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quant-ph/0611009 2026-03-05 quant-ph

Security aspects of the Authentication used in Quantum Cryptography

Jorgen Cederlof, Jan-Åke Larsson

Comments 8 pages, 5 figures, v2: added email addresses, v3: published version

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Journal ref
IEEE Trans. Inf Theory, 54: 1735-1741 (2008)
英文摘要

Unconditionally secure message authentication is an important part of quantum cryptography (QC). In this correspondence, we analyze security effects of using a key obtained from QC for authentication purposes in later rounds of QC. In particular, the eavesdropper gains partial knowledge on the key in QC that may have an effect on the security of the authentication in the later round. Our initial analysis indicates that this partial knowledge has little effect on the authentication part of the system, in agreement with previous results on the issue. However, when taking the full QC protocol into account, the picture is different. By accessing the quantum channel used in QC, the attacker can change the message to be authenticated. This, together with partial knowledge of the key, does incur a security weakness of the authentication. The underlying reason for this is that the authentication used, which is insensitive to such message changes when the key is unknown, becomes sensitive when used with a partially known key. We suggest a simple solution to this problem, and stress usage of this or an equivalent extra security measure in QC.

2603.04401 2026-03-05 astro-ph.CO hep-ph hep-th

Post-inflationary axion constraints from the Lyman-$α$ forest

Olga Garcia-Gallego, Vid Iršič, Matteo Viel, Martin G. Haehnelt, James S. Bolton

Comments 6 pages + Supplemental Material, 3 figures, submitted

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英文摘要

Among the most compelling cold dark matter candidates, the axion has recently been subject to a wide range of astrophysical studies aiming to constraints its properties. We present updated bounds on the isocurvature fraction, $f_{\rm{iso}}$, which parameterizes the contribution of isocurvature perturbations induced by post-inflationary produced axion-like particles (ALPs) to the ordinary power spectrum. We use new simulations based on the Sherwood-Relics suite to fit high-resolution Lyman-$α$ forest flux power spectrum data. With the published noise model of the Lyman-$α$ forest data, we find a tentative detection of $f_{\rm{iso}}$ = ${0.0064^{+0.0012}_{-0.0014}}$ (68% C.L), after accounting for the degenerate effect of IGM thermal evolution. With a more conservative modelling of the residual noise in the data, the upper bound is weakened to $f_{\rm{iso}}< 0.0084$ (95% C.L), which translates into an ALP temperature-independent mass $m_a > 1.73 \times 10^{-18}$eV. Our constraints are stronger than bounds derived from large-scale structure probes at higher and lower redshifts and are competitive with those derived from UV luminosity function data. Interestingly, the best current Lyman-$α$ forest data prefers a non-zero contribution from isocurvature modes.

2603.04400 2026-03-05 gr-qc

Gravitational confinement of ghost scalar fields in neutron stars

Argelia Bernal, Víctor Jaramillo, Néstor A. Montiel-Hernández, Darío Núñez, Nicolas Sanchis-Gual

Comments 18 pages,18 figures

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英文摘要

We investigate the effects, stability, and nonlinear dynamics of ghost scalar matter modeled as a field with a negative kinetic term confined within the cores of neutron stars. To this end, we analyze static configurations of the coupled Einstein-Euler-(ghost, complex) Klein-Gordon system and then we perform fully dynamical numerical evolutions of illustrative cases. Our results demonstrate that neutron stars can gravitationally confine a finite amount of ghost matter and support continuous families of equilibrium solutions, indicating that these configurations are not the result of fine tuning. We analyze the properties of the final states and find that the neutron star undergoes a persistent pulse-like oscillatory motion. In particular, we explicitly compute the frequency synchronization between the stellar fluid oscillation modes and those of the ghost scalar sector.

2603.04398 2026-03-05 quant-ph

HyQBench: A Benchmark Suite for Hybrid CV-DV Quantum Computing

Shubdeep Mohapatra, Yuan Liu, Eddy Z. Zhang, Huiyang Zhou

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英文摘要

Hybrid continuous-variable (CV)-discrete-variable (DV) quantum systems present a promising direction for quantum computing by combining the high dimensional encoding capabilities of qumodes with the control offered by DV qubits on the coupled qumodes. There have been exciting recent progresses on hybrid CV-DV quantum computing, including variational algorithms, error correction, compiler-level optimizations for Hamiltonian simulation, etc. However, there is a lack of a standardized CV-DV benchmark suite for assessing various emerging hardware platforms and evaluating software optimizations on hybrid CV-DV circuits. In this work, we introduce a simulation and benchmarking framework for hybrid CV-DV circuits, implemented using Bosonic Qiskit-a tool specifically designed to model CV-DV systems, along with QuTip for functional correctness verification. We construct and characterize representative CV-DV benchmarks, including cat state generation, GKP state generation, CV-DV state transfers, hybrid quantum Fourier transform, variational quantum algorithms, Hamiltonian simulation, and Shor's algorithm. To assess circuit complexity and scalability, we define a feature map organized into two categories: general features (e.g., qubit/qumode count, gate counts) and CV-DV-specific features (e.g., Wigner negativity, energy, truncation cost). These metrics enable evaluation of both classical simulability and hardware resource requirements. Our results, including one benchmark on real hardware, demonstrate that hybrid CV-DV architectures are not only viable but well-suited for a range of computational tasks, from optimization to Hamiltonian simulation. This framework lays the groundwork for systematic evaluation and future development of hybrid quantum systems.

2603.04397 2026-03-05 astro-ph.CO astro-ph.GA

Exploring gas thermodynamics around galaxies from the Sunyaev-Zel'dovich effects: impact of galaxy-halo connection, 2D projection and velocity field

Sadaf Kadir, Bernardita Ried Guachalla, Sihan Yuan, Emmanuel Schaan, Risa H. Wechsler

Comments Comments are welcome. 13 pages + appendix

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英文摘要

A complete picture of the gas thermodynamics around galaxies is imprinted on the cosmic microwave background (CMB). Indeed, the thermal, kinematic, and relativistic Sunyaev-Zel'dovich effects (tSZ, kSZ, rSZ) measure the gas density, temperature, pressure of baryonic feedback and bulk velocity around galaxies, along with the gravitational potential it sits in. This full thermodynamic picture promises to constrain galaxy formation models and gas related uncertainties in the impact on galaxy lensing. Recent kSZ measurements around galaxies suggest that the gas may be more extended than anticipated, pointing to powerful feedback processes and large baryonic corrections to lensing. How robust are these conclusions about the galaxy-halo connection, including satellite fraction and high-mass outliers, or to 2D projection effects and large-scale velocity modes? In this paper, we give estimates for these effects using a simulated sample of DESI-like luminous red galaxies within the IllustrisTNG hydrodynamical simulation and the Abacus N-body simulation. We show that analyzing projected 2D profiles can lead to biases when computing quantities like the gas fraction. We also find that in the absence of spatial filtering, the 2-halo term is non-negligible for kSZ even at the smaller radii where the 1-halo term dominates. We show that a 1% uncertainty in the satellite fraction of galaxies can propagate into uncertainties of $\pm$1%, $\pm$3% and $\pm$5% in the 1-halo terms of the kSZ, tSZ, and rSZ signals, respectively. We show that masking the 2% most massive objects in the sample reduces the profile amplitudes by up to 10%, 40%, and 75% for the kSZ, tSZ, and rSZ signals, respectively. Finally, we show that naive simulations of the kSZ effect can be biased by an artificial Doppler term, which is automatically removed when high-pass or compensated aperture filtering is applied.

2603.04395 2026-03-05 cs.LG physics.ao-ph

Accurate and Efficient Hybrid-Ensemble Atmospheric Data Assimilation in Latent Space with Uncertainty Quantification

Hang Fan, Juan Nathaniel, Yi Xiao, Ce Bian, Fenghua Ling, Ben Fei, Lei Bai, Pierre Gentine

Comments 23 pages, 12 figures

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英文摘要

Data assimilation (DA) combines model forecasts and observations to estimate the optimal state of the atmosphere with its uncertainty, providing initial conditions for weather prediction and reanalyses for climate research. Yet, existing traditional and machine-learning DA methods struggle to achieve accuracy, efficiency and uncertainty quantification simultaneously. Here, we propose HLOBA (Hybrid-Ensemble Latent Observation-Background Assimilation), a three-dimensional hybrid-ensemble DA method that operates in an atmospheric latent space learned via an autoencoder (AE). HLOBA maps both model forecasts and observations into a shared latent space via the AE encoder and an end-to-end Observation-to-Latent-space mapping network (O2Lnet), respectively, and fuses them through a Bayesian update with weights inferred from time-lagged ensemble forecasts. Both idealized and real-observation experiments demonstrate that HLOBA matches dynamically constrained four-dimensional DA methods in both analysis and forecast skill, while achieving end-to-end inference-level efficiency and theoretical flexibility applies to any forecasting model. Moreover, by exploiting the error decorrelation property of latent variables, HLOBA enables element-wise uncertainty estimates for its latent analysis and propagates them to model space via the decoder. Idealized experiments show that this uncertainty highlights large-error regions and captures their seasonal variability.

2603.04394 2026-03-05 hep-ph

A framework for missing-energy searches with anomalous light vectors

Luca Di Luzio, Marco Nardecchia, Stefano Scacco, Claudio Toni

Comments 28 pages, 3 figures

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英文摘要

We study light spin-1 gauge bosons coupled to electroweak-anomalous currents. For generic charge assignments, anomaly cancellation requires new fermions (anomalons) that are chiral under the new abelian symmetry and carry electroweak charges. If their masses arise from the breaking of the new gauge symmetry, integrating them out generates Wess-Zumino interactions fixed by mixed-anomaly matching, providing the infrared description of the theory. We classify minimal anomalon spectra, derive the corresponding effective interactions, and combine experimental constraints with finite-naturalness considerations to bound the UV completion scale. Motivated by recent NA62 and Belle II results, we then develop a unified phenomenological framework for the missing-energy signatures of these anomalous light vectors, focusing on scenarios where the new vector decays predominantly into neutrinos so that the leading probes are rare processes with invisible final states. As applications, we survey current and projected searches across flavour and electroweak observables, including $K\toπE_{\rm miss}$, $B\to K^{(*)}E_{\rm miss}$, and $Z\toγE_{\rm miss}$, and discuss their interplay with direct searches for anomalons.

2603.04392 2026-03-05 astro-ph.IM cs.LG

SELDON: Supernova Explosions Learned by Deep ODE Networks

Jiezhong Wu, Jack O'Brien, Jennifer Li, M. S. Krafczyk, Ved G. Shah, Amanda R. Wasserman, Daniel W. Apley, Gautham Narayan, Noelle I. Samia

Comments Accepted at AAAI 2026 (Proceedings of the AAAI Conference on Artificial Intelligence)

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英文摘要

The discovery rate of optical transients will explode to 10 million public alerts per night once the Vera C. Rubin Observatory's Legacy Survey of Space and Time comes online, overwhelming the traditional physics-based inference pipelines. A continuous-time forecasting AI model is of interest because it can deliver millisecond-scale inference for thousands of objects per day, whereas legacy MCMC codes need hours per object. In this paper, we propose SELDON, a new continuous-time variational autoencoder for panels of sparse and irregularly time-sampled (gappy) astrophysical light curves that are nonstationary, heteroscedastic, and inherently dependent. SELDON combines a masked GRU-ODE encoder with a latent neural ODE propagator and an interpretable Gaussian-basis decoder. The encoder learns to summarize panels of imbalanced and correlated data even when only a handful of points are observed. The neural ODE then integrates this hidden state forward in continuous time, extrapolating to future unseen epochs. This extrapolated time series is further encoded by deep sets to a latent distribution that is decoded to a weighted sum of Gaussian basis functions, the parameters of which are physically meaningful. Such parameters (e.g., rise time, decay rate, peak flux) directly drive downstream prioritization of spectroscopic follow-up for astrophysical surveys. Beyond astronomy, the architecture of SELDON offers a generic recipe for interpretable and continuous-time sequence modeling in any time domain where data are multivariate, sparse, heteroscedastic, and irregularly spaced.

2603.04389 2026-03-05 physics.optics cond-mat.dis-nn cond-mat.mes-hall cond-mat.soft

Hyperuniform Disorder in Photonic Crystal Slabs with Intrinsic non-Hermiticity

Zeyu Zhang, Koorosh Sadri, Brian Gould, Mikael Rechtsman

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英文摘要

Hyperuniform disorder is a type of correlated disorder characterized by vanishing spectral density at small wavevectors, making the configuration effectively homogeneous on long length scales. In photonics, hyperuniform disorder is promising for generating isotropic photonic pseudogaps and engineering photonic crystal waveguides. However, these studies are largely restricted to idealized lossless settings, although all photonic systems necessarily have loss. In this work, light propagation in photonic crystal slabs with imposed hyperuniform disorder is investigated theoretically and numerically. The system is intrinsically non-Hermitian due to radiative loss, with non-Hermiticity appearing as a complex effective mass of a quadratic photonic band. A theoretical framework for disorder scattering is analytically derived in Hermitian and non-Hermitian quadratic bands with real and complex effective mass, respectively. In contrast to the power law behavior $|\mathbf{k}|^α$ observed in the Hermitian case (where $α$ is the hyperuniformity exponent), the scattering loss in the non-Hermitian band is given by $C_0+C_{β_2}\cdot|\mathbf{k}|^{β_2}$, where $C_0$ is a finite constant and the exponent $β_2\leq 2$. Our theoretical predictions are verified with tight-binding and Finite-Difference Time-Domain simulations with realistic photonic crystal parameters, based on recent experiments.

2603.04386 2026-03-05 math.PR math-ph math.CO math.MP math.SP

The Gaussian Wave for Graphs of Finite Cone Type

Amir Dembo, Theo McKenzie

Comments 20 pages, 2 figures

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英文摘要

We show that for any infinite tree of finite cone type satisfying a mild expansion condition, the only typical process on its vertices with covariance induced by the Green's function is the Gaussian wave. This generalizes a result of Backhausz and Szegedy, who proved this for the infinite regular tree of degree $d\geq 3$. We do this by giving a reduction to a statement concerning the distribution of the inner product of our process with columns of the Green's function, which in turn are straightforward to calculate. As a consequence, for random bipartite biregular graphs, the distribution of local neighborhoods of eigenvectors must approximate the Gaussian wave. Moreover, for generic configuration models including random lifts, the local distribution of a uniformly chosen eigenvector from any arbitrarily small spectral window likewise converges to the Gaussian wave.

2603.04382 2026-03-05 astro-ph.SR

Synthetic disk-integrated absorption lines isolating stellar granulation for high-precision RV studies

Ginger Frame, Heather Cegla, Cis Lagae, Veronika Witzke, Christopher Watson, Sergiy Shelyag, Vatsal Panwar, Michael Palumbo, Alexander Shapiro

Comments 16 pages, 12 figures, accepted by MNRAS

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英文摘要

We present a novel method for constructing high-accuracy, time-varying disk-integrated stellar absorption line profiles that isolate the effects of granulation alone. This framework provides an effectively unlimited supply of physically consistent training data, offering a unique opportunity to study granulation-driven velocity variability with no contamination from other stellar processes or instrumental systematics. Our interpolation scheme enables accurate profile generation at arbitrary limb angles and successfully reproduces observed disk integrated solar bisector shapes from IAG spectra. Using four Fe I lines (525.0, 615.2, 617.3, and 627.1 nm), we produce 1000 model star disk-integrated realisations per line and find an isolated granulation-induced RV scatter of 0.16-0.21 m s^-1. Using our synthetic profiles and assuming infinite signal-to-noise, we find strong correlations between various line-shape metrics and convective blueshift, demonstrating that line-shape diagnostics can, in principle, trace granulation effects. Equivalent width proves the strongest diagnostic, achieving up to 60% scatter reduction. However, the strength of all simple line shape diagnostics rapidly diminishes once photon noise is injected. Even when artificially boosting the signal to represent a spectrum containing ~1000 spectral lines, the achievable improvement with these metrics remains below 10% at typical signal-to-noise ratios. Our results highlight the need for more robust, noise-resilient diagnostics and position our synthetic dataset as a valuable testbed for developing and benchmarking such methods.

2603.04375 2026-03-05 gr-qc astro-ph.CO hep-th quant-ph

Non-Hermitian Quantum Mechanics with Applications to Gravity

Oem Trivedi, Alfredo Gurrola, Robert J. Scherrer

Comments 18 pages with no figures, comments very welcome !

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英文摘要

Hermiticity is usually treated as a foundational axiom of quantum mechanics, guaranteeing real spectra and unitary time evolution. In this work we argue that Hermiticity is more naturally understood as a symmetry law arising from the global conservation of an inner product current. We show that in spacetimes admitting complete Cauchy surfaces without boundary flux this conservation reduces to the familiar Hermiticity condition of the canonical inner product. However, in the presence of causal horizons, most strikingly in black hole geometries, this conservation law becomes obstructed for restricted observers. Tracing over inaccessible degrees of freedom then inevitably yields completely positive trace preserving dynamics with an effective non-Hermitian generator. Using quantum thermodynamics and the monotonicity of relative entropy, we demonstrate that the generalized second law may be reinterpreted as an entropy balance that compensates precisely for the flux of inner product charge through the horizon. The structure of Einstein equations, through the Bianchi identity and the Raychaudhuri focusing equation, provides the geometric mechanism underlying this balance. We also show that black hole ringdown can serve as a realistic observational probe of this idea and may provide quantitative upper bounds on the strength of horizon-induced inner product flux. In this way gravity, entropy production, and effective non-Hermiticity are unified under a single structural principle, with Hermiticity emerging as the special case of globally conserved inner product symmetry.

2603.04374 2026-03-05 astro-ph.SR

Improved Stark Broadened Profiles for Neutral Helium Lines Using Computer Simulations

Patrick Tremblay, Alain Beauchamp, Pierre Bergeron, Antoine Bédard

Comments Accepted for publication in The Astrophysical Journal; 26 pages, 21 figures

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英文摘要

The study of Stark broadening of neutral helium lines, despite significant advances over recent decades, has not led to updated large grids of helium line profiles relevant to the spectroscopic study of helium-rich stars. While the semi-analytical approach based on the standard Stark broadening theory is efficient for generating such grids, it presents challenges in incorporating additional physical effects into the model. Motivated by recent studies that highlight potential issues with line profiles in the context of white dwarf stars, this paper leverages advances in computer simulations to create a new grid of line profiles for 13 neutral helium lines in the optical range. These profiles cover densities ranging from 10^14 to 6 x 10^17 cm^-3 and temperatures from 10,000 K to 40,000 K, with the exception of the narrower He I 4713 line, for which the profile grid begins at 10^15.5 cm^-3. The primary goal of this research is to present the new grid and compare it with both the semi-analytical approach and other simulation results. By doing so, corrections to the previous grid will be explored, providing a foundation for future studies that utilize this updated grid. We also examine the impact of these new profiles on the determination of physical parameters for a range of astrophysical objects, including DB white dwarfs and other helium-rich stars.

2603.04371 2026-03-05 hep-th

Casimir Effect for a Massive Scalar Field in Lorentz-Violating Aether Compactification

K. E. L. de Farias, M. A. Anacleto, A. A. Araújo Filho, M. B. Cruz, R. A. Dantas, Amilcar R. Queiroz, E. Passos

Comments 15 pages, 8 figures

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英文摘要

This work investigates the influence of Lorentz symmetry breaking, introduced by an aether-like field $α_ϕ$, on the Casimir effect within a five-dimensional flat spacetime. By considering a quasiperiodic condition regulated by the parameter $β$ and an extra dimension compactified at scale $b$, we derive closed-form expressions for the Casimir energy and the resulting force between two parallel plates under Neumann boundary conditions. Our results demonstrate that $β$ acts as a crucial control parameter, enabling a continuous transition between attractive and repulsive regimes, with a characteristic symmetry around $β= 0.5$. We show that the Lorentz-violating parameter $α_ϕ$ functions as an enhancement factor, significantly amplifying the vacuum interaction, while the geometric ratio $a/b$ proves decisive for system stabilization. Specifically, we find that the high-compactification regime leads to a plateau in the Casimir force, effectively stabilizing the interaction. Furthermore, we analyze the mass spectrum of the field, recovering standard geometric forms in the massless limit and demonstrating that while light fields ($M \ll 1$) exhibit subtle quadratic corrections, heavy fields ($M \gg 1$) lead to an exponential suppression of the Casimir effect. The interplay between Lorentz violation and extra-dimensional compactification provides a rich mechanism with potential applications in the modulation of vacuum-induced interactions at micro and nano scales.

2603.04362 2026-03-05 physics.flu-dyn

Volumetric effects in viscous flows in circular and annular tubes with wavy walls

Yisen Guo, John H. Thomas

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英文摘要

We point out that, in the usual way of specifying a sinusoidal waviness of the wall of a tube of circular cross section, in which the mean radius is kept constant, the interior volume of the tube increases with increasing wave amplitude. We compare this case with the case where the interior volume is kept constant by reducing the mean radius as the wave amplitude increases. We present and compare numerical results of these two cases for steady, pressure driven, laminar viscous flow in a tube with a stationary wavy wall, for both circular and annular tubes. The volume flow rate and the hydraulic resistance can differ in the two cases by as much as 10% for wave amplitudes as small as 20% of the mean radius and as much as 50% for larger wave amplitudes. For a circular tube, we derive a scaling law that relates the two cases based on dimensional analysis, allowing the behavior in the constant-volume case to be determined from that in the constant-mean-radius case. Additionally, we consider peristaltic pumping due to a moving sinusoidal wall wave and show that the volume-change effect is significant even at small wave amplitudes, and that the volume flow rates in the two cases can differ significantly, by as much as 50% as the wave amplitude approaches its maximum value.

2603.04358 2026-03-05 astro-ph.GA

A Selection Aware View of Black Hole-Galaxy Coevolution at High Redshift

Francesco Ziparo, Stefano Carniani, Simona Gallerani, Bartolomeo Trefoloni

Comments Submitted to A&A. Comments are welcome

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英文摘要

The large population of broad-line Active Galactic Nuclei (AGN) observed with the James Webb Space Telescope (JWST) at $z \gtrsim 4$ opens a new window onto the black hole-galaxy connection in the first Gyr of cosmic history. We use the JADES survey-level dataset and develop a forward-modeling Bayesian framework that explicitly accounts for broad H$α$ detectability, ensuring that selection effects are incorporated into the likelihood function. With this approach, we constrain the black hole-stellar mass ($M_{\mathrm{BH}}$-$M_\star$) relation to be $\log M_{\rm BH} = -4.06^{+0.50}_{-0.51} + 1.17^{+0.06}_{-0.06}\,\log M_\star$, with an intrinsic orthogonal scatter of $σ_{\rm int} = 0.63^{+0.14}_{-0.11}$ dex. The slope and normalization are consistent with local determinations, indicating that the average scaling was already established by $z \sim 4$-6. This suggests that the primary evolution of the relation occurs in its dispersion rather than in its mean normalization. In contrast, the substantially larger intrinsic scatter relative to the nearby Universe reveals a wider diversity of black hole-galaxy growth histories, likely driven by bursty accretion, delayed feedback, and differences in merger or seeding histories. Future JWST samples will be crucial to test whether this increased scatter is a persistent feature of the high-redshift Universe.

2603.04357 2026-03-05 quant-ph cs.IT math.IT

On Error Thresholds for Pauli Channels: Some answers with many more questions

Avantika Agarwal, Alan Bu, Amolak Ratan Kalra, Debbie Leung, Luke Schaeffer, Graeme Smith

Comments 34 Pages, 11 Figures

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英文摘要

This paper focuses on error thresholds for Pauli channels. We numerically compute lower bounds for the thresholds using the analytic framework of coset weight enumerators pioneered by DiVincenzo, Shor and Smolin in 1998. In particular, we study potential non-additivity of a variety of small stabilizer codes and their concatenations, and report several new concatenated stabilizer codes of small length that show significant non-additivity. We also give a closed form expression of coset weight enumerators of concatenated phase and bit flip repetition codes. Using insights from this formalism, we estimate the threshold for concatenated repetition codes of large lengths. Finally, for several concatenations of small stabilizer codes we optimize for channels which lead to maximal non-additivity at the hashing point of the corresponding channel. We supplement these results with a discussion on the performance of various stabilizer codes from the perspective of the non-additivity and threshold problem. We report both positive and negative results, and highlight some counterintuitive observations, to support subsequent work on lower bounds for error thresholds.

2603.04339 2026-03-05 quant-ph hep-lat

Quantum error mitigation by hierarchy-informed sampling: chiral dynamics in the Schwinger model

Theo Saporiti, Oleg Kaikov, Vasily Sazonov, Mohamed Tamaazousti

Comments 17 pages, 8 figures, 1 table

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英文摘要

Quantum simulations on current NISQ hardware are limited by its noisy nature, making efficient quantum error mitigation methods highly demanded. In this paper we introduce a novel mitigation scheme, applicable to arbitrary quantum simulations of time-dependent Hamiltonian dynamics on NISQ devices. The scheme uses a polynomial subset of extended qubit Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy equations as a sampling criterion of possible mitigated candidates for the quantum observables. We show that for favorable Hamiltonians the polynomial subset of BBGKY hierarchy equations leads to a polynomial overhead in both classical and quantum resources. We employ the method to mitigate simulations of the chiral magnetic effect (CME), a chiral feature of the Schwinger model. We empirically show the effectiveness of our scheme at recovering the real-time dynamics of the CME from noisy quantum simulations of the Schwinger model, for a range of different parameter values of the model. We numerically demonstrate a systematic reduction of quantum noise, together with an increasing noise reduction capability as the amount of BBGKY constraints grows.

2603.04336 2026-03-05 quant-ph

Direct derivation of the modified Langevin noise formalism from the canonical quantization of macroscopic electromagnetism

Alessandro Ciattoni

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英文摘要

The modified Langevin noise formalism (MLNF) models the interaction of the quantized electromagnetic field with an arbitrary lossy magneto-dielectric object placed in vacuum using three types of non-interacting bosonic polaritons: scattering, electric, and magnetic. These respectively represent free-space photons scattered by the object, and photons radiated by quantized electric and magnetic dipolar sources embedded within its volume. Recently [A. Ciattoni, Phys. Rev. A 110, 013707 (2024)], this formalism was justified from the canonical quantization of macroscopic electromagnetism (CQME) [Philbin, New J. Phys. 12, 123008 (2010)] in the Heisenberg picture. This was achieved by identifying the polariton operators within the formal solution of the macroscopic Maxwell equations, assuming they obey bosonic commutation relations to retrieve the canonical ones, and showing they diagonalize the CQME Hamiltonian. However, the explicit functional dependence of these polaritons on the underlying canonical field operators remained undetermined. In this paper, we derive the exact analytical expressions for the polariton operators in terms of the canonical CQME field operators. Using these mappings, we provide a direct and rigorous derivation of the MLNF from the canonical theory in the Schrödinger picture. Our derivation is structured in three foundational steps: 1) adopting the derived analytical expressions as the constitutive definitions of the polariton operators; 2) mathematically proving that these operators are strictly bosonic as a direct consequence of the canonical commutation relations; and 3) demonstrating that they exactly diagonalize the macroscopic CQME Hamiltonian.

2603.04332 2026-03-05 quant-ph

On the operational and algebraic quantum correlations

Shun Umekawa, Jaeha Lee

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英文摘要

We investigate the intrinsic ambiguity in the definition of correlation functions arising from the inevitable invasiveness of quantum measurements. While algebraic correlations defined as expectation values of products of observables are widely used, their relationship to operational ones defined through actual measurement procedures remain unclear. We demonstrate that the differences among various definitions of correlation functions and those among their underlying (quasi-)joint probability distributions are bounded above by a quantitative measure of measurement invasiveness. We further obtain a lower bound on the discrepancy among operational and algebraic (quasi-)joint probability distributions, providing a new form of the uncertainty relation. In addition, we identify an equivalence condition under which operational and algebraic correlations coincide. As an application, we analyze the quantum violation of the Leggett-Garg inequality and clarify the structural origin of the equivalence among different approaches to observing the violation, including sequential projective measurements and weak-measurement. Our results provide an operational foundation for the commonly used algebraic concepts of quantum theory.

2603.04327 2026-03-05 cond-mat.mtrl-sci cond-mat.mes-hall

Study on the Effect of Annealing on Ga$_2$O$_3$ Thin Films Deposited on Silicon by RF Sputtering

Ana Sofia Sousa, Duarte M. Esteves, Tiago T. Robalo, Mário S. Rodrigues, Katharina Lorenz, Marco Peres

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英文摘要

Gallium oxide is an ultra-wide bandgap semiconductor with excellent opto-electronic properties, making it a highly promising material for a wide range of applications and devices. In this article, we report how the optical, morphological, structural, and compositional properties of $β$-Ga$_2$O$_3$ thin films deposited by RF sputtering on silicon substrates are affected by thermal treatments. Ellipsometric spectra recorded at multiple angles of incidence from several samples subjected to thermal annealing in the range of 550-1000 $^\circ$C were analyzed to extract the optical functions using appropriate multilayer models. This analysis is complemented by compositional, structural, and morphological characterization techniques. A significant increase of the refractive index was found after annealing at 1000 $^\circ$C, accompanied by a stark improvement in the samples' crystalline structure, as confirmed by complementary structural and compositional characterization techniques.

2603.04318 2026-03-05 cond-mat.mes-hall physics.ins-det physics.optics

Sub-wavelength mid-infrared imaging of locally driven photocurrents using diamond campanile probes

Rajasekhar Medapalli, Nathan D. Cottam, Khushboo Agarwal, Benjamin T. Dewes, Nils Dessmann, Sergio Gonzalez-Munoz, Wenjing Yan, Vaidotas Mišeikis, Sergey Kafanov, Rostislav V. Mikhaylovskiy, Samuel P. Jarvis, Camilla Coletti, Britta Redlich, Amalia Patanè, Oleg V. Kolosov

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英文摘要

Precise and high efficiency concentration of mid-infrared (mid-IR) light into sub wavelength volumes is essential for probing low-energy excitations and achieving strong field enhancements, which can be hindered by absorption losses and coupling inefficiencies at long wavelengths. Here, we introduce an innovative diamond-based metal-insulator-metal campanile probe that adiabatically compresses free-space mid infrared light (10 \mum) into \approx 1 \mum domains. Integrated into a scanning photovoltage microscope, the probe enables sub-wavelength mapping of locally driven photocurrents in graphene, resolving polarization dependent and contact-sensitive responses at energies down to \approx 0.1 eV. Experiments reveal a photocurrent signal density enhancement of 10^3 and coupling efficiencies approaching 80%, in agreement with numerical simulations. Operation of the probe with quantum cascade and free electron lasers demonstrates a robust, spectrally tunable platform for high-resolution exploration of low-energy carrier dynamics in atomically thin materials, opening opportunities for mid-IR optoelectronics and quantum photonics.

2603.04311 2026-03-05 nucl-th

Similarity renormalization group for nuclear forces

Matthias Heinz

Comments 14 pages, 6 figures, invited pedagogical chapter submitted to Encyclopedia of Nuclear Physics (Elsevier, 1st Edition)

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英文摘要

Renormalization group methods generate low-resolution Hamiltonians that are more diagonal and easier to solve. This chapter reviews the similarity renormalization group for nuclear Hamiltonians, which is a popular method for generating low-resolution nuclear forces. It presents the similarity renormalization group flow equations, analyzes how the similarity renormalization group drives the Hamiltonian towards the diagonal, and studies the effect of induced many-body interactions. It concludes by highlighting the progress in first-principles calculations of nuclei driven by low-resolution nuclear Hamiltonians.

2603.04310 2026-03-05 quant-ph

Magic state distillation with permutation-invariant codes and a two-qubit example

Heather Leitch, Yingkai Ouyang

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英文摘要

Magic states, by allowing non-Clifford gates through gate teleportation, are important building blocks of fault-tolerant quantum computation. Magic state distillation protocols aim to create clean copies of magic states from many noisier copies. However, the prevailing protocols require substantial qubit overhead. We present a distillation protocol based on permutation-invariant gnu codes, as small as two qubits. The two-qubit protocol achieves a 0.5 error threshold and 1/2 distillation rate, surpassing prior schemes for comparable codes. Our protocol furthermore distils magic states with arbitrary magic by varying the position of the ideal input states on the Bloch sphere. We achieve this by departing from the usual magic state distillation formalism, allowing the use of non-Clifford gates in the distillation protocol, and allowing the form of the output state to differ from the input state. Our protocol is compatible for use in tandem with existing magic state distillation protocols to enhance their performance.

2603.04297 2026-03-05 cond-mat.mes-hall

Hanle lineshapes and spin-rotation signatures from in-plane anisotropic spin relaxation in heterogeneous spin devices

Josef Světlík, Juan F. Sierra, Lorenzo Camosi, Williams Savero Torres, Franz Herling, Vera Marinova, Dimitre Dimitrov, Sergio O. Valenzuela

详情
Journal ref
Phys. Rev. B 113, 094404 (2026)
英文摘要

Spin precession experiments in lateral spin devices are a powerful tool for probing the spin transport properties of materials. These experiments can be quantitatively described using the Bloch diffusion equation, which offers a practical framework for modeling spin-related phenomena. In this work, we present calculations of the spin density across heterogeneous, diffusive spintronic devices. The modeled devices feature spin transport channels that include both isotropic and in-plane anisotropic spin relaxation regions. We analyze how different geometric configurations and spin transport parameters influence the lineshape of spin precession signals under magnetic fields applied in different orientations and compare with experimental observations. Our results introduce a theoretical framework for interpreting spin transport measurements in lateral graphene spin devices. The framework is especially relevant when the graphene is partially proximitized by other two-dimensional materials, where proximity-induced spin-orbit coupling leads to anisotropic spin relaxation.

2603.04287 2026-03-05 cond-mat.mtrl-sci

The effect of chemical vapor infiltration process parameters on flexural strength of porous α-SiC: A numerical model

Joseph J. Marziale, Jason Sun, Eric A. Walker, Yu Chen, David Salac, James Chen

详情
Journal ref
Journal of the American Ceramic Society, 107, 4604-4620, 2024
英文摘要

The flexural strength variability of α-SiC based ceramics at elevated temperatures creates the need for an Integrated Computational Materials Engineering (ICME) framework that relates the strength of a specimen directly to its manufacturing process. To create this ICME framework a model must first be developed which establishes a relationship between the chemical vapor infiltration (CVI) process and parameters, the resulting mesoscale pores, and the overall macroscale flexural strength. Here a nonlinear single pore model of CVI is developed used in conjunction with a four-way coupled themo-mechanical damage model. The individual components of the model are tested and a sample system under a four-point bending test is explored. Results indicate that specimens with an initial porosity greater than 30% require temperatures below 1273 K to maintain structural integrity, while those with initial porosities less than 30% are temperature-independent, allowing for optimization of the CVI processing time without compromising strength.

2603.04285 2026-03-05 astro-ph.SR

Collective Vortex Dynamics: From Isolated Vortices to their Communities

Lauren McClure, Suzana Silva, Gary Verth, Istvan Ballai, Viktor Fedun

详情
英文摘要

Small-scale vortical motions in the upper solar atmosphere are abundant and occupy about 2.8% of the photosphere at any given time. Although considerable work has focused on the detection and analysis of individual solar vortices, the interconnected and multi-scale behaviour of these coherent structures remains largely unexplored. We present a methodology for studying this behaviour through vortex interactions, to improve our understanding of how small- and large-scale photospheric flows contribute to energy transfer into the upper solar atmosphere and to the driving of solar activity. We represent vortices as a network of interacting structures. We apply a community detection algorithm to derive an optimal reduced network composed of highly interconnected vortex groups. From the interaction patterns and group structure, we define three roles within each community: peripheral, connector and hub. We then track both vortex communities and their member vortices from the photosphere into the chromosphere and across their lifetimes. On average, vortices assigned to these roles persist to greater heights in the chromosphere and have longer lifetimes than unclassified vortices. This shows that community detection can identify vortices with greater dynamical influence on the upper solar atmosphere. We also find that 32% to 58.6% of vortex communities exhibit global periodic behaviour following a helical path. This collective vortical motion may indicate an enhanced mechanism for wave excitation. Solar vortical community detection, therefore, offers a new framework for studying solar vortices and a new perspective on the importance of collective vortex dynamics.

2603.04283 2026-03-05 astro-ph.SR

Near-infrared spectroscopy of RS Ophiuchi in 2021: the calm, the storm, and the abatement

C. E. Woodward, A. Evans, D. P. K. Banerjee, B. Kaminsky, S. Starrfield, K. L. Page, R. M. Wagner

Comments Accepted for publication in MNRAS on 4 March 2026

详情
英文摘要

We present near-infrared (NIR) observations of the 2021 eruption of the recurrent nova RS Ophiuchi. The dataset provides both pre- and post-eruption perspectives on the eruption, as well as NIR spectra at high cadence. The spectrum obtained in 2020 June (14.3 years after the 2006 eruption, and 428.1 days before the 2021 eruption), is that of the red giant secondary, on which are superimposed several emission lines which most likely arise in the red giant wind. Spectra obtained during the eruption consist of emission (including coronal) lines, superimposed on a bremsstrahlung continuum at 8900K. The temperature of the coronal gas is estimated to be $10^{6.0}$K on day 11.7, and $10^{5.9}$K on day 31.7. The high cadence observations, obtained on day 31.7 of the eruption, provide no conclusive evidence for rapid ($<\sim1$~minute) variations in the HeI 1.0833$\,μ$m line. Data obtained about one year after the eruption show that there may have been changes in the spectral type of the secondary after the 2021 eruption.

2603.04281 2026-03-05 astro-ph.CO

DESI DR2 Baryon Acoustic Oscillations from the Lyman Alpha Forest Multipoles

N. G. Karaçaylı, A. Cuceu, J. Aguilar, S. Ahlen, S. Bailey, S. BenZvi, D. Bianchi, A. Brodzeller, D. Brooks, T. Claybaugh, A. de la Macorra, Biprateep Dey, P. Doel, J. Estrada, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, A. X. Gonzalez-Morales, G. Gutierrez, C. Hahn, H. K. Herrera-Alcantar, K. Honscheid, C. Howlett, M. Ishak, R. Joyce, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, M. Landriau, J. M. Le Goff, L. Le Guillou, M. E. Levi, M. Manera, P. Martini, A. Meisner, R. Miquel, J. Moustakas, A. Muñoz-Gutiérrez, S. Nadathur, N. Palanque-Delabrouille, W. J. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou, H. Zou

Comments 15 pages, 7 figures

详情
英文摘要

We present an alternative measurement of the Baryon Acoustic Oscillation (BAO) using Legendre multipole representation of the Ly$α$ forest correlation functions from the second data release (DR2) of the Dark Energy Spectroscopic Instrument survey. Compressing the auto- and cross-correlation functions into Legendre multipoles yields a positive-definite covariance matrix without any smoothing -- unlike the baseline DR2 analysis -- thanks to a significantly reduced data vector size. We introduce the statistical corrections required to debias the finite-sample covariance matrix estimate and demonstrate that monopole and quadrupole terms for both auto- and cross-correlations can be used even when the correlation functions are distorted by continuum errors and contaminated by metals. This formalism has slightly diminished the constraining power of the BAO scale, while considerably weakening constraints on nuisance parameters. We measure the isotropic BAO scale with $0.96\%$ precision at $z_\mathrm{eff}=2.35$, the Hubble parameter $H(z_\mathrm{eff})=(238.7\pm3.4)~(147.09~\mathrm{Mpc}/r_d) ~\mathrm{km~s}^{-1}~\text{Mpc}^{-1}$, and the transverse comoving distance $D_M(z_\mathrm{eff})=(5.79 \pm 0.10)~(r_d/147.09~\mathrm{Mpc})$~Gpc for a given value of the sound horizon ($r_d$). Our BAO results are entirely consistent with the baseline DR2 analysis.

2603.04279 2026-03-05 astro-ph.CO

Hierarchical cosmological constraints through strong lensing distance ratio

Shuaibo Geng, Shuo Cao, Marek Biesiada, Xinyue Jiang, Yalong Nan, Chenfa Zheng

详情
英文摘要

Strong gravitational lensing provides an independent and powerful probe of cosmic expansion by directly linking observables to cosmological distances. Upcoming surveys such as LSST will discover large number of galaxy-galaxy strong lensing systems, offering a new route to precise cosmological constraints. In this paper, we propose a Fisher-like sensitivity factor to map how the cosmological information of strong-lensing distances changes across the lens-source redshift plane. Applying such factor to the distance ratio $D_{ls}/D_s$, the time-delay distance $D_{Δt}$, and the double-source-plane ratio, we determine the ``sensitivity valleys'' where an observable becomes insensitive to a given parameter. The realistically simulated LSST lens population, which largely lies outside the distance-ratio valleys, covers the most sensitive region for $(w_0,w_a)$ parameter space. We then develop a new hierarchical framework, which could calibrate the redshift evolution of lens mass-density slopes and constrain cosmological parameters simultaneously. Focusing on the LSST mock data, we demonstrate that ignoring mass-profile evolution can bias $Ω_m$ by up to $\sim 10σ$, while modeling the lens evolution could perfectly recovers the fiducial cosmology and yield stringent cosmological constraints (e.g., $ΔΩ_m \simeq 0.01$ and $Δw \simeq 0.1$ for $\sim 10^4$ lenses).