Papers

Parity-protected superconducting qubits offer intrinsically long coherence, but many current implementations require magnetic-flux biasing, which introduces flux noise, control overhead, and limited scalability. Here we propose a parity-protected qubit based on a gate-tunable superconductor-altermagnet-superconductor Josephson junction. Altermagnets are compensated magnets with momentum-dependent spin splitting and zero net magnetization, providing spin-dependent functionality without external magnetic fields. In the proposed junction, the two spin sectors acquire opposite phase shifts, generating two Josephson channels whose interference is controlled electrically by the chemical potential. At the tuned $0$-$\pi$ transition, the first Josephson harmonic is strongly suppressed while the second harmonic dominates, yielding a double-well potential with two nearly degenerate states of opposite Cooper-pair parity. For realistic gatemon-compatible parameters, we estimate coherence times of up to tens of milliseconds while maintaining fully gate-controlled qubit operations. These results establish altermagnetic Josephson junctions as a promising route toward protected superconducting qubits with local, scalable, and all-electrical control.

We overview similarities and, importantly, differences in computational bottlenecks and accuracy requirements that can be addressed with machine learning (ML) and artificial intelligence (AI) techniques in electronic and nuclear DFT. From these follow different promising methodological and algorithmic choices depending on whether one machine learns the exchange correlation (XC) functional, the kinetic energy functional (KEF), the density or the basis functions. In particular, while the popular deep neural networks remain a potent choice in the context of KS DFT, we highlight their disadvantages when building KEFs and highlight conceptual advantages - yet to be fully realized - of symbolic regression for both electronic and nuclear DFT. We point out promising approaches that can be carried from the more extensively investigated ML-enhanced electronic DFT to nuclear DFT.

Neutral-atom array and cavity quantum electrodynamics offer complementary strengths for quantum science: scalable, reconfigurable qubit architectures and strong coherent light-matter coupling. Combining them in a single platform requires an optical cavity with simultaneously high cooperativity, sufficient mode volume to accommodate atom array, and ample side optical access for atom trapping, imaging, cooling, and rearrangement, a combination that is challenging to achieve. Here we realize an atomic array integrated with a millimeter-scale Fabry–Pérot cavity whose optically-characterized single-atom cooperativity reaches $\eta_{\mathrm{cav}}=125\pm13$. Atom-cavity transmission spectra of trapped atoms yield an effective spectroscopic cooperativity $\eta_{\mathrm{spec}}=106\pm 3$, providing an in-situ verification of strong coupling in the integrated platform. In this integrated system, we achieve a state-measurement fidelity of $99.925^{+15}_{-18}\%$ for a single atom with a 4-$\mu$s readout time. We also demonstrate simultaneous coupling of up to 21 individually trapped atoms to the antinode of the cavity mode. The key technical advance is a two-step mirror-fabrication method combining precision mechanical shaping and carbon-dioxide laser polishing, which produces concave fused-silica mirrors with sub-millimeter radii of curvature and residual roughness below $2~\r{A}$. Our results establish a regime of cavity-integrated atomic array that simultaneously provides high cooperativity, large mode volume, and flexible manipulation of individual atoms, opening opportunities for cavity-assisted quantum state readout and long-range entanglement-engineering in atom-array platforms.

We present Aditya-L1/VELC spectroscopic observations of 5303Å coronal emission line widths before and after coronal mass ejections (CMEs) which showed coronal dimming. The sit & stare mode of observations enabled us to study the changes in the line widths for the `limb' CMEs noticed on 16 July 2024 and 05 August 2024. The emission line widths during the pre-CME phase are higher than the thermal values in both the cases. After the onset of the CMEs, the widths increased further by ${\approx}15\%$ on 16 July 2024 and ${\approx}7\%$ on 05 August 2024. We find that the power spectral density (PSD) distributions of the line widths for the two events exhibits a power-law behavior. The PSD slopes, measured before and after the CMEs are nearly the same, and close to the Kolmogorov slope of ${-5/3}$. The results suggest that the observed larger than thermal width of the 5303Å emission line, before and after CMEs, is mostly due to turbulence. The additional increase in the line widths after the onset of the CMEs in both the cases are likely because of enhanced turbulence caused by the CME associated coronal dimmings and subsequent coronal magnetic field reconfiguration.

We propose that jointly modeling the thermal X-ray pulse profiles and the polarization position angles offers an effective means of locating the polarization orientation focus of the pulsar's coherent radiation. From the X-ray pulse-profile measurement we constrain the colatitude of the center of the thermal X-ray emission, which corresponds to the center of in-falling particles within the polar cap, while the RVM fitting yields the inclination angle of the focus point of polarization orientations. Thus, consistency between these two independent angle measurements would imply that the RVM fit faithfully recovers the inclination of the plasma flow center, and this center coincides with the polarization orientation focus. Conversely, the discrepancy would suggest that the polarization state of the radio emission changes as it propagates because the evolution of wave modes during wave propagation in the magnetosphere strongly depends on magnetic field orientations.

The theory of quantum error correction was established decades ago. Yet limitations in physical noise levels and available physical-qubit counts continue to hinder the development of scalable quantum computing systems. In this paper, we present analytical estimates of logical error rates for advanced QEC codes across leading hardware platforms and distributed quantum computing systems using a simple but unified framework. The analysis captures dominant contributors to logical error, including effective circuit volume and two-qubit gate overhead. The framework provides a fast and conservative estimate of logical error rates and identification of dominating factors in different hardware platforms, such as circuit volume, routing overhead, inter-QPU operations, or asymmetric noise protection. We show that several qualitative trends observed in larger-scale simulations can be reproduced and interpreted analytically within this framework. We further demonstrate that the framework can be used to find the sweet spot design region of distributed QEC, which is critical for the design of distributed quantum computing systems.

Artificial atom-like systems are a promising candidate for next generation quantum processing. Among them, dark excitons exhibit one of the longest lifetimes at high temperatures. Here, we demonstrate coherent control of dark excitonic states in metal-organic chalcogenolates (MOChas) by using an ultrafast pulse shaper at room temperature. These dark exciton states are optically accessed via two-photon absorption and directly read out with a four-wave mixing process. The system is described by a non-perturbative, two-photon Hamiltonian based on well-known atomic physics and applied to a three level system comprised of two dark excitons. Empirical and theoretical state specific optical access is shown via a simple optical pulse shape. The developed Hamiltonian-based description is a first step towards a quantum processing platform using three-level systems and two photon transitions, one example being dark excitons in the MOCha silver benzeneselenolate (mithrene). Simple conditions for gate operations are laid out and described.

In the theoretical study of nonequilibrium non-Hermitian systems, obtaining exact analytical solutions for their nonadiabatic dynamics is highly desirable yet often challenging. In this work, we identify a class of non-Hermitian quantum systems where this difficulty can be substantially reduced. Employing the Wei-Norman approach, we show that for a spin-$S$ subject to a general non-Hermitian time-dependent drive, the matrix elements of the evolution operator can be expressed in closed analytical forms (via Jacobi polynomials) in terms of the corresponding spin-$1/2$ model. This approach is straightforward and accessible to nonspecialists in Lie algebra. As an application, we investigate a specific nonequilibrium non-Hermitian phenomenon known as defect freezing, i.e., the existence of excitations in the adiabatic limit, in spin-$S$ extensions of the $\mathcal{PT}$-symmetric Su-Schrieffer-Heeger model under linear quenches. We derive exact analytical expressions for the momentum-resolved excitation probabilities and the total excitation densities. Our results reveal that defect freezing occurs exclusively in momentum sectors that traverse the $\mathcal{PT}$-symmetry-broken region – and thus pass through a pair of higher-order exceptional points (EPs) – during the quench; notably, the excitation density exhibits a singularity at a critical value of the non-Hermiticity parameter. This work enriches the analytical toolkit for nonadiabatic dynamics in multi-level non-Hermitian systems and provides quantitative, testable predictions for defect freezing across higher-order EPs, possibly accessible on platforms such as electric circuit networks and photonic lattices.

Large language models can generate plausible quantum code, but it is unclear whether they can reliably target the specific software development kit (SDK) version requested by the user. We study this problem as API drift and introduce quantum-api-drift, a benchmark for measuring version fidelity, defined here as execution success on the requested SDK version, cross-version compatibility, failure modes, and documentation-guided repair in LLM-generated quantum SDK code. We instantiate the benchmark with Qiskit, a representative quantum SDK that underwent substantial interface changes across v0.43, v1.3, and v2.0. We evaluate 17 models on 50 tasks with 3 samples per prompt, yielding 450 generated samples and 1,350 executions per model. Sixteen models are tested in a matched REST API setting with a 1024-token output cap, while GPT-5.4 (Codex CLI) is reported separately as a reference configuration. Across the 16 matched REST models, diagonal Pass@1 ranges from 0.02 to 0.85. Claude Opus 4.7 is strongest on v0.43 and v2.0, while Grok 4.20 is strongest on v1.3 at 0.513. Error profiles differ systematically by model strength: weaker models fail mainly with broken imports, while stronger models more often reach deprecation-level failures. Documentation-guided repair succeeds for 0.19 to 0.59 of repair attempts overall and is consistently much more effective for migration to v2.0 than to v1.3. The benchmark artifacts are publicly available at https://github.com/arasyi/quantum-api-drift. These results show that version alignment is a distinct evaluation axis for quantum code generation and that API drift remains only partly recoverable even with migration guidance.

The Super Tau-Charm Facility (STCF) is a proposed next-generation high-luminosity electron-positron collider operating at center-of-mass energies of 2-7 GeV for precision studies of tau-charm physics. Its high event rate, detector occupancy, and background level impose stringent requirements on real-time track reconstruction in MDC, particularly for low-transverse-momentum particles with strongly curved or multi-turn trajectories. To address this challenge, we develop a GPU-accelerated matrix-based Hough transform method for online track reconstruction in the STCF MDC. Following an algorithm-architecture co-design paradigm, the data representation and computational workflow of the conformal Hough transform are reformulated for GPU execution. The original irregular parameter-space computations are organized into regular matrix-based operations, and the core computations are adapted to CUDA thread organization and the GPU memory hierarchy to exploit the inherent parallelism of the Hough transform and reduce computational and data-transfer overhead. Tests on five representative simulated physics channels with nominal background overlay show an average signal retention ratio of 93.04%, while reducing the retained hit volume to 34.92% of the original level. The GPU implementation processes 1,000 events in approximately 0.14s, achieving a speedup of 151.57 x compared with the CPU baseline. These results demonstrate that the proposed method substantially improves track reconstruction throughput while preserving track-associated hits, providing a new methodological perspective for real-time track reconstruction in future high-luminosity particle-collider experiments.

In spread complexity, the growth rate of the average position of a time-evolved state along its Krylov chain recovers the proper radial momentum of an infalling particle in AdS. It is, however, a measure of the first moment only, irrespective of the spread of the wavepacket away from its classical trajectory. The rate of a normalized Krylov-Wigner negativity can be proposed as a diagnostic of the second moment of the boundary state that captures this spreading. Starting with the seed-normalized Krylov-Wigner distribution, that is, the Wigner transform of the descendant cloud with the decaying return amplitude divided out, we obtain an analytic Bessel form in the macroscopic limit and compute its total negativity explicitly. Retaining the Bessel variable all the way through, we find that the negativity goes as $\sinh^{4\Delta}(\pi t/\beta)$. But the raw normalized-state negativity saturates to an $O(1)$ constant, well below the $O(\sqrt{D})$ bound. Using the exact negative binomial statistics of the Krylov chain, the normalized negativity is at late times a fixed power of the second moment of the Krylov wavepacket, $\mathcal{N}(t)\propto[\mathrm{Var}(\hat{N}_{\mathrm{Krylov}})]^{\Delta}$, for every $\Delta>1/2$. The relation linearizes precisely at $\Delta=1$. In this regime via the momentum dictionary of Caputa et al. (arXiv:2410.23334), the rate becomes the product of the proper radial position and momentum, $\mathcal{R}\propto\mathcal{C}\,P_\rho$, which we interpret as the rate of the tidal stretch of nearby geodesics falling into the horizon. We also comment briefly on a speculative direction for future research, in particular the interpretation of the transverse string size operator in terms of the Krylov number operator through the common $\mathrm{SU}(1,1)$ discrete series.

One of the most promising applications of quantum computing is the ability to simulate quantum systems. A quantity of particular importance in condensed matter physics is the ground-state energy of a system. Here, we present an implementation of a hybrid quantum-classical algorithm known as the variational quantum eigensolver (VQE) to estimate the ground state energy of a prototypical quantum spin system. For this spin system, we use the transverse field Ising model (TFIM) which is known to exhibit a quantum phase transition (QPT) at a critical point. We apply the VQE to a $4$-spin TFIM and evaluate its performance using both a local noise model and IBM quantum hardware to estimate the ground-state energy and reproduce the QPT. The resulting ground-state energy estimates and QPT behaviour are compared with exact-diagonalisation benchmarks.

Nerve impulses can be modelled as electromechanical density waves within the improved Heimburg-Jackson model. The inclusion of higher-order polynomial nonlinearities leads to a generalized Boussinesq equation with third and fourth order nonlinearities that, under a traveling-wave reduction, reduces to a Liénard-type equation. Applying a factorization method yields exact Lambert W-kink soliton solutions that represent localized nonlinear density waves near the membrane melting transition. Beyond providing exact solutions, the factorization uncovers an underlying supersymmetric structure. The associated operators satisfy algebraic relations analogous to those of supersymmetric quantum mechanics, thereby enabling the construction of a partner soliton. This supersymmetric pairing establishes a novel and previously unexplored connection between nonlinear electromechanical wave propagation in biological membranes and supersymmetric quantum-mechanical methods. The resulting framework offers a theoretical foundation for analysing mechanically induced perturbations and their nonlinear propagation in nerve membranes, with potential implications for understanding the biomechanical mechanisms underlying traumatic brain injury.

The covariant Gross-Pitaevskii-like equation for studying systems of interacting relativistic fermions is proposed. The Lagrangian generating such an equation is derived. The considered equation is examined in studying the fermi-liquid, superconductivity and the confinement problem in QCD. The Migdal's step in the fermi-liqiud model, the excitation spectrum of superconductive fermion system are derived in the context of the proposed Gross-Pitaevskii-like equation. We show that the quark fields governing such an equation turn out to be confined in the (3+1) space time.

Cosmological models incorporating a time-dependent equation of state have recently been explored \cite{DESI:2025fii}, showing a preference for a dynamical dark energy component. In this work, we investigate a scenario in which an effective, time-dependent cosmological constant arises as an emergent manifestation of a violation of energy-momentum conservation. In \cite{Landau:2022mhm}, such a violation of energy conservation was studied as a diffusion mechanism affecting matter (dark and baryonic), leading to an effective dark energy component within the framework of unimodular gravity. Here, we present an updated analysis using the more recent Type Ia supernova data set from the Dark Energy Survey (DESY5) and the baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2), along with the CMB temperature, polarization, and lensing data from Planck 2018. Our results identify a transition phase that occurs at intermediate times, with slight evidence in favor of the model relative to the $\Lambda$CDM according to the $\mathrm{\Delta DIC}$ criterion. Interestingly, a non-decisive preference for an evolution corresponding to either a time-decreasing or time-increasing effective cosmological constant is found. However, slightly higher values of $H_0$ favor a time-increasing effective cosmological constant. Although the $H_0$ tension is not significantly alleviated, these results suggest that a more refined modeling of the physics of the diffusion mechanism may offer a viable route toward addressing the current discrepancy in the Hubble expansion rate, while also providing a natural framework for incorporating a dynamical dark energy and addressing the problem of vacuum energy contribution.

Within the framework of generalised entropic cosmology and its equivalent $f(Q)$ gravity, we construct inflationary scenarios consistent with recent Atacama Cosmology Telescope (ACT) observations combined with Planck-BAO data. We work with $f(Q)$ gravity and use the reconstruction scheme from which one can obtain an arbitrary cosmological evolution consistent with desirable theoretical or observational considerations. Explicit inflationary cosmologies of the above theory, which pass ACT-Data Release 6 (DR6) data combined with Planck and BAO, are obtained. For $f(Q)$ gravity coupled with scalar, we obtain ACT inflation for large classes of $f(Q)$ via the choice of the scalar potentials. The entropic cosmology based on generalised entropy, which includes most of the known entropies like Tsallis, Rényi, Barrow, etc as a particular case, is investigated. The corresponding FRW equations, depending on the parameters of generalised entropy, are presented. Using the correspondence between the generalised entropy and $f(Q)$ gravity, we obtain generalised entropic inflation, which is consistent with the ACT-DR6. At the next step, the entropic gravity coupled with scalar is considered. It is demonstrated how one can obtain ACT-DR6-consistent inflation for such a theory based on any generalised entropy considered in this paper via the choice of scalar potentials. These findings may point towards the correct unifying entropy of the early universe.

The correspondence between $2\times 2$ Hermitian matrices and Minkowski $4$-vectors recovers Lorentzian symmetries from the internal degrees of freedom of a qubit, with no reference to an external spacetime. Recent work characterises the resulting Lorentz invariants and leaves the mechanism of emergence – what singles out a time direction – as an explicit open question. We give an elementary answer and, in doing so, correct a natural misattribution. The bare spin space $(\mathbb{C}^2,\varepsilon)$ is $SL(2,\mathbb{C})$-symmetric and singles out no axis; so is the null cone it generates. What selects a future-timelike axis is the choice of a Hermitian inner product, equivalently a positive reference form $\sigma^0$: this choice – made in passing from a normed space to a Hilbert space, before any probability is assigned – reduces $SL(2,\mathbb{C})$ to its maximal compact $SU(2)$, the stabiliser of $\sigma^0$. The Born rule enters one level later: $\langle \xi \vert \xi \rangle = \text{tr}(\sigma^0 \, \xi\xi^\dagger)$ is the projection of the state's null vector onto $\sigma^0$, i.e. its energy in that frame, and under a boost it rescales as a Doppler shift. Thus the Hilbert structure selects the axis; the Born rule is where that axis becomes a measurable energy and where the frame-dependence of $\lvert\psi\rvert^2$ becomes empirical. The ingredients are classical; what we add is their identification as the mechanism the recent programme leaves open, with the symmetry-breaking step located precisely. This is a kinematic identification of that step, not a dynamical account of why a particular axis is selected. We close by handing back the many-qubit case, where the datum is a tuple of such choices.

The precise determination of fragmentation functions (FFs) of hadrons relies on the accurate description of the differential cross sections obtained from both experimental high-energy hadron colliders and theoretical predictions at higher orders in quantum chromodynamics. Various phenomenological strategies have been employed to extract FFs. In this work, we analyze the use of kinematical cuts for reactions including pions and kaons in proton-antiproton collisions to isolate individual FF contributions. This study examines the feasibility of using a similar approach as in proton-proton colliders to analyze FF flavour separation~\cite{Ochoa-Oregon:2023ktx}. In particular, we study photon-hadron production at colliders, including NLO QCD and LO QED corrections to reconstruct the partonic momentum fractions.

Random circuit sampling of bitstrings from a Haar-random quantum state is widely believed to be classically intractable, and has therefore been implemented as a primary benchmark for demonstrating quantum advantage. Here, we challenge this premise by proposing an efficient classical frozen-tree sampling algorithm that exploits the conditional scale invariance of Haar-random quantum states [Oh, arXiv:2602.19448]. The frozen-tree sampler draws bitstrings of $n$ qubits in $O(n)$ time per sample. Moreover, its output probability $p_F(x)$ is statistically identical to the probability $p_C(x)$ of a random quantum circuit, since both are independent instances of the same Dirichlet distribution. Consequently, no statistical test acting on samples alone can distinguish the classical frozen-tree sampler from a quantum random circuit. The claimed quantum advantage of random circuit sampling therefore does not withstand scrutiny: its hardness lies not in sampling from the Dirichlet distribution, which is classically efficient, but in identifying a specific circuit realization.

We develop a Lie-Jordan geometric formulation of finite-dimensional open quantum dynamics, building on the algebraic framework introduced in our previous work (arXiv:2606.26477). The Hilbert-Schmidt operator space is endowed with an orthonormal Hermitian basis, in which the commutator and anticommutator are encoded by the structure tensors \(C_{\mu\nu}{}^\lambda\) and \(B_{\mu\nu}{}^\lambda\). Within this formulation, the von Neumann and Gorini-Kossakowski-Lindblad-Sudarshan equations admit a direct component representation. Our central result is the identification of a basis-independent universal trilinear dissipative map, \( \mathcal D(X,Y)Z=XZY-\frac12\{YX,Z\}, \) whose components define a universal operator-space tensor depending only on the Lie-Jordan structure tensors. The physical dissipator is obtained by contracting this tensor with the expansion coefficients of the Lindblad operators and the Kossakowski matrix, thereby separating the universal algebraic structure from the model-dependent physical information. We further show that the combinations \((B+C)\) and \((B-C)\) generate internal left and right transports, allowing the elementary dissipative map to be expressed as a left-right bimodule action corrected by an ordered Jordan contribution. The universal map satisfies basis-independent trace and Hermitian-conjugation identities, from which trace preservation, Hermiticity preservation of the complete dissipator, and the reality of its component representation in a Hermitian Hilbert-Schmidt basis follow. We also derive its Hilbert-Schmidt adjoint and illustrate the formalism for a qubit with pure dephasing and amplitude-damping channels. This construction provides a tensorial and affine-geometric interpretation of the universal superoperator structure derived in arXiv:2606.26477 while keeping the algebraic and model-dependent sectors explicitly separated.

We study the top singular value for a sum of $m$ independent $n \times n$ random matrices, each of which is a product of $N$ i.i.d. $n\times n$ Gaussian matrices. Our main conceptual observation is that when $m,n,N\rightarrow \infty$, the top singular value coincides with the partition function in a random energy model at the inverse temperature $\beta=\sqrt{2(N-1)/(n\log m)}$, with energies depending on the ratio $N/n$. We provide several non-asymptotic results making this approximation precise.

We investigate a class of time-dependent traversable wormholes within the framework of general relativity by allowing the shape function to vary with time. In this setting, the evolution of the geometry is directly connected to a radial energy flux through the off-diagonal component of the Einstein field equations, providing a natural mechanism for non-static configurations. We obtain exact solutions in which the geometry consists of a static background supplemented by a transient term that diminishes with time. The resulting spacetime satisfies the standard conditions required for a traversable wormhole, including the presence of a throat, the flaring-out condition, and asymptotic flatness. An analysis of the energy conditions indicates that the null energy condition is violated in the vicinity of the throat, although the degree of violation decreases as the system evolves. This feature is examined further through a volume integral that measures the total amount of exotic matter, demonstrating that it approaches a constant value at late times. We also study the response of the system to small perturbations and find that, for a suitable choice of parameters, the configuration remains stable with perturbations decaying over time. We discuss how this flux-driven mechanism relates to the alternative and extensively studied approach in which wormhole evolution is instead carried by a cosmological scale factor, and we identify possible physical origins of the assumed radial flux in terms of null-fluid matter sources. Overall, the model describes a wormhole spacetime whose evolution is controlled by energy transport, leading to a gradual transition toward a static configuration. This framework offers a simple and physically motivated approach to dynamical wormholes and may be useful for exploring more realistic scenarios in both general relativity and extended theories of gravity.

Quantum simulations of gauge theories are typically built on spatial lattices, an approach that has enabled major progress at the cost of requiring fixed background geometries and obscuring the treatment of curved and dynamical spacetimes. Large-$N$ matrix models offer an alternative, encoding spacetime geometry and gauge fields in the commutation structure of a set of Hermitian matrices, with the classical continuum emerging smoothly at large matrix dimensions. Here we introduce a Floquet framework that makes these models directly accessible to programmable quantum platforms. We show that Euclidean path integral weights of a Yang-Mills matrix models are reproduced, at leading order in the coupling, by the ensemble-averaged fidelities of Haar-random states evolved under periodic sequences of matrix operators. The observables for the simulated matrix model can then be accessed through established randomized benchmarking protocols in terms of the Loschmidt echo. The encoding requires exponentially fewer qubits than canonically quantized approaches. Numerically, we validate the fidelity-weight correspondence, demonstrate parallelized quantum circuits that sample the path-integral measure, and identify the deconfinement transition of an $SU(2)$ gauge field on both flat and expanding cosmological backgrounds. By avoiding a fixed spacetime lattice, the framework preserves continuous symmetries and unitarity on dynamical geometries, opening quantum simulation to field and spacetime dynamics beyond the reach of conventional lattice methods.

Standard device-independent self-testing uses Naimark dilation to assume projective measurements, masking the operational limitations of realistic non-unitary observables. We establish a robust pure self-test for the singlet and Pauli observables that entirely circumvents dilation of the measurement apparatus. Assuming a pure state to model an untrusted source, we regularize the physical non-projective operators and derive an analytic $\mathcal{O}(\sqrt{\epsilon})$ robustness bound. Our results suggest that device-independent certification of real implementations is significantly more demanding than standard projective models imply.

Robust control of plasma current ramp-up is an absolute necessity, as an efficient and uncontaminated plasma current ramp-up is essential for achieving prolonged, high-pressure tokamak plasma discharges. In conventional tokamaks with Ohmic breakdown, the plasma current ramp-up is achieved primarily with pre-fixed temporal profiles of the applied toroidal electric field and the equilibrium magnetic field (Bv). The pre-fixed temporal profiles of these fields are often insufficient to maintain a successful plasma current ramp-up, as several unquantified dynamical variables, such as the condition of the vessel wall and plasma-facing components, influence the plasma current rise. Fuel gas injection in an appropriate quantity at a suitable time during the current ramp-up is therefore used to control the plasma current rise rate, ensuring successful plasma current start-up in Aditya-U. The gas injection time and gas quantity are controlled based on real-time measurement of plasma current rise rate using a digital signal processor (DSP) controller. This special control scheme is capable of achieving the plasma current to rise nearly at the desired rate, resulting in a successful start-up and a stable plasma discharge.

Two-halo galactic conformity is commonly interpreted as a manifestation of galaxy assembly bias, but its statistical structure and physical origin remain unclear. We aim to write the quenched-neighbour statistic in correlation-function form, test whether its scale dependence follows the linear matter correlation function $\xi_{\rm mm}^{\rm lin}(r)$, and separate the contributions of halo-mass bias and assembly bias to its amplitude. Using galaxies in IllustrisTNG300-1 at $z=0$, we measure the two-halo galactic conformity statistic of quenched neighbours at distance $r$, $\Delta f_{Q}(r)$, and related quantities in real space, compute the required correlations, perform shuffling tests at fixed halo mass, compare several $\Delta f$ observables, and explore the transformed family $G_n$. We show explicitly that $\Delta f_{Q}(r)$ can be written directly in terms of correlation functions and that, over $\sim 2$–$40\,h^{-1}\,\mathrm{Mpc}$, it is well described by $A_{\rm fit}\,\xi_{\rm mm}^{\rm lin}(r)$. Thus nonlinear and baryonic terms do not dominate the residual scale dependence isolated by this statistic. Halo-mass bias alone predicts lower amplitudes than measured, while fixed-mass shuffling strongly suppresses the signal; in TNG300 the amplitude is therefore dominated by galaxy assembly bias at fixed halo mass. Quenching, colour, and concentration share a common rescaled shape, whereas stellar-mass and halo-mass splits do not. These results suggest that galaxy assembly bias sets the amplitude of two-halo conformity, while the double-difference structure of the statistic suppresses nonlinear residuals when the compared populations have similar halo-mass and transition-scale structure.

Target reflectivity estimation using a two-mode squeezed vacuum (TMSV) probe offers a theoretical advantage over classical schemes, but realizing this potential under the measurement constraints of microwave platforms remains a central challenge. In this work, we study the precision limits for target reflectivity estimation across different energy and loss regimes, while accounting for realistic measurement restrictions. We characterize the optimal measurements and identify a transition in their structure: above a specific reflectivity threshold, a parametric amplifier receiver is optimal, whereas below it, the optimal observables are two-mode squeezing generators. We then study the performance of Gaussian measurements. When restricted to standard local homodyne detection, the TMSV probe is highly non-optimal. However, we show that suitable non-local Gaussian measurements can closely approach the quantum Cramér-Rao bound at the large noise limit. These results demonstrate that near-optimal quantum target reflectivity estimation is achievable in various relevant noisy regimes, even under the restriction of Gaussian measurements.

Energy planning for artificial intelligence focuses on data-centre electricity, missing the induced operational energy change caused by the deployment of AI in commercial buildings, factories and freight networks. Here we map occupation-level AI exposure onto sector energy use and apply a Monte Carlo (MC) joint supply-demand decomposition to estimate each sector's net energy change. Our results show that the US adoption-side energy envelope – the operational energy exposed to AI – is 12.1 Q theoretical and ~1.4 Q observed (1 Q is approximately 293 TWh, summed across electricity, gas, petroleum and process fuels); this measures the scope of exposed energy, not consumption. Decomposing this envelope at full adoption reveals divergent sector net signs: Commercial saves 0.22 Q while Industrial (+1.25 Q) and Transport (+1.12 Q) increase, each sign robust across 88-99% of parameter draws. The induced net change aggregates to +2.16 Q (90% MC range [+0.52, +4.12]; +1.1 Q under a conservative price-channel conversion of the rebound anchors) – several times the ~0.6 Q of current US data-centre electricity that AI energy planning targets. These net changes vary geographically when projected onto each state's occupational and energy end-use mix. Industrial- and freight-heavy states (Texas, Louisiana, Indiana) primarily carry the increase, while commercial-dominated states (New York, Massachusetts, DC) see substantially smaller net changes. We also transfer the analysis to the UK and show an energy envelope of 1.9 Q out of a 3.7 Q national total. Therefore, adoption-side energy is the larger, geographically variable component of AI's footprint, requiring end-use energy surveys to track AI deployment and the resulting task and occupational shifts alongside compute-side forecasting.

Many stabilizer quantum error-correcting codes are built from a finite pattern repeated across space or time, such as lattice codes, translation-invariant graph states, and quantum convolutional codes. Ordinary stabilizer ZX-diagrams capture only finite truncations of such systems, obscuring the repeated structure that defines them. We introduce the delayed stabilizer ZX-calculus, a finite graphical language for these infinite, translation-invariant processes. It extends the odd-prime-dimensional stabilizer ZX-calculus with a single new generator, the delay, which feeds data from one time step to the next. We equip the calculus with two semantics. In the first semantics, we interpret the behaviour of a delayed ZX-diagram as an equivalence class of sequences of quantum channels; where two sequences are identified if they have the same information content. We show that the behaviour of a delayed ZX-diagram uniquely determines an infinite stabilizer group. In the second semantics, we interpret the delay as a formal variable, encoding the translation-invariant families of Pauli operators as generating functions. This allows us to represent a delayed ZX-diagram in terms of a tableau of generating functions, from which the infinite stabilizer group can be recovered. Finally, we give a complete axiomatization of the delayed stabilizer ZX-calculus, featuring generalised Euler decomposition and colour change rules. Using generalised forms of local complementation and pivoting, we reduce every diagram to a unique normal form. This establishes soundness, universality, and completeness for the generating tableau semantics.

Uncovering the physical mechanisms of turbulent flows remains a fundamental challenge in fluid mechanics. In particular, conventional velocity-gradient analysis methods suffer from shear contamination, which hinders accurate identification of the dominant physical mechanisms. This study presents PhysMiner, an automated framework integrating the triple decomposition method of the velocity gradient tensor with large language model-driven reasoning for turbulence-physics discovery. The triple decomposition module automatically decomposes flow fields into rigid rotation, pure shearing, and normal straining components, enabling statistical analysis, contour visualization, vortex-line extraction, and threshold-insensitive vortex identification while eliminating shear contamination. These automated capabilities are validated across five benchmarks, ranging from canonical configurations to complex engineering flows. A discover-physics agent combines flow statistics, spatial structures, and literature-derived knowledge to perform pattern recognition and physical inference, while a review Agent iteratively validates physical consistency to ensure reliable conclusions. A continuously evolving Triple Decomposition Library accumulates statistical knowledge from successfully analyzed flows, enabling cross-case comparison and progressive enhancement of inductive capability. The complete PhysMiner pipeline is validated end-to-end on the periodic hill flow, where the framework autonomously generates turbulence modeling recommendations and derives an improved subgrid-scale model with superior Reynolds-stress predictions. PhysMiner is open to the public and establishes a foundation for long-term collaborative advancement in automated turbulence-physics discovery.