July 15, 2026

Logical Entangling with Phantom Codes in Hypergraph Products

Logical entangling gates are a major source of physical spacetime overhead in fault-tolerant quantum computation. Phantom codes reduce this cost by implementing every ordered in-block logical CNOT through physical qubit permutations and Pauli-frame updates. Whether this mechanism can coexist with the low-weight stabilizer structure of qLDPC codes is a central question for lo...

Heisenberg-limited metrology in the presence of non-Markovian noise with finite control rates

Recently, it has been shown that protocols utilizing infinitely fast controls, such as quantum error correction, can in principle restore Heisenberg-limited frequency estimation in the presence of a broad class of non-Markovian noise models arising from coupling to finite-dimensional environments. However, these controls differ substantially from those used to address Markov...

End-to-End Quantum Key Distribution Across Hybrid Fiber and Free-Space Links with All-Optical Encoding Conversion

Quantum key distribution (QKD) promises information-theoretically secure communication, but future networks must bridge fiber and free-space links that naturally employ different photonic encodings, namely time-bin in fiber and polarization in free space. Here we demonstrate a complete hybrid fiber and free-space QKD link that bridges both media within a single end-to-end pr...

When Close Enough Is Not Enough: Autoregressive Drift in Quantum Circuit Synthesis

Quantum circuit optimization for fault-tolerant computing requires exact functional equivalence while minimizing expensive non-Clifford resources such as T gates. We study this problem using a compact 44.8M-parameter encoder-decoder transformer with structured circuit tokenization, evaluating on parameterized circuits (2-6 qubits) and Clifford+T circuits (3-6 qubits). On par...

Traceable In Situ Microwave Power Measurement at the Cryogenic Device Plane in a Dilution Refrigerator

Accurate knowledge of the microwave power delivered to a cryogenic device under test (DUT) is essential for the characterization and operation of superconducting quantum circuits. However, this information is difficult to obtain inside dilution refrigerators because of distributed attenuation, impedance mismatch, switch-path repeatability, and temperature-dependent microwave...

Emergence of drifted diffusion in quantum walks with subspace restart

Restart of a quantum process is typically modeled as a global reinitialization that erases the system's entire history. Here we introduce subspace restart, a protocol that periodically resets only the internal degrees of freedom while preserving the spatial distribution, as a tunable knob for the quantum-to-classical crossover. Using the discrete-time quantum walk as an exam...

Entanglement and Optical Nonreciprocity in spontaneous Raman Scattering

Inelastic light scattering is a central tool for sample characterization and label-free imaging across the physical and life sciences. Recent work has suggested that scattered light can also exhibit nonclassical correlations. Here, we develop a microscopic theory of Raman scattering that connects naturally to established descriptions of entangled-photon generation in three-...

Collective-State Preparation in a Subwavelength Triangular Trimer Using SUPER Excitation

The Swing-UP of quantum EmitteR population (SUPER) scheme has recently been proposed as a deterministic method for the preparation of collective radiative states in two strongly dipole-coupled quantum emitters (Phys. Rev. Res. \textbf{8}, 013179 (2026)). Here, we extend this approach to an equilateral subwavelength triangular trimer of dipole-coupled two-level quantum emitte...

Expressibility and trainability of a two-dimensional pairwise quantum-circuit ansatz

Parameterized quantum circuits~(PQCs) constitute a central building block of variational quantum algorithms~(VQAs) and quantum machine learning~(QML) methods. Existing ansatz designs often adopt hardware-agnostic or simplified 1D chain/ring entanglement patterns. However, as quantum hardware continues to develop, native 2D connectivity patterns, such as planar superconductin...

A Noise-Aware Quantum Algorithm for Credit Valuation Adjustments on Real Quantum Hardware

Credit Valuation Adjustment (CVA) requires repeated risk-neutral expectation estimation, making it a natural test bed for quantum amplitude estimation, whose coherent amplification can in principle reduce Monte Carlo sampling cost. Whether this advantage survives realistic financial encoding and noisy hardware remains open. We develop an end-to-end, noise-aware quantum workf...

An Agentic Formalization for Certified Quantum Neural Network Design

A central model in quantum machine learning is the quantum neural network (QNN), whose design requires balancing expressivity and trainability. Technically, expressivity is studied through circuit-function analysis, such as quantum signal processing, while trainability is analyzed using dynamical-Lie-algebra (DLA) methods. To support certified QNN design, we formalize these...

Maximal Classicalization of Finite-Group Quantum Reference-Frame Noise

A finite quantum reference token with group-valued misalignment induces a random-unitary channel, but optimal degradation is generally an optimization over all quantum post-processings. For a unitary representation U of a finite group G, we prove that the following conditions are equivalent: U contains every irreducible type; one ancilla-assisted input has an orthonormal G-o...

Detecting Phishing in Ethereum Networks using Quantum Machine Learning

This article explores the potential of Quantum Machine Learning (QML), specifically assessing a Quantum Support Vector Machine (QSVM) and a Variational Quantum Classifier (VQC) for detecting anomalies in real-world financial transaction data. While these QML methods outperform statistical methods, they fall short of cutting-edge deep learning techniques. To bridge this gap,...

A Variational Surrogate Approach to Finite-Horizon Quantum Control via Hardware-Efficient Ansatz

We present a variational quantum framework for finite-horizon quantum control based on hardware-efficient ansätze. The objective is to steer a quantum system from a given initial state to a desired target state over a fixed time horizon by minimizing a terminal cost defined in terms of state fidelity. Instead of explicitly synthesizing time-dependent control fields or enforc...

Forked Physics-Informed Neural Networks for Non-Markovian Open Quantum Dynamics and Control

Physics-informed neural networks (PINNs) provide a pathway to reunify the simulation and control of quantum systems, in which these two tasks are typically decoupled in traditional strategies. However, most work remains confined to Markovian environments. When applied to non-Markovian systems, standard PINN architectures fail to converge reliably due to multi-objective optim...

Benchmarking loss functions for trainable quantum feature maps

Many quantum machine learning models employ quantum feature maps to encode classical data into quantum states. While fixed feature maps often lack sufficient expressivity for complex nonlinear classification tasks, trainable quantum feature maps (TQFMs) enable adaptive quantum kernels with enhanced learning capability. Different loss functions can induce distinct optimizatio...

High-fidelity entanglement of polar molecules by dynamic geometric control

In quantum information systems made of optical tweezer arrays of ultracold molecules, thermal motion of molecules degrades the coherence of their interactions, which limits entanglement fidelity and the concomitant scientific applicability of these systems. We show that by controlling the geometry of the dipolar interaction, even when a molecule occupies many motional states...

Spin Chain Quantum Communication on a Trapped-Ion Processor

Efficient communication between distant qubits is one of the central challenges in scaling quantum processors. Although engineered spin chain protocols have been extensively investigated theoretically, their experimental realization has remained comparatively limited. Here, we experimentally realize engineered quantum communication protocols through digitally simulated spin...

NTHU and Top Taiwan Venture Capital Launch NT$1 Billion ($34M USD) “NTHU Future Fund” for Deep Tech Startups

National Tsing Hua University (NTHU) and Top Taiwan Venture Capital Co., Ltd. have officially launched the NTHU Future Fund. Announced during the 2026 Taiwan Venture Capital & Private Equity Annual Conference in Hsinchu, the public-private partnership establishes a long-term capital vehicle specifically tailored to guide deep-tech research outcomes from academic labor...

Jane Goodall Institute and FormationQ Launch Quantum-Enhanced Primate Behavior Study

The Jane Goodall Institute (JGI) USA and quantum adoption firm FormationQ have announced a first-of-its-kind, two-year research partnership to apply quantum computing to behavioral ecology. Launching on World Chimpanzee Day, the program will explore how environmental and ecological variables influence whether primate societies evolve toward cooperation or intergroup confl...

Quantinuum, Rolls-Royce, Riverlane, and EPCC Partner to Accelerate Fluid Dynamics Simulations

Quantinuum (NASDAQ: QNT), Rolls-Royce, Riverlane, and EPCC (the UK National Supercomputing Centre at the University of Edinburgh) have announced a multi-year collaboration to develop hybrid quantum-classical workflows. The partnership will focus on modeling complex computational fluid dynamics (CFD) for gas turbine design. [ Joint CFD Project Matrix ] Hardware Partner ──►...

QuiX Quantum Delivers “Carina” Core Hardware to DLR QCI for Universal Photonic Computing

Photonic quantum hardware developer QuiX Quantum has announced the commercial launch and physical delivery of Carina, a universal photonic quantum computing architecture designed for data center deployment. Developed under the Universal Photonic Quantum Computer (UPQC) project for the German Aerospace Center’s Quantum Computing Initiative (DLR QCI), the room-temperature s...

IBM Reaffirms $10 Billion Quantum Push Despite Weak Preliminary Quarterly Results

Classiq and ParityQC Partner to Optimize Quantum Circuit Execution

The Infraparticle Edge

I derive the charged-particle spectral edge from the quantum instrument of soft QED. I use two projections of that instrument. Tracing over unresolved photons gives the reduced hard-sector channel. Pushing the outcomes to total energy gives the inclusive energy distribution. Its Laplace exponent is fixed by the diagonal soft intensity. For rmd N_h(ω)=η_hrmdω/ω+rm...

Fixed-Boost Wigner Noise: Strict Trace-Distance Contraction without Quantum Degradability

A Lorentz boost acts on the canonical spin of a massive particle through a momentum-dependent Wigner rotation. We show that, for one fixed observer boost, reducing over an uncertain momentum can strictly contract every pairwise spin-state trace distance without producing a channel that is degradable from the less contracted one. For spin 1/2, we first characterize the exac...

A cryogenic neutral-atom platform with full optical access and 2-hour trap lifetime

Neutral-atom quantum processors are rapidly scaling toward system sizes of more than ten thousand qubits, allowing for the realization of a new class of quantum computing algorithms and quantum simulation experiments. However, current neutral-atom platforms generally have to find a compromise between the optical accessibility and the storage time of atoms in optical potentia...

The log log jam in Gaussian state tomography

Unlike in finite dimensions, quantum information in continuous-variable systems has the peculiar feature that without imposing physical constraints, the sample complexity of state tomography can be unbounded. Remarkably, this is even the case for state-of-the-art protocols for learning Gaussian states, which have finite-dimensional descriptions: the best known rates scale wi...

Nonreciprocal Quantum Mpemba Effect

We demonstrate a nonreciprocal quantum Mpemba effect. Consider a broad class of open quantum systems, each coupled to two isomorphic reservoirs through symmetric ports. Interchanging the parameters of the two reservoirs -- a discrete operation we call the swap -- turns the quantum Mpemba effect on or off without changing the initial states. The swap modifies the Liouvillian,...

Active Quantum Nematics: The First Quantization

Nematic symmetry entails conserved quantized quantities such as number of topological defects and vorticity cells. Correspondingly, countless quantum analogies have been found in Active Nematics. We formalize Active Nematics and Liquid Crystal theory into the framework of Quantum Mechanics by introducing a complex valued Nematic Wavefunction to the Beris Edward equations, th...

Ancilla-Depth Phase Diagrams for Quantum Reference-Frame Comparison

Comparing two noisy quantum reference frames as statistical experiments depends on the dimension of the ancillary memory available to the decision procedure. For finite-dimensional channels A and B with invertible A, we show that exact simulation of all measurements assisted by an r-dimensional ancilla is equivalent to r-positivity of the unique factor Gamma = BA^{-1}. The h...

Large sets of mutually orthogonal quantum Latin squares

How large can a set of mutually orthogonal quantum Latin squares (MOQLS) get? We show that a set of n - 2 MOQLS of order n is necessarily classical and construct large non-classical sets of MOQLS of orders that are prime powers, improving both the previously known lower and upper bounds.

Obstructions to Deformation Quantization of Bundles

Let (M, O_M ) be a smooth algebraic variety over field κ of characteristic $0$ with an algebraic symplectic form ω, or a complex manifold with a holomorphic form ω. Furthermore, let E be a vector bundle over (M, O_M ) and O_ℏ a deformation quantization of O_M compatible with ω. Assuming tha...

Unitary Synthesis with Near-Optimal T-Count for Near-Clifford Unitaries

We present an approach to unitary synthesis that implements an arbitrary n-qubit unitary operator U by a Clifford+T circuit with T-count O(2^n d_F^C(U)), where d_F^C(U) is the Frobenius norm distance of U to the Clifford group. The T-count is shown to be near-optimal when d_F^C(U) is a constant. Our approach improve...

A maximal Hohenberg-Kohn theorem for non-interacting systems via potential theory

In this paper, we show that for Schrödinger operators with weakly correlated ground states, the Hohenberg-Kohn theorem holds within the maximal class of form-bounded external potentials if and only if the single-particle density is positive quasi-everywhere. Furthermore, we show that these conditions are satisfied for the ground state of non-interacting Schrödinger operators...

Time-independent counterdiabatic driving for emergent two-level subspaces in many-body systems

We show that geodesic motion in the Riemannian manifold of quantum states provides a direct route to time-independent counterdiabatic driving. Using the relation between the counterdiabatic Hamiltonian and the quantum metric tensor, we prove that a constant-speed geodesic makes the Hilbert-Schmidt norm of the counterdiabatic Hamiltonian constant. For effective two-level syst...

Thermal Suppression of Dynamical Quantum Phase Transitions in Finite-Dimensional Systems A Quasi-Hermitian Framework

We investigate dynamical quantum phase transitions (DQPTs) in finite-dimensional systems prepared in thermal equilibrium states and subjected to a sudden quench. A mixed-state Loschmidt amplitude is constructed from first principles within a metric-stationary pseudo-Hermitian framework, providing a self-contained derivation of the finite-temperature quench dynamics. Applying...

The Resolution of the Identity as a Generator of Exact Integral Identities: A Coherent-State Approach

The resolution of the identity is typically utilized as a passive representation tool in standard quantum mechanics textbooks. In this paper, we reinterpret this traditional perspective by introducing the resolution of the identity associated with Glauber coherent states as a direct generator of exact complex Gaussian integral identities. By systematically projecting the con...

A Quantum Computing Approach to Track Reconstruction in Strip-Type Detectors

This study investigates the use of quantum annealing for particle track reconstruction in strip-type gaseous detectors. In such detectors, ghost hits and multiple hit combinations can turn pattern recognition into a combinatorial optimization problem. We formulate two reconstruction subproblems as quadratic unconstrained binary optimization problems. The first subproblem sel...

Thermally Activated Long-Range Entanglement from Non-Abelian Conservation Laws

Thermal noise ordinarily suppresses quantum entanglement. We show that a strong non-Abelian conservation law can convert local thermal fluctuations into an unbounded operational resource. For a broad class of finite-range SU(2)-invariant spin chains restricted to the global-singlet sector, an explicit representation-space protocol yields Y_N=1/2log_2 N+O_β(1), and h...

Quantum PDE Solvers in Practice: Application-Driven Benchmarking of the Heat Equation

Quantum PDE solvers are difficult to evaluate in practice because published studies use different discretizations, output models, reconstruction rules, and hardware assumptions. We present a reproducible, application-driven benchmark for the 1-D Dirichlet heat equation that compares eleven kernels under the same problem instances and readout contract. The benchmark covers co...

Quantum metrology with undetected mid-infrared photons for applied non-destructive testing

Metrology with undetected photons is an emerging technique that leverages quantum effects and photon correlations (entanglement) to retrieve valuable information in a target spectral range (e.g., mid-infrared, mid-IR) using measurements in an easily accessible domain (e.g., visible, near-IR). The underlying quantum process of spontaneous parametric down-conversion (SPDC) is...

James-Stein estimation for quantum sensing schemes

Quantum metrology protocols typically consist of four steps: state preparation, evolution, measurement, and data processing. Often, the first three steps are prioritised when designing a scheme as they contain all the quantum elements. The data analysis is generally considered an add-on with an implicit assumption that this step is well behaved and so standard data technique...

Quantum tests via inequalities for joint statistics

In this work we derive statistical inequalities whose violation is equivalent to the impossibility of describing the data by a genuine joint probability distribution. So they are witnesses of the failure of a common probability space. We examine whether the most significant quantum quasidistributions violate these inequalities. We examine also whether these inequalitites are...

From phase space to Krylov space, one shell at a time

In this work, we develop and study the classical Lanczos algorithm allowing us to define Krylov complexity using the symplectic structure of phase space: Poisson brackets take on the role of the quantum commutators and phase-space integrals furnish the inner product needed to define the Lanczos recursion. We show, using general methods of quantum mechanics in phase space, th...

Entropy Transport in Programmable Quantum Junctions

We show that driven qubit junctions enable programmable control of physical entropy transport, with entropy conductance governed by quantum dynamics rather than by reservoir parameters alone. By comparing two simple quantum architectures -- a driven single-qubit junction and a driven two-qubit junction -- we find that the two-qubit junction enhances entropy transfer while re...

Activating thermally charged quantum batteries in finite time: Thermodynamic trade-offs between correlations, work, and information

Thermally charged quantum batteries provide a stable and easy-to-have energy resource, but remain passive and therefore do not allow useful energy extraction on demand via unitary operations. We introduce a time-dependent stirring protocol that activates a thermally charged quantum battery through a time-dependent coupling to an auxiliary activator, thereby generating correl...

Fast measurement-based generation of large-scale Greenberger-Horne-Zeilinger state with atomic nuclear-spin qubits

Large-scale Greenberger-Horne-Zeilinger~(GHZ) state is useful for quantum technologies but difficult to be prepared. Here, we propose fast measurement-based preparation of large-scale GHZ states by a four-qubit quantum phase gate with nuclear-spin qubits of alkaline-earth-like atoms, which is named as quantum ferromagnetic gate~(QFG) due to its analogy to the alignment of mo...

The Quantum Polariton Hamiltonian that Reproduces the Same High-Harmonic Generation Spectra as the Classical Hamiltonian in Strong Laser Fields

This manuscript investigates the possibility of defining a quantum Hamiltonian that leads to the same high-harmonic generation (HHG) spectra as those predicted by Floquet theory in the regime where the number of infrared (IR) pump photons is much larger than the number of emitted UV photons. The key assumption underlying our derivation is that the intensity of the emitted hi...

The Infinitesimal Structure of Quantum Information

This paper establishes a rigorous, unified geometric framework for quantum state spaces by constructing smooth, regular embeddings into higher-order dual number algebras Q_N ≡R[ε]/(ε^(N^2-1)), wherein every quantum state is faithfully represented as a non-reduced scheme-theoretic point. We show that under this unified family of...

Optically Derived Radio-Frequency Benchmark in Methanol: A Sub-kHz Reference for Astrophysical Tests of Fundamental Physics

Methanol radio lines observed in space provide sensitive probes of whether the proton-to-electron mass ratio has changed over cosmic time, but such tests require laboratory rest frequencies with very high accuracy. Here we determine the frequency of the astrophysically important 12.2 GHz 3_(-1)E -- 2_0E transition of CH_3OH by measuring near-infrared rovibrational tr...

Quantum Weakest Preconditions Revisited: Pre-expectations for Expected Runtime Analysis

Quantum weakest preconditions are a fundamental tool for program verification of quantum programs. Many variations have been reported in the literature. We revisit quantum weakest preconditions from the perspective of expected runtime analysis of quantum programs and introduce a novel pre-expectation framework that enables to reason about the preconditions of quantum program...

Coherence enhancement of Rydberg polaritons

Quantum nonlinear optics by Rydberg polaritons can enable single-photon transistor and switch, single-photon source, and deterministic quantum information processing. A major hindrance in this study is the fast motional decoherence. Here, we devise a scheme to significantly enhance the coherence of Rydberg polariton by letting the atoms {\it remember} their velocities, or, a...

Sparse anisotropic positive maps for qutrit entanglement: exact indecomposability and PPT geometry

Positive but not completely positive maps provide one of the most direct ways to detect entanglement beyond the positive-partial-transpose (PPT) criterion. We introduce and analyze an exactly solvable two-parameter family of sparse bistochastic positive maps on qutrits, in which two coherence channels are independently tuned by parameters w and z. The sparse structure ma...

Strain-Induced Detuning of a Dressed Nitrogen-Vacancy Qubit: Effective Two-Level Theory and Its Validity

The nitrogen-vacancy (NV) center in diamond can be operated as a microwave-dressed qubit. In the ideal two-level limit, its transition frequency is first-order insensitive to static magnetic fields, providing robustness against magnetic detuning noise. In practical diamond devices, however, residual transverse crystal strain mixes the ketm_s=±1 spin sublevels and mo...

Deutsche Telekom and AIT to Spearhead EU Quantum Communication Infrastructure via PETRUS2 and HarmoniQCI

Deutsche Telekom and the AIT Austrian Institute of Technology have been awarded two new Coordination and Support Actions (CSAs) by the European Commission to lead the development, standardization, and long-term scaling of the European Quantum Communication Infrastructure (EuroQCI). Under these complementary initiatives, Deutsche Telekom will coordinate the PETRUS2 project...

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...

A Superconductor’s Hidden Identity Revealed

New Mexico Awards $1.2 Million to Six Quantum Technology Companies

NSF Awards $15 Million to Connecticut Quantum Technology Engine

UC Berkeley Quantum Chip to Enter National Time Capsule For America’s 250th

NSF Funds 12 New Regional Innovation Engines Including Quantum Technologies Initiative

enQase Receives FIPS 140-3 Validation for Cryptographic Security Module