory degradation. Payoffs are drawn from cached SeQUeNCe-simulated E91 transcripts, a...

Quantum Approximate Optimization via Noise-Directed Adaptive Warm-Starting

Progress towards a quantum advantage using known heuristic methods for combinatorial optimization is impeded by hardware noise and limited qubit count. Here, we propose a noise-aware adaptive approach to quantum approximate optimization, Noise-Directed Adaptive Warm-Starting (ND-AWS), that builds on recent concepts such as Warm-Start QAOA and Noise-Directed Adaptive Remappin...

Benchmarking Error Mitigation: Artefactual Improvements in Zero-Noise Extrapolation

Reliable benchmarking of Quantum Error Mitigation (QEM) requires distinguishing genuine improvements from artefacts of the post-processing arithmetic. In this paper, we expose a failure mode in Richardson Zero-Noise Extrapolation (ZNE), a widely used technique routinely (and often implicitly) relied upon in benchmarks and experiments. When noise amplification operates beyond...

PCPOP.jl: A Julia package for partially commutative polynomial optimization

Here we present PCPOP, a Julia package for polynomial optimization that supports non-commutative optimization, tracial polynomial optimization, trace polynomial optimization and state polynomial optimization. PCPOP fully supports exact arithmetic computations and incorporates convenient functionalities such as algebraic reductions based on Gröbner basis methods, automatized...

Observation of a Rydberg-atom time crystal with an ultralong lifetime

Continuous time crystals (CTCs) represent a nonequilibrium quantum phase that spontaneously breaks time-translation symmetry without periodic external driving, manifesting as persistent, long-lived oscillations under steady pumping. The lifetime is constrained by the instability of the limit cycle phase, balanced between nonlinear feedback and energy dissipation, which have...

Quantum stochastic thermodynamics of macroscopic systems: an algebraic approach

We build a framework for the thermodynamics of macroscopic quantum systems. In contrast with approaches requiring access to the full density matrix, our framework relies on a coarse-grained description, based on measurement statistics of a few observables. When these observables commute, the outcomes define classical macrostates whose entropy is quantified by observational e...

Quaternary-Squeeze Quantum Identity Authentication: Direction-Scaling Security via Single-Mode Squeezed Light

Quantum identity authentication (QIA) has emerged as a crucial technology for secure communication systems, particularly in the burgeoning era of quantum communications. This paper proposes a novel QIA protocol based on non-classical characteristics of squeezed light fields. By exploiting quantum noise reduction properties of quadrature squeezed coherent states, the protocol...

Measurement Speed Limits for Quantum State Purification

We derive three matched speed limits on the purification of a monitored system, valid in every finite dimension and for every strategy and efficiency. All three are set by one functional, the square root of the state's impurity, whose maximal decay rate is a state-independent constant. For a qubit this reduces to the square root of the determinant, whose protocol-independent...

Quantitative Wigner-Araki-Yanase Theorems for Unitary and Antiunitary Symmetries

Symmetry imposes fundamental constraints on quantum measurement and control. The Wigner-Araki-Yanase theorem and its quantitative extensions capture this restriction for continuous symmetries, in terms of fluctuations of conserved generators. Such generator-based bounds, however, do not provide quantitative limitations for discrete unitary symmetries or for antiunitary symme...

Entanglement entropy in two-particle Grover walks on graphs

We define a two-particle quantum walk of identical particles on a graph G via the one-particle Grover walk on the Kronecker product G ⊗G, and call it the two-particle Grover walk. In systems of identical particles, quantum mechanics requires that quantum states have a certain invariance with respect to the exchange of particles. Focusing on the symmetry of the Kro...

Classically Realizable Incompatibility

Incompatibility constitutes a fundamental aspect of quantum mechanics. However, not every quantum observable non-classical property arises from incompatibility, nor can all quantum scenarios be fully captured by incompatibility alone. Within the framework of partial Boolean algebra (pBA), we research the structural properties of incompatibility scenarios. We introduce a unif...

Quantum Logic as the Logic of Contexts

Quantum logic is usually presented as a non-classical departure from ordinary reasoning forced on us by quantum mechanics, with classical logic kept as the secure starting point. We argue for the opposite order of explanation in a finite and fully computable setting. The free orthomodular lattice on two generators has ninety-six elements, the direct product of a six-element...

Benchmarking Large Language Models on Repairing Qiskit Programs using Bugs4Q

In quantum programs, Bugs4Q is a widely used benchmark containing real quantum defects. However, its evaluation assumes that benchmark labels remain valid and that generated fixes execute in the target environment. We evaluate two Bugs4Q versions containing 67 unique real Qiskit defects, adding executable tests where missing, and re-run all entries across six pinned Qiskit r...

Distillation-Enhanced Continuous-Variable Quantum Teleportation for Satellite Communication Networks

Quantum teleportation (QT) over satellite-based free-space optical (FSO) channels is a promising approach for long-distance quantum communication. However, its performance is significantly degraded by atmospheric loss and turbulence. In this paper, we investigate continuous-variable (CV) QT in a dual-downlink scenario, where a satellite distributes entangled states to two gr...

Quantum Companies Help Develop Hybrid AI for Immune-Targeting Peptides

Israeli Quantum Startups Eye Wall Street as SPAC Interest Accelerates

Why Quantum Computing Needs Strong Ecosystems to Scale

BTQ Technologies and ICTK Complete Design of Quantum-Secure QCIM Security Chip