September 23, 2026

IonQ Demonstrates End-to-End Real-Time Quantum Error DecoderTier 2

Insider Brief PRESS RELEASE — IonQ (NYSE: IONQ), the world’s leading full-stack quantum platform and foundry, today announced a major milestone in fault-tolerant quantum computing. Researchers demonstrated the development and successful testing of the industry’s first end-to-end real-time quantum error correction decoder that runs on a single standard off-the-shelf cen...

Previously: 2026-08-28

Error Suppression in Distributed Quantum Computing with Heterogeneous-Distance Lattice SurgeryTier 3

Distributed quantum computing requires fault-tolerant operations across inter-QPU links that can be substantially noisier than local gates. Uniformly increasing code distance provides additional protection but also enlarges data patches used for local storage and computation. Here, we introduce distributed heterogeneous-distance lattice surgery using an eight-data-patch anci...

Evidence for a low-gap component in compressively stressed niobium thin filmsTier 3

We investigate the microwave response of sputtered Nb films as a function of biaxial film stress. Although transport measurements show nearly identical superconducting transition temperatures (9.0±0.2K) and residual resistance ratios across the stress series, microwave resonators fabricated from highly compressive films exhibit enhanced temperature-dependent loss and la...

Error Correction Properties of Covariant Bosonic EncodingsTier 3

Bosonic codes offer a promising approach towards hardware-efficient fault tolerance, with many leading examples such as the cat-code and the GKP code organized by an underlying symmetry. We build on a representation-theoretic framework of quantum error correction to formalize the construction and analysis of multimode symmetric bosonic codes, focusing on finite groups. Here,...

Tensor Network Simulation of Dynamic CircuitsTier 3

Dynamic circuits, which incorporate mid-circuit measurements and classically controlled operations, extend the expressive power of quantum programs and are central to applications such as quantum error correction, state preparation, and distributed quantum algorithms. However, their classical simulation is challenging due to the exponential growth of execution branches induc...

Photonic CZ gates based on few-photon scattering from emitter-cavity systemsTier 3

In this paper we analyze the performance of photonic CZ gates based on N waveguide-coupled cavities containing two-level emitters. We derive single- and two-photon scattering matrices for one cavity using the input-output formalism of quantum optics and for N>1 cavities using the SLH formalism, allowing us to compute the CZ gate fidelity. We consider two input Gaussian wave...

Universal Fidelity Law for Linear-Optical Entangling GatesTier 3

Imperfect photon sources degrade the performance of interference-based linear-optical entangling gates. We derive a universal fidelity law for these gates in terms of two standard source metrics: Hong-Ou-Mandel visibility and second-order coherence. We model the multiphoton component as an arbitrary overlap between noise and signal photons. While different values of the sign...

Quantum survival in hybrid pursuit dynamics - a lion chasing a lamb problemTier 3

Measurement and classical randomness usually degrade coherence; controlling where and when a subsystem is monitored can instead make them a tunable resource. We introduce a photonic time-multiplexed quantum walk whose fast reconfigurability enables precise position measurements, allowing us to study this interplay in a hybrid quantum-classical pursuit problem: A quantum walk...

When are bosonic Gaussian states classical to learn?Tier 3

A fundamental question in physics is: When does classical behavior emerge from quantum systems? Bosonic Gaussian states provide a natural setting to explore this quantum-classical boundary, as they capture both the classical field behavior and the intrinsic quantum nature of light. Here, we address this problem from a learning-theoretic perspective by asking: When are bosoni...

Neural Network Backflow with Low-Rank Multi-Determinant UpdatesTier 3

Simulating strongly correlated fermions remains a long-standing challenge due to the exponential complexity of the Hilbert space and the intricate sign structure of many-body wavefunctions. We introduce a variational framework centered on a neural network backflow transformation that combines deep learning with variational Monte Carlo. The proposed ansatz employs a multi-det...

Hyperbolic Restricted Boltzmann Machine Neural Quantum StateTier 3

We construct the first type of non-Euclidean non-autoregressive neural quantum state (NQS) in the form of the hyperbolic Restricted Boltzmann Machine (HRBM), which is studied in the variational Monte-Carlo (VMC) setting of the Quantum Sherrington-Kirkpatrick (QSK) model whose ground state exhibits volume-law entanglement. Across a 512-fold increase in the Hilbert space dimen...

Bridge of Ψ's: Quantum Circuit Optimization with Schrödinger BridgesTier 3

Quantum circuit optimization replaces a circuit with an equivalent one of fewer gates and lower depth, reducing execution cost and error rate. We ask whether a generative model can learn this transformation directly from examples, rather than selecting from a fixed rewrite library or rigid algebraic routines. We present Bridge of Ψ's (BOPS), a generative model based on Sch...

Spin-Orbit-Mediated Magnetization Transfer in the Fermi-Hubbard ModelTier 3

We demonstrate spin--orbit-coupling (SOC) catalysis of magnetization-sector transfer in the half-filled Fermi--Hubbard model. Without SOC, conservation of total magnetization confines the dynamics to the initial sector, preventing an antiferromagnetically correlated state from reaching the polarized ferromagnetic sector under a Zeeman ramp. A transient SOC control lifts this...

Tiny Quantum Nanostructures Could Make AI Less of an Energy HogTier 2

Insider Brief PRESS RELEASE — Engineers at the University of Wisconsin-Madison have designed a new type of quantum nanostructure that could enable optical neural networks. This emerging technology has the potential to make artificial intelligence systems, like large language models and image generation, faster and significantly more energy efficient. The research, led...

Non-Markovian Charging of a Micromaser Quantum BatteryTier 3

We theoretically investigate the role played by non-Markovianity in the charging of a quantum battery. We focus on the case of a Micromaser, where the energy is stored in a resonant cavity mode and memory effects are introduced and controlled by coupling this mode to a memory ancilla, described as a two-level system, that in turn sequentially interacts with a stream of two-l...

Maximum-Likelihood Amplitude Estimation for Quantum Monte Carlo Integration on Trapped-Ion Hardware: Convergence, Noise-Floor Saturation, Depth-Dependent BiasTier 3

Quantum Amplitude Estimation promises to accelerate Monte Carlo integration by replacing the classical ε∝N^(-1/2) sampling law with the Heisenberg-limited ε∝N^(-1) scaling, but whether any part of that advantage survives on present-day hardware is an empirical question. We report a systematic experimental benchmark of a Maximum-Likelih...

George Mason Launches Virginia Quantum HubTier 2

Insider Brief PRESS RELEASE — “The Virginia Quantum Hub at George Mason positions the Commonwealth of Virginia at the forefront of this cutting-edge technology that will drive investment and economic opportunity in the decades to come,” said Governor Abigail Spanberger. “As home to the first open-architecture quantum computing system in the National Capital Region, thi...

QuEra Computing Opens Office in Discovery District MarylandTier 2

Insider Brief PRESS RELEASE — QuEra Computing, the Boston-based leader in neutral-atom quantum computing, will open an office in Discovery District Maryland, joining the Capital of Quantum’s expanding roster of quantum companies. The move builds on an agreement between QuEra and the University of Maryland‘s National Quantum Laboratory (QLab) that gives QLab...

Zapata Launches Platform to Help Companies Assess Quantum Use CasesTier 2

Insider Brief PRESS RELEASE — Zapata Quantum, Inc. (OTCQB: ZPTA) (“Zapata,” “Zapata Quantum” or the “Company”), a leader in quantum computing algorithm and application development, today announced early access to Quantum Pilot, a hardware-agnostic, cloud-based software platform designed to close a growing gap between rapidly advancing quantum hardware capabilities and...

Quobly Brings Alloy Forge to qBraid for Silicon Quantum DevelopmentTier 2

Insider Brief PRESS RELEASE — Quobly, a French company developing silicon-based quantum computers, and qBraid, a quantum computing cloud service providing access to more than 24 quantum computers, today announced that Alloy Forge is now available on the qBraid platform, further expanding access to Quobly’s silicon quantum development environment as the company prepares...

An Operator-Theoretic Model of Entanglement Percolation in Series-Parallel Quantum NetworksTier 3

The realization of entanglement distribution (ED) in large-scale quantum networks (QNs), as a fundamental theoretical framework of quantum communication, faces significant challenges. Percolation theory, drawn from statistical physics, has been identified as a potential solution to this problem. Nevertheless, when addressing ED, percolation theory primarily relies on numeric...

Optical Ion Clock with Engineered Immunity to Motion-Induced Frequency ShiftsTier 3

Spectroscopic frequency shifts due to residual motion of the probed atoms significantly contribute to the uncertainty budgets of state-of-the-art optical ion clocks. For clock transitions with second-order Doppler and quadratic Stark shifts of opposite signs, it is possible to configure electrodynamic ion confinement such that these two shift effects become anticorrelated ca...

On the Complexity of Finding Decoherence Free SubspacesTier 3

Decoherence free subspaces are a steady-state structure of the open quantum system which preserves quantum coherence between the states lying with in it and thus has found a variety of applications throughout quantum information science and technology. In this paper we study the computational complexity of deciding whether an open quantum system admits a decoherence free sub...

Quantum Broadcast Channels with Mutually Confidential MessagesTier 3

We study the transmission of two independent confidential classical messages over a quantum broadcast channel, one for each receiver. Each message must remain secret from the other receiver, including when that receiver knows its own message. For classical inputs and quantum outputs, we establish the classical Marton-type inner bound under average reliability and conditional...

Explicit channels with unbounded gains in classical communication using entangled inputsTier 3

We construct an explicit family of finite-dimensional quantum channels for which the optimal classical communication rate achievable with product-state codewords and collective decoding tends to zero, while rates achievable using entanglement only within pairs of channel inputs grow without bound. Our construction combines deterministic qudit Clifford unitaries with a binary...

Strong Selective and List-Decoding Direct Product Theorems for Quantum Query ComplexityTier 3

Quantum strong direct-product theorems for specific functions have been known for nearly two decades. These have been extended to general results for function computation and state generation. The proofs of these results use a version of the multiplicative adversary method that does not naturally extend to relations. Standard strong direct-product theorems apply when algorit...

Strong matchgate designs in nearly optimal depthTier 3

Understanding the resources required to generate approximately random unitaries over various groups is a natural goal of quantum information theory. With respect to one notion of approximation, that of a design, it is known that the full unitary group can be approximated in logarithmic depth by one-dimensional circuits of nearest-neighbour 2-local gates. On the other hand, r...

Fluctuation-Driven Nonlinear Amplification of Quantum StatisticsTier 3

Photon statistics have moved to the forefront of modern optics, as intensity fluctuations and correlations shape multiphoton interactions and reveal information beyond mean-intensity measurements. Developing high-quality photon sources with pronounced correlations is a fundamental necessity in these fields. Here we demonstrate fluctuation-driven nonlinear statistical amplifi...

Geometric construction of optimal probe states in distributed multiparameter quantum sensingTier 3

The choice of probe state is essential to achieving ultimate precision in quantum metrology. For a single parameter, an equal superposition of eigenstates associated with the largest and smallest generator eigenvalues is optimal. This simple construction does not directly extend to multiple parameters, since different parameters can favor different probes. We address this di...

Hamiltonian Learning and Certification via Eigenphase EngineeringTier 3

We study Hamiltonian learning for k-local Hamiltonians at large step size, using only forward time evolution at integer multiples of a fixed time interval. For this task, our new technique, which we call eigenphase engineering, achieves Heisenberg-limited learning with a step size that is optimal up to logarithmic factors. For an unknown s-sparse Hamiltonian with fixed l...

A New Method For Manipulating Circuits, Application To Quantum AddersTier 3

We use a new technique for manipulating controlled quantum circuits to convert between two distinct types of quantum adders, one based on the Quantum Fourier Transform and the other based on the Ripple-Carry technique from classical reversible logic. This conversion takes the form of an explicit gate-level transpilation. We also present a new quantum adder with a natural int...

Preselection-Encoded Weak-Value Interferometry for Optical-Rotation MetrologyTier 3

Optical-rotation measurements benefit from increasing probe photon number, but their performance is often limited by detector saturation and technical noise in the optical readout. Here we introduce preselection-encoded weak-value amplification (PeWVA), in which the quantity of interest is encoded into the probe polarization before a downstream weak-value interferometer. Thi...

Power-resolved ergotropy and correlation redistribution in a bosonic quantum battery driven by a coherent-state superpositionTier 3

Ergotropic-gap relations provide thermodynamic witnesses of quantum correlations, but a direct dynamical connection between extractable work and entanglement remains largely unexplored in multipartite non-Gaussian bosonic systems. Here, we establish such a connection for a bosonic quantum battery driven by a coherent-state superposition. Despite the infinite-dimensional Hilb...

Magnetic tuning of quantum backflow: Schrödinger vs Pauli systemTier 3

Probability backflow is investigated for charged spin-1/2 particles in a uniform magnetic field within the lowest-Landau-level approximation. While single-mode Landau states exhibit only weak and non-robust backflow, it is shown that two-mode interference gives rise to negative probability flux in both the Schrödinger and Pauli formulations. In the Pauli case, orbital and...

Quantum Fisher information of driven-dissipative systems from Keldysh path integralsTier 3

Driven-dissipative many-body quantum systems can be exploited in quantum enhanced sensing protocols. Here, non-classical correlations may allow one to reach a measurement precision that surpasses the standard quantum limit. The relevant figure of merit for assessing such quantum advantage is the quantum Fisher information (QFI). In a many-body setting its computation is chal...

Hilbert-space fragmentation selects channels of strong-to-weak spontaneous symmetry breakingTier 3

Strong-to-weak spontaneous symmetry breaking (SWSSB) can occur in a maximally mixed charge sector even when ordinary charged correlations vanish. We study this order when a charge sector splits into dynamically disconnected fragments. In a one-dimensional t-J_z chain with species-resolved dephasing, each fragment is labeled by a conserved spin word. A charged transfer be...

I Prove, Therefore I Am: Spatiotemporal Multi-Party ComputationTier 3

Secure multiparty computation (MPC) enables mutually distrustful parties to compute on private digital inputs. We initiate the study of spatiotemporal MPC, extending this paradigm to functionalities whose inputs additionally depend on physical facts such as the parties' locations, times, or trajectories. Such protocols must simultaneously hide spatiotemporal information and...

Lattice Lindbladian simulation by patching and mergingTier 3

Simulating the dynamics of dissipative quantum many-body systems governed by local Lindbladians is a fundamental task in quantum computation. While the near-optimal gate count has been achieved for Hamiltonian simulation, comparable results for Lindbladian simulation remain elusive. In this work, we develop quantum algorithms for lattice Lindbladians by exploiting their loca...

Effective-Hamiltonian Quantum Solvers for Differential Equations: Alternative Constructions and Function EncodingsTier 3

Differential equations can be encoded as ground-state problems by constructing a positive-semidefinite effective Hamiltonian whose minimum-energy state represents the solution. We extend this framework in several directions. First, we show how multiple nonzero initial, boundary, and data conditions can be incorporated into the homogeneous formulation A | f⟩=0 using a...

Dynamical, thermal, and ground-state multiparameter quantum metrology: Fundamental limits and their attainability in magnetometryTier 3

We consider the simultaneous estimation of multiple parameters in Hamiltonians of the form H_θ= H_θ^P + H^C, where H_θ^P encodes the unknown parameters and H^C is a control term. We consider three basic paradigmatic frameworks for metrology: (i) dynamical, where the parameters are encoded unitarily, (ii) thermal, and (iii) ground state. We generalize...

On the Computational Complexity of Guided Berry Phase EstimationTier 3

We prove that deciding the Berry phase for parameterised 2-local qubit Hamiltonians is BQP-complete when presented with a classical description of a guiding state, promised to overlap with the ground state of the system. Our results extend to systems with weighted Heisenberg interactions and when restricted to a 2D square or triangular lattice geometry. The techniques we dev...

Nullspace-guided Adaptive Bootstrap of Quantum Many-body SystemsTier 3

We introduce a nullspace-guided adaptive (NGA) bootstrap method that improves the energy lower bounds of quantum many-body ground states by refining the bootstrap basis in a dynamic and incremental way. At each iteration, the optimized moment matrix reveals a nullspace of saturated positivity directions, which is intuitively interpreted as annihilators of the approximate gro...

On the Construction of Trapdoor Claw-Free Functions with Certifiable KeyTier 3

Trapdoor claw-free functions (TCFs) underpin much of classical-quantum cryptographic interaction, yet every TCF-based protocol states its guarantees relative to an honestly generated key. We give a family-agnostic abstraction of key certification for (noisy) TCF constructions, built on two notions: a certifiable key relation, an NP relation capturing a family's honest keys w...

Exponential Quantum Advantage in Testing Fourier DimensionalityTier 3

A boolean function f has Fourier dimension k if its nonzero Fourier coefficients span a subspace of dimension k. We consider the property testing task of determining whether a function has Fourier dimension at most k, or is ε-far from being so. We show that there is a Θ(k) quantum property tester for this problem. With Gopalan \etal's classical lower bound of $Ω(...

Photon-Statistics Control of Strong-Field Rydberg-State ExcitationTier 3

Photon statistics provides a new control dimension for strong-field bound-state formation. Using a quantum-optical phase-space formulation coupled to time-dependent Schrödinger-equation calculations, we show that field fluctuations enhance multiphoton Rydberg excitation by broadening AC-Stark-shifted resonances, but suppress tunneling-mediated recapture even as ionization in...

The Failure of Simultaneous Quantum TypicalityTier 3

We establish exact thresholds for the failure of simultaneous quantum typicality: three parties for mixed states and four for pure states. For the four-qubit Higuchi--Sudbery state, every sequence satisfying the expected purity bounds on three overlapping marginals, with sufficiently small fixed positive entropy slack, is asymptotically perfectly distinguishable from the ten...

Enhanced Atomic Magnetometry with a Pinched Spin StateTier 3

The sensitivity of an atomic spin sensor is fundamentally constrained by the quantum Fisher information (QFI) of the probe state. The pinched state, |F,0⟩, has an (F+1)-fold larger single-particle QFI for transverse-field sensing than the stretched state, |F,F⟩, corresponding to a predicted √(F+1) reduction in the spin-projection-noise-limited fie...

Post-Selection-Based Stochastic Quantum BatteryTier 3

Quantum batteries are quantum systems that store useful energy, which can subsequently be extracted to perform work. In this work, we investigate the charging dynamics under continuous measurements and post-selection-based non-Hermitian quantum battery realized by a three-level system. By post-selecting the trajectories with no quantum jump |1⟩→|0⟩,...

BQP ⊆IP Does Not RelativizeTier 3

We construct an oracle relative to which BQP not⊆IP, resolving a long-standing open question in quantum complexity theory. Together with recent work due to Aaronson et al., our work also gives the first oracle separation between IP and MIP, answering a question dating back to Fortnow's thesis. Our separation is based on the...

Stony Brook Hosts Congressional Briefing on Quantum TechnologyTier 2

Insider Brief PRESS RELEASE — Stony Brook University brought its leadership in quantum science and education to Capitol Hill on September 16, convening members of Congress, senior federal science officials and researchers from across the country for “Winning the Quantum Race: Workforce, Research and Innovation,” a congressional briefing focused on what it will take to...

Fermilab and Microsoft Partner on Quantum Hardware ToolsTier 2

Insider Brief PRESS RELEASE — The U.S. Department of Energy’s Fermi National Accelerator Laboratory is joining Microsoft Quantum as an initial partner in the company’s new quantum hardware makerspace in its newest quantum research center in the University of Maryland’s Discovery District. Here, researchers within the academia, industry, and government sectors will prov...

Microsoft Gives DARPA Access to Majorana System, Opens Maryland Quantum Research CenterTier 2

Insider Brief Microsoft has opened a quantum research center in Maryland that will house one of its topological quantum systems for independent testing by the Defense Advanced Research Projects Agency, widening the government’s role in evaluating the company’s path toward large-scale quantum computers. The 15,000-square-foot center, located in the University of Maryland’s Di...

An asymmetric atom-photon architecture for device-independent quantum key distribution over 25\,kmTier 3

Device-independent quantum key distribution (DIQKD) can guarantee security without trusting the internal workings of the measurement devices, but extending it to fiber networks demands high-quality entanglement, reliable heralding, and faithful photon transmission simultaneously. Here, we address these requirements in an event-ready asymmetric atom-photon architecture implem...

Quantum Advantage for Distributed Symmetry BreakingTier 3

We present a distributed quantum algorithm that $3$-colors cycles in O(1) rounds, with high probability. It follows that all locally checkable labeling problems (LCLs) that have round complexity O(log^* n) in the classical LOCAL model can be solved in O(1) rounds in the quantum-LOCAL model, with high probability; this includes problems such as maximal independent set...

Good Quantum Locally Testable Codes from Product ExpansionTier 3

We construct quantum locally testable codes (LTCs) with constant rate, distance, soundness and locality under a variant of a product expansion conjecture of Bafna and Vyas about Reed-Solomon codes. In particular, we use the high-dimensional expansion framework of Dinur, Lin and Vidick for constructing quantum LTCs, instantiated with the non-Abelian cubical complexes of Rungt...

A quantum lower bound for path finding in welded treesTier 3

In the welded tree problem, an algorithm is tasked with navigating a graph formed from two binary trees joined at the leaves through a ``weld'' of connecting edges. A quantum walk can navigate from root to root exponentially faster than any classical algorithm. However, known efficient quantum algorithms cannot find a path between the roots, as recording the path destroys co...

Transversal non-Clifford gates on good quantum locally testable codesTier 3

We achieve nontrivial transversal logical multi-controlled-Z gates with asymptotically optimal parameters simultaneously on quantum low-density parity check codes and quantum locally testable codes, by applying the gate framework of [arXiv:2604.01874] to the recent good qLTC construction of [arXiv:2609.20780]. To this end, we use the covering space method to construct a no...