June 2, 2026

Chutes and Ladders: Dynamical Automorphisms via the ZX-Calculus

The ZX-calculus is a powerful graphical language for manipulating quantum circuits, which has recently found many applications in quantum error correction. We extend this language to handle Floquet and other dynamical stabilizer codes via the connection between measurement-based code switching and gauge fixing (arXiv:1810.10037). We combine gauge-fixing steps to implement a...

Hybrid Clifford Codes via Operator Algebra Quantum Error Correction and Projective Representation Theory

Clifford codes are a natural generalization of quantum stabilizer codes based primarily on representation theory. This class of codes has previously been extended to the setting of quantum subsystem codes. We formulate a two-fold generalization of Clifford codes, for both the hybrid classical and quantum information and projective representation theory settings. This leads t...

Practical Limits on Integrated Squeezers

Recent experiments have demonstrated the successful generation and detection of moderately squeezed vacuum states with integrated photonics. However, in order to benefit from the reduced noise of highly squeezed light, many different noise sources must be mitigated. Here, we quantify the fundamental limits these noise sources impose on squeezing measurements and find surpris...

Microwave Crosstalk in Planar Superconducting Quantum Devices

Microwave crosstalk poses a major challenge to scaling superconducting quantum devices as it introduces excess control errors. Although its magnitude and impact have been explored in various experimental settings, quantitative physical models capable of explaining measured crosstalk for a given device geometry remain scarce. Here, we address this gap by investigating microwa...

Optimized Point Addition Circuits for Elliptic Curve Discrete Logarithms

Shor's algorithm represents the main threat of quantum computers to cryptography. In order to precisely understand its feasibility, many authors have worked towards reducing its costs, either at the logical level (assuming a fault-tolerant architecture), or at the physical level (taking into account the constraints of envisioned hardware). In particular, recent works by Chev...

Lie Algebra-Based Quantum Optimal Controls Interpolation

We present a framework combining Lie group theory and feed-forward neural networks to efficiently generate quantum optimal control pulses for arbitrary unitary operations in superconducting qubit systems, bypassing the need for explicit optimization at inference time. The exponential scaling of the Hilbert space dimension with qubit number makes standard optimization approac...

An Explicit Scott-Type Bound for Absolutely Maximally Entangled States with Arbitrary Defect

Absolutely maximally entangled (AME) states and, more generally, k-uniform states in (C^q)^(⊗n) are central objects in multipartite entanglement theory, with applications to quantum secret sharing, quantum masking, and quantum error correction. In the extremal case k=lfloorn/2rfloor, Scott (2004) proved a sharp nonexistence bound showing that AME states cann...

Magnetic control of electron scattering in silicene quantum dots

The Klein tunnel effect phenomenon makes it impossible to permanently confine charge carriers in massless nanostructures. However, applying a constant magnetic field allows these electrons to be temporarily localized, thus forming quasi-bound states. In this study, we analyze the mechanism of electron diffusion through a silicene quantum dot (SQD) subjected to a perpendicula...

Quantum Simulation of Nucleon-Antinucleon Interaction in Large-N QCD_2 on an IBM Quantum Nighthawk Processor

We report a quantum simulation of the nucleon--antinucleon interaction in large-N two-dimensional quantum chromodynamics (QCD_2) on the IBM Quantum Nighthawk processor. In the large-N limit, QCD_2 admits a bosonized description in which baryons emerge as topological solitons (kinks) of an effective mesonic field theory, providing a controlled, nonperturbative framewo...

Role of System-Bath Interaction in Non-Markovian Quantum Brownian Otto Cycles

We study finite-time quantum Otto cycles whose working medium is a harmonic oscillator undergoing a quantum Brownian motion described by the Caldeira-Leggett model when the oscillator is in contact with heat baths in isochoric processes. The time evolution of the Otto cycle is studied by analytically solving the exact Heisenberg-Langevin equations for the system variables an...

A Mid-Infrared Platform Based on Strontium Tweezer Arrays

Subwavelength atomic tweezer arrays, in which atoms can be positioned at distances smaller than their emission wavelength, have been proposed as a versatile platform to study collective emission phenomena, such as superradiance and subradiance. Experimentally, the realization of such arrays has been a challenge as typical emission wavelengths in the visible or near-infrared...

Creating and Probing Spin-Squeezed States of Molecules

Polar molecules are a promising platform for quantum-enhanced sensing and precision tests of fundamental physics, owing to their strong long-range dipolar interactions, broad sensitivity to electromagnetic fields, and sensitivity to potential physics beyond the Standard Model. However, the creation of metrologically useful entangled states in molecular systems has remained e...

Quantum optimal control of the Dicke manifold in Rydberg atom arrays

The ability to engineer and control quantum states of many-body systems is a central challenge in quantum information science. For a register of N qubits, the full Hilbert space dimension grows exponentially as 2^N, rendering generic state preparation and control infeasible without exploiting structure or symmetry. A particularly important and physically motivated restri...

Attention-Like Hebbian Learning from Quantum Probability Flow and Quantum-Annealer Tests

We propose a quantum probability-flow principle for deriving local learning rules in associative memory. A transverse field defines leakage channels from data states, and minimizing the measured survival loss gives stability-driven updates. For imaginary-time, dephased dynamics, the local leakage free energy is the log-sum-exp of energy gaps; its gradient is a softmax-weight...

Negative Interaction Quench Dynamics of Density-Ordered Dipolar Bosons in a One-Dimensional Optical Lattice

We explore the nonequilibrium dynamics of a density-ordered dipolar Bose gas in a finite one-dimensional optical lattice following a negative interaction quench, using the numerically exact multiconfigurational time-dependent Hartree method for bosons. The interaction sign reversal, effectively driving a crossover from long-range to short-range interactions, generates rich i...

Quantum Machines Achieves 99.5% Two-Qubit Gate Fidelity Operating Rigetti’s Novera QPU

Quantum Machines (QM) has operated Rigetti Computing’s commercially available Novera superconducting quantum processing unit (QPU) using external control hardware and software, reaching a 99.5% median two-qubit gate fidelity. Configured via the OPX1000 orchestration platform and managed by QUAlibrate automation software, the onsite optimization process achieved full calib...

University of Tennessee Launches Knoxville Quantum Accelerator to Anchor State Initiative

The University of Tennessee, Knoxville (UT) has launched the Knoxville Quantum Accelerator, branded as K-Quantum, to coordinate regional quantum technology research, hardware validation, and workforce training. The initiative operates in alignment with the Tennessee Quantum Initiative, a $43 million statewide economic strategy directed by Governor Bill Lee to establish lo...

Moth Launches Quantum Backrooms, a Quantum Game for Consumers

In a sector traditionally dominated by deep-tech milestones and hardware-centric announcements, London-based quantum software startup Moth has broken rank to launch Quantum Backrooms, the world’s first consumer product powered by live quantum hardware. Demonstrating infrastructure agility, Moth confirmed that its consumer applications are platform neutral. Quantum Backroo...

Strong-to-Weak Spontaneous Symmetry Breaking

Strong-to-weak spontaneous symmetry breaking (SW-SSB) has recently emerged as a useful framework for studying phases of matter in open systems, quantum or classical. Beginning with the simple idea of extending symmetry breaking to general mixed states, and the familiar equivalence between canonical and grand-canonical ensembles in statistical mechanics, the concept has grown...

Spatial and particle-particle entanglement in 1D quantum walks of two distinguishable or indistinguishable bosonic particles

We present entanglement measures between spatially separated regions and between two distinguishable or indistinguishable particles in one-dimensional two-particle continuous-time quantum walks governed by the Hubbard Hamiltonian. The left-right entanglement checks the entropy of coarse-grained states counting the numbers of particles on the left and right halves of the latt...

Closed-loop Structure of Quantum Probabilities from Unitarity

In previous work (Rave, 2008) it was proposed that closed loops should be treated as fundamental quantum entities, and such loops were presented in a quasi-probability framework. We demonstrate that the closed-loop decomposition of quantum probabilities is a direct consequence of unitarity, and that Bargmann invariants arise naturally as the phase-invariant quantities associ...

Thouless Pumping of Large Chern Numbers in Optical Floquet Quasicrystals

Chern numbers are central to correlated and topological phenomena, yet most topological systems are associated with Chern numbers of order unity. Here we propose a scheme to achieve large Chern numbers in an optical Floquet quasicrystal with cold atoms, which can be directly measured via Thouless pumping. We study the quasienergy spectrum of Floquet quasicrystals and charact...

Dynamics of the Density Cube

Density cube theory extends the canonical quantum density matrix ρ_(ij) with the addition of an extra index to ρ_(ijk). The elements of the density cube with two different indices, ρ_(iij) and ρ_(ijj), correspond to the real and imaginary parts of the off-diagonal element ρ_(ij) of the density matrix and describe double-path interference, while those with three dif...

Evolutionary Discovery of Bivariate Bicycle Codes with LLM-Guided Search

Quantum LDPC code discovery requires searching large algebraic design spaces while reliably certifying the parameters and equivalence classes of any candidates found. We introduce an LLM-guided evolutionary workflow in which language models mutate Python programs that generate bivariate-bicycle and perturbed bivariate-bicycle code ansätze. Across five campaigns, the system p...

Bounds on Nonlocality and Random Access Codes from Extended Information Causality Principle

Information Causality was introduced as a physical principle for constraining the set of nonlocal correlations. In recent work, we proposed an extension of Information Causality that allows correlations among Alice's inputs. This extended principle yields tighter constraints than the original formulation and recovers part of the quantum boundary in certain Bell scenarios. In...

Optical Stability and Photophysics of NV Centers in Diamond up to 120 GPa

The nitrogen vacancy (NV) center has emerged as a powerful quantum sensor in high-pressure research, with the observation of optically detected magnetic resonance at megabar pressures. However, some aspects of NV physics require further investigation to optimize the development of NV-based sensing under pressure. Here, we study both experimentally and theoretically the optic...

Spin Correlations in Two-Particle Systems: A Pedagogically Motivated Comparison of Computational Approaches

In this work we present a pedagogically motivated analysis of spin-correlation calculations in a quantum system composed of two spin-1/2 particles. Rather than aiming at new physical results, our purpose is to clarify and bring attention to different strategies for evaluating expectation values of the form ⟨ψ| S^((1))_u S^((2))_(boldsymbo...)

Defect Holonomy Near Rank-Deficient Mixed States

We investigate the geometry of mixed quantum states near rank-changing points, showing that these singularities function as effective geometric defects. The Uhlmann connection is well-defined only on the full-rank sector of the density-matrix manifold, while rank-deficient states form singular boundary strata where the bundle structure degenerates. By restricting to a punctu...

Multidimensional Reconciliation in Continuous-Variable QKD: Review, Coding Schemes, and Open Source Simulation

Continuous-variable quantum key distribution (CV-QKD) requires highly efficient reconciliation techniques to operate at low signal-to-noise ratios and long distances. Multidimensional reconciliation addresses this challenge by transforming the physical Gaussian quantum channel into a virtual binary-input additive white Gaussian noise (BIAWGN) channel, enabling the use of mod...

Is the most random pattern random? Maximizing localization in a two-dimensional lattice with engineered disorder

We investigate localization in two models: a single particle in a two-dimensional square lattice described by the tight binding Hamiltonian, and a two-dimensional square qubit lattice. It is well-known that Anderson localization occurs under suitable conditions in which the system parameters are chosen randomly from some statistical distribution. We propose a situation in wh...

Hidden u(2,1) symmetry and Jordan chains in a resonant ghostly three-dimensional model

We investigate a three-dimensional ghostly Hamiltonian realisation of the fully degenerate resonant sixth-order Pais-Uhlenbeck oscillator. On the classical level, the phase-space flow is non-diagonalisable and decomposes into two complex-conjugate Jordan chains of length three, explaining the appearance of oscillatory solutions with secular terms. Upon quantisation, we const...

Information scrambling in all-to-all interacting models

Information scrambling is a hallmark of quantum chaos and thermalization in isolated quantum many-body systems. We investigate scrambling dynamics in the all-to-all interacting spin Sachdev-Ye-Kitaev (SYK)-q model using both pure- and mixed-state entanglement measures. We show that von-Neumann and Rényi entropies exhibit rapid growth followed by saturation near Haar-random...

Iterative C_Z-gate-based protocol for squeezed Schrödinger cat state engineering

Squeezed optical Schrödinger cat states constitute a key resource for both fundamental tests of quantum theory and up-to-date quantum technologies. We propose a measurement-assisted gate for the generation and manipulation of the cat states. In this scheme, an ancilla in the non-Gaussian small-amplitude (in general, squeezed) Schrödinger cat state and the target oscillator i...

Quantum-inspired Topographic Stereovision

We challenge the long-unquestioned triangulation in distant stereovision, where shape rather than distance is the relevant observable. Our information-regret analysis reveals that the optimal measurements for absolute distance and distance gradient are unexpectedly different and incompatible. To resolve this observable-measurement mismatch, we introduce stereo regularization...

Spin Hamiltonian as Matrix-Free Linear Map

We present an algorithm that computes the action of a generic spin Hamiltonian on a state vector on the fly, entirely avoiding explicit matrix assembly. This is achieved through mixed-radix indexing of the full tensor-product basis, which translates local spin operations into simple integer offsets. The result is an explicit framework for evaluating single- and two-site term...

Information Hierarchy in Many-Body Berry Phase

Many-body topology is a central concept in modern theories of solids, and identifying effective degrees of freedom that capture it is important both fundamentally and practically. This work studies the extent to which geometric information of an interacting many-body ground state can be inferred from a finite number of local correlations. Starting from the Resta formula, $ z...

Can scrambling protect quantum state distinguishability under noise?

Quantum state distinguishability is a fundamental concept in quantum information science that underpins a wide range of important practical tasks. Traditionally formulated for pairs of states, quantum state distinguishability is here extended to quantum state ensembles, which we characterize through the average pairwise trace distance. Motivated by both theoretical and pract...

Quantum Dynamics of a Particle in a Linear Potential: Invariant Operator Approach and Discrete Spectrum Solutions

We investigate the quantum dynamics of a particle subjected to a linear potential using the Lewis--Riesenfeld invariant operator method. Starting from the time-dependent Schrödinger equation associated with a constant external force, we construct the most general Hermitian quadratic invariant and derive the corresponding coupled differential equations for its time-dependent...

Penalty-free quantum optimization applied to lattice protein folding

Identifying minimum-energy structures of lattice proteins is a challenging discrete optimization problem. Quantum approaches such as analog quantum annealing and the gate-based quantum approximate optimization algorithm (QAOA) can address this problem after mapping it to a binary representation, which typically involves introducing penalty terms to enforce valid chain config...

A Minimal Duality Estimate for the Surface-Code Threshold under Nearest-Neighbor Correlated Errors

We apply the single-equation duality criterion to the square-octagonal random-bond Ising model recently obtained from an exact error-edge map for a surface code with nearest-neighbor correlated errors. The calculation is performed for the minimal cell after the error-edge reduction. For the symmetric case p_1=p_2=p_3=p, this gives p_c=0.0288427147, in close agreement...

Branch-Aware Quantum Constant Propagation for Dynamic Quantum Circuits

Compile-time optimization is important for improving the efficiency and reliability of quantum circuits on current noisy hardware. While many existing methods simplify circuits using structural patterns or quantum-state information, most of them target only unitary circuits and do not support dynamic circuits with mid-circuit measurements and classical feedforward. In this w...

Quantum resonance encryption for secure data storage and communication with quantum kicked top

In a shared quantum computer, how to ensure data privacy and protection from access by unauthorized parties? We propose a genuine quantum protocol for protecting user's data which is not accessible even to the service provider. The protocol is based on quantum kicked top -- the dynamics of a spin system --operating at quantum resonance regime. This protocol ensures perfect r...

Quantum secure blind decryption with two users

We propose two types of protocols for quantum secure blind decryption, involving two users and servers. User 1 holds the encrypted ciphertext. The servers store several indexed keys including the key encrypting the ciphertext. User 2 aims to obtain the decrypted text. The protocols are designed to preserve the following types of secrecy: Users ensure the secrecy of the text...

Half the Interference, Most of the Answer: Approximate Quantum Simulation via Path-Sum Pruning

Classical simulation of quantum circuits is expensive for two distinct reasons. The obvious one is state-space size: an n-qubit system requires exponentially many amplitudes. The less obvious one is interference: useful output distributions emerge only after many computational histories have been coherently combined at common endpoints, and this aggregation step is itself a...

Revisiting the Quantum-Guided Cluster Algorithm: Improvements and Numerical Experiments

We study correlation-guided cluster algorithms for solving the Max-Cut problem that iteratively try to improve solutions by updating clusters of nodes. Building on the recently proposed quantum-guided cluster algorithm (QGCA) [arXiv:2508.10656], which leverages precomputed two-point correlations to guide collective updates, we extend the cluster construction by incorporating...

Coherent Exchange and Decoherence in Dirac-Spin-Liquid Quantum Interconnects

We develop a susceptibility-based open-system theory for two localized qubits coupled through a candidate two-dimensional U(1) Dirac-spin-liquid-like bath. The central input is the gauge-invariant retarded physical spin susceptibility Chi^R(q,ω) of the bath. We show that this single response kernel controls both coherent and dissipative qubit dynamics: its real...

Non-destructive cavity readout of molecules for precision measurements

We propose a non-destructive method to measure the population of molecules in a selected rotational-hyperfine state by coupling them to a high-finesse optical cavity. In contrast to traditional techniques, our approach enables fast (less than 1 ms) repeated measurements with reduced heating and losses, and with precision below the standard quantum limit. The method is partic...

Pauli-structured preconditioning for quantum linear system solvers

Preconditioning is a fundamental technique for accelerating classical linear system solvers, and understanding when its benefits persist in quantum linear system (QLS) solvers is important for assessing the practical resource requirements of quantum linear algebra. In QLS algorithms, however, the potential advantage of preconditioning may be offset by the normalization overh...

Asymptotic Recovery in Fourier Spectral Methods for the Schrödinger Equation with Point Singularities

This paper studies the Fourier spectral method (FSM) for the Schrödinger equation with singular potentials V ∈H^s, where s > max{d/2-2,-1} and d denotes the spatial dimension. This setting includes a broad class of singular potentials, such as the 3D Coulomb potential and the 1D Dirac-delta potential. First, we combine the Feshbach-Schur map with a refined pert...

Correlated Quantum Sensing at the Seemingly Classical Limit

It is a difficult task to detect the indivisible quanta of weakly interacting radiation fields, and even more challenging to probe their quantum statistics. Nevertheless, if barely functional high-quality resonant detectors are feasible for weakly interacting radiation fields, they do come with certain statistical advantages to probe quantum effects at the seemingly classica...

Extensible Fluxonium Architecture Using Tunable Couplers with Low Shunt Capacitance

Fluxonium qubits have demonstrated high-fidelity operations and long coherence times in small-scale systems, highlighting their promise for quantum computing. However, large-scale integration into a high-performance two-dimensional (2D) qubit array remains the central challenge for practical applications. In this work, we introduce an extensible architecture for scaling up f...

Podcast with Sebastian Hassinger, Host of The New Quantum Era Podcast

This week, Yuval Bogar interviews Sebastian Hassinger, host of The New Quantum Era podcast, and author of a new book by the same name. Sebastian and Yuval have many things in common beyond their jobs in quantum. They are both podcasters, neither of them has a PhD, and they are both authors of new books [...]

Pramatra Space Secures Pre-Seed Capital to Advance Space-Based Quantum Key Distribution Hardware

Pramatra Space Technology Pvt. Ltd., a deep-tech quantum security venture based in Bengaluru, has closed an undisclosed pre-seed financing round led by Seafund Ventures. The investment round included participation from Rebalance, Magnivia Ventures (co-investing with the Peaceful Progress Fund), and angel investors including Awais Ahmed, founder of earth observation compan...

UK Quantum Biomedical Hub Secures £902,000 ($1.2 Million USD) Allocation to Develop Clinical Sensing and Imaging Hardware

The UK National Quantum Biomedical Research Hub (Q-BIOMED) has been awarded £902,000 ($1.2 million USD) from the Engineering and Physical Sciences Research Council (EPSRC). Delivered through the government's Accelerating Capability Fund—a flexible financial mechanism anchored to the UK's £2.5 billion National Quantum Strategy—the capital injection supports six targeted wo...

University of Illinois Team Advances Monolithic 3D Chip Design

Penn State Files Three Patent Applications Related to Delta Sponsored Research

How a New Phase of Matter Could Impact Quantum Technology