Papers

A single-molecule experiment on a driven enzyme or motor resolves only a few of the transitions the machine makes, yet one would like to know how much free energy it dissipates in total, including on the steps that stay hidden. The mean and the fluctuations of the currents on the watched transitions are shown to certify this hidden dissipation, with no knowledge of the transition rates and no access to the hidden transitions: when the watched transitions span the cycles of the network, the observed-current covariance recovers the full density-contracted quadratic current geometry, including the contribution of transitions that are never seen. The mechanism is that fluctuations are set by the dynamical activity, or traffic, the symmetric partner of the current. Contracting the large-deviation cost of empirical currents over density fluctuations identifies the observed-current covariance with a traffic-weighted metric, and turns partial observation into a minimum-energy completion problem over the unseen cycles, whose solution is the certified hidden cost. Existing current-fluctuation uncertainty relations bound dissipation from chosen currents but do not say when partial observation fixes the hidden contribution; the cycle-observability condition derived here does. The statements concern long-time means and fluctuations; finite-time estimates require separate error control.

Scalable cryogenic wafer level testing is emerging as an essential tool for the development of quantum devices and cryogenic microelectronics, but the main motivation, the actual operational on-wafer temperature, remains largely unverified. In this work, utilizing a cryogenic wafer prober (CWP) enables wafer-scale electrical testing of Coulomb blockade thermometers (CBTs), while the CBTs simultaneously provide an independent static and dynamic assessment of the prober's thermal performance through primary and in situ calibrated secondary electron thermometry, realizing a reciprocal characterization approach. Using recently introduced scalable normal metal TiW-based CBTs, which require no superconductivity suppressing magnetic fields, we have measured on-wafer electron temperatures of 630-660 mK across a full 150 mm wafer, representing, to our knowledge, record-low electron temperatures measured in a CWP. These exceed the nominal 600 mK chuck setpoint by approximately 40 mK on average, demonstrating the necessity of direct on-wafer thermometry. Self-calibrated secondary CBT thermometry resolves the thermal transients caused by chuck movement and reveals a thermal settling time within 5 minutes after probe touch down. This reciprocal wafer-scale approach simultaneously evaluates the device under test and the thermal performance of the measurement environment, providing a practical methodology for scalable sub-kelvin characterization of quantum devices and cryogenic microelectronics.

Integer factorization is a central computational problem with important applications in public-key cryptography. Here, we demonstrate a quantum factorization protocol using a superconducting circuit. Microwave drives are used to engineer a highly tunable effective two-level Hamiltonian whose eigenvalues can be measured spectroscopically. The target integer \(N\) and each candidate factor pair (\(p\),\(q\)) are encoded into the amplitudes, frequencies, and phases of the applied microwave fields. By scanning the candidate pairs while monitoring the spectral response at zero energy, we identify the factor pairs of integers up to six digits. The protocol requires neither two-qubit gates nor quantum entanglement. Its performance is currently limited by the precision of microwave control and the finite linewidth of the spectroscopic response. Improved control accuracy and longer coherence times would extend the accessible range of integers.

We study the Hagedorn transition of the single-winding Dutta-Gopakumar unitary matrix model at finite rank $N$. Its Schur expansion is a sum of Plancherel probabilities restricted by the finite-rank wall on the number of rows, and the Vershik-Kerov-Logan-Shepp limit shape reaches this wall when the number of boxes equals $N^2/4$. Two scaling windows around the Hagedorn point resolve the wall at different scales. In the outer window the Baik-Deift-Johansson theorem gives a Tracy-Widom crossover, and summing it identifies Liu's critical free-energy coefficient with the first moment of the GUE Tracy-Widom distribution. In the inner window the same sum determines the canonical probability law of the Polyakov loop at the Hagedorn point: the normalized loop $\mathrm{tr}\,U/N$ is uniformly distributed on a disk of radius one half, so the order parameter does not self-average at large $N$. The intensity $|\mathrm{tr}\,U|^2/N^2$ has the same limiting law as the Schur degree $n/N^2$: at the Hagedorn point the canonical degree weights become asymptotically equal below the macroscopic finite-rank wall. Under the partial-deconfinement dictionary the uniform disk becomes a linear probability density for the deconfined color fraction, and its fully deconfined endpoint is the Young-diagram endpoint of Berenstein and Yan. The Tracy-Widom mean also fixes the first finite-$N$ correction to the Polyakov-loop Laplace transform and to all of its fixed radial moments. Bessel-Toeplitz evaluations up to $N = 100$ confirm the free-energy coefficient, the uniform law, and the predicted correction.

We study the dynamics of a domain wall (DW) in a type-II superconductor connected to two heat reservoirs. We employ a generalized time-dependent Ginzburg–Landau framework in which the superconducting order parameter and the nonequilibrium quasiparticle distribution are treated as coupled dynamical variables. Within this framework, the effect of the thermal bias is imposed through boundary conditions on the quasiparticle distribution, which are set by the reservoir temperatures. We show, both numerically and within linear response, that the DW moves toward the hotter boundary. From the local momentum-balance relation implied by the model, we identify a viscous force and a force arising from the coupling between the order parameter and the nonequilibrium distribution function. The nonequilibrium distribution separates exactly into a boundary-driven part and a part generated by the motion of the DW itself. The former sets the sign of the DW velocity, whereas the latter renormalizes the relaxation of the order parameter. These results provide a microscopic basis for the phenomenological local-temperature description developed in our previous work.

We decode the excited open charm mesons $D$ ($c\bar{q}$, $q=u,d$) and charm strange $D_s$ ($c\bar{s}$) families within a nonrelativistic quark-antiquark potential model based on the Cornell (Coulomb plus linear) potential supplemented by a Gaussian smeared spin-spin interaction. With only seven parameters determined by fitting the ground state masses, the numerically solved Schrödinger equation reproduces the masses of essentially every confirmed $D$ and $D_s$ state to better than $1\%$. The same wave functions are then employed to get a complete decay analysis including pseudoscalar and vector decay constants ($f_D = 231.8$~MeV, $f_{D_s} = 252.2$~MeV, the latter within $0.4\%$ of the world average), leptonic branching fractions reproducing the measured $\mu\nu$ and $\tau\nu$ modes, electromagnetic $E1$/$M1$ widths, and all kinematically open strong channels in heavy quark effective theory (HQET). Going beyond width ratios, we extract the full set of HQET couplings $g_H$, $g_S$, $g_T$, $g_X$, $g_Y$, $g_Z$, and $g_R$ directly from the measured total widths and convert our predictions into absolute widths. The $D$ and $D_s$ sector extractions of each coupling agree ($g_T = 0.42$ vs. $0.39$, $g_X = 0.22$ vs. $0.21$, $g_Y = 0.39$ vs. $0.40$), a nontrivial test of heavy quark flavor symmetry, while the pure $c\bar{s}$ picture demands a $1^3P_0$ width nearly two orders of magnitude above the observed $D_{s0}^*(2317)$ bound demanding it to be of exotic nature. Linear and parallel Regge trajectories in the $(J,M^2)$ and $(n_r,M^2)$ planes, with slopes $\alpha \simeq 0.55-0.65$~GeV$^{-2}$ and $\beta \simeq 0.36 - 0.39$~GeV$^{-2}$, identify the assignments of $D_J(3000)^0$, $D_J^*(3000)^0$, and $D_2^*(3000)^0$ as the $3^1S_0$, $3^3S_1$, and $3^3P_2$ states. Our predictions provide concrete, testable targets for LHCb, BESIII, and Belle~II.

Crosstalk is one of the major issues for scalability of superconducting quantum processors. But it can also be used by threat actors to intentionally sabotage computations and steal information. This paper analyzes data leakage due to crosstalk during qubit measurement. Prior research yielded an accuracy of 96% in classifying measurement of one qubit in IBM quantum computers. When evaluated on superconducting hardware from VTT, we achieved an accuracy of 71.68% with similar framework. Our extended framework with additional labels yields an accuracy of 76.30% for classifying measurement of one qubit and 53.37% for measurement of two qubits using Support Vector Machine (SVM). Experimental results indicate that measurement operation on a qubit can affect the probability of measuring adjacent qubits. The impact on the target qubit is dependent on the number of neighboring qubits measured and also the measurement outcome.

In this manuscript, we investigate the shadow and polarization images of a Simpson-Visser rotating black hole surrounded by a ballistic approximation accretion flow model. Solving the numerically geodesic and radiative transfer equations, we discuss the influence of the regularization parameter $g$, spin parameter $a$, and observer inclination angle $\theta_o$ on the resulting images at $230\,\mathrm{GHz}$ with an infalling motion. The results interpret that, a bright circular ring corresponding to higher-order images is observed, accompanied by an inner region of decreased intensity. Both $g$ and $a$ has little influence on the size of the higher-order images, but significantly changes their shape and intensity distribution. Whereas, variation in $\theta_o$ modify the image morphology, producing a crescent-shaped bright region on the left side. Finally, the polarization patterns trace the brightness distribution and vary with both $g$ and $a$, reflecting the spacetime structure. These results demonstrates that the intensity and polarization in thick disk models provide probes of Simpson-Visser rotating black holes and near-horizon accretion physics.

We study the two-dimensional XY model with the nonanalytic pair potential $2[(1-\cos\delta)/2]^{p}$, whose small-angle law $\propto|\delta|^{2p}$ carries a cusp for $p<1$ and a flat bottom for $p>1$, invalidating the harmonic spin-wave expansion. Two questions arise: the nature of the low-temperature ($T$) phase and of the phase transition. A naive energetic argument would predict genuine long-range order and an enhanced transition temperature for $p<1$, and no transition at all for $p>1$. Large-scale Monte Carlo simulations contradict both: for every $p>0$ the \dengrevxxi{low-$T$ phase} is quasi-long-range ordered, with anomalous dimension $\eta(T)\propto T^{1/p}$, and terminates at a Berezinskii–Kosterlitz–Thouless transition. Using a vortex-free noncompact lattice-field description and utilizing a duality transformation, we show that coarse-graining drives the height-difference distribution onto a single Gaussian fixed point, renormalizing the cusp and flatness into a finite harmonic stiffness that restores the spin-wave description and the BKT scenario for all $p>0$.

DNA nanostructures are emerging as programmable components for engineering synthetic cell membranes, yet how their collective packing and deformability regulate molecular dynamics at membrane interfaces remains poorly understood. Here, we investigate the packing and mobility of DNA nanostars with tunable stiffness on lipid-coated droplets. The negatively charged nanostars spontaneously adsorb onto cationic membranes, and their interfacial packing is changed by the bulk DNA concentration and droplet size, which together determine the number of encapsulated nanostars. Combining fluorescence recovery after photobleaching experiments with coarse-grained simulations, we reveal distinct packing-dynamics relationships for rigid and soft nanostars. For rigid nanostars, diffusion first decreases gradually and then drops sharply with increasing interfacial packing, approaching a dynamically arrested state consistent with jamming-like behavior. In contrast, at equivalent experimental conditions, soft nanostars systematically reach lower interfacial packing fractions and show a weaker decrease in apparent mobility. This behavior is consistent with their weaker membrane affinity, which facilitates adsorption-desorption with the bulk. When this exchange is suppressed in simulations, crowding reduces the lateral diffusion of both nanostar types, but produces distinct dense configurations: soft nanostars become strongly deformed, whereas rigid nanostars largely retain their shape and form interlocked, gear-like arrangements. Nanostar adsorption also impedes lipid diffusion, while differences in membrane affinity result in distinct lipid mobile fractions. These findings reveal how the interplay between nanostar packing and deformability regulates molecular transport at membrane interfaces, providing a physical design principle for tuning lateral fluidity and crowding in artificial cells.

A weighted dynamical version $\mathbf{Z}_f$ of the classical Ihara zeta function is presented on connected finite regular graphs, expressed in terms of weighted periodic orbit data. We establish its meromorphic continuation, with poles given by the resonances of the associated non-backtracking transfer operator acting on a suitable Banach space, and compute its residues. At simple spectral parameters, the residue of $\mathbf{Z}_f$ is identified with the invariant Ruelle distribution on the graph phase space. Combining this result with a relation obtained by Arends-Palmirotta, we further derive Patterson-Sullivan and Wigner residue formulae. This provides a finite-graph analogue of residue formulae for weighted dynamical zeta functions for geodesic flow on rank one locally symmetric spaces, in the spirit of Schütte-Barkhofen-Weich.

We show that for positive semidefinite $A$ and $B$ the relative entropy can be written as $D(A\|B)=2\int a\log(a/b)\,\mathrm{d}\mu_{A,B}(a,b)$, where $\mu_{A,B}$ denotes Heinävaara's tracial joint spectral measure. This allows us to obtain a unified derivation of several known integral representations of relative entropy from scalar equalities. Scalar inequalities can be used in the same way to derive Pinsker-type bounds. We further show that the testing curve $t\mapsto \mathrm{tr}[A-tB]_+$ is piecewise affine exactly when $A$ and $B$ commute, which is equivalent to their testing region being a polygon. This gives a characterization of noncommutativity through the curvature. As further applications, we derive inequalities for relative entropy variance and the loss of relative entropy under positive trace-preserving maps.

We study thermal leptogenesis in three predictive type-I seesaw models in which the neutrino Dirac mass matrix is equal to the mass matrix of up-type quarks, or down-type quarks, or charged leptons. In this framework, the seesaw relation permits a full reconstruction of the heavy right-handed neutrino mass matrix from low-energy neutrino parameters, which greatly reduces the parameter freedom. A systematic numerical scan based on density matrix Boltzmann equations is performed to examine whether the observed baryon asymmetry of the Universe can be obtained. Successful leptogenesis occurs for normal ordering of light neutrino masses with nonzero Majorana phases. In this case, viable solutions are found in model B, associated with down-type quarks, and model C, associated with charged leptons. Both point to a close-mass pair of heavy neutrinos satisfying $|M_i-M_j|/M_i<10^{-3}$, while remaining outside the conventional quasi-degenerate resonant regime. Four representative benchmark points are selected to show the evolution of the asymmetry and the impact of different treatments of spectator effects. Neutrinoless double beta decay is further studied for all parameter points that can generate an acceptable baryon asymmetry $\eta_B = (6.12 \pm 0.20)\times 10^{-10}$. The predicted effective Majorana mass for certain cases can be probed by next generation experiments with sub-10 meV sensitivity, such as LEGEND-1000, nEXO, JUNO 50 tons, and CUPID-1T. This framework therefore provides clear targets for future searches.

Magnetars, neutron stars harboring the strongest magnetic fields known in the Universe, are associated with a broad range of observational phenomena, from giant flares to fast radio bursts, and have also been proposed as potential sites of heavy-element nucleosynthesis. These phenomena are thought to be closely linked to the structure and composition of magnetar crusts. The outer crust consists of fully ionized nuclei embedded in a degenerate electron gas, while the inner crust additionally contains free neutrons. We investigate how strong magnetic fields modify magnetar crusts, accounting for the spin polarization of free neutrons. Arising from the coupling between the magnetic field and the neutron magnetic moment, neutron spin polarization lowers both the pressure and matter density marking the boundary between the outer and inner crusts for magnetic field strengths $B \gtrsim 10^{17}~\mathrm{G}$. As a consequence, the outer crust becomes thinner, the formation of the superheavy nuclei predicted in previous studies is suppressed, and the neutron ocean permeating the inner crust becomes spin-polarized. These effects may have important implications for the diverse manifestations of magnetars and for $r$-process nucleosynthesis in the ejecta of magnetar giant flares.

Charge transport in solid-state materials is often governed by charge carrier hopping processes in the presence of long-range electrostatic interactions. Kinetic Monte Carlo (kMC) simulations provide a framework for describing such rare-event dynamics over extended timescales. However, the efficient treatment of long-range interactions remains a major computational challenge, since each particle jump modifies the energy landscape globally and, in principle, requires updating all transition rates after every carrier motion. We present an efficient and generally applicable update process for these transition rates in the presence of long-range electrostatic interactions. To illustrate the method, we study charge diffusion on a simple cubic host lattice under an external electric field. The transport behavior is investigated in high states of charge (SOC), and the influence of temperature, electric field strength, and SOC is examined. Our simulations show strongly suppressed transport at 100\,% SOC (50\,% occupation) caused by a freezing of the charge carriers into a Coulomb superlattice. Slight deviations from this reference in terms of charge carrier concentration lead to a rapid increase in conductivity. A deeper analysis reveals that this behavior can be rationalized as transport of non-interacting defects in the Coulomb superlattice. These results demonstrate the capability of the proposed update procedure to efficiently capture non-equilibrium transport phenomena in interacting charged systems and provide a foundation for simulations of more complex charge diffusion problems.

Optical image processing offers a promising pathway to overcome the latency and energy limitations of conventional electronic image processors. However, existing approaches based on passive photonic devices are often constrained by signal attenuation, lack of nonlinearity, fixed functionality, and heavy training overhead. Here, we introduce a programmable image processor based on a highly multimode degenerate cavity laser (DCL), shifting the computational framework from passive extracavity transformation to active intracavity evolution. By manipulating the intracavity loss distribution and exploiting the nonlinear lasing dynamics, we map computational tasks to the spontaneous mode selection within the DCL, realizing image processing directly at the source. We experimentally demonstrate that by simply altering the encoding scheme of input images, the platform can be flexibly reconfigured for multifunctional tasks, including high-fidelity edge detection and robust image denoising. The computation proceeds autonomously without dataset training, featuring an intrinsically low latency ($\sim$90 $\mu\mathrm{s}$) with $\mathcal{O}(1)$ complexity. Furthermore, the high intensity sustained within the resonator enables intracavity nonlinear upconversion of the processed image. This work extends the frontiers of laser applications, providing a compelling candidate for next-generation optical processors.

In two-dimensional crystals, electrostatic gating can modulate the charge carrier density, thereby tuning their electrical properties. In magnetic materials such as CrSBr, this approach can also enable direct electrical control of magnetoresistance. Non-volatile gating is particularly attractive since it allows the carrier density to be maintained at a desired level without the need for a continuous gate bias, offering significant advantages for technological applications. Here, we demonstrate a simple device architecture in which a solution-processed ferroelectric P(VDF-TrFE) layer is integrated directly onto a CrSBr channel, enabling non-volatile control of its magnetoresistance. We investigate the magnetotransport response over a broad temperature range and demonstrate a reproducible and robust gate dependence. Notably, the ferroelectric gate achieves a gating efficiency approximately one order of magnitude higher than that of a conventional SiO$_2$ dielectric, highlighting the potential of ferroelectric gating for electrical control of 2D magnetic materials.

The deployment of a geoengineering program to cool Earth's climate may be imminent. It is crucial that tools be developed to ensure that such a program would achieve its objectives while minimizing disruption. Here we exploit recently developed differentiable atmospheric models to demonstrate a novel geoengineering control strategy. In the differentiable primitive-equation atmospheric model JAX-GCM we impose a uniform $+4$\,K ocean warming and ask what pattern of sea-surface temperature cooling – in five ocean-masked zonal bands of prescribed SST forcings whose amplitudes are free – returns land near-surface air temperature closest to the model's own unwarmed climatology. This idealized set-up represents a cooling pattern that could be delivered physically either by marine cloud brightening or stratospheric aerosol injection. Gradients through chaotic dynamics decorrelate from the true sensitivity beyond the Lyapunov horizon, so we optimize greedily over segments of 8 to 14 days, following receding-horizon control. The learned strategy removes $92.3 \pm 0.4\%$ of the realized land warming across a ten-member ensemble of two-year rollouts, and a three-year run sustains it. If we use the spatial pattern of land temperature as the optimization objective, the distributions of precipitation, evaporation, and specific humidity over land are restored as well, even though they are not included in the objective function. The learned strategy from JAX-GCM replayed in the AI emulators LUCIE and NeuralGCM without re-optimization is successful, suggesting robustness. These promising results demonstrate a strategy for designing optimal climate interventions that can be applied broadly for geoengineering scenarios under consideration.

The Wigner's friend thought experiment raises the question of whether quantum theory can be applied consistently to systems that include observers. Extended Wigner's Friend Scenarios develop this question by considering several observers who may assign different descriptions to the same experiment. In the Local Friendliness (LF) framework, these scenarios lead to experimentally testable inequalities derived from assumptions such as Absoluteness of Observed Events and Local Agency. Motivated by the "Thoughtful" version of the Local Friendliness no-go theorem, which points towards future LF tests with human-level artificial agents implemented on quantum computers, this work implements the "friend" with explicit agent-like functionality within a reversible quantum circuit. Drawing from the literature on Artificial Intelligence, we construct rudimentary agent-like systems and embed them into a one-friend Extended Wigner's Friend Scenario. These agents store measurement outcomes, condition later operations on stored information, and, in the most structured case, use Born-rule probabilities to bet on the outcomes of their own future observations based on past observations. The circuits are simulated ideally and with an IBM-device noise model and executed on ibm_marrakesh. Ideal simulations reproduce the maximal quantum violation of a Local Friendliness inequality up to finite-shot fluctuations, while hardware runs show positive LF violations for all implemented agents. These results provide a first step towards more structured agent-like friend models in LF experiments on quantum computers.

We demonstrate that superconducting unconventional magnet junctions harbor transverse spin and charge diode effects with perfect rectification efficiencies. This nonreciprocal transverse transport is governed by the interplay of mirror reflections and spin rotation with respect to the Néel vector, a mechanism that is universally applicable to all unconventional magnets. Interestingly, the transverse spin diode features pure spin currents, while the charge diode yields spin-polarized charge currents, both exhibiting highly controllable rectification functionalities at vanishing net magnetization. Our results position superconducting unconventional magnets at the forefront of orthogonal engineering in next-generation transverse superconducting spintronics.

We derive thermodynamic speed limits for isolated quantum systems undergoing finite-time unitary driving. The key ingredient is a set of generalized second-law inequalities: for the Gibbs entropy and for several thermodynamically motivated observational entropies, the entropy production is bounded from below by a function of the Vu–Saito quantum Wasserstein distance between the initial and final coarse-grained states. These inequalities yield lower bounds on the operation time in terms of the average entropy-production rate. We apply the framework to system–bath coarse-graining, local-energy coarse-graining, and diagonal entropy, and illustrate the resulting bounds with numerical and analytically solvable examples. Our results provide a thermodynamic characterization of finite-time state transformations in isolated quantum systems and clarify how coarse-grained entropy production constrains macroscopic reachability.

The analysis of critical current anisotropy is important for improving superconductor-based devices. This article critically evaluates contemporary techniques for analyzing the angular dependence of critical current in practical superconductors, focusing on second-generation high-temperature superconducting tapes (coated conductors). These techniques are based on the scaling model, vortex path model, or anisotropic pinning model. We present empirical findings on critical current angular dependencies in coated conductors of different chemical compositions. Distinctive features are highlighted: the complex effect of rare-earth substitution in the HTS composition on the pinning landscape, peak asymmetry, and the dependence of critical current on Lorentz force direction at fixed magnetic field direction. The described techniques are then applied to the experimental dataset. A refined anisotropic pinning model is introduced to accurately describe certain observed phenomena. Approximation accuracy of the models is assessed using the coefficient of determination adjusted for the number of fitting variables. The fundamental disparity in interpreting angular dependencies with different models is emphasized. No universal methodology yet comprehensively explains all features or links them to the defective structure of the HTS material. This is a critical gap in understanding superconductor behavior under varying conditions and highlights the need for further research.

Rhombohedral multilayer graphene has emerged as a remarkably versatile platform for exploring strong correlation driven quantum states arising from low-energy topological flat bands. When reconstructed by the moire superlattice, these bands host a wide range of emergent novel states, including integer and fractional Chern insulators and unconventional superconductivity. Here, we firstly report the simultaneous emergence of widespread spin polarized SC and high Chern insulators in twisted bilayer multilayer RMG system 2+n where n=4,5,6. The SC states in 2+n system exhibit different responses to the in plane magnetic field, with SC being suppressed, enhanced and induced by in plane magnetic field . The latter two are consistent with spin-triplet pairing. Along with SC, angle and layer dependent HCIs with tunable Chern numbers emerge. Moreover, the fractional high Chern insulator in the system survives under high in plane magnetic field which can induce SC in the same device. Our work not only establishs twisted bilayer multilayer rhombohedral graphene as a unified platform for studying SC and high Chern insulators, but also opens a pathway towards multiple copropagating chiral Majorana channels by coupling spin-polarized SC to high Chern insulators.

Quantum neural networks (QNNs), one of the fundamental algorithms in quantum machine learning, have been widely used in classification and identification tasks. However, the capabilities of QNNs are constrained by their size, which is determined by the dimension of the Hilbert space of the underlying quantum processor. Multi-level quantum digits (qudits) offer access to a higher-dimensional Hilbert space compared to two-level qubits, enabling the construction of more expressive QNNs. In this work, we report an experimental demonstration of qudit-based QNN using a trapped $\rm ^{40}Ca^+$ ion. We train the QNN using a hybrid quantum-classical implementation of backpropagation and achieve an experimental classification accuracy of $95.7\%$ on a test image set. This demonstration highlights the potential of qudit-based processors to QNN architectures and provides a framework for implementing qudit-based QNNs across various quantum devices.

From its birth, celestial mechanics has been deeply intertwined with the question of the Solar System's dynamical stability. For the inner planets, this question is now statistically settled: Mercury's orbit carries a $\sim$1% chance of destabilization before the Sun leaves the main sequence. The outer Solar System has seemed more secure, with its intrinsic dynamical lifetime estimated at $\sim10^{18}$ years. Even accounting for the Sun's mass loss and stellar flybys, the orbital architecture of the giant planets had been expected to persist for $\sim$100 Gyr. Here we show that these estimates rest on the assumption that solar mass loss is smooth. The recently measured white dwarf recoil demands asymmetric mass loss that is most readily attributed to discrete, independently directed ejections that impulsively perturb stellar motion. As the Sun sheds its envelope in such parcels, the planets' orbits random-walk with amplitude set by the mass-loss granularity. At a coarseness corresponding to observationally permitted kicks, this stochastic forcing restructures the outer Solar System concurrently with the Sun's death. In particular, our numerical experiments reveal that orbit crossings can commence on the red giant branch, with $\sim$40% of realizations undergoing disruption or violent scattering before the white dwarf forms and $\sim$90% self-destructing within 3 Gyr. The outer Solar System's dynamical lifetime thus collapses from $10^{18}$ years to approximately a gigayear after white dwarf formation.

The two-dimensional one-component plasma forms a droplet in the case that the one-body potential is proportional to the number of charges. Our interest is in studying the large $N$ form of the corresponding partition function, with the plasma confined to the surface of the cylinder. The one-body potential is (up to technical restrictions) allowed to be arbitrary in the direction of the axis of the cylinder, whereas the coupling is restricted to the exactly solvable value $\beta = 2$. It is demonstrated that a change of variables can be made to an annular droplet plasma model, up to a certain Jacobian factor. The latter can be interpreted as the characteristic function of a certain linear statistic, which generalises the original aim of our study to also analysing the large $N$ form of the characteristic function for the annular droplet plasma model. While this is well known in the case of soft wall boundary conditions, our analysis (based on Laplace's method applied to certain integrals, and the Euler-Maclaurin summation formula) covers the case of one or two hard walls at the boundary, or inside, of the droplet for which the soft edge formulas are shown to no longer hold. Use of this to study the large $N$ expansion of the cylinder partition function requires knowledge of the same expansion in the annular case. This is not available in the case of two hard walls inside the droplet, which we treat instead via a direct analysis. In distinction to the case of the annular partition function, the large $N$ expansion of the logarithm of the cylinder partition function is found to always have no term proportional to $\log N$, independent of the presence of hard walls.

We report a theoretical and numerical study of plasma-wave instability in a current-driven InGaAs/GaAs gated electron channel. A finite drain current drives the channel away from a uniform plasma-wave cavity: the carrier density and plasma velocity decrease toward the drain, while the electron drift velocity increases. This current-induced spatial nonuniformity modifies both the propagation time and amplification of plasma waves and becomes increasingly important as the sonic regime is approached. Using a hydrodynamic description combined with the unified charge-control model, we determine the nonuniform steady state and analyze the resulting plasma-wave frequency and instability growth rate. The oscillation frequency is found to be governed by wave propagation through the entire channel rather than by the local drain conditions, leading to a pronounced current-induced frequency reduction that is not captured by a uniform-channel approximation. The instability results from the competition between boundary-induced plasma wave gain and distributed losses due to momentum relaxation and electron viscosity. The finite-viscosity theory shows good quantitative agreement with the simulation data over the subsonic regime and regularizes the singular behavior of the inviscid description near the sonic point. At higher currents, the dynamics become increasingly sensitive to the near-sonic structure and contact boundary conditions, indicating that the eventual suppression of the instability cannot be attributed to bulk hydrodynamics alone.

Resampling removes the modeled phase evolution of a frequency-evolving signal, transforming it into a monochromatic one. We introduce a novel implementation for long-transient gravitational-wave searches that evaluates the Fourier spectrum of the resampled data using a type-I non-uniform fast Fourier transform (NUFFT). This implementation can be up to two orders of magnitude faster than some previous implementations, depending on coherent length, sampling rate, and desired accuracy. To demonstrate its application, we benchmark the method with a semicoherent search for long-duration inspiral signals from subsolar-mass primordial black hole binaries. For a search over $40$–$60\,\mathrm{Hz}$ and chirp masses of $5\times10^{-4}$–$10^{-1}\,M_\odot$, with a coherent duration of $30\,\mathrm{s}$ and a realistic computing cost, the estimated horizon distance exceeds the Galactic Center for all of the parameter space considered and exceeds Andromeda for chirp masses above approximately $2\times10^{-2}M_\odot$. These results establish NUFFT-based resampling as a computationally efficient and broadly applicable approach for searches for modeled, frequency-evolving gravitational-wave signals.

Helicon current drive is an attractive solution for driving current to sustain steady state tokamak operation in reactor conditions. Dedicated DIII-D experiments have been conducted with a MW-level helicon system and successfully demonstrated core power deposition and current drive with helicon waves launched via a traveling wave antenna. The profile of the measured electron temperature response to helicon power injection is in good agreement with time-dependent integrated modeling that incorporates ray tracing and the effects of thermal transport simultaneously. When the helicon power is injected continuously to drive co-$I_p$ current, the reconstructed safety factor profile flattens significantly faster and sawteeth are triggered earlier than in comparison shots where the helicon is replaced by a comparable amount of electron cyclotron heating. Calculation of the helicon-driven current profile yields a peaked profile in the core, consistent with the observed power deposition profile and in good agreement with ray tracing predictions. Taken together, these experimental results represent strong evidence for the first definitive observation of auxiliary current drive due to helicon waves on any device.

Magnetic fields play a crucial role in regulating the collapse of dense molecular clouds, shaping the early stages of protostellar evolution. We present polarization observations in submillimeter wavelengths with the SCUBA-2/POL-2 instrument on James Clerk Maxwell Telescope toward the Class 0 protostellar system L1527 IRS (IRAS 04368+2557). The magnetic field morphology varies across the core of L1527 IRS. Magnetic fields in the eastern region are perpendicular to the outflow axis, while those in the western region show a pinched morphology, overall aligned with the outflow cavity. These distinct bipolar outflow regions also have a clear color difference in near infrared observed by James Webb Space Telescope. In addition, the spectral index derived from 450 {\mu}m and 850 {\mu}m observations reveals that the northwestern region of the protostellar system is colder and denser compared to the southeastern region. Furthermore, in the large-scale structures and magnetic fields revealed by Herschel and Planck, we find a ~0.1 pc scale filamentary structure parallel to the large-scale magnetic fields in the eastern region and a relatively isotropic mass distribution in the western region. Based on these results, we propose an accretion scenario of the protostellar system in which an asymmetric mass distribution causes the distinct features observed in near-infrared and submillimeter wavelengths.