August 20, 2026

Connectivity--Interference Competition in Coherent Transport on Percolated Hierarchical Small-World Networks

Adding links generally improves classical transport by increasing the number of available paths. We show that coherent quantum transport can display the opposite behavior. Using continuous-time quantum walks on a percolated hierarchical small-world network, we identify a coherent overconnectivity penalty: root-to-boundary transport is maximized at intermediate bond probabili...

Quantum circuit optimization using deep reinforcement learning: Applications across multiple gate sets

The practical implementation of quantum algorithms on noisy intermediate-scale quantum devices encounters operational limitations due to decoherence and other sources of noise inherent in real hardware. To mitigate these errors while preserving the original functionality of the algorithm, shorter quantum circuits are therefore preferred. This motivates the development of eff...

Quantum Magic in High Energy Collision

Quantum magic, or nonstabilizerness, is a quantum resource associated with computational advantage in quantum systems. In high energy collisions, Quantum Electrodynamics (QED) is inefficient at generating magic while the weak mixing angle, a fundamental constant of nature, sits near a value that minimizes magic production in charged-lepton scattering. These observations were...

Realizing Logical Diagonal Gates via Transversal Physical Z-Rotations in CSS Codes

Calderbank-Shor-Steane (CSS) codes, constructed from nested classical codes C_2 ⊆C_1, are typically optimized for good code parameters. However, practical quantum computing equally demands fault-tolerant logical gates. In this work, we characterize nested pairs (C_1, C_2) whose resulting CSS codes realize a target logical diagonal gate via transversal physical $...

RushHour: A Dynamically Reconfigurable Lattice-Surgery Architecture

Practical fault-tolerant quantum computing (FTQC) requires efficient lattice surgery (LS), so that large algorithms fit on resource-constrained quantum chips. Existing approaches, however, are rigid: qubits, routing space, and resource states are allocated ahead of execution, which prevents running on small chips, leaves statically scheduled executions with large time overhe...

Subsystem Symmetries and Fracton Models in Quantum Error Correction

Constructing new quantum codes and understanding their error resilience are central challenges in the development of robust quantum memories. Topological codes are particularly promising due to their favorable error-correcting properties and their connections to phases of matter in many-body physics. In this thesis, we explore the interplay between classical Ising models and...

An ultra-bright, highly-scalable, squeezed light source for hybrid quantum photonics

Hybrid quantum photonics seeks to combine the complementary advantages of continuous- and discrete-variable quantum optics. This typically entails photon-counting measurements on entangled states generated by interfering many single-mode squeezed-vacuum (SMSV) states. However, because conventional photon-counting schemes are mode-insensitive, it is critical that the SMSV sta...

AlphaClifford: Efficient Clifford Synthesis and Transpilation with Model-based RL

Clifford circuits play a foundational role in quantum computing, particularly due to their importance in quantum error correction and fault-tolerant logical synthesis. While these circuits can be efficiently simulated and represented as symplectic matrices, standard synthesis methods-such as the Aaronson-Gottesman algorithm-often yield sub-optimal circuits with excessively h...

Bernstein-Vazirani Networks: Quantum Machine Learning by Interference

We introduce Bernstein-Vazirani Networks (BVNs), a non-variational quantum machine learning framework that leverages quantum interference for supervised learning, demonstrated on vision and representation learning tasks. In their standard form, BVNs follow the principle of quantum Fourier sampling: labelled data are placed in superposition and interfered in the Fourier basis...

Interface Capacity and Architectural Replenishment Determine Entanglement-Generation Speed in Quantum Networks

We show that entanglement-generation speed across a fixed network interface is governed by two distinct resources: the entangling capacity of the interface itself and the ability of the surrounding architecture to replenish it with fresh degrees of freedom. For fermionic Gaussian dynamics, we derive the coefficient-sharp bound Σ_k|dotθ_k|≤1/2‖K_(AB)‖_* on the...

Quantum Tensor Network Learning with DMRG

Tensor Networks are a relatively new machine learning approach. The architectures proposed initially are inspired by approaches from quantum many-body physics simulations. One common layout is the matrix product state (MPS) also known as a tensor train optimized with gradient descent techniques. We introduce a global normalization condition, so that the MPS represents a quan...

The exact price of local realism in CHSH experiments: a measurement-dependence-detection trade-off surface, a moiré phase-locking mechanism that saturates it, and an unmeasured fringe in the fourfold coincidence sum

For local hidden-variable accounts of the CHSH experiment that are faithful -- reproducing the observed singles and coincidence rates and unbiased marginals of a polarization singlet with symmetric detector efficiency η_(rmeff) -- I determine the minimal measurement dependence M (Hall's variational measure) needed to achieve a CHSH value S. Linear programming over al...

Secure Medical Data Transmission Using Quantum Key Distribution and Post-Quantum Cryptography in Real-World Fiber Networks

The threat quantum computers pose to classical public-key cryptography motivates the deployment of quantum-safe communication for critical infrastructure such as healthcare, finance, and energy systems. Quantum key distribution (QKD) and post-quantum cryptography (PQC) offer complementary security guarantees, information-theoretic key exchange and quantum-resistant end-to-en...

A single design choice determines whether machine learning models of materials make physically impossible predictions

Machine-learned models are replacing first-principles calculations across materials discovery, and physical symmetry is the central guarantee built into them. The debate over how much symmetry to hard-wire rather than learn has run on rotations, where a symmetry error is an approximation error. Some constraints are exact: symmetry forces certain property tensors to exactly z...

Direct fidelity estimation through joint fiducial grouping

Fault-tolerant quantum computation hinges on the requirement for low physical error rates. Reaching below threshold regime requires the accounting of circuit dependent noise, that is inherent to the execution context in which a quantum gate is usually embedded. Direct fidelity estimation is a technique that offers natural context preservation as it solely requires the insert...

Sampling isometric tensor network states with monitored quantum circuits

Projected entangled pair states (PEPS) provide an efficient variational ansatz for two-dimensional quantum phases, but computing observables remains challenging because PEPS contraction is generally costly. Here, we parameterize two-dimensional quantum states using variational PEPS subject to isometric constraints and map the resulting ansatz onto monitored quantum circuits,...

Electrostriction in a Bose-Einstein Condensate of Dipolar Molecules

The recent creation of a Bose-Einstein condensate (BEC) of dipolar molecules has opened a new frontier for many-body quantum systems in which dipolar interactions can drive novel self-organization phenomena. Here, we observe electrostriction in a molecular BEC, an elliptical deformation driven by anisotropic dipolar interactions. We use double microwave dressing, involving $...

3D trapping of a meta-atom in an intensity minimum

High-refractive-index particles have recently attracted a growing interest in optical levitation experiments, offering the ability to further engineer optical forces through electromagnetic Mie resonances. Unlike standard silica particles, which are predominantly trapped in the dipole regime and exhibit trap frequencies mainly determined by material density, resonant meta-at...

Diraq Opens First U.S. Quantum Laboratory in Chicago

IBM Connects Two Modular Cryogenic Systems for Quantum Computing

New Tantalum Process Could Ease Manufacturing of Superconducting Quantum Chips

IonQ and CMC Microsystems Announce Collaboration to Expand Cloud Quantum Computing Access in Canada

State--Generator Geometry of Open Quantum Systems: Compatibility and Covariant Transport

We develop a geometry for transporting stationary-state response across the control space of an open quantum system. A physical model is represented by the ordered pair of its stationary state and dynamical generator. Embedding these pairs in a common ambient space induces a metric, a response one-form, and a closed two-form on the control manifold. The ambient space admits...

Quantum Speedups Require Structure or Depth

One of the most basic conjectures in quantum complexity theory states that every t-query quantum algorithm can be simulated on most inputs by a poly(t)-query classical algorithm. If true, this would provide broad justification for the need for structure in quantum speedups. We settle this conjecture for parallel quantum algorithms, showing that every t-query $...

Entanglement battery and entanglement catalyst in local state discrimination problems

In this work, we study the limitations and advantages of using entanglement battery and entanglement catalyst in local state discrimination problems. We consider both cases of such tools, i.e., exact and approximate cases. We show that to distinguish any set of orthogonal pure bipartite entangled states perfectly under local operations and classical communication using an (e...

Non-Local Search-to-Decision Reduction over F2

Non-local search-to-decision asks whether two noncommunicating parties, given the two shares of a bipartite encoding of a uniformly random string x∈F_2^n, can both predict the same random parity ⟨r,x⟩ without there also being local measurements with which both parties recover x. We prove that if their optimal probability of both recovering x...

Distinct Modes of Quantum Information Transfer in Power-Law Long-Range Spin Networks

We identify different regimes of quantum state transfer in long-range coupled spin-1/2 systems, where naturally occurring power-law interactions enable rapid, high-fidelity transfer with minimal engineering. Across a broad range of interaction profiles, from effectively nearest-neighbour coupling to Coulomb interactions, we show how long-range connectivity fundamen...

Molecular Implementation of the Machine-Learned Skala Exchange-Correlation Functional in CP2K through GauXC

Machine-learned exchange--correlation (XC) functionals offer a route to improve Kohn--Sham density-functional theory without incurring the cost of explicitly correlated electronic-structure methods. Their use in production simulation codes, however, requires a well-defined mapping between the learned model and the host-code density representation. We formulate and implement...

Deviation from linear reduced dynamics always occurs for each non-factorisable system-environment unitary evolution

In the simplest approximation, the reduced dynamics of a quantum system S interacting with its environment E is considered to be given by a completely positive map. But, in general, this is not the case. In fact, the reduced dynamics of the system in not even linear, in general. Whether the reduced dynamics is linear or not is determined by two factors: the set of possib...

Quantum-Enhanced Atomic Sensor via Spin Nonequilibrium Criticality

The sensitivity of quantum sensors is fundamentally constrained by the standard quantum limit (SQL) arising from intrinsic quantum fluctuations. While non-classical resources like squeezing or entanglement can surpass this limit, their utility is often restricted by the extreme fragility of entangled states and the complexity of their preparation. Quantum criticality offers...

Real Classical Shadows with Noise

The real classical shadows protocol of West et al. replaces the unitary (Clifford) ensemble of the Huang--Kueng--Preskill scheme by the orthogonal (real Clifford) ensemble, and for symmetric observables achieves strictly smaller estimator variances: a factor approaching two for global evolution and an exponential factor (3/2)^k for k-local real Pauli observables. Real ha...

Copy-Protection with Correlated Challenges: Point Functions and More via Decisional Coset Monogamy

Copy-protection encodes a functionality in a reusable quantum state that cannot be split into two states (freeloader adversaries) which remain simultaneously useful. Prior plain-model results handle only independently sampled challenges; the more natural identical-challenge notion, also tied to unclonable bits and copy-protection of point functions, has remained open. We str...

Quantum Mixedness Testing with Pauli Measurements

We consider a fundamental problem of \emph{mixedness testing}: Given n copies of an N-qubit state ρ, determine whether ρ= I_d/d or ‖ρ-I_d/d‖_1 ≥ε with high probability, where d = 2^N. In particular, we focus on performing this task in the practical setting of single-qubit measurements, where measurements are prepared independentl...

Interior skin focusing and directional mirror transfer in a graded non-Hermitian Krawtchouk network

Spatially graded nonreciprocity can move skin weight away from a boundary, but it does not generally preserve a real commensurate spectrum or analytically controlled dynamics. We study a finite open Krawtchouk network with oppositely graded directed hoppings. For a broad intermediate range of asymmetries, their local imaginary gauge field changes sign in the bulk, and its ac...

On the quantum communication complexity of total functions

We present a total function with a polylogarithmic two-message quantum protocol, whereas every randomised protocol, even with arbitrarily many rounds, requires polynomial communication.

Robustness of spin state superpositions for noisy quantum metrology

Quantum metrology faces major challenges in noisy environments, where decoherence rapidly degrades useful quantum resources. We investigate the dynamics of the precision limits given by the quantum Fisher information (QFI) for phase estimation under spatially correlated dephasing. We characterize the dynamics of the QFI by the sensitivity and degradation indicators that can...

Seeded SU(1,1) interferometry for Fourier-domain optical coherence tomography

We demonstrate Fourier-domain optical coherence tomography (FD-OCT) based on a seeded SU(1,1) interferometer. Multilayer objects are probed with broadband light centered at 1550nm, while depth-resolved 3D images are reconstructed from photon flux measurements centered at 810nm. We show that, in the low parametric-gain regime, seeding increases the photon flux, enabling volum...

Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility

We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a O(100) m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULD...

Genuine Tripartite Entanglement Selects Gauge-Invariant Theories

Recent studies have explored whether physical constants and symmetries can be selected by extremizing bipartite entanglement entropy. We extend this approach to a three-particle setting. Specifically, we consider a 2+1-particle system in which particles B and C are initially entangled, and then particles A and B scatter without the direct participation of particle...

Nonlinear collective dynamics and microwave comb generation in a diamond maser

Optically pumped room temperature masers are a promising platform for driven dissipative spin photon physics beyond steady state emission. Here we observe a sequence of dynamical thresholds in a room temperature nitrogen vacancy diamond maser as the optical pump is increased above the conventional masing threshold. The first threshold yields narrow-line continuous wave emiss...

Experimental zero-added-loss multiplexing Bell-pair source for long-haul quantum networks

Boosting the communication rate of quantum networks is a central challenge in quantum information science. Recently, an efficient entanglement distribution scheme employing quasi-deterministic Bell-pair sources based on time-frequency multiplexing, referred to as zero-added-loss multiplexing~(ZALM), has been proposed. Its implementation, however, requires high-fidelity entan...

(Almost) quadruply optimal unitary designs in 1D

We construct n-qubit approximate unitary k-designs in 1D systems, achieving circuit depth O(log(n/ε) + klog k) with relative error ε and requiring O(nklog k) magic gates. This matches existing lower bounds Ω(log(n/ε) + k) for circuit depth, and Ω(nk) for the required number of T gates, up to a log k factor, achie...

Branching (Almost) Everywhere And All at Once

It is sometimes said that a reason to prefer Everettian quantum mechanics is that it allows one to avoid the kind of spooky action at a distance that is a consequence of quantum entanglement according to other approaches. There is a straightforward argument to show EQM has this virtue, however some advocates argue that this requires we see branching as a local causal process...

Exact Matching-Polynomial Solution of the Periodic Baxter-Fendley Z_N Clock Chain

The periodic non-Hermitian Baxter-Fendley Z_N clock chain has lacked a complete finite-size spectral solution, whereas its open-chain counterpart admits a solution in terms of independent quasienergies. For the periodic model we show that the operator-valued matching polynomial associated with its cyclic Weyl algebra simultaneously generates a set of conserved quantities,...

Inverse Feshbach's problem: Solvability and solutions

Given a certain specific, M by M matrix form of the Feshbach's effective (i.e., energy-dependent) Hamiltonian H^((M))_(eff)(E), the inverse-problem reconstruction of the full-space, N by N matrix Hamiltonian H^((N)) is considered and reduced to the solution of a coupled set of polynomial algebraic equations. Using computer-assisted symbolic manipulations, an...

Know Your Qubits, Know Your Users: Personas for Quantum Software

The advancement of quantum hardware and the intricacies of quantum computing make well-designed quantum software increasingly necessary. Due to the interdisciplinarity of the field, it is crucial to understand the perspectives and specific needs of involved stakeholders, for example, to balance the desired level of abstraction with the exposition of (hardware)-specific detai...

Superfast hole spin qubits enabled by uniaxial strain-boosted spin-orbit coupling

Two-dimensional (2D) electron/hole gases confined in semiconductor heterostructures suffer from weak Rashba spin-orbit coupling (SOC) for manipulating spin degreee of freedom via an electric rather than a magnetic field. Here, we show that complementary metal-oxide-semiconductor technology-accessible strain could substantially enhance the linear Rashba SOC of the top hole su...

Unified Strong-Field Dynamics Simulations from Atoms to Heterostructures

We present \textsc{TDSE-Z}, a high-performance open-source framework for strong-field quantum dynamics in atomic, molecular, and semiconductor effective-mass systems. The core engine implements a weak-form Galerkin discretisation of the Hermitian BenDaniel-Duke operator, T_(BDD) = -1/2∇·(m^(-1)(r)∇), on geometry-adapted B-splin...

GMV Builds Broad Quantum Portfolio Across Computing, Space, Communications and Cybersecurity

Caltech Team Uses Quantum Simulator to Probe Universal Rules of Quantum Matter

Korean Researchers Identifies Cause of ‘Beat’ Signal in Topological Insulator Nanowires

EigenQ and Silicon Valley Acquisition Corp Submit Draft S-4 for Proposed Business Combination

Ideon Technologies Joins Consortium for Laser-Driven Muon Imaging