May 6, 2026

FTPrimitiveBench: A Benchmark Suite For Logical Computation Under Hardware-Motivated and Biased Noise Models

Fault-tolerant quantum computing requires understanding how error-correcting codes perform on diverse physical hardware. This is typically assessed via noisy stabilizer simulation of logical circuits at HPC scale, combined with a noise model that yields a logical error rate for the relevant code distances and depths. The uniform depolarizing model is the standard baseline, b...

Fast, accurate, high-resolution simulation of large-scale Fermi-Hubbard models on a digital quantum processor

We report experimental digital quantum simulation of the one-dimensional Fermi-Hubbard model on a superconducting quantum processor at a scale beyond the reach of exact statevector simulation and challenging for state-of-the-art tensor-network methods. We encode this problem using up to 120 qubits through an efficient mapping that reduces circuit complexity, and we improve a...

Regev's reduction as a candidate quantum algorithm for the discrete logarithm problem in finite abelian groups

We revisit the reduction of Cheng and Wan, which transforms instances of the discrete logarithm problem (DLOG) over finite fields into a decoding problem for Reed--Solomon codes, and study how Regev's reduction can be used to solve these instances. Regev's reduction turns a decoder for a code into a quantum solver for a decoding problem on the dual code. The quantum advantag...

An extensive theory of nonlinearly intercoupled pseudomodes for noise model reduction in circuit QED

Superconducting circuit quantum electrodynamical (cQED) platforms present a persistent modeling challenge: the intrinsic nonlinearity of the Josephson potential couples to a dissipative electromagnetic environment in ways that resist both perturbative treatment and naive Markovian reduction. Standard approaches either scale poorly with system size or absorb undeclared approx...

Magic-Informed Quantum Architecture Search

Nonstabilizerness, commonly referred to as magic, is a fundamental resource underpinning quantum advantage. In this paper, we propose a magic-informed quantum architecture search (QAS) technique that enables control over a quantum resource within the general framework of circuit design. Inspired by the AlphaGo approach, we tackle the problem with a Monte Carlo Tree Search te...

Variational Joint Magnetometry and Gradiometry on Dipolar Spin Chains

Estimating a uniform magnetic field B0 and its spatial gradient g on a dipolar-coupled spin chain calls for a multiparameter figure of merit. The GHZ state, optimal for single-parameter Heisenberg-limited sensing, has a rank-one quantum Fisher information matrix with det(Q^GHZ) = 0 at every chain length N, ruling it out for the two-parameter problem. We present a variational...

Space-Time Tradeoffs of Pauli-Based Computation in Distributed qLDPC Architectures

Pauli-based computation (PBC) provides a universal framework for executing fault-tolerant quantum algorithms using Pauli measurements and magic states. In monolithic architectures, the serialized nature of PBC directly ties runtime to a circuit's T-gate count, making it slow on metrics like circuit depth. However, in distributed quantum computing (DQC), the primary bottlenec...

Telecom-band quantum memory with chlorine defects in silicon carbide

Realization of quantum memory with a photonic interface in the telecommunication bands in a wafer-scalable platform is a central requirement for long-distance quantum networks. Silicon carbide (SiC) provides a technologically mature host for integrated quantum photonics, yet only a limited number of defects combine spin functionality with telecom emission. Here we report on...

Ergotropy Protection via Cavity Detuning in Collective Open Quantum Batteries

This study investigates the performance and ergotropy protection of open collective quantum batteries subject to superradiant decay. By employing a passive spectral detuning strategy within an intermediate cavity, an optimal detuning value (Δ^*) is analytically derived and numerically verified to spectrally isolate the system and protect quantum coherence, achieving up to...

Selecting optimal unrestricted Hartree-Fock trial wavefunctions for phaseless auxiliary-field quantum Monte Carlo: Accuracy and limitations in modeling three iron-sulfur clusters

Phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) has emerged as a promising electronic structure method for correlated electronic systems. However, the quality of its predictions depends critically on the choice of trial wavefunction, and it is not obvious how to make an optimal choice especially for strongly correlated states of large systems. Mean-field wavefunctio...

Fisher-Informational Time: A Causal-Geometric Framework for Emergent Clock Time Physical Distinguishability

We develop a Fisher-informational reformulation of physical time in which clock time is not regarded as a fundamental ontological substance, but as an emergent calibration of causally ordered distinguishability among physical states. The operational starting point is that clocks do not measure time itself; rather, they instantiate reproducible physical processes whose distin...

Time-dependent variational Monte Carlo without bias

When combined with highly expressive ansatz functions such as neural quantum states, variational Monte Carlo (VMC) constitutes a versatile numerical approach to tackle the quantum many-body problem in and out of equilibrium. However, its traditional formulation exhibits a subtle estimation bias leading to inaccuracies, which can be particularly detrimental when addressing re...

Graph Neural Networks in the Wilson Loop Representation of Abelian Lattice Gauge Theories

Local gauge structures play a central role in a wide range of condensed matter systems and synthetic quantum platforms, where they emerge as effective descriptions of strongly correlated phases and engineered dynamics. We introduce a gauge-invariant graph neural network (GNN) architecture for Abelian lattice gauge models, in which symmetry is enforced explicitly through loca...

Parameterized Families of Toric Code Phase: em-duality family and higher-order anyon pumping

Within the toric-code phase, we study parameterized families of topologically ordered states. We construct $1$- and $2$-parameter families of local Hamiltonians and confirm their non-triviality via topological pumping. For the $1$-parameter family, we show that the em-exchange defect is pumped into the bond Hilbert space of a tensor-network representation. For the $2$-para...

The power of entanglement in distributed quantum machine learning

The quantum internet aims to interconnect distant devices and enable large-scale computation through distributed quantum algorithms. One of the key obstacles is communication latency during computation. Even separations of a few hundred kilometers introduce millisecond-scale delays, which exceed the coherence times of many solid-state qubit platforms. In contrast, entangleme...

Quantum Multi-Level Estimation of Functionals of Discrete Distributions

We propose a quantum multi-level estimation framework for a functional Σ_(i=1)^n f(p_i) of a discrete distribution (p_i)_(i=1)^n. We partition the values p_i into logarithmically many intervals whose length decays exponentially. For each interval, we perform non-destructive singular value discrimination to isolate the relevant p_i, enabling adaptive estimation of...

Ensemble Engineering to Overcome Destructive Cancellation in Quantum Measurements

On noisy intermediate-scale quantum (NISQ) devices, expectation values of many observables are obtained through sampling-based approximations to trace-like quantities. A central limitation of this approach is destructive cancellation under near-uniform ensembles, which can render physically relevant signals effectively unresolvable. Here we show that this limitation is not s...

Quantum Vault: Secure Token Authentication Without Classical State Information Benchmarked on IBMQ

Quantum tokens are underlying primitives for quantum money and network proposals, which leverage the no-cloning theorem to realize unforgeable authentication. A relevant but overlooked type of attack to such architectures is a hacker that steals the classical side information of the token states from the issuing agent (e.g. a bank), allowing the forgery of fake tokens withou...

BBQ-mIS: a parallel quantum algorithm for graph coloring problems

Among the limitations of current quantum machines, the qubits count represents one of the most critical challenges for porting reasonably large computational problems, such as those coming from real-world applications, to the scale of the quantum hardware. In this regard, one possibility is to decompose the problems at hand and exploit parallelism over multiple size-limited...

AQT Reports Quantum Volume of 32768 on LYNX System

Quantinuum and BMW Group Expand Quantum Computing Collaboration with New Multi-Year Partnership

Clemson University Launches Quantum Sentinel Initiative to Advance Cybersecurity of Smart and Connected Cities

eleQtron Secures €57 Million in Series A Funding Round

Cleveland Clinic, RIKEN And IBM Model a 12,635-Atom Protein — The Largest Known to Be Simulated With Quantum Computers

Sequential vs. Simultaneous Entanglement Swapping under Optimal Link-Layer Control

Connection-less, packet-switched quantum network architectures distribute entanglement across multi-hop paths through sequential entanglement swapping, in which each node acts on purely local state information. The architectural advantages over the connection-oriented alternative -- simultaneous SWAP-ASAP -- are compelling, but sequential swapping holds partial chains in int...

Entanglement transitions in translation-invariant tensor networks

We study the complexity of approximately contracting translation-invariant tensor networks. The computational cost of row-by-row tensor network contraction, which defines a discrete time evolution governed by a fixed transfer matrix, is associated with the entanglement of the state of a row. By analyzing a family of tensor networks whose transfer matrices interpolate between...

Quantum work beyond classical (commuting) limits

Free energy fixes the maximum work of a thermodynamic process once the state and Hamiltonian are specified. A work-extraction task asks a different question: how much average work can a single device realize across several preparations and Hamiltonian settings? A classical work device is one whose Hamiltonian settings are mutually commuting. We place every branch at its best...

Entangling gates for the SU(N) anyons

The model of a topological quantum computer is a promising one due to its natural resistance to noise and other errors. Operations in such a computer are implemented by braiding the trajectories of anyons. While it is easy to understand how to build one-qubit operations, two-qubit operations are more difficult. In arXiv:2412.20931 we suggested an approach to build such opera...

Nonlinear Compton scattering in a frequency-modulated field

When an electron is accelerated, it emits radiation. In the relativistic quantum realm the elementary radiation process is the emission of a single photon, a process known as nonlinear Compton scattering in the case of an electron moving in the presence of a strong electromagnetic wave. This process is typically described within the Furry picture, where the electromagnetic w...

Quantum Dispersive Waves and Multimode Squeezing in Pure-Kerr Parametrically Driven Cavity Solitons

Parametrically driven cavity solitons (PDCS), unlike single-pumped cavity solitons, are localized optical pulses arising from parametric processes. These cavity solitons, recently discovered in pure-Kerr media, offer great promise for nonlinear dynamics studies and metrology. Here, we present the first multimode quantum description of pure-Kerr PDCS. In the below threshold r...

Phase-Reference Control of Steady-State Entanglement in Open Quantum Systems

We show that steady-state entanglement in open quantum systems is controlled by the phase reference of a phase-sensitive reservoir. Using a covariance-matrix approach for Gaussian-preserving dynamics, we demonstrate that purely local, phase-sensitive dissipation can generate entanglement when combined with coherent coupling. The steady state exhibits a finite entangled regio...

Quantum metrology of mixed states via purification

We introduce new formulations of the quantum Cramér-Rao bound (QCRB) and the Holevo Cramér-Rao bound (HCRB) in multi-parameter quantum metrology via purification, where we show their values for any mixed state are connected to that for its purification with nuisance parameters introduced on the environmental system. Using this technique, we develop a new method for asymptoti...

Factoring $2048$ bit RSA integers with a half-million-qubit modular atomic processor

Shor's algorithm is one of the most promising applications of quantum computers. However, since ~10^6 physical qubits are believed to be required for established approaches, the algorithm will need to be distributed across many modules. In this paper, we provide a distributed compilation of Shor's algorithm on a modular atomic processor. We present an end-to-end compil...

Inverse-designed release-free optomechanical crystal with high photon-phonon coupling

Interactions between light and mechanics provide a powerful interface between optical and microwave-frequency signals, with applications spanning classical signal processing and quantum technologies. High-performance optomechanical devices require both strong photon-phonon coupling and tolerance to parasitic laser heating. Release-free optomechanical crystals provide improve...

Path integral quantization of the electromagnetic field in nonlinear dielectric materials

We construct a quantum theory of light in nonlinear dielectric media with dispersion and absorption. We employ a mesoscopic model for the light-matter interaction that include a fourth-order nonlinearity in the material response. Quantization is performed by constructing an effective action in a path-integral formalism by integrating out matter and bath degrees of freedom. W...

Reply to Comment on "Controlling the Dynamical Evolution of Quantum Coherence and Quantum Correlations in e^+e^- →ΛΛ Processes at BESIII"

We thank the Commentator for his detailed critique, which provides an opportunity to clarify the physical foundations of our work. While we appreciate the emphasis on rigor when applying quantum information concepts to high-energy physics (HEP), we respectfully disagree with the assertion that our assumptions lack a physical or operational basis. In the following sections, w...

A Berry-Esseen Bound for Quantum Lattice Systems

It is expected that the statistical fluctuations of local observables in large quantum systems obey the central limit theorem, and approximate a normal distribution as their size grows. Here, we prove a version of the Berry-Esseen theorem for quantum lattice systems, which strengthens that central limit theorem by providing a rigorous convergence estimate towards the normal...

Coherent transport in non-Abelian quantum graphs

We study quantum charge transport in two-dimensional networks in the presence of a magnetic field and spin-orbit interaction. The interplay of the corresponding Abelian and non-Abelian gauge fields leads to an intricate behavior of the conductance, which has different periodicities in the diffusive and ballistic regimes. We classify all configurations of magnetic and spin-or...

The Geometric Part of Decoherence: Quasi-Orthogonality in High-Dimensional Hilbert Spaces

We isolate a geometric mechanism that complements the dynamical suppression of macroscopic interference: In a high-dimensional Hilbert space, almost all state vectors are nearly orthogonal, accommodating an exponentially large reservoir of mutually quasi-orthogonal environmental records. This geometry explains why macroscopic alternatives fail to exhibit visible interference...

Caustics and catastrophes in strong-field physics -- Picard--Lefschetz theory as a universal approach to saddle-point methods in attosecond science

Ultrashort laser pulses on the attosecond timescale are typically achieved via high-order harmonic generation (HHG), a nonlinear process in which atoms interact with intense light fields to emit a broad spectrum of harmonics. HHG is commonly described in terms of a `quantum orbits' model based on several interfering electron trajectories, thereby incorporating both quantum-m...

Computation of entanglement for quantum states by a Consensus-Based Optimization method

The computation of quantum entanglement can be formulated as a high-dimensional nonconvex optimization problem with orthogonality constraints. In this work, we propose structure-preserving consensus-based optimization (CBO) methods for entanglement computation, with one approach based on a Hermitian formulation and the other evolving directly on the unitary manifold. To hand...

A density-matrix derivation of the Hartree--Fock equations in a nonorthogonal atomic-orbital basis

We present a pedagogical derivation of the Hartree--Fock equations using the second-quantization atomic-orbital density-matrix formalism developed by Kjærgaard, Jørgensen, Olsen, Coriani, and Helgaker for AO-based response theory. The purpose is to introduce an alternative derivation of the Hartree--Fock equation, showing that the standard AO Hartree--Fock stationarity condi...

Design and Analysis of Quantum Dual-Containing CSS LDPC Codes based on Quasi-Dyadic Matrices

Building scalable quantum computers requires quantum error-correcting codes that enable reliable operations in the presence of noise. Motivated by such need, this paper introduces two constructions of high-rate, quantum dual-containing (DC) Calderbank-Shor-Steane (CSS) low-density parity-check (LDPC) codes based on quasi-dyadic matrices. Their DC structure enables the transv...

Construction of a Non-Linear Entanglement Witness Operator in Arbitrary Dimension Using a Given Linear Witness Operator

Entanglement detection is one of the important problems in quantum information theory. To deal with this problem, many entanglement detection criteria have been proposed. Among the proposed criteria, the detection of entanglement through witness operator (also known as linear entanglement witness (LEW) operator) may be considered as the most practical. Although the witness o...

Experimental demonstration of a coherent detector blinding attack on a real CV-QKD system

Continuous-variable quantum key distribution provides a theoretical unconditionally secure solution to distribute symmetric keys among users in a communication network. However, the practical devices used to implement these systems are intrinsically imperfect, and, as a result, open the door to eavesdropper attacks. In this work, we present a novel implementation of a cohere...

Sensitivity limits of non-stationary quantum sensors

The concept of the dissipative quantum limit (DQL) was first put forward in 1980s and was analyzed in detail much later in Ref. [Phys. Rev. A 103, 043721 (2021)] for the particular case of stationary (invariant with respect to a shift of time) systems. Here we extend that analysis to the general non-stationary case.

Shortest Path in Pauli Forest -- An Algorithm for Decomposing Pauli Exponentials to Quantum Circuits

Decomposing Pauli exponentials efficiently to quantum circuits has been the subject of intense research in recent years. Pauli exponentials are an essential component of many different quantum algorithms. Due to the error-prone nature of current and near term quantum devices, it is crucial that quantum circuits are as compact as possible. Several different types of algorithm...

KIST Accelerates U.S. Expansion of Quantum Deep-Tech Startups Through SelectUSA 2026

QuantWare Raises $178 Million to Build Quantum Processors at an Industrial Scale

In NASDAQ Debut, Horizon Quantum Reports It’s Scaling Up Software And Hardware Strategy

Quantum Art Advances Wave Propagation Modeling with Quantum Methods

Quantum Machines Acquires QHarbor