August 24, 2026.

Quantum phase estimation for nondestructive monitoring and Wigner tomography of bosonic fieldsTier 3

Quantum phase estimation is usually introduced as an algorithmic primitive for extracting eigenphases of unitary operators. Here we show that, when implemented through a dispersive light-matter interaction, it can also be used as a nondestructive measurement tool for bosonic fields. We consider a bosonic mode coupled to a multi-qubit register and calibrate the photon-number...

Japan’s Full-Stack Neutral-Atom Quantum Computer is OperationalTier 2

<a href="https://thequantuminsider.com/2026/08/24/japans-full-stack-neutral-atom-quantum-computer-is-operational/" rel="nofollow" title="Japan’s Full-Stack Neutral-Atom Quantum Computer is Operational"><img alt="Japan Neutral Atom" class="webfeedsFeaturedVisual wp-post-image" height="676" src="https://thequantuminsider.com/wp-content/uploads/2026/08/Japan-Neutral-Atom.jpg" s...

Quantum Zeno and Anti-Zeno Responses: Universal Spectral Criterion for Measurement-Induced DecayTier 3

We develop a general framework for characterizing the response of an evolving quantum system to repetitive quantum measurements. Modeling each evolution-measurement cycle as a quantum channel induced by an effective Liouvillian generator, we find that the Liouvillian spectral gap determines the measurement-induced decay rate. We analyze how the spectral gap responds to the m...

Continuous-angle logical rotations in the Steane codeTier 3

We experimentally demonstrate continuous-angle logical $Z$ rotations in the $[[7,1,3]]$ Steane code on the IonQ Forte trapped-ion processor. A round of the protocol applies a transversal physical $Z$ rotation by $θ$, followed by Steane syndrome extraction and decoding, which induces a syndrome-dependent logical $Z$ rotation. We analytically derive the effect of dephasing noi...

Axiomatization of the Levin--Wen Wave FunctionTier 3

The Levin--Wen model provides a lattice realization of topological orders associated with a given unitary fusion category. A longstanding open problem is to characterize Levin--Wen ground-state wave functions intrinsically, without assuming a priori categorical symmetry data or a Hamiltonian. We address this by proposing six axioms on a family of wave functions defined on la...

Characterizing Multimode Effects in a Guided Matterwave GyroscopeTier 3

We theoretically investigate the performance of a compact matterwave vortex gyroscope formed by a two-component Bose-Einstein condensate in a toroidal potential. Unlike conventional atomic gyroscopes that rely on the Sagnac effect, the topological stability of the vortex state yields rotation sensitivity independent of the enclosed area, making the device robust against geom...

The four-dimensional Chamon codeTier 3

Fracton models have attracted considerable interest as candidates for quantum memories because of their unconventional ground-state degeneracy (GSD) and restricted-mobility excitations. The four-dimensional (4D) Chamon code introduced in our previous work is constructed via the 4D XYZ product of two two-dimensional (2D) toric codes. Its GSD grows exponentially with the syste...

Symmetry Constrained Quantum Error Mitigation for the Schwinger ModelTier 3

Quantum error mitigation (QEM) is at the very heart of near-term quantum simulations and lattice gauge theories are no exceptions, rather their physical symmetries provide natural consistency checks on noise quantum states. In this work, we exploit the parity and fermion-number symmetries of a gauge theory, the (1+1)-dimensional Schwinger model, under depolarising noise and...

Slepian Bounds on the Success Probability of Virtual DistillationTier 3

Virtual distillation is a powerful near-term error-mitigation primitive, but it is also a spectral filter: it amplifies the dominant eigenvector component already present in the noisy density matrix. We show that, for a finite-band variational state, this filtering cannot create new concentration inside a set of accepted measurement outcomes. The asymptotic success probabili...

Dissipative framework for subsystem dynamics of noninteracting quantum chainsTier 3

When only local observables of a many-body quantum system are of interest, it is desirable to formulate a reduced description within the Hilbert space of the corresponding subsystem, with the remaining degrees of freedom traced out and acting as an environment. Assuming initially uncorrelated states and Gaussian environments, we develop a framework for reconstructing the loc...

Hypothesis testing between quantum ensemblesTier 3

Quantum state ensembles are important in quantum information processing. For example, quantum $t$-designs model highly entangled states in complex systems, while projected ensembles appear in generative quantum machine learning and studies of thermalization. With their sample state accompanied by a classical label, these ensembles contain operational information beyond their...

Neural quantum states in condensed matter: advances, best practices, and prospectsTier 3

Neural quantum states provide flexible variational representations of quantum many-body wave functions by combining neural-network parametrizations with Monte Carlo sampling. In this perspective, we review recent advances in their application to condensed-matter systems, focusing on frustrated quantum magnets, interacting lattice fermions, and non-equilibrium dynamics. We di...

Revealing Physical Redundancy in the Two-dimensional Fermi-Hubbard Model via Transferable Observable ReconstructionTier 3

The Fermi-Hubbard model provides a paradigmatic setting for studying strongly correlated quantum matter, where different observables are commonly used to probe charge, interaction, and spin correlations. In this work, we investigate whether these observables contain mutually transferable physical information beyond their apparent distinction. We quantify such physical redund...

Predicting Resource Efficient Hamiltonian Decomposition for Continuous-Time Quantum Walk SimulationsTier 3

Simulating a continuous-time quantum walk (CTQW) on a graph in the circuit model of quantum computing requires decomposing its Hamiltonian into terms that can be Trotterized into hardware-native gates. We consider two such decompositions: the standard Pauli decomposition and the recently introduced matching decomposition. Prior work suggests that the matching decomposition u...

Symmetry Adapted Hierarchical Equations of Motion for Exact Simulations of Large Polariton SystemsTier 3

Hierarchical equations of motion(HEOM) provide exact dynamics of open quantum systems coupled to harmonic baths, but their computational cost becomes prohibitive for systems with many independent local environments. In this work, we develop a symmetry-adapted HEOM formalism to significantly reduce the computational cost for the permutationally invariant Holstein-Tavis-Cummin...

Prediction of a layer nonlinear Hall effect in bilayer nonmagnetic or antiferromagnetic systemsTier 3

Nonlinear Hall effects provide a powerful probe of quantum geometry in solids and enable rectification phenomena beyond the constraints of linear response. In this Letter, we predict a \emph{layer nonlinear Hall effect} (LNHE) in stacked bilayer systems composed of nonmagnetic or antiferromagnetic materials with a vanishing linear Hall conductivity. In such systems, the seco...

RFI and Safeheron Test Post-Quantum Cryptography for Digital Asset TransactionsTier 2

<a href="https://thequantuminsider.com/2026/08/24/rfi-safeheron-post-quantum-security-digital-assets/" rel="nofollow" title="RFI and Safeheron Test Post-Quantum Cryptography for Digital Asset Transactions"><img alt="RFI and Safeheron logo" class="webfeedsFeaturedVisual wp-post-image" height="691" src="https://thequantuminsider.com/wp-content/uploads/2026/08/2026-08-24_13-48....

When More Becomes Less: Topology-Reversed Three-Qubit Gate Performance on IBM Quantum ProcessorsTier 3

The exact Toffoli gate admits a six-CX decomposition, denoted by $CCX_6$, that is optimal under unrestricted two-qubit connectivity. On a linear three-qubit topology, however, $CCX_6$ contains 4 nearest-neighbor CX gates and 2 non-nearest-neighbor CX gates. By contrast, an alternative exact decomposition, denoted by $CCX_8$, uses only 8 nearest-neighbor CX gates. Because CCX...

Who’s News: Strategic Appointments at D-Wave, BTQ Technologies, Symmatrics, and Rigetti ComputingTier 2

<p>D-Wave Quantum Inc. has appointed Kevan P. Krysler to its Board of Directors and Audit Committee. Krysler currently serves as Chief Financial Officer of Carbon Robotics and brings over two decades of financial leadership experience from previous executive roles, including Chief Financial Officer of Everpure, Inc., and Senior Vice President of Finance and Chief Accounting...

The Entanglement Content of Quantum Measurement BasesTier 3

Bell-state measurements are essential ingredients in many protocols for quantum information processing, ranging from quantum teleportation and dense coding to entanglement distribution in quantum networks. Their power relies on the fact that they are measurements in an entangled basis of a two-particle system and that the used Bell-state basis can be generated from a single...

Distributed synthesis of arbitrary graph states in quantum networks via rank-two GF(2) reductionTier 3

Existing schemes for synthesizing graph states in quantum networks are essentially edge-by-edge constructions, so quantities such as the time-slot depth and the resource overhead grow significantly with the edge density of the target graph. This paper proposes a new method. Exploiting the mathematical equivalence between joint Pauli-X measurements and graph pivot operations,...

Tools for Reducing Service Time in Near-Term Quantum NetworksTier 3

Architectures have been proposed to control entanglement generation in multi-user quantum networks. To allow time for local operations and classical communication at end nodes, these architectures insert fixed separations between consecutive batches of entanglement generation attempts. This reduces network utilization when attempts fail, leaving the network idle during the s...

China Puts Quantum Technology Among Priorities in New 2030 Cyber Industry PlanTier 2

<a href="https://thequantuminsider.com/2026/08/24/china-puts-quantum-technology-among-priorities-in-new-2030-cyber-industry-plan/" rel="nofollow" title="China Puts Quantum Technology Among Priorities in New 2030 Cyber Industry Plan"><img alt="a red map of asia on a white background" class="webfeedsFeaturedVisual wp-post-image" height="1067" src="https://thequantuminsider.com...

Microsoft’s Skala AI Model Joins CP2K to Improve Quantum Mechanical SimulationsTier 2

<a href="https://thequantuminsider.com/2026/08/24/microsofts-skala-ai-model-joins-cp2k-to-improve-quantum-mechanical-simulations/" rel="nofollow" title="Microsoft’s Skala AI Model Joins CP2K to Improve Quantum Mechanical Simulations"><img alt="quantum similation" class="webfeedsFeaturedVisual wp-post-image" height="744" src="https://thequantuminsider.com/wp-content/uploads/2...

Classical versus non-classical photon states for detecting vacuum non-linearityTier 3

Quantum electrodynamics (QED) predicts that the vacuum should behave as a non-linear medium. For many schemes aimed at verifying this fundamental prediction, the signal consists of one or more photons in a certain mode (determined by polarization $σ$ and wave-number $\boldsymbol{k}$) which would be empty in the absence of a QED vacuum non-linearity. Here we consider modifyin...

Quantum annealing through a first-order phase transition: field theory approachTier 3

Unlike second-order phase transitions, a first-order transition has a stage, in which a system is trapped in a metastable state. The decay of this state leads to abundant excitations over the ground state. We present a field theory for kinetics of defects emerging during quantum annealing computations. This theory predicts several power laws for the error generation rate dur...

Tomographic Limits of the Petz Recovery MapTier 3

The Petz recovery map is considered one of the key candidates for the quantum analogue of Bayesian inference and Jeffrey's conditionalization. Since, there seems to be a natural connection between Bayesian inference and the notion of state tomography, it is natural to ask if the Petz recovery can be used for this latter task. In this paper, we discuss such recent results on...

Random quantum circuits, chaos and quantum thermalizationTier 3

These notes accompany lectures given in June 2025 at the summer school \emph{Fundamental Problems in Statistical Physics XVI}. They offer a short introduction to random quantum circuits as simple models for generic many-body quantum systems. They give an outline of the motivation for introducing these models, starting from ideas of random matrix theory. They also provide a s...

Exponential-in-$N_c^2$ cost reduction of product-formula-based quantum simulations of quantum chromodynamicsTier 3

Quantum algorithms for simulating quantum chromodynamics (QCD) have matured steadily since the pioneering work of Byrnes and Yamamoto [PRA 73, 022328 (2006)]. The most popular strategies for Hamiltonian simulation involve product-formula decompositions. However, the application of product-formula methods to SU($N_c$) lattice gauge theories by Byrnes and Yamamoto leads to $O(...

Eavesdropper-Blind Remote State Preparation and Applications to Quantum Public-Key EncryptionTier 3

Remote state preparation (RSP) is a central primitive in quantum cryptography, enabling classical parties to remotely construct quantum states using only classical communication. As a result, RSP serves as a key building block in numerous protocols involving classical clients and quantum servers, allowing classical parties to leverage the advantages offered by powerful quant...

Probing quantumness of superpositions of Gaussian states via Tsirelson probabilityTier 3

Superpositions of Gaussian states, including circular states and generalized circular states, exhibit a rich variety of nonclassical features such as Wigner negativity and sub-Planck phase-space structures. The Tsirelson probability, central to the Tsirelson precession protocol, is defined as the average probability that a precessing quadrature yields a positive outcome when...

Fixed-ray escort representations of sandwiched and $α$--$z$ Rényi divergences on von Neumann algebrasTier 3

We represent sandwiched and $α$-$z$ Rényi divergences as averages of ordinary relative entropy. The $α$-$z$ Rényi divergence is shown to be an integral over the relative entropy of a canonical family of fixed-ray escort states along the ray $z=cα$. We prove this representation for normal states on an arbitrary von Neumann algebra, using Haagerup non-commutative $L^p$ spaces...

Quantum Fisher information in a quenched $p + ip$ superfluidTier 3

The quantum Fisher information (QFI) is widely used to characterize quantum phases and transitions, but its diagnostic power sometimes relies on selecting special generators based on prior knowledge of the underlying physics. We ask whether this requirement can be relaxed in nonequilibrium systems by studying the QFI of the long-time asymptotic state of a two-dimensional p+i...

Entangling Power Dynamics: Ergodicity and MixingTier 3

We study quantum dynamics through the lens of entanglement generation and characterize the underlying unitary evolution by the distinct signatures it imprints on the time-dependent entangling power. For a unitary operator, we characterize ergodicity by the equality between its long-time-averaged entangling power and the Haar-averaged linear entropy. We define mixing more str...

Quantum thermodynamics and semidefinite optimization: Boltzmann, Fermi-Dirac, and Bose-Einstein frameworksTier 3

Here we argue how quantum thermodynamics offers a unifying interpretation for a wide class of semidefinite programs (SDPs) that arise in quantum information. Three SDP variable constraints, namely trace-one density operators, operator-bounded measurements, and the unbounded positive semidefinite cone, admit thermodynamic regularizations associated with Boltzmann, Fermi-Dirac...

An autonomous feedback protocol: responding to temperature and potential changes in energy convertersTier 3

Nanoscale thermoelectric devices convert tiny amounts of heat into power. But what happens if the external conditions and resulting temperature differences are not a priori known? We propose a feedback mechanism that optimizes the performance of a quantum-point-contact-based heat engine (QPC). A quantum-dot detector measures the external conditions and gives autonomous feedb...

Quantifying Entangling Power of Controlled Unitary GatesTier 3

Applying controlled unitary gates to generate entanglement between qubits is a routine task in both quantum communication and computation. The existing tools for predicting how much entanglement a given gate can generate require either simulation of the entangling circuit or averaging over a distribution of inputs for a given controlled unitary gate. Here, we introduce a com...

Minimization of micromotion for nanoparticles in a Paul trapTier 3

When a charged particle in a Paul trap is displaced from the node of the AC trapping field, excess micromotion arises as an undesired effect. Excess micromotion heats the particle, limits the precision with which the particle can be localised, and acts as a decoherence channel in quantum mechanical experiments. However, thus far there is no standard procedure for micromotion...

Degeneracy beyond the parity-symmetry protection in the Lipkin-Meshkov-Glick modelTier 3

Degeneracy patterns in quantum mechanics stem from the system symmetries. In particular, the broken-symmetry phase in the well-known Lipkin-Meshkov-Glick (LMG) model is composed of doubly-degenerate states of different parity. In this work, we show that such doublets can exist even if parity is not conserved. For this purpose, our starting point is an anharmonic LMG Hamilton...

A Classification of Translation-Invariant Quantum Codes in Any DimensionTier 3

Quantum error-correcting codes with two-dimensional translation invariance are known to be equivalent to copies of the two-dimensional toric code. Such a simple classification is not possible for quantum codes with higher dimensional translation invariance due to the existence of multiple types of toric codes and infinite families of fracton codes. Here, we focus on D-dimens...

Finite Weyl polynomials and the approach to Tsirelson's bound in relativistic scalar quantum field theoryTier 3

We construct four bounded Hermitian operators, each one a finite polynomial in the unitary Weyl operators, for the Bell-CHSH inequality in a free massive scalar field in $1+1$ dimensions. The operators are localized in complementary wedges. Odd Weyl harmonics provide two exactly anticommuting axis observables in each wedge, while normalizable packets with compact support in...

Anisotropic dynamical reconstruction of quantum geometry in quenched Chern insulatorsTier 3

Under unitary dynamics, the Chern number of an evolving quantum state remains conserved even when a quench drives the Hamiltonian across a topological phase transition. In sharp contrast, we reveal an anisotropic dynamical reconstruction of the quantum metric. Following a sudden quench in a two-dimensional Chern insulator, the metric develops a principal frame in which one e...

Dissipation driven boundary localization in higher order topological insulatorsTier 3

We study dissipation driven boundary localization in a Bernevig Hughes Zhang type second order topological insulator by introducing inhomogeneous, spin dependent boundary dissipation. After projection onto the edge subspace, the dominant component of the boundary dissipation lies in the same Pauli channel as the kinetic term. This channel gives both counter-propagating edge...

Spin models with critical ground space degeneracy from Lie algebra relationsTier 3

We introduce an $\mathrm{SO}(3)$-symmetric spin model derived from the algebraic structure of $\mathfrak{so}(3)$: It is obtained as the nearest-neighbor parent Hamiltonian of a Matrix Product State (MPS) built from the generators of the Lie algebra $\mathfrak{so}(3)$ and the identity matrix, and therefore encodes the quadratic relations of the Lie algebra. We characterize th...

Non-Hermitian sensing via end-to-end Green's functionsTier 3

Sensing hinges on two key attributes: high sensitivity and resilience to noise. Here, we present a scheme that unites these features within a single framework. By harnessing the exponential amplification of end-to-end Green's functions-a direct signature of the non-Hermitian skin effect-our scheme achieves an exponential sensitivity scaling of exp(αL) with α a model-specific...

First-principles design of main-group dimer defects in ZnO as candidate quantum defectsTier 3

Zinc oxide (ZnO), a wide-band-gap semiconductor with mature growth techniques, is a promising host for optically active quantum spins. Yet, optically active quantum defects in ZnO remain largely unexplored. Here, we identify and characterize a family of double substitutional impurities in ZnO, formed by main-group donor-acceptor (DA) pairs, as candidates for optically active...

Coherence-Based Identification of Carbon-Based Spin Qubits in Hexagonal Boron Nitride from First PrinciplesTier 3

Carbon-related defects in hexagonal boron nitride are promising room-temperature single-spin qubits and quantum sensors, but their atomic structures remain largely unidentified. Here we show, using first-principles calculations of electron-spin decoherence, that the atomic structure of each defect is imprinted in its spin coherence. Mapping the Hahn-echo dynamics of seven ca...

Qubits for Dark Matter HuntingTier 3

An introductory review is provided for those who are interested in exploring applications of qubits and other quantum excitations to the detection of dark matter (and any other physics beyond the Standard Model). Topics covered include the fundamental properties of qubits, the excitation mechanism of qubits due to the electric field induced by dark matter (with attention to...

Hybrid dynamical decoupling and coherent driving for high-fidelity nuclear-spin control in diamondTier 3

Nitrogen-vacancy (NV) centers in diamond provide room-temperature electron-nuclear spin registers for quantum sensing and quantum information processing, with surrounding 13C nuclear spins serving as long-lived quantum memories. However, coherent control of large nuclear-spin registers is limited by finite electron-spin coherence and spectral addressability. Existing approac...

Activate genuine nonlocality from distinguishable sets in tripartite systemsTier 3

A set of orthogonal quantum states in multipartite systems is of genuine nonlocality if it is locally indistinguishable in every bipartition. If it is locally reducible when the parties are separated, we say that it has genuine nonlocality of type~\uppercase\expandafter{\romannumeral 1}; otherwise, it has genuine nonlocality of type~\uppercase\expandafter{\romannumeral 2}. F...

Laziness of Quantum Walks on GraphsTier 3

The trace of the average mixing matrix of a quantum walk measures the "laziness" of the walk: the higher the trace, the more likely that the walker returns home in the long run. In this paper, we develop tools to study this graph invariant arising from Laplacian quantum walks. It is known that the complete graph $K_n$ is the laziest connected graph on $n$ vertices. Using our...

Restoring heat and particle flow in strongly coupled non-equilibrium devicesTier 3

Under non-equilibrium conditions, energy/particle currents flow through a quantum system coupled to multiple baths. Although the fluxes increase in the weak coupling regime as the coupling strengthens, the reason why they decrease to zero for large coupling remains unknown. This counterintuitive behavior of energy exchange or transport phenomena is called the turnover effect...

Difference-Set Weyl Channels: Exact Capacity, Optimizer Bifurcation, and Scalable Entanglement SeparationTier 3

In odd local dimension $D$, complete Wigner positivity yields stochastic phase-space dynamics on Wigner-nonnegative states but does not control signed inputs, entanglement across channel uses, or collective decoding. Using a subsystem-resolved Weyl decomposition, we characterize the equality conditions of the tensor-stable output-purity bound. Cyclic difference sets are prec...

On quantum channels: extreme points, topology, and categorical propertiesTier 3

In this thesis, quantum channels are studied from the point of view of Mathematics. We studied the CPTP (completely positive trace preserving) and UCPTP channels, the latter being the unital channels. In both cases, the sets are compact convex, so they are the closure of their extreme points. We constructed extreme CPTP maps for every possible rank. We also constructed extre...

Brookhaven And Stony Brook Researchers Demonstrate ‘Wireless’ Capability for Quantum NetworkTier 2

<a href="https://thequantuminsider.com/2026/08/23/wireless-capability-quantum-network/" rel="nofollow" title="Brookhaven And Stony Brook Researchers Demonstrate &#8216;Wireless&#8217; Capability for Quantum Network"><img alt="quantum information" class="webfeedsFeaturedVisual wp-post-image" height="667" src="https://thequantuminsider.com/wp-content/uploads/2026/08/BNL-Image-...

Previously: 2026-08-22

A Bayesian formulation of hybrid quantum-classical dynamicsTier 3

We develop a Bayesian formulation of diffusive quantum-classical dynamics by treating the wave function and classical variables as components of an ordinary stochastic process. The joint probability density P(ψ,x,t) obeys a classical Fokker-Planck equation, while the quantum state appears as its second moment. Requiring this second moment to evolve linearly and autonomously...

Multi-Die Assemblies Dominate At 2nm And BelowTier 2

<p>Chips are getting bigger, more modular, and much more capable as new innovations mix with existing processes and long-researched projects go mainstream.</p> <p>The post <a href="https://semiengineering.com/multi-die-assemblies-dominate-at-2nm-and-below/">Multi-Die Assemblies Dominate At 2nm And Below</a> appeared first on <a href="https://semiengineering.com">Semiconducto...

GE Vernova introduces medium-voltage UPS to help accelerate the buildout of AI factories and energy-intensive industriesTier 2

PARIS, France, (24 August 2026)&nbsp;– GE Vernova Inc. (NYSE: GEV) today announced its new medium-voltage uninterruptible power supply, or MV-UPS, designed to keep data centers, AI factories and other energy-intensive facilities running on stable, continuous, high-quality power around the clock