Papers

We show that the standard power-series method described in many textbooks of quantum-mechanics and quantum-chemistry is simpler and more powerful than the wavefunction approach proposed by Ikhdair and Sever [Cent. Eur. J. Phys. 6, 697 (2008)]. As illustrative examples we choose the pseudoharmonic and Kratzer-Fues potentials already treated by those authors.

Finite element analysis (FEA) is essential for structural design but remains computationally expensive, particularly when evaluating multiple design iterations or load scenarios. Machine learning surrogate models offer a promising alternative, yet most approaches struggle with a critical limitation: generalizing across varying geometries. This work presents a mesh graph network (MGN) for predicting von Mises stress fields in 2D structural components with arbitrary hole geometries. Unlike traditional machine learning approaches that use absolute node coordinates as features, the proposed model builds on existing MGN frameworks that encode node types (e.g., fixed boundary, free surface, hole edge), relative edge features (distance between neighbors), and global features (applied load). This architecture is inherently translation- and rotation-invariant, enabling generalization to unseen geometries without retraining. The MGN was trained on 11 plate geometries under 20 load conditions and evaluated on 7 unseen geometries and 3 unseen loads. In the most favorable case, the model achieves $R^2 \geq 0.97$ on an unseen geometry and unseen load, compared to $R^2 \approx 0.01$–$0.86$ for conventional models (Random Forest, Gradient Boosting , K-Nearest Neighbors) trained on identical data. However, even in less favorable cases, the MGN model still outperforms conventional models. This work extends the mesh-based simulation framework of Pfaff et al. (arXiv:2010.03409) to structural mechanics, demonstrating that graph neural networks can serve as efficient surrogates for finite element analysis across varying geometries.

Physical human-robot interaction requires yielding transiently to contact yet recovering the commanded reference under sustained load. Finite-stiffness impedance control retains a static deflection there, while predictive alternatives typically optimize a nonlinear robot or impedance model online. Operational-space cancellation instead exposes a translational error double integrator with a fixed transition matrix and a configuration-scheduled input map, making interaction a predictive quantity rather than a property re-derived per configuration. We build on it a compact offset-free interaction-error MPC for torque-controlled manipulators: a force-domain random-walk state estimates persistent interaction and model error, and a 30-variable convex QP maps the correction through the current task inertia while constraining the applied joint torque. Conditional results establish impedance equivalence of the unconstrained passive feedback, offset-free regulation at feasible frozen configurations, and quadratic stabilizability of the scheduled backbone. In a 1kHz MuJoCo simulation of a 7-DOF Franka FR3, the estimator cuts steady-state error under a repeated 15N step from 2.77mm to 0.042mm when added to the otherwise identical 100Hz MPC. A stiffness-and-damping-calibrated impedance baseline attains 2.59mm but briefly saturates and needs 3.3x the peak positive joint power. Adding ideal measured-force cancellation to that baseline gives 1.39mm, so constant-load rejection is not unique to MPC; the sensorless controller still reaches 0.042mm in the moving task, a 65x reduction without force sensing and without the baseline's saturation or power cost. Demonstrated in simulation under a shared actuator budget, the contribution is an efficient operational-space realization complementing rather than replacing broader interaction-control architectures.

We study the parametric sensitivity of two-dimensional massive Dirac fermions subject to Aharonov-Bohm flux insertion, using the Bures metric (fidelity susceptibility) as the central statistical-mechanical response function. Near integer values of the reduced flux, the low-energy spectrum undergoes a flux-induced avoided crossing whose structure is controlled by the Dirac mass. Through a controlled low-energy projection of the full Dirac=Aharonov-Bohm operator onto an effective two-level subspace, valid near integer flux, we derive an exact closed-form expression for the ground-state Bures metric, which takes a universal Lorentzian profile centered at integer flux with width set by the mass parameter. The peak value scales as $g^{\max}_{\lambda\lambda}\sim m^{-2}$, diverging in the chiral limit in direct analogy with the divergence of thermodynamic susceptibilities near critical points. We introduce an integrated geometric susceptibility $\chi(m) = \pi/(8m)$, whose inverse-mass scaling is the information-geometric counterpart of power-law critical behavior, with the Dirac mass playing the role of a relevant coupling controlling the distance from the chiral fixed point. The Lorentzian profile is shown to arise from the curvature of the ground-state manifold on the Bloch sphere, requiring no dynamical input beyond the spectral structure. Importantly, this geometric response is independent of Berry curvature and topological invariants, emerging instead from a universal local spectral mechanism. Through its spectral representation, the Bures metric is identified as the geometric (paramagnetic) contribution to the persistent current susceptibility, encoding the sensitivity of persistent currents and orbital magnetization to flux variations and connecting information geometry to measurable response functions in mesoscopic Dirac systems.

Quantum reinforcement learning (QRL) is a promising approach to learn effective decision strategies across several applications with stochastic environments. Instead of directly modeling the random variables that govern these environments, existing QRL architectures indirectly approximate environment behavior by estimating expected outcomes, which limits their expressive power and adaptive potential. Overcoming such challenges requires a novel QRL approach that exploits the distributional nature of quantum computers to directly model environment random variables as quantum state distributions. Hence, in this paper, a novel framework dubbed quantum-native reinforcement learning (QnRL) is proposed. QnRL is a distributional RL framework that learns conditional distributions naturally in Hilbert space via superimposed and entangled quantum states. Thus, QnRL can directly model the behavior of stochastic learning environments via the natural properties of quantum systems. QnRL accomplishes this via a novel, proposed quantum amplitude kickback (QuAK) algorithm that enables comparing the $n$-th power of the $m$-th moment of multiple superimposed distributions. It is theoretically proven that a conditional action policy distribution is distilled from the moments of a quantum generative model entirely within Hilbert space via QuAK, and optimized via QnRL. This complex distribution composition is also shown to provide extra dimensions for expressing environment correlations that are unknown to purely classical and classically-sampled quantum distributional models. Experimental results across diverse environments show that QnRL achieves up to $82.9\%$ higher evaluation scores, with up to $94.3\%$ fewer parameters on average, more accurately estimates the expected return for unseen observations, and better adapts to varying stochastic conditions compared to the baseline.

The recent Belle II measurement of $\mathcal{B}(B^+\to K^+\nu\bar{\nu})$, which deviates from the Standard Model prediction, provides a strong motivation to search for New Physics in $b\to s\nu\bar{\nu}$ transitions. We perform a model-independent analysis within the low-energy effective theory, focusing on dimension-six vector operators involving right-handed neutrinos. Using the Belle II measurement of $\mathcal{B}({B\to K\nu\bar{\nu}})$ together with the upper limit on $\mathcal{B}({B\to K^{*}\nu\bar{\nu}})$, we constrain the new physics interactions. We study the correlation of $\mathcal{B}({B\to K\nu\bar{\nu}})$ with $\mathcal{B}({B\to K^{*}\nu\bar{\nu}})$, $\mathcal{B}({B_s\to\phi\nu\bar{\nu}})$, $\mathcal{B}({\Lambda_b\to\Lambda\nu\bar{\nu}})$, and the longitudinal polarization fraction $F_L^{K^*}$. We find sizeable enhancements in all branching fractions studied, while $F_L^{K^*}$ offers complementary sensitivity to the underlying RHN interaction structure. These results provide testable signatures of right-handed neutrino interactions at Belle~II and LHCb, and at the future FCC-ee experiment.

We study high-energy charged-lepton-flavor-violating (cLFV) channels in $e^- \mu^+$ scattering to probe heavy sterile neutrinos, which arise naturally in minimal extensions of the Standard Model. For $\sqrt{s} \le 2M_W$, we consider the process $e^- \mu^+ \to e^+ \mu^-$, which is dominated by one-loop box diagrams. We numerically evaluate these diagrams, involving a high-energy extension of the Inami-Lim functions, and find that the amplitudes are strongly suppressed because of their quartic dependence on light-heavy mixing. Using current bounds on active-sterile neutrino mixing, we determine the maximal rates allowed by existing constraints. For $\sqrt{s} > 2M_W$, we analyze the process $e^- \mu^+ \to W^+ W^-$ and compute the corresponding cross sections in both single-sterile and minimal type-I seesaw scenarios. We find this latter process to be significantly more promising for revealing the presence of heavy sterile neutrinos at $e-\mu$ colliders.

Neutron stars consist of cold, dense, neutron-rich nuclear matter under charge neutrality and $\beta$-equilibrium. In most nuclear equation of state (EOS) studies, the isospin dependence of asymmetric nuclear matter is described using the conventional quadratic/parabolic approximation to the nuclear symmetry energy. However, its validity in the highly neutron-rich inner core of neutron stars remains uncertain. In this work, we systematically investigate the role of higher-order isospin corrections to the symmetry energy within the framework of Skyrme-like effective nuclear interactions. We first analyze the standard SLy4 parametrization and quantify deviations arising from successive higher-order terms in the expansion of the energy per nucleon with respect to the isospin asymmetry parameter. We then extend the analysis to a large population of physically viable Skyrme EOSs sampled over a broad parameter space constrained by conventional nuclear saturation density bounds, thermodynamic stability, and causality, as well as the requirement to support astrophysical neutron-star mass observations exceeding $2\text{M}_{\odot}$. We find that higher-order isospin corrections become increasingly important at supra-nuclear densities and can significantly modify composition-sensitive quantities under $\beta$-equilibrium, including the neutron-proton chemical potential difference, proton fraction, leptonic sector properties, and the direct-Urca process. In contrast, the $\beta$-equilibrated EOS, energy density, pressure, and sound speed remain comparatively insensitive to these corrections for most viable EOSs. Our results demonstrate that while the quadratic approximation captures bulk thermodynamic behavior reasonably well, higher-order isospin contributions play a non-negligible role in determining the detailed composition and microscopic properties of dense matter in neutron-star interiors.

The four-body decay $\Lambda_b^0\to pK^-\pi^+\pi^-$ has led to the first observation of baryonic $CP$ violation. However, the underlying subprocesses $\Lambda_b^0\to N^* M$ and $\Lambda_b^0\to \Lambda^* M$, as well as the roles of excited nucleon ($N^*$) and hyperon ($\Lambda^*$) resonances, remain largely unexplored. Within the constituent quark model, we identify the relevant resonant states contributing to these underlying two-body transitions, including $N(1535)$, $N(1520)$, $\Lambda(1670)$, $\Lambda(1690)$, together with the remaining $1P$-wave baryon states. We obtain the resonant branching fraction ${\cal B}(\Lambda_b^0\to pK^-\pi^+\pi^-) =(30.0^{+2.8+4.0}_{-1.3-3.4}\pm1.8)\times10^{-6}$, while the resulting ${\cal A}_{CP}(\Lambda_b^0\to pK^-\pi^+\pi^-)=(3.18\pm0.11\pm0.13\pm0.11)\%$ provides a natural interpretation of the first observed baryonic $CP$ asymmetry. Our analysis establishes the first comprehensive framework for quantifying the impact of excited baryon resonances in multi-body beauty-baryon decays, with the associated mechanism generally applicable to baryonic $CP$ asymmetries.

Swampland and compactification data tell us where a chosen EFT description can lose parametric control; stochastic cosmology asks which histories survive near that edge. We turn this question into a survival problem for fluctuating moduli over cosmological time scales. Given a valid stochastic generator, hard loss surfaces, soft degradation profiles, and finite horizons define a survival probability, whose logarithm is the survival action. The Doob transform then converts this logarithmic survival cost into the drift of the ensemble conditioned to remain on the controlled side. Near a regular hard boundary with nonzero normal diffusion, the inward normal component of the conditioned response is universal: it is fixed at leading order by the proper distance to the wall and the normal diffusion coefficient. The same finite-horizon construction also determines loss probabilities, first-exit statistics, survival hazards, and the control margin required to retain a prescribed fraction of histories. In this way, tower/species cutoffs, weak-coupling limits, string and Kaluza-Klein thresholds, and carefully qualified potential-based diagnostics acquire stochastic boundary layers without becoming microscopic forces. The inverse map tests when a conditioned drift is compatible with a scalar operational loss surface and reconstructs its boundary-normal Doob class. The construction therefore gives a stochastic survival interface between quantum-gravity control data and the cosmological histories that remain inside the prescribed EFT domain.

We investigate the mechanisms governing particle settling in turbidity currents using Eulerian$\unicode{x2013}$Lagrangian direct numerical simulations. The Eulerian carrier flow is driven either by solutal buoyancy or particle feedback, with the Lagrangian phase comprising passive tracers or inertial particles, respectively. The effective particle settling velocity is decomposed into a fluid velocity sampled at particle positions and a particle-fluid slip velocity. The Eulerian mean profiles of these velocities are obtained using a concentration-weighted average of the coarse-grained fields. The mean sampled fluid velocity is shown to be approximately equal to the ratio of the vertical turbulent flux of particles to their mean concentration and reflects biased sampling of upward turbulent fluctuations at particle positions, despite the zero Eulerian mean vertical fluid velocity. The passive-tracer cases show that the upward bias does not require particle inertia and arises from turbulent transport acting on concentration gradients, as it persists for inhomogeneous tracer seeding but disappears under uniform seeding. For the weakly inertial regime considered here, the upward bias dominates downward-directed biases associated with particle inertia. The mean slip velocity is well approximated by the terminal settling velocity predicted for a quiescent fluid. This is consistent with a leading-order balance between buoyancy and drag in the slope-normal direction. Modelling the sampled fluid velocity from the turbulent flux and using the slip-velocity approximation yield an Eulerian prediction for the settling velocity, in good agreement with the simulation data for the dilute, weakly inertial particles considered.

Quantum Hall isospin ferromagnetism in multilayer graphene offers a versatile playground for exploring flat band correlated physics, driven by the intricate coupling of spin, valley, orbital, and layer degrees of freedom. However, a nanoscale probe capable of simultaneously mapping local conductivity and chemical potential in these exotic phases has yet to be realized. Here, we introduce scanning conductivity and chemical potential microscopy (SCCM), a technique integrating scanning microwave impedance microscopy and Kelvin probe force microscopy. We demonstrate SCCM by probing the quantum Hall states and many-body Landau level energy spectrum in bilayer graphene. Applied to marginally twisted double bilayer graphene, SCCM then reveals a cascade of quantum Hall isospin ferromagnetic states with unexpected re-emergence behaviors. Significantly, experimental many-body Landau level energy spectrum further uncovers the intricate connections of these complex phenomena to inter-subband Landau level crossings and Landau level single-particle wavefunctions. These insights enable the construction of a comprehensive quantum Hall phase diagram. Our results demonstrate SCCM's capability in decoding complex quantum phenomena, establishing it as a versatile nanoscale probe for electron correlation and topology.

Topological states in antiferromagnets (AFMs) offer a promising platform for exploring novel physical phenomena and advancing the applications of AFM spintronics. The AFM topological insulator (TI) state stands out as one of the most representative and prominent cases. Unlike the previously proposed AFM-TI states in noninteracting systems, here we employ an extended Kane-Mele-Hubbard model to demonstrate that electron correlations can give rise to a $\mathcal{PT}$-symmetric AFM-TI state. This state breaks both spatial inversion symmetry $\mathcal{P}$ and time-reversal symmetry $\mathcal{T}$, and enables intrinsic topological nonlinear responses to dominate the leading-order dynamics of the system. The competition between electron correlations and spin-orbit coupling drives the system across a topological phase transition, where the closure of the bulk band gap induces singular behaviors in higher-order quantum geometric tensors. Such microscopic singular characteristics manifest macroscopically as pronounced enhancements in thermoelectric performance, charge conductivity, and thermal conductivity. These giant tunable transport signatures, which can be effectively modulated by mechanical strain and electrostatic gating, provide a feasible experimental route to probe and understand correlated topological materials.

This work presents a semi-analytical framework for analyzing spatially discrete traveling-wave modulated (SDTWM) loop networks, which exhibit cavity-like behavior and support discrete spatiotemporal modes. We introduce a computationally efficient method, based on the Interpath Relation, to analyze periodic networks using a single unit cell. This allows characterization of driven systems with single-tone, multi-tone, and multi-conductor loop configurations. The framework captures both multi-modal and multi-frequency harmonic interactions, and is extended to compute the spatial Green's functions of such loop networks using analytic array scanning. The analysis of example designs, such as an electrically small antenna and a non-magnetic circulator, is presented. These examples confirm that the proposed approach is computationally efficient and offers physical insight, making it well-suited for the optimization of multifunctional and nonreciprocal SDTWM electromagnetic systems.

The observed shift of the $\Delta(1232)$ resonance peak in $\pi$-$p$ femtoscopic correlations challenges the conventional Breit-Wigner description of resonances in femtoscopy. We revisit the Koonin-Pratt framework by formulating femtoscopy in the momentum-space representation. By employing the T-matrix approach to disentangle on-shell and off-shell contributions, we show that the finite spatial extent of the emission source naturally induces sensitivity to off-shell scattering dynamics. Using a Friedrichs-Lee model constrained by low-energy $\pi$-$p$ scattering data, we numerically demonstrate that this off-shell sensitivity leads to a peak shift accompanied by a dip on the high-momentum side of the peak. The predicted high-momentum side dip is absent in the data, pointing to source properties beyond the simple Gaussian approximation.

A well-known model in game theory, the Volunteer's Dilemma describes a group of $n$ players who decide whether to volunteer for a collective benefit at a personal cost, or to abstain and risk forfeiting the benefit altogether. A quantum version of this dilemma, developed within the Eisert-Wilkens-Lewenstein framework, allows each player to manipulate one qubit of a shared entangled state, leading to symmetric Nash equilibria with higher expected payoffs than in the classical game. Existing analyses, however, assume maximal entanglement, which is experimentally demanding for hardware-constrained quantum systems. Within the same framework, we introduce a generalized Quantum Volunteer's Dilemma with a tunable entanglement parameter $\gamma$ and study the extent to which equilibrium behavior depends on the level of entanglement. We derive explicit conditions relating $\gamma$, the number of players, and the players' strategies under which symmetric Nash equilibria exist, focusing on two canonical strategy profiles: one for $2\leq n\leq 9$, and one for even $n$. We find that maximal entanglement is not required to sustain symmetric equilibria. Instead, equilibrium behavior persists above a threshold value, which we compute analytically in both cases. We also demonstrate that the threshold value directly depends on system size.

We investigate the collision dynamics of complex kink solutions in the complex sine-Gordon (CSG) model, focusing on the influence of the relative phase and initial velocity. The model's internal \( U(1) \) symmetry gives rise to a variety of solitary wave solutions, including complex kinks, radiative profiles, and Q-ball configurations. Through numerical simulations, we reveal rich and nontrivial phase-dependent behaviors such as the emergence of red and blue critical speeds, radiative emissions, bion and breather formations, and phase-sensitive oscillation modes. Moreover, we identify extreme values in energy and field quantities at the collision point, uncovering discontinuities that signify transition thresholds in the dynamical system. These findings underscore the complex interplay between internal degrees of freedom and dynamical variables in non-integrable soliton systems, offering new insights into field theories with internal symmetries.

Gravitational-waves from astrophysical sources are characterized by their extreme faintness, which remains a primary obstacle for both current and next generation detectors. While rotating black holes dressed in superradiant clouds of ultralight bosons are recognized as promising probes of physics beyond the Standard Model, their capacity to actively emit and modulate gravitational radiation remains largely unexamined. Here we demonstrate that these gravitational atoms can function as natural amplifiers of gravitational-waves via a stimulated emission mechanism analogous to astrophysical masers. By formalizing the interaction between the bosonic cloud and an ambient stochastic gravitational-wave background, we establish the rigorous selection rules and threshold conditions that govern this amplification. Our analysis reveals that the emission rate depends critically on the boson mass, potentially yielding an enhancement of several orders of magnitude over spontaneous processes. For representative mass ranges, these amplified signals bridge the sensitivity gap between ground-based interferometers and pulsar timing arrays. These findings suggest that superradiant clouds can effectively boost previously undetectable signals, offering a novel observational frontier for exploring ultralight fields and the Kerr spacetime environment.

In this paper the Clifford groups of general multipartite quantum systems with configuration space $\mathbb{Z}_{n_1}\oplus\cdots\oplus\mathbb{Z}_{n_k}$, $k\geq 1$ are studied. It is known that the Clifford group is a natural semidirect product provided the dimension $N=n_1\cdots n_k$ of the corresponding Hilbert space is an odd number. For even $N$ special results on the Clifford groups are scattered in the mathematical literature, but they do not concern the semidirect product structure. Using the relation of generators of the associated symplectic group $\mathrm{Sp}_{[n_1,\dots,n_k]}$ we prove that for even $N=n_1\cdots n_k$ both Clifford group and the projective Clifford group are natural semidirect products if and only if $N$ is not divisible by four.

The so called Harada gravity with non conserved energy-momentum tensor is here taken into account. It includes Rastall gravity as a special case. The field equations are written as Einstein equations where the source is supplemented by a divergence-free conformal Killing tensor and a tensor proportional to the metric, linear in the scalar curvature and the trace of the energy-momentum tensor. These terms can be natural candidates for dark sector and give rise to a coupling of the dark sector with the matter content. The field equations are the conformal Killing extension of Rastall gravity, and include Unimodular gravity. In a Friedmann-Robertson-Walker background, the Cosmic Microwave Background restricts parameters so that the dark sector only couples with the trace of the energy-momentum tensor. The explicit form of the tensor for the dark sector is found, and the Friedmann and continuity equations are presented, with a standard cosmological analysis. The sum of energy-momentum tensors of dust matter and of dark fluid is conserved, and the dust energy density evolves with the scale function with exponent -3/(1+tau), modified by the coupling tau with the dark fluid.

Most statistical and machine learning methods for directed interactions focus on pairwise effects among variables. Even existing cyclic models represent feedback primarily through node-level dependencies, making large-scale recurrent organization difficult to estimate and compare. This limitation is particularly acute in biological and neural systems, where interactions are highly recurrent and involve many overlapping cycles. We introduce a variational framework for statistical inference on cyclic interactions. Directed interactions are represented as edge flows on a simplicial complex and evolved under an energy-minimizing dynamical system. The resulting dynamics separate transient interaction components from persistent harmonic flows, yielding a low-dimensional cycle space that captures stable recurrent organization. Rather than enumerating individual cycles, the proposed framework represents cyclic interactions as elements of a Hilbert space, enabling projection, averaging, comparison, and population-level statistical inference. We establish theoretical properties of the harmonic projection, including characterization of the cycle space, variance reduction, and population inference. Simulations demonstrate substantially improved recovery of cyclic structure in dense recurrent systems compared with existing directed-interaction methods. Applied to resting-state fMRI from 400 human subjects, the framework reveals reproducible large-scale cyclic organization that is not detectable through edgewise averaging. These results provide a scalable statistical framework for studying recurrent interactions in high-dimensional dynamical systems.

The interaction between turbulent flows and bubbles is a complex phenomenon ubiquitous in natural and industrial settings. In this work, we experimentally investigate, from a fundamental perspective, the interaction between a rising bubble and a vortex ring in counterflow. Using time-resolved three-dimensional Lagrangian Particle Tracking (4D-LPT) coupled with shadowgraphy, we obtain simultaneous measurements of the bubble motion and the surrounding liquid flow. This approach enables detailed observation of bubble dynamics, deformation, and eventual breakup, as well as the fluid motion. We examine several flow configurations by varying the vortex circulation and the Weber number while maintaining a comparable vortex-to-bubble size ratio. Based on these measurements, we classify the interaction events into three categories according to their impact on bubble dynamics and vortex stability over time. Through experiments, we address for the first time the three-dimensional effects of these interactions, which had not been considered in previous studies. The analysed experiments comprise: Case I, corresponding to a weak interaction in which neither the bubble nor the vortex is significantly affected; Case II, where the bubble is captured and advected by the vortex, leading to a strong distortion of the vortex due to the presence of the bubble within its core; and Case III, involving a stronger vortex capable of capturing the bubble and breaking it into two fragments without a severe loss of energy in the vortex core. The analysis of these results provides insight into the bubble breakup process and the mechanisms responsible for the destabilisation of the vortex ring.

We study conserved worldsheet charges associated with spacetime supersymmetry in heterotic pure-spinor superstrings on curved ten-dimensional superspace backgrounds. Requiring BRST invariance and worldsheet conservation gives a covariant set of superspace constraints. In flat superspace these conditions reproduce the standard ten-dimensional supersymmetry generator. In curved superspace, they organize the requirements for global supersymmetry in terms of a normalizable spinor superfield.

We prove that every rank-2 bipartite entangled state is already steerable with projective measurements, closing the first possible gap between entanglement and Einstein-Podolsky-Rosen (EPR) steering. In arbitrary finite local dimensions, any rank-2 entangled state is projectively steerable in at least one direction; when the effective dimensions are equal, steering is two-way. The argument is geometric: a rank obstruction forces some projective outcome on the larger local system to reach the boundary of the trusted-state space. From this boundary contact, a neighboring measurement produces a linear displacement that cannot be reproduced by a local-hidden-state model, because positivity only permits a quadratic filling into a kernel direction. This same block witnesses partial-transpose entanglement. If the contact is degenerate, a Schur complement removes one product layer and reduces the problem to a lower-rank entangled residual; each such reduction lowers the rank, so the recursion terminates. More broadly, we derive a directional rank criterion: if an $m\otimes n$ entangled state $\rho$ satisfies $\rank\rho\le 1+\lfloor(m-1)/(n-1)\rfloor$, then it is projectively steerable from $A$ to $B$. Since counterexamples already occur at rank three, rank two is the unique mixed rank for which entanglement guarantees projective steering, and the proof provides an operational certificate based solely on the support and kernel of the density matrix.

We extended the higher-dimensional quantum Oppenheimer-Snyder model to the case with a cosmological constant. For AdS case, we discuss its thermodynamic properties in extend phase space formalism and make comparison with classical black holes. For quantum-corrected small black holes in AdS spacetime, the temperature no longer diverges but tends to zero. Additionally, the heat capacity exhibits characteristic behavior indicative of an extra phase transition induced by quantum corrections, highlighting the profound impact of quantum effects on black hole thermodynamics.

Triple-layer cuprate superconductor $\mathrm{HgBa_2Ca_2Cu_3O_8}$ (Hg1223) keeps the record of the highest superconducting (SC) critical temperature $T_{c}\sim 134$K among all the existing materials at ambient pressure. $T_{c}$ further increases under pressure up to $T_{c}\sim 160$K. However, its microscopic mechanism remains to be elucidated. We solve ab initio Hamiltonians for Hg1223 using a variational solver supplemented by a neural network. The pressure dependence of the $d$-wave SC order parameter and estimated $T_{c}$ show a $T_{\mathrm{c}}$ peak around 30GPa in quantitative agreement with the experiments. The origin of the strong SC amplitude at ambient pressure is identified as strong local Coulomb repulsion $U$ attributed to poor screening. Further increase in $T_{c}$ under pressure is understood from interplay of three elements, namely increased electron hopping $t$, decreased $U$ and more importantly, strongly reduced offsite Coulomb repulsion $V$ with increasing pressure. Pairing mechanism is identified as the emergent local attraction counterintuitively generated from the originally strong local repulsion $U$. The emergent attraction is interpreted from “attraction from reduced repulsion”, originating from the release of the fluctuating doubly-occupied sites characterized from the “false vacuum” in the Mott insulator to the double-occupation-free $d$-wave SC states upon carrier doping. This instantaneous attraction is in contrast with the conventional BCS SC mediated by bosonic glues. The local attraction is consistent with the electron fractionalization supported in experimental analyses. The coexistence of the SC and antiferromagnetic order is also demonstrated as a characteristic feature of the multilayer system. The microscopic understanding of Hg1223 offers a new route explicitly using this emergent attraction to design and optimize SC materials.

We present pre-perihelion observations of methanol, carbon monoxide, and hydrogen cyanide in the Oort cloud comet C/2017 K2 (PANSTARRS), performed with the APEX 12-m and Onsala 20-m telescopes from April to July 2022. As the comets heliocentric distance decreased from 3.4 to 2.7 AU, CH3OH line intensities increased substantially (by factors of 1.1-4.0), with the most pronounced enhancement in lines with the upper-level energies Eu > 40K. In contrast, the brightness of the CO and HCN lines remained constant. We estimate the best-fit gas kinetic temperatures Tgas > 100 K and water production rate of Q(H2O)=(3-10)*10(28) 1/s. The derived methanol-to-water abundance ratio approx. 0.01-0.04, depending on the observed period. Our results demonstrate that non-LTE effects are dominant in the coma and must be accounted for to accurately derive molecular production rates. We also report weak non-thermal excitation, including potential maser activity in the CH3OH 8(0)-7(1) line.

Liquid-gas equilibrium is described using a pair of Ising-like thermodynamic variables. The first is a combination of density and energy fields that is even under phase coexistence, derived from the Gibbs-Duhem and Clausius-Clapeyron relations. The second is the normalized density deviation $M=\rho/\rho_d-1$, which distinguishes the coexisting phases and serves as an odd ordering variable. Combining these variables with the empirical linearities of the binodal diameter and the Zeno line leads to a projective mapping between continuum-fluid and lattice-gas states. The implications of such mapping are tested against coexistence-density and saturation pressure data for the two-dimensional Lennard-Jones fluid, as well as physisorbed molecular monolayers of simple molecular fluids like argon and methane. Finally, a heuristic microscopic interaction-variable formulation that motivates continuous fluids versus lattice model description is also discussed.

We present a review of theoretical studies of the structure and reactions of N=7 and N=8 nuclei in the vicinity of 11Li, carried out within a framework based on Nuclear Field Theory. The coupling of valence nucleons to low-lying surface vibrations of the spherical core plays a central role, giving rise to self-energy processes that renormalize single-particle states and transfer form factors, as well as to an induced pairing interaction arising from the exchange of collective vibrations, which renormalizes the bare pairing force. Excitation spectra and cross sections for one- and two-nucleon transfer reactions populating states in the quasi-continuum are calculated and compared with available experimental data. Collective excitations in the particle-particle channel are investigated, with particular emphasis on Giant Pairing Vibrations and on their damping mechanisms arising from coupling to more complex configurations and continuum states. Comparisons with other theoretical schemes are also presented. We conclude that a coherent understanding of experimental data requires the detailed consideration of particle-vibration coupling effects.

In this article, the surface tension and stability of quark matter modified by the vector interaction in a strong magnetic field are investigated in the quasiparticle model with the multiple reflection expansion. The self-consistent thermodynamic treatment of the chemical-potential-dependent quark mass is maintained by the effective bag function, which depends on both the chemical potential and the magnetic field. It is found that the vector interaction could enlarge the surface tension in both the parallel and transverse directions with respect to the magnetic field. In a stronger magnetic field region, the presence of the vector repulsive interaction leads to an increase in transverse surface tension with the magnetic field strength, which is opposite to the vanishing value without repulsive interaction in the previous work. Consequently, it is concluded that a moderate-intensity magnetic field is required for the formation of a quark matter bubble with the vector interaction. Finally, it is demonstrated that the vector interaction slightly reduces the stability of quark matter.