High Energy Physics (Phenomenology)
The Living Guide of Machine Learning for Particle Physics
Claudius Krause, Ramon Winterhalder, Matthew Feickert et al. (+1 more)
We started the Living Review of Machine Learning for Particle Physics (HEP-ML Living Review) in 2020 as a community-maintained, near-comprehensive bibliography of machine learning in particle physics. The field was then growing faster than any single researcher could follow, finding the relevant papers was hard, and a structured, continuously updated reference paid off immediately. Since then the literature has grown by more than an order of magnitude, the methods reach far beyond the classification and generation tasks of the early years, and the community has built its own ecosystem of topic-specific reviews,
benchmark papers, and software frameworks. The original model no longer serves this field well, and we can no longer sustain it. We therefore change direction. We freeze the Living Review as an archival reference covering the literature up to 1 June 2026, where it remains a stable record of the first phase of HEP-ML. A new resource, the HEP-ML Living Guide, replaces it. It does not list everything. It curates, it annotates, and it points readers to foundational and representative work, so that researchers can find their way into a mature and rapidly diversifying field. In this article we explain why we make this change and how the new resource works.
Read the full abstract ▾
All authors Claudius Krause, Ramon Winterhalder, Matthew Feickert, Benjamin Nachman
Applied Physics
The Tilting Mode: A New Degree of Freedom for Magneto-Mechanical Resonator Sensors
Nora Timm, Florian Hartwig, Jonas Faltinath et al. (+3 more)
Magneto-mechanical resonators (MMRs) are an emerging class of passive, wireless sensors. Their torsional oscillation mode has recently been established for sensing and tracking applications. In this work, we report the identification and characterization of a second mechanical mode, the tilting mode, that provides sensitivity along an axis inaccessible to the torsional mode, opening up a new degree of freedom for tracking and sensing with a single MMR sensor. We derive an analytical model predicting the tilting frequency as a function of the
geometric and
magnetic parameters of the resonator, compare the tilting mode frequency to that of the torsional mode, and obtain a characteristic frequency ratio between the torsional and the tilting mode in the small angle approximation. Experimental characterization using three-axis excitation and detection confirms the mode's existence and its directional selectivity. Notably, the three-axis frequency response shows no observable cross-coupling between the torsional and the tilting mode. We further show that the tilting mode frequency follows the predicted dependence on magnet distance, confirming the analytical model and the mode's applicability for sensing, analogous to that of the torsional mode.
Read the full abstract ▾
All authors Nora Timm, Florian Hartwig, Jonas Faltinath, Sarah Reiss, Pascal Stagge, Tobias Knopp
Quantum Physics
Compound beams for direct experimental comparison of quantum operations
Kishore Thapliyal, Jan Perina Jr., Pavel Pavlicek et al. (+1 more)
Compound beams composed of simple experimental blocks (detected in simultaneous detection windows) that form specific
quantum-correlated structures are suggested for simulating the properties of different
quantum operations used for creating highly nonclassical and entangled multi-mode states needed in
quantum communication, metrology, and information protocols. Qualitative and quantitative comparison of multi-
photon addition and subtraction in compound multi-mode thermal as well as sub-Poissonian beams and multi-mode twin beams with their intensities extending over two orders in magnitude is provided. Adding and subtracting up to twenty photocounts, optimal conditions for the generation of experimental nonclassical states are identified. In general,
photon addition is identified as advantageous over
photon subtraction for the multi-mode thermal and sub-Poissonian beams: It induces (enhances) the nonclassicality in the former (latter) state. Contrary to this,
photon subtraction outperforms
photon addition in the multi-mode twin beams. Moreover, exploiting temporal
photon-pair correlations in compound twin beams when post-selecting, nearly ideal experimental
photon(s) addition is demonstrated. The results apply for the beams with mean
photon number per mode much less than one.
Read the full abstract ▾
All authors Kishore Thapliyal, Jan Perina Jr., Pavel Pavlicek, Antonin Cernoch
Quantum Physics
Faster Algorithms for Multimarginal Optimal Transport
Brandon Augustino, Yue Sun, Atithi Acharya et al. (+4 more)
We study constructive discrete multimarginal optimal transport (MOT) among $m$ distributions on $n$ points, where the cost tensor $C$ has $N=n^m$ entries. For additive accuracy $\varepsilon$, let $\kappa=\max\{1,(\max C-\min C)/\varepsilon\}$. Classically, we give two
algorithms that return exactly feasible additive-$\varepsilon$ couplings. A deterministic box–simplex method with rounding runs in $O(m^2N\kappa\log N)=\widetilde O(m^3N\kappa)$ time, while an exact reduction to positive packing followed by rank-one completion runs in randomized time $\widetilde O(m^2N\kappa)$. At fixed $\kappa$, both match the $\Omega(N)$ cost of writing a dense coupling, up to factors in $m$ and logarithms. Quantumly, in the general entry-access model, tensor Sinkhorn followed by sparse recovery returns an exactly feasible additive-$\varepsilon$ coupling as a classical list of $\widetilde O(m^2n\kappa^2)$ atoms, using $\widetilde O(m^4\sqrt{Nn}\,\kappa^3)$ coherent cost queries without materializing the tensor. Finally, for fixed $m$ and constant normalized accuracy, we prove sparse-output lower bounds of $\widetilde\Omega(N)$ randomized classical queries, even with unrestricted output size, and $\widetilde\Omega(\sqrt{Nn})$
quantum queries for outputs with at most $n\operatorname{polylog}(n)$ atoms. Hence, for fixed $m$ and normalized accuracy between $(\log n)^{-O(1)}$ and a sufficiently small constant, explicit sparse MOT construction has query complexity $\widetilde\Theta(N)$ classically and $\widetilde\Theta(\sqrt{Nn})$ quantumly.
Read the full abstract ▾
All authors Brandon Augustino, Yue Sun, Atithi Acharya, Shouvanik Chakrabarti, Junhyung Lyle Kim, Shree Hari Sureshbabu, Charlie Che
Astrophysics of Galaxies
Dust production in the harsh environment of Sgr A* - MIRI/JWST observation of the O-rich asymptotic giant branch star IRS~3
F. Peißker, M. García Marín, A. Eckart et al. (+18 more)
Studies of the interstellar medium (ISM) have frequently revealed signatures of the
dust produced in the envelopes of asymptotic
giant branch (AGB)
stars, demonstrating a connection between the
dust composition of the ISM and that of AGB
stellar envelopes. Investigating this relationship in the extreme, radiation-dominated environment surrounding Sgr A*, the center of our own
galaxy, reveals how such conditions might influence
dust composition and the recycling of material in
galactic centers. IRS 3, the brightest L band source in the
Galactic center and most prominent AGB
star within the inner parsec of the Milky Way, is embedded in a dusty envelope with an estimated radius of $\sim$10000 AU. We aim to conduct a comprehensive spectral analysis to more tightly constrain the
dust composition and line-emitting species within the envelope of IRS 3 in the immediate vicinity of Sgr A*. In 2025, we observed the inner parsec of the Milky Way with the Mid-Infrared Instrument (MIRI) on board the James Webb Space
Telescope (JWST) as part of the guaranteed time observations (GTO) program Mid-Infrared Characterisation of Nearby Iconic
galaxy Centres (MICONIC). We used the MIRI Medium Resolution Spectrometer (MRS) to study the spectroscopic characteristics of the AGB
star IRS 3, located about 0.17 parsecs in projection from Sgr A*.
Read the full abstract ▾
All authors F. Peißker, M. García Marín, A. Eckart, G. Wright, O. C. Jones, D. Dicken, A. Alonso Herrero, D. Rouan, D. Law, T. Böker, T. Henning, M. Baes, A. Labiano, L. Pantoni, L. Hermosa Muñoz, P.O. Lagage, P. van der Werf, G. Östlin, J. A. D. L. Blommaert, M. Güdel, P. Guillard
Quantum Physics
Gate-based emulation of boson sampling using photonic qubits
Aastha P. Zalone, S. P. Dinesh and C. M. Chandrashekar
Boson sampling arising from multiphoton interference in linear-optical networks is a prominent non-universal model for
quantum computation. Here, by encoding the multi-
qubit state to bosonic Fock state, we present a scalable
quantum-
circuit framework for simulating
boson sampling on a universal
quantum computing platform. Beginning with balanced beam-splitter transformations on the single- and two-
photon sectors, we derive equivalent
quantum-
circuit implementations and unify them within a common
Hilbert-space representation using an ancilla-assisted encoding. This construction is then generalized to arbitrary interferometers by replacing each optical beam splitter with a repeating
quantum-
circuit unit that selectively acts only within the relevant local interference subspace, requiring $N+1$
qubits for a two-
photon $N$-mode interferometer and a linear-overhead subspace-identification procedure. Using this framework, gate-based
quantum circuit for a four-mode
boson-sampling
circuit is developed and experimentally implemented on a four-
qubit gate-based photonic
qubit system. The
qubit framework for emulating
boson sampling of $n-$
photons in $m-$mode will be useful to solve a broad class of sampling complexity problem on a gate-based
quantum computers.
Read the full abstract ▾
Applied Physics
200 mm Wafer-Scale Monolithic 3D Integration of Atomic Layer-Deposited Oxide Semiconductors
Chang Niu, Linjia Long, Luqi Zheng et al. (+9 more)
Monolithic 3D (M3D) integration offers a pathway to overcome the scaling limits of conventional silicon complementary metal-
oxide-
semiconductor (CMOS) technology by extending dense vertical stacking of multifunctional logic and
memory devices. Here, we demonstrate wafer-scale M3D integration of three tiers of atomic-layer-deposited (ALD) indium
oxide (InOx)-based devices (>100,000 fabricated), including ferroelectric, enhancement-mode, and depletion-mode field-effect transistors, on 200 mm silicon wafers. We achieve threshold voltage standard deviation as low as 0.04 V, average electron mobility up to 91.6 cm2V-1s-1, and fully functional cross-tier
circuits. A four-tier 3D computing-in-
memory (CIM) accelerator targeting large
language model workloads is developed using a custom InOx process design kit, delivering 1.4x to 2.9x speedup and comparable energy-delay product improvements over 2D baselines. These results establish ALD InOx M3D integration as a scalable and CMOS-compatible platform for next-generation artificial intelligence hardware and advanced electronics.
Read the full abstract ▾
All authors Chang Niu, Linjia Long, Luqi Zheng, Shuting Du, Jian-Yu Lin, Kisoo Nam, Zehao Lin, Chang Liu, Juanjuan Lu, Haiyan Wang, Haitong Li, Peide D. Ye
Quantum Physics
Genuinely Unextendible Product Bases from Maximum Distance Separable Codes
Mao-Sheng Li
The existence of genuinely unextendible product bases (GUPBs), incomplete orthogonal sets of fully product states whose orthogonal complements contain no product vector across any bipartition, has remained an open problem. Here we construct GUPBs for any number $N\geq3$ of parties using classical maximum distance separable (MDS) codes. The MDS property imposes a
rigidity on the induced product tiling across every bipartition; combined with
Fourier mode deletion and a stopper state, this
rigidity enforces genuine unextendibility. Consequently, the orthogonal complement of each GUPB is a genuinely entangled subspace whose normalized projector is invariant under partial transposition across every bipartition, yielding an explicit family of multipartite bound entangled states. We further construct GME witnesses that detect these states even though no fully decomposable witness can do so. Moreover, the resulting indistinguishability persists under arbitrary finite tensor powers and measurements separable across any bipartition. These results establish a direct connection between error-correcting codes and multipartite
entanglement and provide an algebraic route to certifying genuinely multipartite bound
entanglement.
Read the full abstract ▾
Applied Physics
A Superposition-Based Framework for Rapid Estimation of Arbitrary Antenna-Array Patterns
Amir Dayan, Nabeel Ali Khan, Inchara Lakshminarayan et al. (+4 more)
Antenna array theory is a well-established field. However, a systematic approach for fast pattern estimation in arrays with arbitrary
antenna locations and orientations has not yet been developed. In this paper, based on simulated (or measured) radiation patterns of a single element, we present a Superposition-Based Framework (SBF) for numerically computing array radiation patterns in which the positions and orientations of the
antenna elements can be readily modified. To validate the framework, a compact dual-layer circularly polarized patch
antenna at 5.02 GHz (ESA's Celeste frequency) is designed and used as an array element in an 8-element ring
antenna. Using the proposed framework and the single-element far-field pattern, the array radiation pattern is computed in 13s (excluding single-element simulation time), which is at least 50 times faster than the corresponding full-wave simulation while maintaining comparable accuracy. Comparisons with CST simulations show a peak E-field error of less than 0.5% for the intended polarization. Full-wave simulations are
memory- and energy-intensive, and hence, impractical for larger arrays. The proposed SBF requires low computational power, making it energy-efficient and sustainable.
Read the full abstract ▾
All authors Amir Dayan, Nabeel Ali Khan, Inchara Lakshminarayan, Wahyudin Syam, Noori BniLam, William Whittow, Aakash Bansal
Quantum Physics
Autoregressive Projective Quantum Monte Carlo: From a Hermitian to a Non-Hermitian Perspective
Lavoisier Wah, Remmy Zen and Flore K. Kunst
Accurately determining the ground-state properties of
quantum many-body systems remains a central challenge. In this work, we introduce an autoregressive projective
quantum Monte Carlo (PQMC) framework that leverages recurrent neural networks (RNNs) to guide the
stochastic dynamics. By incorporating autoregressive sampling into PQMC, we demonstrate substantial improvements in accuracy compared to standard unguided PQMC, while retaining
polynomial computational cost. We
benchmark our approach against conventional variational RNN ansätze and find that the autoregressive PQMC consistently achieves lower energies and higher fidelity, regardless of system size or whether the
Hamiltonian is Hermitian or non-Hermitian. Our results highlight the versatility and power of neural-guided PQMC methods, paving the way for promising scalable simulations of low-energy states in complex
quantum many-body systems.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Effects of Born-Infeld Electrodynamics on Chiral Symmetry Restoration and Meson Susceptibilities in Holographic QCD
Hiwa A. Ahmed and Peshwaz A. Abdoul
Within a
holographic QCD framework, we numerically investigate
chiral symmetry breaking and the associated phase transition at finite temperature and chemical potential. The model is constructed on a nonlinear charged Born-Infeld black hole background. The
chiral condensate, extracted from the asymptotic behavior of the bulk scalar field, serves as the primary order parameter. At zero chemical potential, we find a
chiral crossover transition for physical
quark masses with a pseudocritical temperature of $T_{pc}=0.1477$ GeV. In the
chiral limit, the transition becomes first-order with a critical temperature of $T_{c}=0.1337$ GeV. A critical strange
quark mass of $m_s=37$ MeV, at zero light
quark mass, separates first- and second-order transition regions. For finite chemical potential ($\mu$) and a physical strange mass ($m_s=95$ MeV) with massless light
quarks, the transition remains second-order, with $T_c$ decreasing as $\mu$ increases. These results are further supported by the behavior of
meson susceptibilities $(\chi_{\pi}-\chi_{\sigma})$, which exhibit a rapid thermal decay and convergence across the phase boundary. Introducing the Born-Infeld parameter $\beta$ shifts the second-order phase boundary to higher temperatures for smaller $\beta$ (stabilizing the chirally broken phase) but does not alter the transition order or introduce a critical endpoint within the studied range. Our findings are consistent with previous soft-wall model studies and highlight the significant role of nonlinear bulk electrodynamics in modifying the
chiral phase diagram.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Dynamical Barbero–Immirzi field coupled to quintessence: gravitational-wave propagation constraints and next-generation forecasts
Zhi-Fu Gao, Hui Wang, Luiz Carlos Garcia de Andrade et al. (+3 more)
We investigate the imprints of a dynamical Barbero–Immirzi (BI) field $\gamma(x)$ coupled to a quintessence scalar field $\phi$ on gravitational-wave (GW) propagation. In the framework of Einstein–Cartan–Holst
gravity, promoting $\gamma$ to a dynamical scalar introduces a stress–energy that back-reacts on the metric, modifying the GW friction term. A minimal coupling $\propto\beta\,\phi^2\gamma^2$ between the BI field and quintessence leads to a two-parameter extension of the Belgacem–Maggiore parametrization, characterized by $\xBI$ (from the isolated BI field) and $\xcp$ (from the coupling). Using the LIGO–Virgo–KAGRA GWTC-3 dark-siren constraint $\Xi_0=1.2^{+0.7}_{-0.7}$, we obtain the first simultaneous constraints: $|\xBI|\lesssim0.7$ and $|\xcp|\lesssim0.13$ at 90% credibility. We then forecast the sensitivity of next-generation detectors Einstein
Telescope (ET) and
Cosmic Explorer (CE), showing that a 10-year observation campaign can improve these bounds by roughly one to two orders of magnitude depending on the parameter—a factor of $\sim\!20$ for $\xBI$ and $\sim\!20$ for $\xcp$—reaching $\sigma(\xBI)\sim3\times10^{-2}$ and $\sigma(\xcp)\sim1.2\times10^{-2}$. Translated into microscopic parameters, this corresponds to $\gamma_{\rm dyn}\lesssim10^{-12}$ and $\beta\lesssim10^{-3}$, providing a powerful new observational window into the interplay between
quantum-
gravity phenomenology and dark energy.
Read the full abstract ▾
All authors Zhi-Fu Gao, Hui Wang, Luiz Carlos Garcia de Andrade, Na Wang, Guo-Qiang Jin, Zhou-Jian Cao
Computational Physics · Cross-listed from cs.LG
Hierarchical rank-evolving representation for physics-informed neural networks
Ruoyang Su, Xi-Le Zhao, Kun Li et al. (+1 more)
Recently, tensor-based physics-informed neural networks (T-PINNs) have received increasing
attention. However, existing T-PINNs still face a fundamental challenge: they mainly rely on pre-specified low-rank tensor decompositions with manually tuned ranks, which limits their ability to capture the underlying structures of multivariate solution functions and hinders their practical deployment. To address this challenge, we propose a hierarchical rank-evolving (abbreviated as HRE) representation for multivariate functions, which endows us to faithfully capture the underlying structure of the targeted multivariate function accompanying with automatic rank determination. Concretely, in the hierarchical design of HRE representation, the target multivariate function is decomposed as a small-scale inner tensor with a set of univariate functions along each mode, where a customized tensor network decomposition can be readily deployed to capture the underlying structure of the small-scale inner tensor. In HRE representation, the crucial hyperparameters, ranks, can be adaptively revealed during the decomposition, freeing us from manual rank tuning and making HRE practically applicable to real-world problems. Besides, we build the HRE-PINNs correspondingly. Extensive numerical experiments, including high-dimensional static problems (Helmholtz equation and Poisson equation), nonlinear time-dependent problems (Klein-Gordon equation), and complex fluid-dynamics problems (flow mixing equation and Navier-Stokes equation), demonstrate that HRE-PINNs consistently outperform existing state-of-the-art approaches in terms of accuracy.
Read the full abstract ▾
All authors Ruoyang Su, Xi-Le Zhao, Kun Li, Liang Li
Physics and Society
The impact of the path ensemble on path percolation
Yunhao Ding, Andreas Münch and Renaud Lambiotte
Traffic-induced failures, from packet loss in communication networks to congestion breakdown in transport systems, occur when flows progressively exhaust the edges they traverse. Path percolation models this process by removing edges along sampled origin-destination paths. Existing work assumes locally tree-like networks and deterministic shortest-path routing, leaving unclear how path degeneracy and routing stochasticity affect fragmentation in the clustered networks typical of real systems. We introduce a generalised path-percolation framework where paths are drawn from a temperature-controlled routing ensemble interpolating between geodesic and noisy transport. We argue based on box-covering renormalisation and our numerical experiments that, for any finite routing horizon $C$, the process coarse-grains to ordinary mean-field percolation. Routing details affect non-universal quantities, especially the percolation threshold $p_c$, through the
entropy of the load distribution and the capacity of finite clusters to accommodate flow. Load
entropy therefore acts as a robustness measure for networks under path-based failures. When the routing horizon is tuned to the mean-field correlation length, $C=N^{1/3}$, within a source-uniform ensemble, the system enters a crossover regime with scaling exponents distinct from shortest-path percolation with infinite budget. In this regime, path elongation becomes decoupled in time from structural fragmentation: the characteristic path length reaches a growing maximum, associated with routing temperature, asymptotically ahead of the collapse of the
giant component. These results clarify how microscopic routing organisation shapes macroscopic resilience, and identify path elongation as a measurable precursor of failure in communication and transport infrastructure.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Global simulations of accretion flows onto perturbers embedded in magnetized disks -I. MRI and jet formation in ideal MHD
Raúl O. Chametla, F. J. Sánchez-Salcedo, Martin E. Pessah et al. (+1 more)
We present the highest resolution global MHD simulations to date of gas flow around a low mass a perturber with mass ratio $q\in[10^{-4},10^{-3}]$, embedded in an
accretion disk around a massive central object. We find that gas flow onto the secondary self-consistently forms a turbulent, magnetized mini-
accretion disk. The mini-
accretion disk sustains a large-scale
magnetic field generated by the dynamo effect of the MRI and the
accretion flow into the perturber. Simultaneously, a bipolar, collimated, magnetized
outflow is launched, extending beyond the perturber's Hill sphere. The bipolar
outflows are driven by the combined action of
magnetic pressure, in the innermost regions of the mini-
accretion disk, and the magnetocentrifugal acceleration of gas, which may attain speeds comparable to the escape velocity from the massive central object. Our results establish an important conceptual connection in
accretion disk physics across a wide range of astrophysical systems -from mini-
accretion disks to circumstellar and black hole
accretion disks-by demonstrating that no fine-tuning is required for small-scale disks to naturally enter an
outflow-launching regime. Beyond identifying the physical mechanism responsible for launching small-scale
outflows, our framework lays the groundwork for developing more sophisticated physical models of mini-
accretion disks around embedded low-mass perturbers.
Read the full abstract ▾
All authors Raúl O. Chametla, F. J. Sánchez-Salcedo, Martin E. Pessah, Mauricio Reyes-Ruiz
Mathematical Physics · Cross-listed from math.NA
Second order unfitted ghost-FEM for elliptic interface problems with applications to low-dimensional semiconductor devices
Clarissa Astuto and Giovanni Nastasi
We develop an unfitted ghost finite element method for
elliptic interface problems with discontinuous
diffusion coefficients and apply it to the electrostatic simulation of low-dimensional
semiconductor devices. The proposed approach is based on a fixed Cartesian grid and represents the geometry by level-set functions, avoiding mesh generation and remeshing even in the presence of interfaces. A snapping-back-to-grid strategy is used to control the small-cut-
cell issue, while interface conditions are weakly enforced by a symmetric Nitsche formulation. The method is first validated on
benchmark elliptic interface problems with different geometries and coefficient jumps, showing second-order accuracy for the solution and first-order accuracy for its gradient. As an application, we consider a
graphene field-effect transistor described by a self-consistent drift-
diffusion-Poisson model. The electrostatic potential is computed in a two-dimensional
oxide/
graphene/
oxide structure, while charge transport in the
graphene layer is modeled by one-dimensional bipolar drift-
diffusion equations in the degenerate case and by including a field-dependent mobility model. The coupled nonlinear system is solved by a damped fixed-point iteration combined with a domain-decomposition treatment of the three-layer geometry. Numerical simulations reproduce transfer characteristics with a clear transition from an OFF state to an ON state and show the influence of the gate voltage on the two-dimensional electrostatic potential. The results also indicate that the effective thickness and discretization of the
graphene layer affect the transverse potential profile, supporting the use of a full two-dimensional electrostatic description with explicit
oxide/
graphene interface conditions.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Quantum sensing composite excitations in an anisotropic ferromagnet via a qubit
Amey S. Rodge, Tarek Moussa, Akashdeep Kamra et al. (+1 more)
Ordered magnets harbor intrinsically squeezed ground states and magnonic excitations characterized by
entanglement between
spins and nonclassical
magnon number composition. A pathway to detecting the superpositions of noneigenmode
magnon number states underlying these nonclassical
magnetic ground states has recently been demonstrated by utilizing a
qubit coupled to the
magnon mode via a direct dispersive interaction. Here, we theoretically develop this
qubit spectroscopy further delineating the capabilities and limitations of this
qubit spectroscopy for sensing the
quantum superpositions that underlie the excited states. We demonstrate that the spectroscopy lends itself naturally to unraveling the superpositions that underlie the various quantized squeezed-
magnon number states. However, excited states comprising superpositions of multiple squeezed Fock states become increasingly hard due to the large number of possible transitions, and resulting peaks, in the
qubit spectroscopy thereby requiring
qubits with narrower linewidths. Along the same lines, we theoretically demonstrate the
qubit spectroscopy of a low amplitude coherent squeezed-
magnon state analyzing the tradeoff between frequency crowding due to multiple transitions and peak linewidths. Our work lays the groundwork and design equations for deploying high-quality
qubits towards sensing the composite nature of
spin excitations in
magnetic systems.
Read the full abstract ▾
All authors Amey S. Rodge, Tarek Moussa, Akashdeep Kamra, Bashab Dey
High Energy Physics (Experiment)
A Reusable Four-Port S-Parameter to Link-Level Signal-Integrity Analysis Framework for High-Speed Detector Interconnects
D M S Sultan, D. Bortoletto, R. Plackett et al. (+4 more)
A reusable MATLAB signal-integrity (SI) framework is presented that converts compatible four-port S-parameter data, measured by VNA or obtained from electromagnetic simulation, into traceable link-level evidence rather than a single loss metric. Its contribution is the checked, traceable automation of established SI operations while keeping source data, model assumptions, analytical projections, and finite-record observations distinct. The framework is demonstrated on the four 1.25 Gbps differential routes (DP1-DP4) of the PPCB-1347-MuPix11 probe card using PTSL CST Microwave 3D-Solver-derived four-port S-parameters and a virtual time-domain solver. The automated pipeline preflights file structures, performs a power-normalized mixed-mode transformation, applies route-length-aware loss decomposition, constructs a causally loaded channel model, and propagates full PRBS-31 sequences into eye-diagram, conditional-BER, and 8b10b-coded-link analyses. At the 1.25 Gbps data rate (Nyquist 0.625 GHz), DP1-DP4 exhibit differential insertion loss (SDD21) from -0.350 to -0.300 dB, differential-to-common conversion from -31.038 to -28.236 dBc, and modeled FEB-input eye openings from 0.586 to 0.588 V. The comparison shows that path length alone is not an adequate SI ranking variable: DP3 has the lowest Nyquist insertion loss, DP1 the strongest differential-to-common isolation, and DP4 the largest modeled eye. All analytical BER values remain below the reporting floor and therefore do not support a BER ranking. By preserving the distinction between route-dependent waveform behavior, model projections, and finite-record observations, the framework provides an extensible basis for comparative high-speed-interconnect SI analysis from design review through calibrated VNA measurement interpretation.
Read the full abstract ▾
All authors D M S Sultan, D. Bortoletto, R. Plackett, A.E. McDougall, A.S. Rotelli, A.J.A. Knight, J. Vossebeld
Quantum Physics
Probing Non-equilibrium baths: Frequency-Resolved Thermometry and Quantum Heat Current Turnover
Akhil Bhartiya, Tobias Kramer and David Gelbwaser-Klimovsky
Quantum heat transport for non-
equilibrium steady state (NESS) exhibits a characteristic turnover effect, where the heat current reaches a maximum and subsequently declines as system-bath coupling increases. Although numerically exact methods can simulate this non-monotonic behavior, they offer limited information on the thermal state of the heat baths. Here, we introduce a frequency-selective thermometric protocol to probe the baths sustaining an NESS. By extracting a frequency-resolved effective temperature spectrum using a tunable two-level probe, we demonstrate that spectral dispersion serves as a direct witness for the non-
equilibrium state of the heat baths. To demonstrate the protocol, we applied the hierarchical equations of motion to
spin-
boson and two-
qubit models, though any exact method can be used. For both models, the turnover effect can be explained by how the thermal state of the heat baths evolves as the system-bath coupling strength increases.
Read the full abstract ▾
Optics
Femtosecond Engineering of PolyMethylPentene(PMP) Nonlinearity via NA, Spin/orbital angular momentum (OAM), and In-Situ SC Diagnostics
Siyang Zheng, Guangyu Zhu, Walter Perrie et al. (+4 more)
While femtosecond
vortex beams are widely studied for photonic fabrication, how OAM affects third-order susceptibility, energy deposition, and structural
symmetry in transparent
polymers remains unclear. To address this gap, we investigate femtosecond
vortex beam interactions with polymethylpentene (PMP) to establish OAM control over beam shaping and energy deposition in
laser micromachining. A 775 nm femtosecond
laser is frequency-doubled to 387.5 nm and phase-shaped by a reflective
liquid crystal-spatial light modulator, with OAM imprinted via computer-generated holograms and independently controlled
spin via a quarter-wave plate. Theoretical modeling of the tensorial nonlinear polarization, combined with systematic experiments on low-NA filamentation, supercontinuum spectroscopy using an advanced spectrometer, and high-NA inscription with NA = 0.4 and 0.7, reveals that the same $\chi^{(3)}$ tensor components govern all regimes. The transition from perturbative to dissipative behavior is determined solely by whether the local intensity exceeds the
plasma formation threshold. Through an analytical framework based on the isotropic material model, the key innovation lies in identifying that $\chi_{1122}$ governs the energy deposition and
plasma threshold, whereas $\chi_{1221}$ mediates the transverse nonlinear current and helicity-dependent asymmetry, thereby converting phase
topology into permanent
chiral structures. This enables OAM-controlled structuring with sub-micrometer feature sizes (approximately 0.43 $\mu$m diameter and approximately 200 nm$^2$ area) and localized intensities reaching $10^{14}$–$10^{15}$ W/cm$^2$, providing an engineering framework for deterministic fabrication of
chiral waveguides and photonic devices through precise control of topological charge and focusing conditions.
Read the full abstract ▾
All authors Siyang Zheng, Guangyu Zhu, Walter Perrie, Dongzhi Wang, Runzhen Zhou, Juan Ignacio Ahuir-Torre, Puxiang Lai
Cosmology and Nongalactic Astrophysics
CMB Spectral Distortion Anisotropies from Acoustic Damping with primordial non-Gaussianity
Jens Chluba, Atsuhisa Ota and Nicola Bartolo
In this paper, we evaluate the precise distortion source and transfer functions caused by mixing of blackbodies of different temperatures using the recently developed frequency hierarchy (FH) treatment of CosmoTherm. With this we are able to evaluate the effects of
primordial non-Gaussianity (PNG) on the $\mu T$, $\mu E$, $y T$ and $y E$ cross-power spectra including the coupled spectro-spatial
evolution and important
photon-transport effects retained by the FH treatment. For local-type PNG, we compare our results with those from previous works, illustrating new aspects that were previously not captured. We then demonstrate how the $\mu T$ and $\mu E$ signals change in the presence of enhanced
curvature perturbations at small scales. For a nearly scale-invariant
primordial spectrum, our results agree broadly with previous estimates on large angular scales but exhibit additional small-scale damping and modified $y$-distortion correlations arising from the scale dependence of the heating source and the distinct transport of distortion perturbations. Tight-coupling and monopole-source approximations accurately reproduce the $\mu$-distortion spectra, while the $y$-distortion signals remain more sensitive to the detailed source
evolution. For enhanced small-scale power, anisotropies generated by propagation of the distorted average spectrum can become comparable to those from anisotropic dissipation. Their different angular dependences and parameter scalings principally allow the small-scale power amplitude and
primordial non-Gaussianity to be constrained separately. The results presented here thus pave the path for studying PNG in new regimes using existing and upcoming high precision CMB anisotropy data to measure
primordial distortion correlations.
Read the full abstract ▾
Quantum Physics
A non-Markovian approach to spin-phonon coherence and the breakdown of the Markovian approximation
Mohamed Belhassen, Tim Schröder and Gregor Pieplow
Qubit coherence is an essential figure of merit for
quantum information processing applications such as
quantum computing, or
quantum repeaters. Understanding the coherence properties of the underlying physical
qubits that facilitate such applications is therefore are often limited by coupling to
lattice phonons, which in turn constrains operation temperature. Here we study
phonon induced electronic
spin decoherence in group-IV vacancy centers in diamond. We begin by modeling the
spin-
phonon interaction and then employ the widely used Born-Markov approximation, highlighting its inconsistencies in this setting and its deviations from experimental observations. To close the gap between theoretical predictions and experimental results, we relax certain approximations, investigate their contributions to the predicted coherence times, and identify the dominant sources of discrepancy. We further demonstrate that experimentally measured electronic
spin coherence dynamics are consistently captured within a non-Markovian framework, and we show how the
magnetic field orientation influences the
qubit coherence time.
Read the full abstract ▾
Accelerator Physics
An accelerator-based source of high-intensity quantum-entangled annihilation gamma photons
Riad Suleiman
We present the concept and development of a novel accelerator-based source of high-intensity
quantum-entangled 511 keV gamma-ray pairs produced through positron-electron annihilation. The source leverages the unique capabilities of the proposed Jefferson Lab positron facility to generate polarized, high-current positron beams with a well-defined time structure. These beams enable the production of entangled annihilation
photons at intensities far exceeding those available from conventional radioactive sources. The resulting gamma-ray pairs can be characterized using Compton polarimetry techniques, providing a powerful platform for precision studies of
quantum entanglement. The combination of high intensity, controllable polarization, and precise timing also opens new opportunities in medical imaging, materials science,
quantum information science, and spintronics. Compared with traditional radioactive sources, the proposed system offers orders-of-magnitude higher
photon flux, tunable beam parameters, and unprecedented control of the annihilation process. We discuss the source design, methods for
entanglement characterization, potential applications, and future development directions.
Read the full abstract ▾
Astrophysics of Galaxies
The Environmental Dependence of Star Cluster Demographics
Jianling Tang, Kathryn Grasha, Mark R. Krumholz et al. (+1 more)
Both the
star cluster mass function and the lifetimes of clusters may vary with
galactic environment, but measuring this variation is challenging because in observational surveys real features of cluster demographics are invariably entangled with catalogue incompleteness. Here we analyse $\approx$ 8300
star clusters in 12
galaxies drawn from the LEGUS survey using the slug
Bayesian forward modelling framework coupled to our new c-4 neural network-based completeness
estimator, which allows us to incorporate realistic catalogue-inclusion probabilities directly into the likelihood and compensate for these biases. We show that this approach allows us to fit observed cluster luminosity functions with excellent fidelity at both
galactic and sub-
galactic scales. We find that mass function slopes are relatively universal and broadly consistent with a power law $M^{-2}$ form, but high mass truncations vary by orders of magnitude both between and within
galaxies. Our fits also strongly favour models where cluster disruption is mass-independent, but the time at which disruption begins again shows wide environmental variations. Our results demonstrate that young cluster demographics are environmentally dependent, with the clearest signal appearing at the upper end of the cluster mass function, but that these variations are not well-explained by any of the models currently in the literature, and do not correlate straightforwardly with properties such as
star formation rate per unit area or strength of shear.
Read the full abstract ▾
All authors Jianling Tang, Kathryn Grasha, Mark R. Krumholz, Tomasz Różański
Quantum Physics
Biocompatible Vaterite Carriers Enable Multimodal Quantum Sensing with Nanodiamonds
T.Amro, M.Attrash, A.Droby et al. (+8 more)
Mobile nanodiamond
quantum sensors in
liquids are affected by Brownian rotation, variable
photon collection, and perturbations from optical trapping. Here we assemble 40-nm nitrogen-vacancy nanodiamonds on porous, birefringent vaterite microspherulites, creating mobile sensors with a polarization-addressable body frame and a chemically active carbonate interface. Under 976-nm trapping, the sensors retain
spin resonance and longitudinal relaxation, with less than 7% variation in contrast and an approximately 1-MHz resonance shift at 0.8 W. Zeeman-split resonances resolve
magnetic fields from 0 to 0.8 mT, with a response metric of 78–144 $\mu$T Hz$^{-1/2}$. In
cell-culture medium, a 10.7-$\mu$M
proton-equivalent dose shortens $T_1$ from $23.4 \pm 2.3$ to $9.0 \pm 1.2$ $\mu$s, yielding concentration and pH sensitivities of $6.46$ $\mu$M Hz$^{-1/2}$ and $6.54$ mpH Hz$^{-1/2}$, respectively. A 500-fold larger
proton dose in ethanol produces a weaker response. A grand-canonical charge-regulation model links
proton chemical potential to interfacial switching, establishing a route to
multimodal quantum sensing in complex
liquids.
Read the full abstract ▾
All authors T.Amro, M.Attrash, A.Droby, A.Ushkov, R.Malkinson, P.Penshin, A.Hen, V.Bobrovs, P. Ginzburg, H.Barhum, N.Bar-Gill
Materials Science
Time-resolved study of carbonization and growth of ultrathin 3C-SiC on Si(111) under ultra-high vacuum
Pranjali Jadhao, Mojdeh Fallahpour, Josef Polčák et al. (+6 more)
The early-stage formation of silicon carbide (SiC) on Si(111) by ethylene exposure under ultra-high
vacuum (UHV) was investigated to resolve the time-dependent chemical and morphological
evolution of an ultrathin layer. Clean Si(111) substrates were exposed to C$_2$H$_4$ at 800 {\deg}C for 2 min to 4 h, and the surfaces followed by in-situ X-ray photoelectron spectroscopy (XPS) and ex-situ AFM, SEM, AES, SIMS and TEM. Si 2p and C 1s peak analysis shows the progressive conversion of elemental silicon into a carbidic Si-C phase, the SiC fraction overtaking the elemental component between 120 and 160 min and saturating near 80-81% beyond 180 min, leaving about 19-20% residual elemental silicon. Correlative SEM and AFM reveal a parallel morphological progression, from sparse isolated islands to a coalesced, near-continuous layer. AES depth profiling confirms carbon incorporated into the near-surface region rather than weakly adsorbed as contamination, assigning the islands to early SiC
nuclei. TEM confirms the zinc-blende
lattice and the presence of cubic silicon carbide (3C-SiC). Together, these results provide a time-resolved picture of SiC nucleation, coalescence and layer growth on Si(111), relevant to 3C-SiC heteroepitaxy, and can be utilized in the optimization of SiC/Si(111) templates for growth of III-nitride and other carbide systems on silicon (e.g. Mo$_2$C).
Read the full abstract ▾
All authors Pranjali Jadhao, Mojdeh Fallahpour, Josef Polčák, Eva Kolíbalová, Michal Horák, Jan Michalička, Petr Bábor, Stanislav Voborný, Tomáš Šikola
Physics Education
QTris: a pedagogical board game to teach Quantum Mechanics
Alessandro Amabile, Maria Bondani, Immacolata De Simone et al. (+3 more)
In this paper we introduce the new version of QTris, a board game designed to teach and learn
Quantum Mechanics within the framework of
Quantum Information and Computation. The key idea behind the game is that every game sequence simulates a process on a system of
qubits. Thus, QTris can be effectively integrated as a pedagogical tool to teach
Quantum Mechanics at high-school level following a two-state approach. After arguing in support of this latter approach, we describe QTris' basic rules and some of its possible extensions, emphasizing how the game mechanics puts in clear light key
quantum concepts such as incompatibility, probabilistic measurement and
unitary transformation. Moreover, we report on the results of a QTris-based educational activity which involved about 150 high-school students and provided encouraging preliminary indications that QTris can be a useful pedagogical platform to promote an immediate understanding of some key concepts of
Quantum Mechanics.
Read the full abstract ▾
All authors Alessandro Amabile, Maria Bondani, Immacolata De Simone, Michela Nazzaro, Michele Viscardi, Alioscia Hamma
Nuclear Theory
Neutron radii and semi-phenomenological treatment of neutron distributions for Mg isotopes
Govind Kumar, M. Imran, Z. Hasan et al. (+1 more)
Involving the charge radii of \rm Mg isotopes, as calculated using the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), we have extracted the
neutron radii of $^{24-38}$\rm Mg isotopes by studying their reaction cross sections ($\sigma_{R}$) from $^{12}$\rm C at 240 MeV/nucleon within the framework of Glauber model. The calculations use (i) descriptions of
nuclei in terms of the Slater determinant involving harmonic oscillator single-particle wave functions (SDHO), and (ii) two-parameter
Fermi (2pF) shape of density distribution, with the aim to assess the density dependence of
neutron skin in $^{24-38}$\rm Mg isotopes. To understand the asymptotic behavior (spread) of
neutron distribution, we propose to introduce the use of core+n ($S_{n}<S_{2n}$) or core+2n ($S_{n}>S_{2n}$) description for stable as well as unstable isotopes; $S_{n}$ ($S_{2n}$) is the one-
neutron (two-
neutron) separation energy of the considered isotope. The core+n (core+2n) is treated semi-phenomenologically. In this work, the core+n is employed for $^{25-38}$\rm Mg isotopes, and is subjected to reproduce the same
neutron radius of the given isotope, as we obtained from $\sigma_{R}$ calculations. To validate the core+n description, we have revisited the reaction cross sections of $^{25-38}$\rm Mg isotopes. The results are found to agree well with the experimental values. Moreover, the core+n
neutron distributions clearly demonstrate the one-
neutron halo structure of $^{37}$\rm Mg. These findings motivated us to use the core+2n description for the
neutron distribution of $^{40}$\rm Mg in predicting its
neutron radius, and $\sigma_{R}$ from $^{12}$\rm C at 240 and 1000 MeV/nucleon. The trend of the
neutron radius and $\sigma_{R}$ suggests that $^{40}$\rm Mg exhibits two-
neutron halo like structure.
Read the full abstract ▾
All authors Govind Kumar, M. Imran, Z. Hasan, Z. A. Khan
Soft Condensed Matter
When Spectroscopies Speak the Same Language: Unifying Rheology, Electrochemical Impedance, and Dielectrics
Shivangi Mittal, Sachin Shanbhag and Yogesh M. Joshi
Spectroscopic techniques measure the dynamical response of physical systems subjected to oscillatory perturbations. For small perturbations around the
equilibrium state, these spectroscopic methods are unified by the common mathematical framework of linear response theory. This work presents a unified perspective on rheological or mechanical spectroscopy, electrochemical impedance spectroscopy, and broadband dielectric spectroscopy through the lens of linear response theory. Subtle conceptual similarities and differences among these techniques are highlighted by analyzing their mapping to the linear response theory, basic building blocks, elementary models, and time and frequency domain response functions. Data validation and analysis approaches, including Kramers-Kronig relations, equivalent
circuits, and multimode models are discussed. The shared fundamentals of different spectroscopies enable seamless exchange of ideas across domains.
Read the full abstract ▾
Chemical Physics
Nonadiabatic Forward-Flux Sampling of Rare Molecular Gas-Phase Ammonia Photodissociation
Madlen Maria Reiner, Johannes C. B. Dietschreit, Leticia González et al. (+1 more)
Simulating rare events in photochemistry by brute-force surface hopping is computationally prohibitive: most propagated trajectories either remain nonreactive or follow dominant relaxation channels, while the reaction of interest may occur with very low probability. Path sampling methods have long addressed this problem for ground-state dynamics, but their extension to nonadiabatic processes has so far been limited to low-dimensional analytical models. Here, we demonstrate that our recently developed nonadiabatic forward-flux sampling (NAFFS) method can be applied to efficiently simulate rare-events in full-dimensional molecular systems. As a representative
benchmark, we investigate the rare molecular photodissociation channel of gas-phase ammonia, NH$_3$ + h$\nu \rightarrow$ NH + H$_2$. NAFFS samples reactive trajectories with the correct statistical weight, reproduces the reaction rate constant obtained in previous brute-force dynamical studies, provides direct access to mechanistic information through an averaged committor analysis, and reduces the simulation time per transition trajectory by up to three orders of magnitude. These results establish NAFFS as an efficient and statistically rigorous framework for investigating rare nonadiabatic processes in realistic molecular systems.
Read the full abstract ▾
All authors Madlen Maria Reiner, Johannes C. B. Dietschreit, Leticia González, Christoph Dellago