July 22, 2026

Dark matter searches with a 13 meV threshold superconducting sensor array

Many well-motivated dark matter models predict meV-scale energy deposits in interactions with terrestrial experiments, but this regime is challenging to probe due to a lack of mature single-quantum detectors. Here we report results from QUALIPHIDE (QUAntum LImited PHotons In the Dark Experiment), a cryogenic dark matter search using a $41$-pixel array of energy-resolving mic...

Steady States of a Single Trapped-Ion Spin Coupled to an Engineered Non-Markovian Bath

Quantum simulation of open quantum systems offers a pathway towards better understanding various non-equilibrium physics that would otherwise be challenging to study. Most open quantum systems studied are modeled as obeying the Markov approximation, where the bath into which the system dissipates information is assumed to be unaffected by the system-bath interaction. However...

Gaussian Boson Sampling for Asset Clustering in Statistical Arbitrage Portfolios

Gaussian Boson Sampling (GBS) provides a native photonic quantum heuristic for sampling dense subgraphs from adjacency matrices, offering a scalable physical approach to combinatorial graph search problems. Simultaneously, correlation matrix clustering algorithms, such as Spectral and SPONGE, have established robust benchmarks for identifying co-moving assets from correlatio...

Simultaneous calibration of rotation and phase errors in a single experiment

In weakly anharmonic qubits, coherent control errors take two generic forms -- over/under-rotation and phase errors -- whose suppression normally requires iterated experiments. We show that, for any symmetric π/2 pulse in the weak-driving regime, both follow from a single parametrization, X(π/2)=Z(δ)X(π/2+ε)Z(δ), that ties the rotation error ε and the phase e...

A Reversible Continuous-Variable Photonic Memory Architecture Based on Displacement-Evolved Coherent-State Dynamics

Modern information systems increasingly require memory architectures capable of storing not only static data but also the evolution of information over time. While continuous-variable photonic platforms have been extensively studied for quantum communication and computation, their potential as dynamically evolving memory systems remains largely unexplored. In this work, we i...

Motional Kerr-Cat States of an Atom in an Optical Tweezer

Schrödinger cat states - quantum superpositions of classically or macroscopically distinct states - constitute a powerful resource for quantum computing, enhanced metrology, and probing coherence on large scales. Encoding such states in the phase space of an oscillator requires a nonlinearity, typically inherited from an auxiliary degree of freedom such as atomic spin or a J...

Nonlinear Optics Mediated by Chiral Waveguide QED: Generation of Momentum-anticorrelated Photon Pairs

In recent years, chiral quantum optics has emerged as an active research area due to the promising applications in quantum information processing as well as nonlinear optics. We present results on the properties of the incoherent component of the transmitted light after transmons chirally coupled to a waveguide. The well-known resonance fluorescence of one chiral transmon re...

Quantum Reservoir Computing: Recent Advances and Future Directions

Quantum reservoir computing (QRC) uses the dynamics of a fixed or weakly tuned quantum system to transform temporal and sequential inputs into measured features, while training is typically confined to a classical readout. This separation reduces reliance on repeated quantum parameter updates and avoids the barren plateaus associated with variational circuit training. Its co...

Bound state solutions of the Schrödinger equation for the atomic systems interacting with the radial screened Coulomb potential: analytical approximation methods

We investigate the bound state properties of the hydrogen-like atoms in the radial screened Coulomb potential (RSCP). using three complementary analytical approaches - expectation values with Coulomb and Kratzer reference states, variational optimization with a scaled Kratzer basis, and the Hellmann-Feynman theorem - we derive approximate energy eigenvalues as function of th...

Enhanced NQS via Annealed Gradient Descent

Neural quantum states offer expressive representations of quantum many-body wave functions, yet their practical accuracy can be limited by stochastic optimization rather than representational capacity. Here we identify a finite-sample instability, termed subspace trapping, in which physically important configurations become strongly underestimated, remain absent from success...

Quantum sensing of low-frequency electric signal enabled by modulated auxiliary field in Rydberg atoms

Rydberg atoms have emerged as a versatile and efficient platform for high-sensitivity quantum sensing of free-space electric fields, with remarkable progress in detecting low-frequency signals. To date, low-frequency Rydberg receivers have relied on a constant bias field, typically realized via intra-cell electrodes or Rydberg plasmas generated by photoelectric effects or in...

SoK: Adversarial Robustness of the Variational Quantum Eigensolver via Red-Teaming

The Variational Quantum Eigensolver (VQE) is a leading algorithm for estimating molecular ground-state energies on near-term quantum hardware, with applications spanning quantum chemistry, materials science, and drug discovery. As VQE workloads are increasingly deployed through cloud-based ``VQE-as-a-service'' pipelines, they become exposed to adversaries such as compromised...

Spontaneous optical emission of a randomly oriented chiral quantum source

We derive the form of the one-photon state of the electromagnetic field resulting from spontaneous optical emission of a randomly oriented chiral quantum source, including electric dipole, magnetic dipole, and electric quadrupole contributions to the radiation. We describe how spatial coherence in the emission can be exploited to reveal hidden information about the emitter....

Quantinuum and SoftBank Publish Framework Linking Quantum Hardware to Enterprise Use Cases

In a joint white paper published today, Quantinuum (NASDAQ: QNT) and Japan-based telecommunications conglomerate SoftBank Corp. have outlined a strategic timeline mapping industrial quantum chemistry and graph analytics workloads directly onto Quantinuum’s multi-generational hardware roadmap. The publication, titled "Quantum Computing Frontiers," establishes a framework t...

SAXON Q Launches 100+ Qubit Diamond-Based Room-Temperature Quantum Computers

German quantum computing startup SAXON Q has announced the commercial release of the SXQ128 (128 qubits) and the SXQ512 (512 qubits), marking the first diamond-based nitrogen-vacancy (NV) center quantum processors to exceed ten physical qubits. Spun out of Leipzig University, the company’s systems operate entirely at room temperature without requiring cryogenic refrigerat...

Photon Queue Raises $4M Oversubscribed Seed Round to Commercialize Room-Temperature Quantum Memory

Quantum hardware spin-out Photon Queue has closed an oversubscribed $4 million seed funding round led by Palo Alto-based deep-tech venture firm Playground Global. Additional investors in the round include Cerberus Capital Management, Illinois Ventures, Roadrunner Venture Studios, and MFV Partners. Spun out of the University of Illinois Urbana-Champaign in 2024, the Champa...

Maybell Quantum Deploys Dilution Refrigerators at Roadrunner Quantum Lab

Cryogenic infrastructure provider Maybell Quantum has announced a hardware and operational expansion into New Mexico, becoming the third major quantum equipment manufacturer to anchor the state's Roadrunner Quantum Lab (RQL). Headquartered in Denver, Colorado, Maybell will deploy a fleet of four dilution refrigerators at the Albuquerque-based facility, providing the ultra...

Joint Study by AWS, NVIDIA, LBNL, and NASA Establishes Framework for Quantum-HPC Integration

A cross-institutional research team comprising scientists from Amazon Web Services (AWS), NVIDIA, Lawrence Berkeley National Laboratory (LBNL), and NASA has published a quantitative performance model to evaluate when quantum processing units (QPUs) must be tightly co-located with classical high-performance computing (HPC) supercomputers—and when standard remote cloud conn...

BTQ Technologies and TIDAL PWR Partner to Develop Trusted Quantum Data Center Reference Architectures

Quantum infrastructure developer BTQ Technologies Corp. (Nasdaq: BTQ / Cboe CA: BTQ) has entered into a strategic collaboration with Texas-based power generation and data center developer TIDAL PWR. The partnership focuses on building a standardized, repeatable blueprint for integrating quantum processing units (QPUs) and post-quantum security protocols directly into next...

Quantum Synchronization

Natural and engineered classical systems are replete with examples of synchronization, understood as the adjustment of rhythms of physical systems. Such synchronization is at the heart of the stability of several classical technologies, such as mechanical bridges and electrical networks. Given the advent of quantum simulation and computation technologies, it is natural to st...

Perfect state transfer in Grover walks on normal Cayley graphs

A Cayley graph Cay(Γ,S) over a finite group Γ is said to be normal if its connection set S is a union of some conjugacy classes of Γ. This paper investigates perfect state transfer in Grover walks on normal Cayley graphs. The Grover walk is a widely studied discrete-time quantum walk. We establish a necessary and sufficient condition for the occurrence...

A general estimation framework for continuous-variable systems

We show that informational completeness, while sufficient to have a bijection between ideal measurement probabilities and quantum states, does not guarantee statistically stable reconstruction from finite measurement data. To address this problem, we develop a general estimation theory for continuous-variable systems in which stable reconstructibility is characterized by the...

Efficient quantum transport in disordered Floquet networks

We propose a mechanism for fast and efficient quantum transport through disordered networks with variable on-site energies, inspired by photosynthetic complexes. The mechanism relies on an interplay between inter-site couplings of the network and driving by external vibrations. Two design principles are shown to ensure close-to-perfect transport despite the disorder, namely...

The Limits of Quantum Computers for Power Flow

This letter proves realistic grid properties limit the applicability of quantum computers for power flow. Grids that split into two large regions meeting at only a few buses, common in transmission networks, force the pseudo condition number of the DC susceptance matrix to grow polynomially in the network size, and long chains of lines bridging such regions force quadratic g...

Teleportation Game: Quantum Teleportation in Multi-Agent Systems for Interactive Music

This paper introduces an interactive music system with quantum musical agents that communicate by teleporting quantum states to one another. Human performers interact in real time with agents whose melodic and rhythmic behaviours are encoded as quantum states using Single Qubit Probability Amplitude Modulation (SQPAM) and structured through Quantum Phase Estimation (QPE). Up...

Dynamical correlation functions of extensive charges after global quantum quenches

We investigate the n-time cumulant generating function (or n-Full Counting Statistics, n-FCS) of extensive U(1) charges following a quantum quench. Exploiting space-time duality we characterise this function when evolving from initial states that are symmetric under the action of the charge. In particular, we show that if the correlations in time are sufficiently wea...

Experimental quantum cryptography with single photons and imperfect devices

Quantum key distribution (QKD) allows for provably secure key distribution between two trusted parties. Because the security and performance of QKD protocols rely on devices that behave according to specific assumptions, idealized or inaccurate assumptions about device behavior can introduce security loopholes. Real devices can never be perfectly characterized, and their per...

The Thermodynamic Geometry of Conditional Control

Information is widely regarded as the resource underlying the thermodynamic advantages enabled by conditional control. We show, however, that informational quantities such as Holevo information and accessible distinguishability, although constraining the achievable advantage, do not uniquely determine its thermodynamic value. The missing ingredient is a passive spectral rear...

Boundary quenches in (1+1)-dimensional conformal field theory

We investigate a class of local quantum quenches in which the conformal boundary condition of a (1+1)-dimensional conformal field theory is abruptly changed. We derive a remarkably simple and universal expression for the time evolution of one-point functions on the half-line. This result provides a direct description of the propagation of the disturbance generated by the que...

Dimension Reduction for Quantum Adaptive Agents

Adaptive agents realise complex reactive behaviours by using a memory of past input stimuli and output actions to guide structured future responses. Quantum adaptive agents can operate while storing less information in memory than optimal classical counterparts; yet, this does not necessarily translate into a reduced dimension of the memory that must be physically realised....

Nonlinear Response via Sublinear Optics

Sublinear optical response, in which the emitted field scales as a fractional power of the driving field, lies beyond the conventional perturbative hierarchy of nonlinear optics. Here, we show that such a response can be engineered in a hydrogen atom using tracking control. Rather than prescribing the driving waveform, the field is determined self-consistently from the evolv...

Quantum Circuits for Quantum Spatial Search on d-Dimensional Lattices

We propose an explicit quantum circuit for quantum spatial search based on discrete-time quantum walks on d-dimensional lattices. In this algorithm, the flip-flop shift operator moves the walker to a neighboring site along the selected spatial direction and reverses the corresponding direction label after the move. By encoding each pair of opposite directions so that they...

The arrow of time, irreversibility, equilibrium and measurement in quantum mechanics

Quantum mechanics is widely recognised as being incomplete. It is not consistent with the second law of thermodynamics and does not provide a scientifically credible physical account of the measurement process, the means by which coherence is broken and classically observable states are recorded. This had led to many ad hoc assumptions being used to account for various prope...

Quantum limits to chiroptical molecular discrimination

Discriminating enantiomer pairs is of central importance in the molecular sciences. The preferential interaction between chiral light and matter is commonly employed in this discrimination, despite fundamental challenges. Here we present quantitative error bounds for classifying the handedness of a chiral, randomly oriented, quantum optical emitter from the perspective of cl...

Single Link Removal Perturbation in Szegedy Quantum Walk: from Graph Completeness Testing to Integrity Monitoring

We present a rigorous perturbative analysis of the Szegedy quantum walk search algorithm on the complete graph with marked nodes, when a specific anomaly is present in the graph. This is motivated by the problem of monitoring the integrity of dense trusted communication networks with a quantum-assisted procedure. The topology of these networks is modeled as a complete graph,...

Quasi-Non-Hermitian Edge Bursts Induced by Nonuniform Loss

Non-Hermitian quantum walks on lossy lattices with open boundaries can exhibit an anomalous peak of the loss probability at the boundary, known as the non-Hermitian edge burst (NHEB). This phenomenon has been attributed to the combined effect of the non-Hermitian skin effect (NHSE) and a gapless imaginary spectrum. Here we investigate a class of models in which the NHSE is i...

Lower Bounds on Spectral Gaps of Parent Hamiltonians via Tensor Networks

Proving spectral gaps above the ground space is a central problem in quantum many-body physics. Yet, finding lower bounds on the gap is notoriously difficult. We revisit the martingale method, originally developed by Fannes, Nachtergaele, and Werner [Fannes '92, Nachtergaele '96] to prove the existence of spectral gaps of parent Hamiltonians of Matrix Product States (MPS), a...

How to improve the discrimination power of classically simulable measurements?

Classically simulable measurements (CSMs) constitute an important class of restricted measurements in the odd-prime-dimensional magic resource theory, referring to those measurements with positive discrete Wigner functions. Since their discrimination power is weaker than that of global measurements, it is necessary to study how to improve the discrimination power of CSMs. In...

Metric completion of the Bender--Brody--Müller Hamiltonian: dilation spectrum and missing eigenstates

The Bender--Brody--Müller (BBM) Hamiltonian was proposed as a non-Hermitian Hilbert--Pólya operator. We analyze the Hilbert completion induced, on the standard half-line L^2 core, by BBM's candidate metric η=sin^2(p/2)=Δ^†Δ/4. The form η_0=Δ^†Δ is positive with trivial kernel but is not coercive. Completing C_c^∞(0,∞) in the norm $\|ψ\...

Bound Entanglement Is Insufficient for an Exponential Quantum Learning Advantage

While entanglement is known to enable exponential improvements in the sample complexity of quantum learning, it remains unclear which properties of entangled resources are responsible for such improvements. We address this question through the reduction criterion, a condition obeyed by all bound-entangled states. In n-qubit Pauli-channel learning, we show that restricting...

Sixteen-State Energy Mapping for First-Principles Four-Spin Ring Exchange: Validation on La_2CuO_4 and SrFeO_2

Four-spin ring (cyclic) exchange J_(ring) is an essential ingredient of the Heisenberg spin Hamiltonian of cuprates and other square-lattice magnets, yet it has lacked the kind of direct, local first-principles extraction that the four-state method provides for bilinear exchange, J. We supply it by generalizing that method to a sixteen-state (2^4) scheme. Symmetry redu...

Coherent-disorder-driven complexity transitions in a quantum-advantage architecture

While decoherence is known to erode classical hardness in quantum random sampling, the impact of coherent spatial disorder remains an open question. We study a square-lattice instantaneous quantum polynomial-time (IQP) architecture subject to two-qubit gate-angle disorder and single-qubit dephasing using exact tensor-network simulations up to 576 qubits. For finite systems w...

Collective Coherent Perfect Absorption in a Synthetic Photon-Phonon Lattice

Coherent perfect absorption (CPA) has emerged as a powerful paradigm for controlling classical and quantum light, and has been demonstrated across a broad range of physical platforms. CPA realized in optomechanics relies on interference between the input field and the mechanically scattered field, but is intrinsically confined to the weak-cooperativity regime, resulting in a...

MOSAIQC: Mixed-topology-aware Optimization for Scalable Approximate noise-Informed Quantum circuit Cutting

Current quantum computers do not yet have the required qubit resources to meet the demands of most practical quantum algorithms. To circumvent this constraint, the practice of dividing these algorithms into parts through quantum circuit cutting has been explored. Many of these works either show exponential scaling or are far from optimal solutions. In this paper, MosaiQC is...

Quantum Dynamics of H_2^+ in Orthogonal Two-Color Fields

We present full-dimensional quantum simulations of H_2^+ dissociative ionization driven by strong orthogonal laser fields. We consider equal-frequency orthogonal components, which generate elliptical or circular polarization depending on their relative phase and amplitude, as well as orthogonal $800$- and $400$-nm two-color fields. These two-dimensional fields strongly mod...

Quantum-Enhanced Multi-Objective Optimization

Multi-objective combinatorial optimization requires identifying Pareto-optimal trade-off solutions among conflicting objectives, often making it more demanding than its single-objective counterpart. Although quantum multi-objective optimization methods have begun to emerge, most existing quantum optimization workflows are still built around single-objective or fixed-scalariz...

Collective modes in non-Hermitian fermionic superfluids

The Higgs and Nambu-Goldstone modes are paradigmatic collective excitations in superconductors and superfluids. These modes are commonly analyzed within the pseudospin formulation of BCS theory, where the dynamics are obtained from the Heisenberg equations of motion for pseudospins. However, this construction becomes inconsistent when directly extended to non-Hermitian syste...

Simulating Majorana fermions in black hole with Ising Models

Quantum field theory (QFT) in curved spacetime has led to profound predictions, including the Unruh effect and Hawking radiation, yet their direct observation remains extraordinarily challenging because of their extremely weak signatures. Here, we show that the transverse-field Ising model provides a quantum simulator for Majorana fermions in a Schwarzschild black hole backg...

Quantum Sensing Beyond Exceptional Points via Hidden symmetry-protected vacuum-noise fixed point

Exceptional-point (EP) sensing has attracted considerable interest because of its anomalous response scaling. However, recent studies have shown that the enhanced response near an EP is inevitably accompanied by amplified quantum noise, fundamentally limiting the achievable signalto-noise ratio (SNR). Here, we propose a fundamentally different route toward non-Hermitian quan...

Trade-off between predictability and quantum coherence for multi-path interferometry and its operational interpretation

The complementarity principle is a cornerstone of quantum mechanics. In this work, we investigate a complementarity relation between the predictability and quantum coherence, respectively, representing the particle-like and wave-like behaviour in wave--particle duality, in a multi-path setup. We introduce a basis-dependent predictability defined by the Bures distance between...

Monogamy inequalities of entanglement of assistance in 2⊗2⊗d systems

The monogamy relations characterize the distribution of quantum correlations among the multipartite quantum systems. We study the monogamy relations of the entanglement of assistance in 2⊗2⊗d systems. We present explicitly the relations satisfied by the concurrence, the tangle and the concurrence of assistance, which can be used to derive rigorous monogamy re...

Dismantling the Stoquastic Dichotomy

We challenge the notion that a stoquastic binary governs fundamental computational boundaries in quantum computing and classical simulation of quantum systems. We argue that vanishing geometric phase (VGP), a geometric condition on the Hamiltonian's transition graph, more adequately captures these boundaries. To distinguish VGP from stoquasticity, we construct VGP 3-local Ha...

From Canonical to Tunable Phase Diagrams in Open Quantum Long-Range Systems

We investigate the dissipative dynamics of a generalized Lipkin-Meshkov-Glick (LMG) model coupled to a thermal environment. In this generalized model, in addition to the conventional quadratic interaction, one considers quartic interactions between spin-1/2's coupled all-to-all and evolving in presence of a transverse field. Employing the usual linear Lindblad master equat...

State k-designs from Hamiltonian evolution

We study the generation of state k-designs from time evolution under a fixed Hamiltonian. Specifically, we consider the ensemble E={e^(-iHt)|ψ_0⟩| t~Unif[0,T], |ψ_0⟩~E'}, where the initial states are sampled from an ensemble E'. For Hamiltonians drawn from the Gaussian unitary ensemble, we der...

QuantX Labs Achieves In-Orbit Commissioning of World’s First Space-Based Optical Frequency Comb

South Australian deep-tech pioneer QuantX Labs has announced the successful in-orbit commissioning and operational verification of its space-qualified optical frequency comb. Supported by the Australian Space Agency's Moon to Mars Demonstrator Program, the achievement marks the first time an optical frequency comb has been deployed and successfully operated in the space e...

New Mexico Awards $1.2M to Expand State Quantum Cluster Across Six Tech Startups

The Technology & Innovation Office (TIO) of Economic Development New Mexico has awarded $1.2 million in non-dilutive capital through the inaugural New Mexico Quantum Technologies Award. Divided into competitive $200,000 grants, the program funds early-stage hardware, optics, and software developers committed to expanding or establishing operational hubs in the state....

Bloch Quantum Tech Hub Secures $55M in Federal and Matching Grants to Build U.S. Quantum Supply Chain

The U.S. Department of Commerce’s Economic Development Administration (EDA) has selected The Bloch Quantum Tech Hub for a $30 million federal implementation award. Managed by the Chicago Quantum Exchange (CQE), the multi-state consortium spans Illinois, Indiana, and Wisconsin—a region referred to as the "Quantum Prairie". The federal award has unlocked an additional $25 m...

Main Sequence Promotes Alejandra Romero to Principal

UK Government Puts AI at Cabinet Level as DSIT Is Dissolved, Raising Questions For Quantum Strategy