Papers

Measuring part of a many-body wave function generates a projected ensemble of pure quantum states on the unmeasured subsystem. Recent advances in deep thermalization have shown that, in chaotic systems, this ensemble universally converges to the maximally random ensemble compatible with its average density matrix, known as the Scrooge ensemble. By contrast, free-fermion systems are nonchaotic, and their quantum states are constrained to remain Gaussian. Motivated by this distinction, we introduce the fermionic Gaussian Scrooge ensemble to describe deep thermalization in generic free-fermion systems. This ensemble is defined as a distortion of the Gaussian Haar ensemble by the average density matrix, and its moments reveal an enlarged symmetry of Gaussian states in the replicated Hilbert space. We demonstrate the emergence of the fermionic Gaussian Scrooge ensemble in two complementary settings: (1) we analytically prove that the projected ensemble of the SYK$_2$ model follows the fermionic Gaussian Scrooge ensemble at arbitrary evolution times; (2) we provide numerical evidence that it emerges at sufficiently long times in random Gaussian circuits with charge conservation. Our results establish the fermionic Gaussian Scrooge ensemble as a universal description of deep thermalization in free-fermion systems.

The coherent dynamics of lattice waves is of significant importance for exploring the nonadiabatic phenomena of the electron-phonon coupling under nonequilibrium conditions. Here, we propose a theoretical model for phonon interference induced by a defect pair, in which lattice waves with the selective modes are launched independently by each of defects due to the strongly local electron-phonon coupling. We find that the intensities of phonon interference fringes could be directly evaluated by a measurable quantity in experiments–Huang-Rhys factor, and the geometry of interference patterns could be modified by the internal parameters of defect pair, including the charge states, spatial distance, energy-level depth and localization strength. In particular, several novel quantum states, such as the Dirac-like and nodal-line topological states are emerged for the appropriate internal parameters. Furthermore, using Huang-Rhys model, we simulate the ultrafast optical spectroscopy in the phonon interference duration when defect pairs are excited as the color centers, where interference fringes are perfectly matched by intensities of spectrum, similar to the $\textit{lock-key}$ pattern. These results show that defect pair, serving as the driven force for the coherent dynamical processes for multidegrees of freedom, offers an ideal platform to explore fundamental quantum phenomena in nonequilibrium and ultrafast physics.

Graphene nanoribbons (GNRs) are a highly tunable class of one-dimensional (1D) quantum materials that can be fabricated through bottom-up synthesis. Precise control over GNR band gaps and band-edge alignments has established them as a promising nanoelectronics platform, but forming high-quality electronic interfaces remains challenging. Here we combine sequential on-surface synthesis and scanning tunneling microscopy (STM)-induced dehydrogenation to directly write metallic 7-iGNR segments into otherwise semiconducting H$_2$-7-iGNRs without changing the GNR width or carbon backbone connectivity. The resulting metallic segments exhibit nonzero spectral weight at the Fermi level ($E_\mathrm{F}$) and spatially extended electronic states, consistent with two dispersive bands crossing $E_\mathrm{F}$. The new metallic states are well described by an extended Su–Schrieffer–Heeger zigzag-ladder Hamiltonian. Scanning tunnelling spectroscopy (STS) and first-principles calculations show that the valence band edge of adjacent, connected semiconducting GNR segments lies close to $E_\mathrm{F}$ for the metallic segments. STS spectra recover bulk GNR properties within $\sim$1 nm on either side of the metal-semiconductor GNR interface, with no discernible depletion region. The observed GNR band edge alignment is consistent with a small energy barrier for hole injection, thus suggesting a possible route towards atomically precise, low-barrier p-type contacts for future GNR-based electronic devices.

We prove that a quasi-local quantum Gibbs sampler rapidly mixes to the Gibbs state of any 1D finite-range Hamiltonian at all finite temperatures in $\mathcal{O}\left(\log (n/\varepsilon)\right)$ time. Each update traces out a contiguous block of constant length and reconstructs it using the Petz recovery map, following early proposals for quantum heat-bath Gibbs samplers by Kastoryano and Brandão~\cite{kastoryano2016quantum}. Our proof directly bounds the distance between the updated state and the target Gibbs state using quantum Wasserstein distance of order $1$. We further provide $\mathcal{O}(\text{polylog}(n/\varepsilon))$ depth of quantum circuits to prepare these Gibbs states. We hope these techniques will facilitate the analysis and design of other Gibbs samplers.

The Full Event Interpretation (FEI) algorithm is a central component of the Belle II analysis framework, designed for the efficient reconstruction of exclusive B-meson decays. The FEI performs a hierarchical reconstruction of hadronic and semileptonic final states, using multivariate classification techniques to tag one of the two B mesons produced in electron-positron collisions. The FEI is particularly important for studies of signal-side decays involving missing energy. By reconstructing one B meson with the FEI, the kinematics of the other, signal-side B meson are tightly constrained, leading to improved background rejection. In this contribution, we present the design, implementation, and recent developments of the FEI. We outline the reconstruction strategy, candidate selection, and multistage multivariate training based on gradient boosted decision trees. Recent improvements to the FEI workflow, including improvements in the simulated data used for training, reconstruction of intermediate particles, and improved robustness of the multivariate inputs, are discussed in detail. Beyond algorithmic updates, we also discuss newly developed techniques for the calibration and performance evaluation of the FEI. These include refined procedures to calibrate the efficiency, check the performance across decay channels and data-taking conditions, and application of reweighting techniques to diagnose and mitigate discrepancies between simulation and data. Finally, we briefly discuss ongoing and future developments aimed at further improving reconstruction performance and computational efficiency.

The negatively charged nitrogen-vacancy ($\mathrm{NV}^-$) defect in diamond can be used for quantum information processing via the readout of the radiative decay of the excited state into the ground state. The large refractive index mismatch of diamond and air causes low photon extraction efficiency due to total internal reflection losses. Here, we investigate the photon extraction numerically and report additive solid immersion lenses (SILs) consisting of the high-k dielectric yttria-stabilized-zirconia (YSZ) for surface modification and enhanced light extraction of shallow implanted nitrogen-vacancy centers. We demonstrate an average increase of 63% in saturation intensity using a scalable bottum up room temperature pulsed laser deposition and photolithography structurization process. The average necessary laser intensity for saturation is reduced by 33% by the SILs.

We study the dynamic critical behavior of the two-dimensional random-bond three-state Potts model using large-scale Monte Carlo simulations with the Wolff and Swendsen–Wang cluster algorithms. At the disorder-dependent critical temperature, we compute integrated and exponential autocorrelation times and extract the dynamic critical exponent $z$ via finite-size scaling. Critical slowing down is significantly weakened by bond randomness, with the dynamic exponent decreasing from $z \approx 0.54$ in the pure system to $z \approx 0.24$ at strong disorder. From the finite-size scaling of the Wolff cluster size, we obtain $\gamma/\nu \approx 1.73$, where $\gamma$ and $\nu$ are the susceptibility and correlation-length exponents, respectively, consistent with the universality class of the two-dimensional three-state Potts model. These results indicate that bond randomness strongly affects the critical dynamics but leaves the underlying static universality class unchanged. Furthermore, both static and dynamic observables, including the specific heat and the autocorrelation times, show a lack of self-averaging.

We investigate a transverse-field Ising chain with dimerized anisotropic Gamma interactions and demonstrate that, both in the absence and presence of Ising interactions, the competition between Gamma anisotropy and the transverse field gives rise to vector chiral order and dynamical quantum phase transitions. The phase diagram comprises positive and negative vector chiral phases and a paramagnetic phase, characterized by the vector spin chirality and the vector chiral order parameter. In the absence of Ising interactions, we identify a gapless critical line that exhibits no finite-size drift, along which the spin-spin correlations and subsystem entanglement entropy display behavior distinct from that of Ising criticality. Furthermore, we find that the critical times of dynamical quantum phase transitions form periodic or aperiodic sequences, depending on the quench path. Our findings highlight how dimerized off-diagonal exchange enriches both equilibrium ordering and dynamical critical behavior in a quantum Ising chain.

At terahertz drive frequencies, magnetization dynamics enter an inertial regime beyond the scope of standard Landau-Lifshitz-Gilbert (LLG) theory. We reveal a nutational damping torque comprising a bulk term and an interfacial contribution that describes spin emission into adjacent metals. The interfacial term generates nutational spin pumping: a dc spin current that scales quadratically with the drive frequency. Using a scattering approach, we relate this effect to microscopic material parameters and predict pronounced enhancements in ultrathin films and low-Fermi-energy conductors. Nutational spin pumping can be detected directly via the inverse spin Hall effect or indirectly via thickness-dependent renormalization of nutational damping.

Quantum correlations are fragile under noise, motivating quantitative measures that track not only their presence but also their degradation during physical evolution. We develop a robustness framework for the hierarchy of Bell nonlocality, EPR steering, and entanglement, establishing an ordering of the corresponding robustness measures and relating robustness to noise-induced transition times. We further formulate the instantaneous robustness decay along Lindblad dynamics as a directional derivative determined by both the evolution and the robustness functional. Applications to isotropic depolarizing noise and amplitude damping illustrate, respectively, the resulting resource transition times and the directional dependence of steering robustness. The framework provides an approach to characterizing the degradation and lifetime of bipartite quantum correlations under noisy dynamics.

We study the wetting transition for a two-dimensional Solid-On-Solid (SOS) interface above a hard wall in the presence of quenched disorder. The interface is represented by a nonnegative integer-valued height function $\phi$, with Hamiltonian $\mathcal H^\omega(\phi)=\beta\sum_{x\sim y}|\phi(x)-\phi(y)|-\sum_x(h+\alpha\omega_x-\lambda(\alpha))\mathbf 1_{\{\phi(x)=0\}}$, where $(\omega_x)_{x\in\mathbb Z^2}$ is an i.i.d. centered field, $\alpha\ge0$ is the disorder strength, and $\lambda(\alpha)=\log\mathbb E[e^{\alpha\omega_0}]$. This normalization is chosen so that the annealed model coincides with the corresponding homogeneous wetting model. As the wall attraction $h$ increases, the interface undergoes a transition from a delocalized phase, in which contacts with the wall have vanishing density, to a localized phase with a positive density of contacts. For sufficiently large $\beta$, the homogeneous wetting point and its sharp near-critical free-energy behavior are known. We prove that, for every fixed $\alpha\ge0$, the quenched critical point coincides with the homogeneous wetting point, $h_c(\beta,\alpha)=h_w(\beta)=-\log(1-e^{-4\beta})$. Moreover, writing $u=h-h_w(\beta)$, we show that the quenched excess free energy satisfies $\overline F_\beta(\alpha,u)=\overline F_{\mathrm{homo}}(\beta,u)+o(u^3)$ as $u\downarrow0$, where $\overline F_{\mathrm{homo}}(\beta,u)$ denotes the leading homogeneous wetting asymptotic and satisfies $\overline F_{\mathrm{homo}}(\beta,u)\asymp u^3$. Thus, at the level of both the critical point and the leading near-critical free-energy asymptotics, the quenched model has the same behavior as the homogeneous SOS wetting model. This contrasts with the disordered SOS pinning model, in which quenched disorder leaves the critical point unchanged but modifies the leading critical behavior of the free energy.

We propose an analyticity bootstrap method to determine the reduction of Feynman integrals (FIs). The key observation is that, at any kinematic point, a dimensionally regularized FI possesses a Taylor expansion region (analytic region), and the finiteness of the Taylor region strongly constrains the integral reduction coefficients, which are rational functions of the kinematic variables. By writing the most general ansatz compatible with the singularity structure and then fixing the remaining parameters with only a few integration-by-parts (IBP) samples or asymptotic expansions, one can obtain the full reduction. We develop the method systematically in both single-variable and multi-variable cases, with many explicit examples. Interestingly, the differential equations (DEs) of the master integrals determine all these analyticity constraints and, conversely, the constraints facilitate the construction of the DEs. In particular, we show that the DEs in the auxiliary mass flow method can be constructed at significantly reduced cost and can even be fully determined without using IBP.

The static tidal Love numbers of black holes vanish in general relativity (GR), but are generically non-zero, and in fact 'run' logarithmically with scale, in more general theories or beyond the static limit. We expose a model-agnostic framework for the running of Love numbers at the dynamical level, valid for any tidal perturbation on any static, spherically symmetric, asymptotically flat background, based on the near-zone expansion in powers of the frequency $\omega$ and on the monodromy at spatial infinity. A master recurrence formula determines the monodromy generator to all orders in $\omega^2$, whose three independent entries fully encode the running of the Love numbers. This structure explains the quadratic nature of the renormalization group equation, here proved to all orders and for any type of Love number. We discuss the scheme dependence of the logarithmic coefficients, which is made transparent by the monodromy form. In particular, this clarifies that the anomalous exponents of the tidal field, the so-called 'renormalized angular momentum' of the Mano-Suzuki-Takasugi formalism, are scheme-invariant and directly computable on any spacetime, without need of explicit solutions. We discuss several applications to black holes, including the derivation of a closed-form formula for the leading dynamical running of axial Love numbers of Reissner-Nordström black holes, proving in particular that it vanishes in the extremal limit. For generic black holes beyond GR, we prove that dynamical running probes deformations of the metric at lower multipoles than the static one, and we illustrate the power of the method by deriving some exact results for the Hayward and Bardeen regular black holes.

Long-range electronic correlation can be represented in terms of coupled fluctuations of atomic charges and higher multipoles, motivating a density-response description beyond local dipolar polarization, particularly in low-dimensional, conducting, and small-gap systems where collective electronic fluctuations become important. We extend the frequency-dependent polarizable force field ACKS2$\omega$ to electronic-structure references containing exact exchange by deriving both the static and additional frequency-dependent exchange contributions, with particular attention to HFsrPBE, which combines long-range Hartree–Fock exchange with short-range PBE exchange and correlation. Numerical validation of ACKS2$\omega$ using dipole polarizabilities and $C_6$ dispersion coefficients for the 27 molecules of the TS27 set, with HF, PBE, B3LYP, and HFsrPBE as the underlying electronic-structure references, shows that including the exchange contributions and enriching the response basis improve agreement with the corresponding orbital-space linear-response calculations, although finite-response-basis errors remain molecule dependent. Long-range correlation energies evaluated through the adiabatic-connection fluctuation-dissipation theorem using the ACKS2$\omega$ parameters reproduce the corresponding HFsrPBE orbital-space results for small test molecules when the response basis is made complete within the chosen orbital basis, while a local multipole decomposition resolves the finite-basis energies into monopole–monopole, mixed, dipole–dipole, and remaining higher-multipole contributions, providing a route to evaluating long-range correlation energies in terms of charge fluctuations within atom-condensed models.

This paper reports a computational scheme which predicts the light-matter interaction in multiple mesoscopic plasmonic nanowires (NWs), each of which includes concentric or eccentric constituent wires. Lying at the core of the proposed scheme is the S-Matrix of each individual cylindrical interface. The optical response of the materials inside and outside each interface can be described by three popular mesoscopic models: the Hydrodynamic Drude model (HDM) and its diffusive variant, namely the Generalized Nonlocal Optical Response (GNOR) model, as well as the Surface Response Model (SRM). To take into account the relative displacements between the cylindrical interfaces, the addition theorem is applied to construct the main equation behind the algorithm, where the possibility of longitudinal waves intrinsic in the HDM and GNOR models is also included. The optical responses calculated by the proposed S Matrix Method are compared with an in-house developed boundary element method (BEM) toolbox for a single gold NW and an eccentric dual-material NW, and excellent agreements are seen. The algorithm is further physically checked for a sodium nanolens trimer featuring large field focusing, and the effects of the HDM and the SRM are compared.

Morohoshi, Nakayama, Manabe, and Mitarai proposed a physically motivated quantum machine learning problem in which the goal is to predict quantities of the form $\operatorname{Tr}[f(H)\rho]$ from classical descriptions of a Hamiltonian $H$ and a quantum state $\rho$, where $f$ is an unknown function. We call this problem Hamiltonian function learning in this paper. They constructed an efficient quantum learning algorithm under suitable conditions, while leaving a rigorous proof of average-case classical hardness open. In this paper, we rigorously prove the average-case classical hardness for two distribution-specific Hamiltonian function learning problems for $f_{\cos,\pi}(\lambda)=\cos(\pi\lambda)$ and $f_{\exp,\beta}(\lambda)=e^{-\beta\lambda}$ discussed in the paper of Morohoshi et al. under the assumption of the average-case hardness of factoring random RSA moduli. More specifically, we show that an efficient classical randomized learner under squared loss whose output hypotheses are evaluable in classical polynomial time for either problem would yield a classical randomized polynomial-time algorithm for factoring random RSA moduli.

We present an environmental analysis and overdensity catalog for a large sample of submillimeter galaxies (SMGs) in the COSMOS field in order to understand whether SMGs are signposts of megaparsec-scale overdensity structures. We apply the Poisson Probability Method (PPM) protocluster finder to characterize the significance ($\sigma$) and overdensity value ($\delta$) of any overdense structures surrounding specific 'beacon' galaxies. These beacons include 449 SMGs from A3COSMOS (including 168 with spectroscopic redshifts, 52 of which have CO or [CII] 158$\mu$m line detections), as well as a control sample of over 5000 main-sequence star-forming galaxies (SFGs) selected from the 40-band photometric-redshift catalog in COSMOS2025. We successfully reproduce 15 known protoclusters and clusters in COSMOS (including Hyperion large-scale structure, CL J1001+0220 at z~2.5, and AzTEC-3 protocluster at z~5.3), and report 26 new PPM-based high-overdensity ($\delta$ $\geq$ 5), high-significance ($\sigma$ $\geq$ 5), robust candidates. We measure an overdensity fraction of 11.5-71.2% (1.3-61.0%) in the CO/[CII] 52 SMG (full 449 SMG) sample with different criterion categories, confirming that SMGs are signposts of overdensities compared to the control SFG sample. We also notice that the fraction is lower than 100%, indicating that not all SMGs are associated with overdensities. We thus inspect the JWST morphology and argue that the triggering of starburst in SMGs must have non-environmental mechanisms, for instance, merger and violent disk instability. Finally, we further conduct a spatial distribution analysis, finding that the location of SMGs in overdensities has a redshift evolution, with SMGs being more concentrated in the inner regions of overdensities at higher redshift.

We prove the Gromov-Hausdorff convergence of the state spaces, equipped with Connes' distance function, of the operator systems associated with spectral truncations for noncommutative $n$-tori, $n\ge 2$. The action of the $n$-torus on the noncommutative $n$-torus, together with an appropriate use of Bochner integrals, enables us to construct an $C^1$-approximate order isomorphism that establishes the convergence. The earlier convergence result for the classical case of tori [20] follows as a special case of our result. We conclude by studying the $C^*$-envelopes and propagation numbers of the truncated operator systems and show that the structural properties of the truncated operator systems for tori persist under deformation.

It is well known that quasi-symmetric (QS) stellarators are isomorphic to tokamaks in terms of their neoclassical-transport properties, and the corresponding transport coefficients can be calculated in the same manner as in tokamaks. However, less is known regarding the turbulent-transport properties of QS stellarators, e.g. the transport coefficients from the ion-temperature-gradient (ITG) mode. In this work, a systematic theory of the “equivalent tokamaks” for QS stellarators is presented based on the local gyrokinetic formulation and the near-axis expansion theory. It is shown that to zeroth order in the minor radius, the equivalent tokamaks can be chosen to have circular flux surfaces and can be characterized by three geometric quantities: the aspect ratio, the rotational transform, and the magnetic shear. To achieve first-order accuracy, however, not all QS stellarators have equivalent tokamaks, but good approximations can be found for some cases either as global or local equilibria. Local and global gyrokinetic simulations of ITG transport are performed for a selection of QS configurations, and quantitative agreement in the turbulent transport levels is found between the stellarators and their equivalent tokamaks.

We develop Multivariate Quantum Signal Processing for designing matrix-valued transformations of multiple noncommuting nonnormal block-encoded matrices. Our framework equips quantum transducers with the analytic structure of multiport Infinite-Impulse-Response (IIR) filters and establishes a transfer-function methodology for designing quantum query algorithms. Efficiently computable analytic bounds that hold uniformly across the oracle promise yield efficient quantum circuits with logarithmic error dependence and near-unity success probability, paralleling the approximation-theoretic guarantees of univariate QSP/QSVT. We provide a complete characterization of achievable transfer functions and a principled library of analytic IIR components. Our modular designs greatly improve or resolve the per-oracle query complexity of open multi-oracle problems: (1) Hamiltonian simulation under $H=\sum_j H_j$ with weighted quasinorm cost $\approx t\langle\vec\lambda,\vec C\rangle_{1/2}+\mathcal{O}(\|\vec C\|_1\log(1/\epsilon))$ for block-encoding normalizations $\vec\lambda$ and costs $\vec C$; (2) sparse simulation with optimal time–norm $\Theta(\sqrt{d}\|H\|_{\rm 1\to2}t)$ and additive error dependence; (3) solving linear systems and (4) differential equations under minimal matrix assumptions with optimal weighted state-preparation and multi-term cost; (5) ground-state preparation and energy estimation; (6) generalized eigenvalue problems. We apply these to exactly simulate downfolded Hamiltonians with leading cost $t\langle\vec\lambda_{\rm eff},\vec C_{\rm eff}\rangle_{1/2}$ further reduced by fractional dynamic correlation energy contributions from coarse-grained Hamiltonians, and show similar classical-data-input-reduction results for multiscale graph classification via Kron reduction. We also show the online generalization with anisotropic Kalman filtering of streaming quantum data.

The 35-day superorbital modulation of the X-ray binary Her X-1 was systematically investigated using a 35-year multi-instrument X-ray observational baseline. We developed a Rank-Searching method using the peak intensity of the main high state to identify anomalous low states (ALSs) with an objective and reproducible criterion. The method recovers the known ALSs, identifies two previously unrecognized candidate episodes, ALS 1991 and ALS 2015, and independently recovers the recently reported ALS 2025. We then characterized the long-term superorbital phase evolution, identifying seven epochs that alternate between smooth and variable behavior. The smooth component is empirically described by a cubic trend, while the recurrent variable epochs have a characteristic timescale of approximately 3400 days. Within a first-order tilted-disk framework, the secular phase evolution corresponds to an inferred cumulative disk-mass increase of $\sim1.8\%$ and an outer-disk-radius expansion of $\sim0.9\%$, while the short-term phase excursions can be reproduced by disk-mass variations of $\lesssim2.4\%$. A viscous diffusion timescale of approximately 168 days provides a characteristic timescale for the short-term disk response. Finally, the stable phase relation and high profile similarity between the main and short high states indicate that the warped disk maintains a remarkably stable global geometry over the observational baseline.

In neutron-star and dense quantum chromodynamics (QCD) physics, it is important to understand how baryonic matter evolves into quark matter at high density. A continuous hadron–quark crossover is one of the most attractive candidates because it can reconcile the comparatively soft equation of state around nuclear density with the rapid stiffening required to support massive neutron stars. Recent neutron-star observations motivate equations of state that stiffen rapidly across the intermediate-density regime, while quarkyonic-matter descriptions feature a shell-like baryon momentum distribution there. In this paper, we review our recent work on the microscopic description and interpretation of these phenomena by drawing an analogy with the Bose–Einstein condensate (BEC) to Bardeen–Cooper–Schrieffer (BCS) crossover in ultracold Fermi gases and two-color QCD. As pairing fluctuations play a crucial role in the BEC–BCS crossover, we discuss the role of its three-body counterpart, that is, tripling fluctuations associated with baryon formation in the hadron–quark crossover. In terms of a phase-shift representation of tripling fluctuations, the interplay between a three-body bound-state pole and the scattering continuum suppresses low-momentum baryonic occupation, generates a baryonic momentum shell, and reduces the density susceptibility, thereby producing a peak in the speed of sound. We review the demonstration of this mechanism in a one-dimensional three-component Fermi gas, its relativistic extension, and its connection to phenomenological quarkyonic equations of state.

We discover a universal trade-off between the dissipation required to maintain a quantum state more sensitive than a thermal one and the sensitivity gain for a driven single-mode bosonic system under a thermal environment. Specifically, for Gaussian states, we rigorously derive a lower bound on the entropy production rate in the steady state in terms of the quantum Fisher information gain relative to a thermal reference state. Numerical investigations of Kerr nonlinearities further support that these bounds can hold beyond the Gaussian regime. Our results establish a new connection between steady-state thermodynamics and quantum metrological performance.

This letter presents a method to compute fundamental bounds on the total efficiency of pixel antennas. Using semidefinite relaxation, we obtain an upper bound on the optimization problem of maximizing the antenna's total efficiency subject to binary-valued pixel states. The bounds are demonstrated for antennas with varying numbers of pixels and compared with realizable solutions obtained using the genetic algorithm.

In this study, we construct a bayesian holographic QCD model by integrating the Einstein-Maxwell-Dilaton (EMD) framework with lattice quantum chromodynamics (QCD) data at zero chemical potential, specifically entropy, the square of the speed of sound, and baryon number susceptibilities, while systematically incorporating error estimates from the lattice QCD (LQCD) results. Leveraging a bayesian inference framework, we first achieve a precise calibration of the model parameters, then perform a comprehensive investigation into the thermodynamic properties of \((2+1)\)-flavor QCD at both zero and finite chemical potentials, and finally provide a prediction for the location of the critical end point (CEP) in the QCD phase diagram. Our results indicate that, under the maximum a posteriori (MAP) estimation, the CEP is located at $(T, \mu)_{\mathrm{MAP}} = (0.119, 0.615)\mathrm{GeV}$. Furthermore, we provide the predicted regions for the CEP at $68\%$ and $95\%$ confidence levels (CL), yielding $(T, \mu)_{68\% \mathrm{CL}} = (0.1176\text{--}0.1204,0.59\text{--}0.63)\mathrm{GeV}$ and $(T, \mu)_{95\% \mathrm{CL}} = (0.1172\text{--}0.1206,0.58\text{--}0.63)\mathrm{GeV}$, respectively. A thorough comparison with predictions from other theoretical models validates the robustness and predictive power of our approach. This work not only establishes a novel analytical framework for holographic modeling but also provides valuable theoretical insights into the phase transitions of strongly interacting matter under extreme conditions.

Dual resonance reconstructs a scattering amplitude from pole expansions in different channels. We propose analytic dual resonance (ADR), requiring that the complete leading pole sum at an integer resonance admit an absolutely convergent local contour integral. ADR yields one-dimensional pairing relations between residues in arbitrary triangulations. Together with an integer planar spectrum, a joint crossing-spin bound, and complex Regge decay permitting unsubtracted reconstruction, these relations uniquely fix the scalar string amplitude for every $n\ge5$. ADR also predicts higher-dimensional pinch relations, which we examine at five and six points. These results connect the analytic structure of dual resonance to the uniqueness of string interactions.

Spin qubits are an attractive platform for scalable quantum computation, and recently, laterally gated quantum dots (QDs) in Ge heterostructures have emerged as a leading implementation. Radio-frequency (RF) single-hole transistor (SHT) spin readout and integrated superconducting resonator charge readout have demonstrated in Ge QDs, but their wiring overhead and on-chip size can pose challenges, while gate dispersive (GD) readout, which requires less on-chip overhead, has yet to be demonstrated for Ge QDs. Here we demonstrate compact, low-overhead RF-GD charge readout of a Ge double QD (DQD), both directly, and assisted by a proximal single-hole box (SHB). We resolve QD loading and interdot transitions with both techniques. We obtain unity signal-to-noise ratio (SNR) in 2.7 millisecond and 135 microsecond integration time, for gate-dispersive detection of the DQD and SHB-DQD systems, respectively. We find that the SHB enhances the interdot signal-to-noise ratio (SNR) of our 540 MHz circuit by a factor of 20 for a DQD coupling $t_c \approx 5$ GHz. Power and temperature dependent measurements verify that SNR is limited by dielectric loss. We argue that with achievable improvements in dielectric loss and amplification, high-fidelity (99%) readout in less than 1 microsecond should be possible, assuming ideal spin-to-charge conversion, which has seen rapid recent progress. These results establish a simple and compact gate-based readout approach for direct and SHB-enhanced readout of Ge heterostructure QDs.

Distributed quantum processors could scale variational algorithms beyond single devices, but circuit depth, communication overhead, and noise limit their performance. We compare ladder, mixed-canonical, and brick-wall realizations of matrix-product-state (MPS) pretraining with matched per-layer two-qubit-block resources. Despite comparable ideal variational quantum eigensolver performance and gradient scales, the shallower brick-wall architecture reduces circuit duration, idle-time decoherence, and zero-noise-extrapolation (ZNE) overhead, yielding superior noisy and ZNE-assisted performance. We then extend MPS-pretrained circuits to modular processors with one communication qubit per quantum processing unit (QPU); a nearest-neighbor QPU-path schedule keeps the per-layer depth constant as QPUs are added. Distributed circuits whose inter-QPU links realize long-range interactions of the target Hamiltonian match or outperform the single-processor brick-wall under noise when communication idle time is short compared with the coherence time. These results establish hardware-aware co-design of tensor-network pretraining, circuit scheduling, and communication topology as a principle for variational quantum computation on noisy modular hardware.

An important and unresolved problem in the physical sciences is explaining the predictions made by neural networks. Several explainable artificial intelligence (XAI) methods have been proposed to address this problem, including gradient XAI, Integrated Gradients, and GradientSHAP. We evaluate the baseline XAI methods according to four scores: sensitivity (XAI patterns strongly affect predictions), attribution (XAI patterns reproduce the change in prediction relative to a baseline), robustness (XAI patterns remain stable for nearby inputs), and coherence (XAI patterns are spatially smooth). We also introduce a new method, average gradient outer product (AGOP) XAI, that uses global gradient information to identify an important direction for a specific input. We apply XAI to neural network predictions of the El Niño-Southern Oscillation (ENSO) based on data from the Zebiak-Cane model. AGOP XAI achieves the highest attribution, robustness, and coherence scores in the architecture and lead-time comparisons reported here. Its sensitivity is surpassed by gradient XAI, which is maximally sensitive by definition. Beyond diagnosing neural-network behavior, AGOP XAI can generate candidate hypotheses about physical mechanisms. The method highlights an equatorial thermocline-depth signal consistent with recharge oscillator physics, together with a southeastern-Pacific lobe that may be specific to the Zebiak-Cane model. Finally, we test the physical relevance of AGOP using optimized perturbations that move the Zebiak-Cane model along AGOP explanation coordinates. Such perturbations can suppress the selected extreme events or, from a near-neutral ensemble, generate strong El Niño or La Niña events 10 months later.

We consider a cavity quantum electrodynamics (CQED) setup where an ensemble of spin-1 atoms driven by a classical field interacts with two driven cavity field modes. We show that the two sub-systems - the atoms and the two-mode cavity field, exhibit limit-cycle or quantum synchronization depending on the cavity drive strengths and other system parameters. In order to visualize the limit cycle and synchronization in the field, we introduce generalized two-mode field Husimi-Q function using SU(2) coherent states. For atomic spin states, we make use of spin-1 Husimi-Q function to visualize the same. We further corroborate the occurrence of field synchronization and limit cycle by analyzing $U(1)$ symmetry breaking, Wigner quasi-probability distribution, coherence properties of reduced field density matrix. Our results reveal intriguing interplay between the limit-cycle and quantum synchronization behavior, highlighting emergent quantum phenomena in driven dissipative interacting quantum systems. Additionally, we calculate Wehrl mutual information between the two modes and find that the field synchronization and Wehrl mutual information are mutually exclusive. Our study would be important to extract quantum advantages in quantum metrology using coupled atom-cavity systems.