October 14, 2026

Lifting: Quantum State Discrimination Framework for Mid-Circuit MeasurementsTier 3

Quantum computing promises new capabilities beyond classical computation. Mid-circuit measurements (MCMs) enable error correction and outcome-dependent control, but their reliability is limited by noise on superconducting hardware. These operations depend on accurate quantum state discrimination (QSD), which assigns measured signals to state labels. Neural network-based (NN-...

Previously: 2026-10-13, 2026-10-11, 2026-09-17

Local error correction prolongs time-crystalline memoryTier 3

Discrete time crystals are non-equilibrium phases of matter with spatiotemporal order and a response that breaks the time-translation symmetry of a periodic external drive. Interactions, spatial disorder and correlated random driving can in theory stabilize this order. In experiments, however, coupling to the environment limits the time crystal lifetime. Here we use stochast...

Development and experimental implementation of noise characterisation techniques on a superconducting quantum processorTier 3

Noise characterisation not only enables error mitigation but also provides valuable information about the intrinsic performance of a quantum device, identifying dominant error contributions and bounding noise stability well beyond the aggregated calibration data. Deploying such methods on a specific hardware topology must combine efficiency and accuracy, assess noise stabili...

TAIYI Quantum Surpasses RMB 1 Billion in Funding to Advance Fault-Tolerant Neutral-Atom Quantum ComputingTier 2

Insider Brief PRESS RELEASE — TAIYI Quantum, a quantum computing company developing ytterbium (Yb) neutral-atom technology, announced that its cumulative funding has exceeded RMB 1 billion (approximately US$140 million) following its latest financing round, less than a year after its founding in January 2026. The latest round attracted participation from venture capita...

Deterministic and programmable generation of mechanical multipartite entangled statesTier 3

Multimode mechanical resonators offer a large set of densely packed, long-lived bosonic modes within a single compact device, making them attractive for quantum simulation, quantum information processing, and quantum-enhanced sensing. Many such applications rely on multipartite entanglement, yet deterministic mechanical entanglement has so far been largely limited to pairs o...

Quantum-enhanced mechanical sensing with machine-learning estimationTier 3

Massive mechanical oscillators couple directly to forces, accelerations and gravity, making them attractive probes of new physics and of quantum mechanics at macroscopic scales. Pushing sensitivities beyond the standard quantum limit for signals of unknown phase requires non-Gaussian quantum states, whose metrological advantage has so far been confined to lighter systems suc...

Experimental Realization of a C-Shunt Flux-Qubit Coupler for Controlled-Z Gates between TransmonsTier 3

Fast entangling gates and low-interaction idling require distinct operating conditions in superconducting quantum processors. We experimentally realize a transmon-C-shunt-transmon (TCT) device in which a flux-tunable, three-junction capacitively shunted flux-qubit coupler connects two transmon data qubits. The C-shunt coupler provides a flux-tunable, positively anharmonic sp...

A complete quantum process model for physically realistic photo-detection in the joint photon-number and spectral degrees of freedomTier 3

Photo-detection is a fundamental component of experimental photonics, yet theoretical models often treat detectors solely in the photon-number basis, neglecting other relevant degrees of freedom such as spectral characteristics. We present a complete quantum process model for physically realistic photodetection that incorporates both photon-number effects and frequency-depen...

Explicitly correlated ground states with a feedback-free variational hybrid algorithmTier 3

Explicitly correlated methods, which represent dominant short-range correlations by a diagonal Jastrow-type correlator, are designed to accurately describe systems of strongly correlated electrons, such as the fully periodic 2D Fermi--Hubbard model. However, as the reference state is compact in momentum space whereas the correlator acts naturally in real space, there is a fu...

Experimental Benchmarking of a 256-Qubit Room-Temperature NV-Diamond Quantum Processor with an Optically Programmable Biomolecular Quantum BusTier 3

We report Zeus-256, a room-temperature nitrogen-vacancy (NV) diamond processor with 256 simultaneously active processor-level logical qubits arranged in a 16 x 16 array. Each logical qubit combines an NV electron-spin ensemble with nuclear-spin memory and ancillary resources. OpenQASM 2.0 circuits are transpiled into RFSoC-controlled microwave, radio-frequency, optical, timi...

Can the system dynamics remain structurally non-Markovian while its experimentally accessible memory signatures disappear?Tier 3

We investigate how unresolved quasistatic disorder in system bath coupling affects non-Markovian dynamics in spin environments. The coupling is fixed within each experimental shot but varies between shots, so repeated shot tomography reconstructs a disorder averaged dynamical map. For a single spin bath with pure dephasing Ising interaction, disorder can drive a transition t...

Steering the Fidelity in State Preparation on Noisy Bosonic Systems with Risk-Seeking OptimizationTier 3

In order to execute quantum algorithms on bosonic quantum computers, it is necessary to encode their inputs into a desired target quantum state, with a process called state preparation. In real settings, state preparation methods operate in stochastic scenarios, where the prepared state is represented as a mixed state, that is a probabilistic ensemble of pure states. Therefo...

Unequal Coherent Ergotropy at Equal Interferometric Visibility and Energy in Quantum-Controlled InterferometersTier 3

The ergotropy, or unitarily extractable work, of a quantum system naturally splits into incoherent and coherent contributions, respectively set by population inversion and coherences in the energy eigenbasis. We show that this split makes the coherent ergotropy of a Mach--Zehnder qubit sensitive to path predictability that the output interference fringes do not reveal. We se...

A Tutorial on Quantum Amplitude Embedding with Data Re-UploadingTier 3

Amplitude embedding lets a variational quantum model read many classical features with few qubits, but the model output is then only a quadratic form in the normalized input. Data re-uploading, which encodes the input repeatedly between trainable blocks, can be used to enrich such a model. Because every additional upload of an amplitude embedding repeats a costly state prepa...

PADO-Pauli: A GPU-Accelerated Implementation of Pauli PropagationTier 3

Variational quantum algorithms utilize parameterized circuits many times during training, at new parameter values, over batches of data, and with gradients. Pauli propagation approximates the expectation values of such circuits classically by evolving the observable in the Heisenberg picture as a truncated sum of Pauli strings. We present PADO-Pauli, a GPU engine for Pauli p...

Representation Geometry and Inductive Biases in Quantum Classifiers across Classical Visual BenchmarksTier 3

Quantum Machine Learning (QML) has a theoretical advantage over classical algorithms for specific synthetic data that is computationally hard. However, it remains unclear whether such theoretical advantages play a meaningful role for realistic classical data, such as natural images. Quantum structural properties induced by unitary operations or entanglement introduce inducti...

Swinburne University and IQM Partner to Advance Quantum Ecosystem in Australia and EuropeTier 2

Swinburne University of Technology and IQM Quantum Computers have partnered to advance quantum science and technology across Australia, Europe, and the Indo-Pacific. This collaboration will focus on workforce development through joint training and internships, technology translation via co-development of quantum applications, and international exchange programs for resear...

Qilimanjaro Quantum Tech Announces Nearly €20 Million First Close of Series A Led by Indra GroupTier 2

Insider Brief PRESS RELEASE — Qilimanjaro Quantum Tech has completed a €19.6 million — about $22 million USD — first close of its Series A funding round, led by Indra Group through IndraMind with a €10 million investment. The Spanish Society for Technological Transformation (SETT), under the Ministry for Digital Transformation and Public Administration, is...

SkyWater and D-Wave Sign Multi-Year Quantum Manufacturing AgreementTier 2

Insider Brief PRESS RELEASE — SkyWater Technology (“SkyWater”), the first quantum foundry in the U.S., and D-Wave Quantum Inc. (Nasdaq: QBTS) (“D-Wave”), the only dual-platform quantum computing company providing both annealing and gate-model systems, software and services, today announced a multi-year agreement. This collaboration extends the long-establis...

Scalable long-distance quantum fan-out gates with reduced resource overheadTier 3

Scalable long-distance quantum gates are essential for distributed quantum computation and scalable quantum networks. We propose an efficient scheme for implementing an n-qubit fan-out gate C^n (also known as a controlled-NOT-⋯-NOT gate) across spatially separated parties. Our protocol requires only a pre-shared n-qubit Greenberger-Horne-Zeilinger state, n loc...

Gaussian entanglement and quantum communication: geodesic optimization and multimode boundsTier 3

Loss and noise limit the use of light to distribute entanglement, transmit quantum information, and establish secret keys. Gaussian states have a compact description in terms of means and covariance matrices, but their entanglement still requires global optimization. We develop a framework for computing Gaussian-restricted versions of the relative entropy of entanglement and...

On the coincidence of discrete and continuous definitions of Entanglement of FormationTier 3

It is proved that every Borel ensemble of pure states on a separable bipartite Hilbert space with finite average entanglement admits a countable ensemble with the same barycenter and arbitrarily small additional average entanglement. Consequently, the discrete and continuous versions of the Entanglement of Formation coincide on the whole space of states of infinite-dimension...

EFILeftrightarrow1PRSTier 3

A series of recent works has established EFI pairs as the "minimal" assumption for quantum cryptography. Recently, Cavalar et al. [CCC+26] showed that EFI pairs are equivalent to non-uniform expanding single-copy pseudorandom state generators (1PRS), and obtained a non-uniform meta-complexity characterization of EFI pairs. We remove the non-uniformity in their construction a...

Relative-Entropy Geometry and Convergence in Nonconvex Wiretap OptimizationTier 3

We develop and analyze an entropic descent method for a nonconvex optimization problem on probability simplices arising in classical and quantum secure communication. The optimization variables describe a randomized encoder, allowing its input distribution and stochastic preprocessing to be optimized jointly. An exact relative-entropy identity yields a channel-independent ma...

Finite-energy two-way assisted capacities: Exact formulas for multimode loss and fadingTier 3

We study quantum communication, entanglement distribution, and secret-key generation through multimode bosonic loss and fading channels, assisted by local quantum operations and two-way classical communication. Using sector teleportation, we determine the exact two-way quantum and secret-key capacities of multimode pure-loss channels under a mean photon-number constraint, al...

PULSUS: Direct Frequency-Domain Multidimensional Spectroscopy Beyond the Impulsive Rotating-Wave ApproximationTier 3

We introduce PULSUS, a direct frequency-domain framework for multidimensional spectroscopy of open quantum systems beyond the impulsive rotating-wave approximation. Coherence-frequency intervals are represented through Liouvillian resolvents, while finite Gaussian pulses are incorporated through operator-valued functions of the field-free Liouvillian. This enables direct eva...

Dark state preparation in a zero-field-split molecular tripletTier 3

We propose a protocol to prepare and probe dark states in a single-molecule electron spin resonance based on atomic force microscopy (ESR-AFM), thus extending existing techniques developed to address Rabi oscillations. To this end, we simulate in analogy to atomic physics the coherent manipulation of a three-level system in the V-configuration using a multifrequency magnetic...

T-efficient unitary synthesis via block-sparse Hamiltonian simulationTier 3

We construct Clifford+T circuits implementing arbitrary n-qubit unitaries with worst-case T-count O(N^(8/7)) at constant operator-norm error, where N=2^n, improving the previous exponent 5/4. The construction uses O(N^(6/7)) clean ancillas. The main idea is to reduce the data addressed by each query to the block-encoding circuit for a sp...

On the Increase of Boltzmann Entropy in Closed Macroscopic Quantum SystemsTier 3

We consider a closed macroscopic quantum system in a pure state ψ evolving unitarily with Hamiltonian H in a finite-dimensional Hilbert space mathscrH. Following von Neumann, we assume a decomposition of mathscrH into mutually orthogonal subspaces mathscrH_ν, where each ν represents a macro state, and mathscrH_ν contains the pure states compatible w...

Phases of a rotating Bose-Einstein condensate trapped in a hard-wall potentialTier 3

We investigate the rotational properties of a zero-temperature Bose-Einstein condensed gas, which is confined in a hard-wall potential. For weak interactions the gas carries its angular momentum via vortices of multiple quantization. As the coupling increases and for sufficiently slow rotational frequencies of the trap, the multiply-quantized vortex states become unstable ag...

Orbital Angular Momentum Transfer and Beam-Quality Limits in Fork-Grating Electron DiffractionTier 3

We analyze fork-grating generation of electron vortex beams beyond the ideal single-mode approximation. The incident beam is described as a paraxial Gaussian ensemble with finite transverse momentum spread and a first electromagnetic Hartree phase accumulated before the grating. Within Fresnel propagation we derive an analytical expression for each diffraction order and dete...

V-type Atomic Variance SqueezingTier 3

Variance squeezing of a V-type atom interacting with a dissipative cavity is investigated. First, the influence of atomic initial state parameters on the variance squeezing is explored. The results show that the atomic variance squeezing switches alternately between Sx and Sy as the initial state parameter alpha sweeps from -pi to pi. The two squeezing intervals are symmetri...

Role of dissipation dilution in achieving high mechanical quality factors in van der Waals resonatorsTier 3

Dissipation dilution has driven a revolution in the quality factors (Q) of top-down nanomechanical resonators. Yet it has not been leveraged for van der Waals (vdW) materials. Here we report quality factors up to 372,000±37,000 in monolayer MoS_2 drums at 4 K, nearly an order of magnitude beyond the previous best for any vdW material at this temperature, enabled...

Towards an autonomous optomechanical Maxwell Demon engineTier 3

We present a fully autonomous model of a mechanical Maxwell demon engine that converts heat absorbed by a qubit into population inversion in an attached quantum battery. A damped mechanical oscillator acts as a pointer that incorporates the essential demon function of information acquisition about the qubit state and subsequent feedback into the system dynamics, replacing ex...

Resource-based reliability of quantum-coherent devicesTier 3

Quantum devices can lose the resource needed for a specified function without entering a fixed failure subspace. We propose a resource-based reliability framework for this situation, quantifying the remaining task-relevant resource relative to a stated ideal capacity. The resource measure is selected through its operational connection to the task and the allowed operations....

Optical parametric amplification of spatiotemporal optical vorticesTier 3

Spatiotemporal optical vortices (STOVs) are structured light featuring a phase singularity in the spatiotemporal domain, exhibiting unique topology that couples spatial and temporal dimensions. To date, amplification of STOVs remains unexplored, and their wavelength tunability is limited by available light sources. In this work, we present the theoretical analysis and experi...

Theory of Trotter Error with Variable-Weight SchedulesTier 3

Trotterization is a widely used algorithm for simulating quantum evolutions and consists of approximating a target unitary through a local linear decomposition of its generator that is repeated over N steps. We introduce {scheduled trotterization}, a variable-weight modification in which the coefficients of the local linear decomposition are allowed to change from step to...

Optimal Lower Bound on the Sample Complexity of Coherent Classical Shadows for Mixed StatesTier 3

We study coherent classical shadows protocols for an unknown d-dimensional quantum state of rank at most r, allowing an arbitrary joint measurement on all available copies. For observables with operator norm at most one and centered squared Frobenius norm at most F, we study the minumum number of copies T needed for the protocol to successed with propbability $1 - δ$...

Lossless Reductions and Hybrid Sampling for Phylogeny Using the Maximum Compatibility CriterionTier 3

Maximum compatibility provides a criterion for phylogenetic reconstruction in which the objective is to retain a maximum set of mutually compatible characters. For binary characters, pairwise compatibility can be represented by a weighted graph whose vertices correspond to characters and whose edges connect compatible pairs. A leading algorithm by Cherry [BMC Bioinformatics,...

Ergotropy of multipartite entangled states in the quantum atmosphereTier 3

We investigate the ergotropy of tripartite Greenberger-Horne-Zeilinger (GHZ) and W states in the quantum atmosphere of a Schwarzschild black hole, focusing on how the extractable work is redistributed under Hawking-induced thermalization. We find that the two classes of multipartite entanglement exhibit qualitatively different ergotropy structures. For GHZ states, the ergotr...

Dynamical BEC formation and vanishing entropy for trapped bosons in non-relativistic QED via nonlinear resonance cascadesTier 3

The dynamical formation of a complete Bose-Einstein condensate and the asymptotic purification of trapped bosons coupled to a quantized radiation field are rigorously established. By tracking the macroscopic one-particle density matrix κ_T through a nonlinear resonance cascade, it is demonstrated that radiative relaxation irreversibly depletes all excited trap modes, even...

Dynamics of low energy wave packets in the one-dimensional quantum Heisenberg ferromagnetTier 3

Spin wave theory plays a central role in the analysis of low-energy properties of the quantum ferromagnetic Heisenberg model. In this work, we present a first step towards a rigorous justification of this approximation in the context of quantum dynamics in one dimension. According to spin wave theory, the evolution of a spin wave state should be well approximated by its free...

Emergent Non-Biorthogonal Born Rule at Dynamical Quantum Phase TransitionsTier 3

Non-Hermitian dynamics possesses distinct left and right eigenstates, but their normalization freedom obscures a direct probabilistic interpretation. Starting from a globally Hermitian system governed by the standard Born rule, we generalize dynamical quantum phase transitions (DQPTs) from a reference state to a physical subspace. This generalization provides a clear probabi...

Broadening the reflection band of atomic mirrors by engineering the emitter-waveguide couplingTier 3

We theoretically investigate single-photon coherent transport through a finite waveguide quantum electrodynamics (QED) array with spatially modulated emitter-waveguide couplings. By combining exact scattering calculations with spectral factorization and a semiclassical WKB analysis, we identify how the coupling profile controls the reflection bandwidth and its finite-size de...

How many switches does two-Hamiltonian universality require?Tier 3

Any pair of sufficiently generic Hamiltonians on C^d generates the full unitary group, i.e., any W∈U(d) can be synthesized to arbitrary precision by alternating between the two evolutions for suitably chosen durations. For any given pair of Hamiltonians, the minimal number of switches required to cover the entire group is at least d and unbounded in general...

Multi-parameter estimation enhanced by level crossing Hamiltonian structure with Bayesian feedbackTier 3

Level crossings, where two quantum energy levels intersect, are ubiquitous in quantum systems and play a central role in controlling quantum dynamics. In this study, we establish a framework that connects these level crossing structures to the ultimate precision limits of quantum metrology. By analyzing a Hamiltonian with the level crossings structure, we identify the condit...

SEALSQ Presents Research on Side-Channel Attacks Against ML-KEMTier 2

Insider Brief PRESS RELEASE — SEALSQ Corp (NASDAQ: LAES) (“SEALSQ” or “Company”), a company that focuses on developing and selling Semiconductors, PKI, and Post-Quantum technology hardware and software products, today announced that its research team presented a peer-reviewed technical article on a novel side-channel attack targeting the encodin...

Coinbase Urges Early Work on Bitcoin’s Post-Quantum TransitionTier 2

Insider Brief Coinbase says Bitcoin should begin preparing for quantum computing threats before a machine capable of breaking its cryptography is announced. In a blog post outlining its technical priorities, the cryptocurrency exchange and custodian said protecting Bitcoin will require more than selecting a new digital signature system. The transition must also work for ordi...

Quantum Firms Backed to Keep UK Railways Running And Cut Waiting ListsTier 2

Insider Brief PRESS RELEASE — British businesses developing quantum technologies are being backed to keep our railways running, reduce eye scan waits, and keep our military connected – improving lives for people across the country. Quantum technologies use the behaviour of tiny particles including atoms to do things that are difficult or impossible with today’s […]

Google Researchers Propose Using Error Records to Improve Quantum Results After ComputationTier 2

Insider Brief Errors can survive even a quantum computer’s built-in correction system, leaving researchers with results that look reliable but remain slightly off. Now, Google Quantum AI researchers report on a “measure now, mitigate later” approach in a preprint study on arXiv that uses error records saved during the calculation as a way to reduce […]

QEDIA: Quantum Program Verification in LeanTier 3

Practical quantum programs interleave quantum and classical computation: classical data shape the quantum operations that are performed, and measurement outcomes shape the classical computation that follows. Formal verification of such programs in a proof assistant requires mechanizing a program logic that handles this interplay consistently at every level, from the mathemat...

Beyond Gaussian Entanglement: Practical Criteria for Polynomially Excited Quantum StatesTier 3

Polynomial excitations consisting of creation and annihilation operators are studied. Subsystem entanglement is proven produced and preserved by such manipulations. NPT entanglement already present between any two subsystems of a general pure or mixed multipartite Gaussian state is preserved under all polynomial excitations. Nevertheless, these excitations can create NPT ent...

Infleqtion Receives £9 Million to Develop Quantum RF Sensing SystemTier 2

Insider Brief PRESS RELEASE — Infleqtion (NYSE: INFQ), a global leader in quantum computing and quantum sensing powered by neutral-atom technology, has been awarded £9 million (~$12M) by Innovate UK, part of UK Research and Innovation (UKRI), to continue development of a deployable quantum radio frequency (QRF) direction finding (DF) system as part of the […]

Previously: 2026-07-29, 2026-07-23