August 14, 2026

Experimental Quantum Key Distribution in an Indefinite Causal Order

In quantum physics the order in which different operations occur can be placed in superposition. The resulting processes have an indefinite causal order and are both of fundamental interest and can be viewed as a novel quantum resource that enables a variety of new protocols. Here we report an experimental implementation of one such protocol, where we perform BB84-like quant...

Clifford Circuit Synthesis for Distributed Quantum Architectures with Arbitrary Network Topology

To achieve large-scale fault-tolerant quantum computation, it may be easier to combine many small sets of qubits than to construct a single large set. For example via quantum error correction with block codes, or distributed quantum processors utilizing shared entanglement. In these regimes, the time or error budget of the overall quantum computation may be dominated by non-...

Inductively-protected Andreev (IPA) spin qubit

The spin of a quasiparticle trapped in a quantum dot Josephson junction forms the basis of an Andreev spin qubit (ASQ): a semiconductor-superconductor device where the interplay between a localized spin degree of freedom and superconductivity leads to a spin-resolved Josephson potential. In this work, we show that shunting an ASQ with a linear inductor enhances its relaxatio...

Exponential quantum advantage for learning signals with a single qubit

Quantum technology has the potential to transform scientific discovery, but quantum advantages often require processing capabilities well beyond the reach of experimental platforms. We show that coupling a single controllable qubit to an otherwise conventional sensor can exponentially reduce the number of measurements required to learn classical signals. These rigorous quant...

Spectral Localization Principle for Entanglement Harvesting

We propose a unified physical principle for entanglement harvesting: the entanglement that two localized detectors can extract from a quantum field is determined solely by how localized the field's effective spectral density is. We demonstrate this in an analytically solvable model of two qubits coupled to a leaky single-mode cavity, which in turn couples to a continuous ele...

Universal magic state concentration

Magic plays a dual role in quantum computation: it promotes stabilizer dynamics from efficient classical simulability to universality, but it presents a central challenge for fault tolerance, since non-stabilizer operations are harder to protect against noise. Magic state distillation addresses this issue; however, existing protocols typically assume prior structure in the i...

Heterogeneously Integrated Squeezed-Light Generation and Detection on a Single Photonic Chip

Squeezed light underpins quantum-enhanced sensing and continuous-variable quantum information processing, and integrated photonics offers a route to producing it at scale. Universal to these applications are squeezed-light generation and measurement. Importantly, quantum measurements serve not only as readout but also as active operations in quantum-state evolution. However,...

Mid-circuit ground-state cooling and ancilla readout in the omg architecture

The trapped-ion optical-metastable-ground (omg) architecture for quantum processors promises the full functionality of two-species experiments, including sympathetic cooling and non-destructive ancilla readout, without the corresponding hardware overhead. We confirm that we can cool a global motional mode of a mixed metastable-ground state Coulomb crystal to the m...

Quantum simulation of non-Markovian dynamical systems

Existing quantum algorithms for simulating dynamical systems -- from Hamiltonian simulation to linear and nonlinear differential equations solvers -- simulate Markovian dynamics, in which the system's future evolution depends solely on its current state. We turn our attention to developing quantum algorithms for non-Markovian dynamical systems where the system's future evolu...

Controlled dynamics of a multi-component discrete-time quantum walker

We investigate a discrete-time quantum walk of a three-component quantum particle on a one-dimensional lattice. As coin operators, we employ parameterized rotations generated by the Gell-Mann matrices, which enable systematic tuning of the couplings between the internal components. We analyze how these couplings influence and control the dynamics by systematically exploring...

Time evolution of nonlinear dynamics on a quantum processor

From fluid flow and transport to collective dynamics, numerical simulation of nonlinear partial differential equations underpins modern scientific computing. Extending this capability to quantum computers remains a longstanding challenge because nonlinear and non-Hermitian evolution is fundamentally incompatible with conventional Hamiltonian-based quantum simulation. Here we...

Time-ordered free energy in correlated quantum systems: An agentic approach

How much work can an agent extract from a temporal sequence of quantum states when it can only operate online under causal constraints---deciding which energy extraction method to use with knowledge of what it has observed before? Here, we study this problem in the context of quantum state sequences that are potentially non-Markovian---generated by some underlying hidden Mar...

Hybrid HPC-Quantum Simulations: DFT-Quantum Embedding for Molecular Systems

Scientific simulations demand methods combining scalability with predictive accuracy. Density Functional Theory (DFT) on High-Performance Computing (HPC) enables large-scale electronic-structure simulations but is limited by approximations affecting strongly correlated systems and band-gap predictions. Quantum computing offers a pathway to address this, though current Noisy...

A Finite-Window Recovery Hierarchy for Local Quantum Memory

When quantum information initially stored in a local qubit disappears, it need not be lost: it may have moved into nearby degrees of freedom or become inaccessible to shallow local control. We introduce finite-window recoverability as an operational channel benchmark that separates these possibilities. It compares optimal recovery from the target site, recovery by a bounded-...

Classical Simulation and Design Frontiers for IBM's Doped Clifford Sampling Experiment

We classically simulate the IBM doped Clifford random circuit sampling experiment, comprising $70$ qubits, $70$ entangling layers, and $468$ inserted T gates. A deterministic temporal-boundary tensor network contraction approach is specifically designed to tackle such open-boundary one-dimensional brickwork circuits with operator-Schmidt-rank-$2$ entangling gates. For an $...

One-sided stripe supersolidity from engineered non-axisymmetric dipolar interactions

A supersolid combines density order with phase coherence, and doped lattice solids ask whether added defects can become coherent without melting the ordered background. We study a soft-core Bose-Hubbard model with isotropic hopping and an engineered non-axisymmetric dipolar interaction, V_(ij)=V_2(x_(ij)^2-y_(ij)^2)/r_(ij)^5+W_6/r_(ij)^6, where the sign-changing d_(x^2...)

DARPA Awards Contract to Qunnect to Advance Real-Time Polarization Compensation for Quantum Networks

The Defense Advanced Research Projects Agency (DARPA) has awarded a research contract to quantum networking hardware startup Qunnect to enhance the signal stability and resilience of entanglement-based telecom fiber networks. Associated with DARPA's Quantum Augmented Networks (QuANET) program and Small Business Innovation Research (SBIR) initiatives, the contract provides...

BTQ Technologies Signs MOU with ITCENGLOBAL Subsidiary ITCEN PNS to Deploy Post-Quantum Security in South Korea

Quantum technology provider BTQ Technologies Corp. (NASDAQ: BTQ) has signed a Memorandum of Understanding (MOU) with ITCENGLOBAL CO., Ltd. (KOSDAQ: 124500) through its listed security platform subsidiary, ITCEN PNS Co., Ltd. (KOSDAQ: 232830). The partnership establishes a commercial framework to integrate post-quantum cryptography (PQC), quantum-safe authentication, and h...

New York State Launches $60M RFP for Regional Quantum Technology Commercialization Hubs

New York Governor Kathy Hochul has announced the launch of a competitive Request for Proposals (RFP) to establish up to four Regional Quantum Technology Commercialization Hubs across the state. Funded with $60 million allocated in the FY 2027 state budget and administered by Empire State Development’s Division of Science, Technology and Innovation (NYSTAR), the program [....

ORIENTOM and Fondazione LINKS Form Research Partnership for Financial Quantum Computing

Seoul-based quantum software developer ORIENTOM and Italian research institution Fondazione LINKS (Links Foundation) have signed a Memorandum of Understanding (MoU) to advance quantum computing, quantum-inspired algorithms, and High-Performance Computing (HPC) integration across the finance, banking, and insurance sectors. The strategic collaboration will verify technical...

Yonsei University to Upgrade On-Premises IBM Quantum System One to Next-Generation Nighthawk QPU

The Yonsei Quantum Initiative at Yonsei University (Songdo Campus, Incheon, South Korea) has announced an operational hardware upgrade for its on-premises IBM Quantum System One facility. Scheduled for November 2026, the university will replace its current 127-qubit IBM Eagle quantum processing unit (QPU) with IBM's 120-qubit Nighthawk QPU, making Yonsei the second facili...

New York Opens $60 Million RFP for Quantum Technology Hubs

Every PPT channel has finite entanglement-breaking index

We prove that every PPT linear map has finite entanglement-breaking index, thereby establishing the eventual entanglement-breaking property of PPT channels in full generality. Furthermore, by utilizing completely positive maps with low entanglement dimensionality, we show that a large family of PPT maps, which strictly containing the class of 2-superpositive maps, has entang...

Ambient unitaries don't enable shallow group designs

Characterising the efficiency with which designs over various subsets of the unitary group may be constructed is an important goal of quantum information theory. While it is now known that approximate unitary designs can be realised in depth logarithmic in the system size, it has recently been shown that ensembles of local nearest-neighbour sublinear-depth one-dimensional ci...

Quantum correlations and Basis-Independent Coherence Distribution in Two Gravitational Cat States

We study the distribution of quantum correlations and basis-independent coherence in a pair of massive particles confined in a double-well potential and coupled through their mutual Newtonian gravitational interaction. Non-classical correlations are characterized using Bures distance of entanglement and quantum discord, while coherence is quantified through the square root o...

Strong unitary designs in optimal depth and space

Unitary designs provide finite-moment approximations to Haar-random unitaries, with wide-ranging applications across physics and quantum information, from scrambling and black-hole dynamics to foundational primitives in quantum algorithms. Strong unitary designs capture a more demanding operational notion of approximation, requiring indistinguishability from Haar randomness...

Aperiodicity is sufficient for macroscopic thermalization

We identify a general mechanism for the finite-time thermalization of macroscopic observables, such as coarse-grained charge densities, in terms of elementary forms of the quantum dynamics of initial states: (1) aperiodicity, which provides a computable measure of (2) a dynamical partially ergodic exploration of the Hilbert space. Specifically, this mechanism predicts the eq...

Field-Widened Multimode Interferometer with Long Time-Bin Delay Using a Multi-Pass Herriott Cell

Interference of optical signals in free-space channels requires optical receivers to support many spatial modes due to atmospheric turbulence, typically necessitating adaptive optics systems. Field-widened interferometers offer a passive alternative, making them particularly attractive for time-bin encoded signals with delays on the order of one nanosecond. Here, we demonstr...

Quantum-Inspired Phase Bicoherence Spectroscopy: A Framework for Detecting Universal Textural Angular Order Across Multi-Modal Complex Datasets

Classical image analysis routinely discards structurally meaningful orientation signatures encoded within Fourier phase, which are easily corrupted by local cellular rotation. Although quantum-inspired data processing offers new avenues for complex signal characterization, practical tools for directly extracting gauge-invariant angular correlations without explicit phase rec...

Robust Genuine Multipartite Entanglement in Two Walker Quantum Walks

Discrete-time quantum walks provide a versatile framework for investigating the generation, redistribution, and transport of quantum correlations in composite quantum systems. Here, we study the dynamics of bipartite and genuine multipartite entanglement in a two-walker discrete-time quantum walk on a one-dimensional lattice. By employing logarithmic negativity and the gener...

Phase information transfer by post-selection in Spin--Mechanical assisted magnetometry

Quantum information transfer between light-matter-type systems is poised to enable important applications, while also serving as a testbed for theoretical investigation. Such systems can be realized with spins coupled to a mechanical oscillator, a platform that has been extensively studied both theoretically and experimentally. Early demonstrations of quantum information tra...

Heat transport in driven quantum systems: Comparison between the Floquet-Redfield equation and the master equation in the instantaneous eigenbasis

We provide a comprehensive study of heat transport in periodically driven quantum systems using a combination of master equation and Floquet approach. We give exact results (within the weak coupling Redfield theory, with no Markovian or secular approximations) and compare them with alternative approaches involving further approximations. Numerical and analytical results obta...

Homomorphic Aggregation of Continuous-Variable GKP States

Aggregating logical quantum information encoded in continuous-variable phase space is essential for distributed quantum computing. However, passive linear optics fail for non-Gaussian Gottesman-Kitaev-Preskill (GKP) codes due to symplectic lattice compression and entanglement-induced decoherence. We present an active, measurement-based framework for the homomorphic aggregati...

Critical Microwave Mach-Zehnder-Type Interferometry with Dual-LO Rydberg Atoms

High-precision phase measurement of microwave fields underpins a wide range of applications, including wireless communications, distributed radar, plasma diagnostics, and antenna metrology. Existing Rydberg-atom-based approaches, however, often face trade-offs among phase resolution, measurement range, and system complexity. Here we demonstrate a Rydberg-atom-based microwave...

Ion trap on borosilicate substrate with integrated femtosecond-laser-written waveguide

We present an ion-trap platform on borosilicate glass with an integrated femtosecond-laser-written waveguide for on-chip light delivery. The optical layer is physically separated from the electrode substrate and bonded atop the trap, remaining compatible with silicon-based integration. We engineer single-mode low-loss guidance at 729 nm with tunable mode-field diameter and a...

Counter-examples for Tensorization Property of Strong Data Processing Inequality for Quantum Divergences

The data processing inequality is a fundamental property that describes the loss of information through noisy channels. A more refined description is characterized by the strong data processing inequality (SDPI). In classical information theory, the tensorization of strong data processing inequality holds for a whole family of f-divergences. However, its quantum counterpar...

Entanglement distribution and quantum storage of more than 8000 modes over a metropolitan network

Entanglement generation between telecommunication photons and matter is central to fibre-based quantum repeaters. Achieving practical communication rates requires multiplexing, which multimode quantum memories can provide. Rare-earth-ion ensembles offer large temporal multimode storage by exploiting the numerous spectral channels within their absorption spectrum. Here, we re...

Witnessing the architecture of quantum circuits

Determining whether a target unitary can be implemented within a prescribed quantum circuit architecture is a fundamental problem in quantum information, with direct implications for optimisation and compilation of quantum circuits, and hardware-efficient quantum computation. While existing synthesis and compilation methods are primarily constructive, they generally do not p...

Controlling quantum transport by measurement-rate modulation

Temporal modulation of the measurement rate provides a powerful mechanism for controlling open-system dynamics through measurement backaction. We demonstrate this mechanism in a minimal exactly solvable model of a continuously monitored quantum particle on a switching lattice. We derive exact analytical expressions for the long-time current under both periodic and stochastic...

Formal Verification of Quantum Ancilla Safety

Ensuring ancilla safety is a critical correctness requirement for quantum compilation, since ancilla qubits are routinely introduced to implement complex operations with fewer gates and reduced depth. However, formally verifying this property is computationally hard due to state-space explosion in the number of qubits, particularly for dirty ancillae, which carry unknown ini...

Time-resolved correlation engineering in DLCZ Raman photon sources

Memory-assisted quantum networks require photon sources with controllable temporal and correlation properties. The Duan-Lukin-Cirac-Zoller (DLCZ) protocol provides a platform based on spontaneous Raman scattering in atomic ensembles, but a unified predictive theory connecting control parameters to correlations under realistic propagation and noise conditions remains lacking....

Robust controlled-Z gate for Rydberg atoms based on level-crossing-free echoing rapid adiabatic passage

We propose a controlled-Z gate scheme for Rydberg atoms based on level-crossing-free echoing rapid adiabatic population transfer. We design antisymmetric Rabi frequency pulses and symmetric detuning pulses, enabling the system to completely avoid level-crossing points throughout the evolution, and the dynamical phase is naturally eliminated by the time-reversal symmetry of t...

Quantifying nonclassicality in qubit systems via positive operator-valued measures

We introduce an operational measure of nonclassicality for qubit systems based on the violation of Kolmogorov consistency conditions in sequential measurements. In contrast to previous work by Milz et al.~\cite{Milz-2020}, who characterized classicality via NCGD maps, and Sakuldee et al.~\cite{Sakuldee-2022a, Sakuldee-2022b}, who studied quantum correlations under measuremen...

Local and quasilocal conservation laws of three-state IRF cellular automata and their quantum deformations

Using patch-matrix-product methods, we study two reversible three-state interaction-round-a-face cellular automata introduced by Klobas and Prosen [J. Phys. A 55, 094003 (2022)] - the species-preserving and species-flipping rules - and a coherent quantum deformation interpolating between them. Within an explicit translationally invariant ansatz, the two classical rules share...

Completeness for flow-preserving rewrite rules

Complete sets of graphical rewrite rules enable fully graphical reasoning about quantum computations and have been an area of active research for more than a decade. Many recent applications of the ZX-calculus have made use of the close correspondence between ZX-diagrams and computations in the one-way model of measurement-based quantum computation. In this model, various ki...

Geometry versus excitation sector in the decoherence of asymmetric N-qubit W states

We investigate how network geometry and excitation sector separately control pairwise entanglement decay in asymmetric multipartite W states. To disentangle these effects, we introduce an analytically tractable N-qubit generalization of the asymmetric Lohmayer geometry and its complementary-excitation partner, yielding inequivalent vertex-base (VB) and base-base (BB) pai...

Encoding Circuit Satisfiability in Rydberg Atom Arrays

Rydberg atom arrays natively encode the maximum-weight independent set (MWIS) problem through the blockade mechanism, so the Boolean circuit satisfiability problem (Circuit-SAT) can be brought onto the platform once it is reduced to MWIS. The conventional encoding of Circuit-SAT in the Rydberg atom array proceeds through conjunctive normal form (CNF) and incurs a substantial...

Shots-to-Approximate-Solution Scaling in Neutral-Atom Quantum Optimization

Whether neutral-atom quantum optimization protocols exhibit genuine concentration toward low-energy solution structure remains an open question. Here, we introduce a shots-to-approximate-solution metric, STS(r), where r denotes the approximation ratio, and evaluate it using postprocessed outputs modeled by a degeneracy-weighted shell distribution governed by a single effecti...

Improved Measurement Cost Scaling in the Nonorthogonal Quantum Eigensolver

Quantum subspace diagonalization methods are promising algorithms for quantum chemistry on near-term quantum computers. These methods can estimate low-lying energies of molecular systems using shallow quantum circuits, at the cost of many circuit repetitions to estimate the projected matrix elements. Errors in these matrix elements can be converted into much larger eigenvalu...

Sector-resolved non-Bloch topology and nonlocal entanglement dynamics in a bond-dissipative Kitaev chain

A core characteristic of dissipative non-Hermitian topology is that the relaxation dynamics tracks the non-Bloch bulk-boundary correspondence, rendering an algebraic decay in the gapless regime and an exponential falloff in the gapped phase, so that local observables directly diagnose the topology. We show that this correspondence breaks down in a dissipative topological sup...

A Minimum-Cardinality Genuinely Unextendible Product Basis in Three Qutrits

It has remained an open question whether a genuinely unextendible product basis (GUPB) exists. We resolve this problem by constructing an explicit three-qutrit GUPB of cardinality fourteen in the smallest tripartite Hilbert space in which a GUPB can exist. Together with the nonexistence of three-qutrit GUPBs of cardinality less than fourteen, our construction proves that fou...

Correlation versus Causation in Quantum Criticality

Correlation functions ⟨O_1(x) O_2(0) ⟩ reveal scaling dimensions through spatial decay. We instead consider static susceptibility, the change in ⟨O_1(x) ⟩ from perturbing the Hamiltonian by O_2(0), which we term causation for short. In a conformal field theory (CFT), dimensional analysis predicts decay of |x|^(-2Δ) for correlation and $|x|^{...

Levitation of a YIG sphere using a magnetic Paul trap - towards strongly coupled quantum magno-mechanics

Magnetic levitation offer passive levitation of massive objects for use in advanced inertia sensors, for the generation of non-classical macroscopic motional states, and towards the table-top testing of low energy gravity with quantum mechanics. Magnons, a quanta of spin wave, couple to many physical quantities and strongly to electromagnetic fields, even at room temperature...

T-SQUARED Begins Construction on Infleqtion’s Quantum Innovation Centre in Oxford

Specialized engineering firm T-SQUARED has commenced construction on a new Quantum Innovation Centre at Oxford Technology Park for neutral-atom quantum technology company Infleqtion (NYSE: INFQ). The facility will triple the capacity of Infleqtion’s UK operations, expanding its research, manufacturing, and systems integration infrastructure for neutral-atom quantum comput...

SDT Joins Canadian Non-Profit Open Quantum Design as Official Manufacturing Partner

South Korean quantum equipment developer and systems integrator SDT has joined Canadian non-profit organization Open Quantum Design (OQD) as a primary hardware manufacturing partner. Announced at Quantum Korea 2026, the strategic agreement tasks SDT with translating OQD’s open-source hardware blueprints into physical trapped-ion quantum processing units (QPUs) and integra...

Infleqtion Reports Q2 2026 Results: Record Revenue Up 116% YoY, Raised Guidance to $43M, and $100M CHIPS Act LOI

Infleqtion, Inc. (NYSE: INFQ) has announced its financial results for the second quarter ended June 30, 2026. The Louisville-based neutral-atom quantum computing and quantum sensing leader delivered record quarterly performance driven by 100% organic growth across its dual computing and sensing verticals. The table below summarizes key GAAP financial metrics for Q2 2026 c...

DARPA Funds Qunnect to Improve Quantum Network Reliability

BTQ Technologies Partners With ITCEN PNS to Expand Post-Quantum Security in Korea

SDT Partners With Open Quantum Design to Build Open-Source Quantum Hardware

Guest Post: Why Quantum Readiness Is Becoming a Venture Capital Question

Infleqtion Reports Q2 Revenue Growth and Raises 2026 Outlook

Guest Post — Quantum Strategy Demands a New Operating Model: From Uncertainty to Readiness.

Kartik Srinivasan Appointed Editor-in-Chief of Optica Quantum