Since the discovery of charge density wave (CDW) and superconductivity, kagome metal ${\mathrm{AV}}_3{\mathrm{Sb}}_5$ ($\mathrm{A}=\mathrm{K}$, Rb, Cs) provides a new platform for exploring novel many-body quantum phenomena. In ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$, a stripelike CDW with commensurate wave vector $q=3/8$ was observed under moderate pressures, which leads to a peculiar superconducting double-dome behavior in pressure-dependent phase diagram. Previous density functional theory (DFT) calculations indicate that the pressure-induced stripelike CDW is beyond conventional phonon softening scenario, suggesting a nontrivial role of electronic correlations. However, an in-depth understanding for the pressure-induced unconventional CDW remains elusive. Here, we performed pressure-dependent ${}^{51}\mathrm{V}$ nuclear magnetic resonance (NMR) measurements on ${\mathrm{KV}}_3{\mathrm{Sb}}_5$ and ${\mathrm{RbV}}_3{\mathrm{Sb}}_5$. Although the superconducting double-dome behavior is absent in pressurized ${\mathrm{KV}}_3{\mathrm{Sb}}_5$ and ${\mathrm{RbV}}_3{\mathrm{Sb}}_5$, a pressure-induced CDW phase, ascribed to a possible incommensurate triple-$Q$ CDW, is identified by NMR spectra in both materials, indicating that the pressure-induced unconventional CDW beyond DFT calculations is a common feature for kagome metal ${\mathrm{AV}}_3{\mathrm{Sb}}_5$. In contrast to the stripelike CDW, the pressure-induced incommensurate triple-$Q$ CDW does not strongly suppress the superconducting temperature ($T_{\mathit{c}}$) but coincides with an almost plateau behavior at intermediate pressure regime in the pressure-dependent superconducting phase diagram. Furthermore, by systematically analyzing the Korringa relation between Knight shift and nuclear spin-lattice relaxation rate in ${\mathrm{AV}}_3{\mathrm{Sb}}_5$, Van Hove singularity-driven electronic fluctuations are revealed as an effective knob for the pressure-induced unconventional CDW. Finally, our present findings underscore the pressure-induced unconventional CDW as a novel correlated quantum state in kagome metal ${\mathrm{AV}}_3{\mathrm{Sb}}_5$.

Recent experiments [Phys. Rev. B 109, 245123 (2024)] revealed striking inverse-current ($1/I$) quantum oscillations in quasi-one-dimensional charge-density-wave (CDW) insulators and proposed an intrinsic Floquet sideband mechanism arising from the sliding condensate. Here, we develop the complete theoretical framework underlying this proposal. We provide an exact Floquet diagonalization of the uniformly sliding CDW problem, yielding split gap edges and a ladder of Floquet sidebands with explicit unitary transformation and spectral functions. Using this exact solution, we formulate weak-probe tunneling spectroscopy and demonstrate that the local Floquet spectrum naturally yields $1/I$ oscillations as successive sideband edges cross a fixed contact chemical potential. The measured period fixes $N_{\mathrm{eff}}\epsilon \simeq 4.80\mathrm{eV}$, where $\epsilon$ is the local contact-to-gap-edge offset. Combining this relation with the experimentally resolved low-temperature oscillations constrains the effective coherent channel count to be at most of order ${10}^3$, far below the geometric estimate $N_{\mathrm{geom}}\sim 3\times {10}^4$, while $\epsilon =10\mathrm{meV}$ gives the representative value $N_{\mathrm{eff}}\simeq 480$. This reduced coherent scale is naturally realized by a spatially nonuniform percolating network, but does not require $N_{\mathrm{eff}}$ independent end-to-end wires. Furthermore, using a segmented multiterminal model, we show that inelastic phase-slip dephasing near the contacts explains the experimentally observed suppression of oscillation visibility on outer voltage probes. Finally, we contrast the persistent-current-driven multiterminal geometry with a homogeneous voltage-biased two-terminal reference calculation. Our results establish a nonequilibrium transport framework for the observed $1/I$ oscillations and identify an observability condition in which the Floquet spacing must exceed collective and quasiparticle broadening.

Human behaviors, particularly nonpharmaceutical interventions (NPIs), are dynamically coupled with epidemic spreading. However, most models assume a linear relationship between perceived risk and infection rates, failing to capture the nonlinear nature of real-world behavioral responses. Here, we propose a behavioral epidemic model by incorporating nonlinear feedback and social influence, and analytically derive its critical thresholds. Notably, once the infection rate exceeds a critical threshold, the fraction of NPI adopters abruptly drops to zero, in contrast to classic findings in linear models. This paradoxical decline indicates a social dilemma: While abandoning NPIs is individually optimal at high infection rates, it collectively triggers an explosive epidemic surge. Furthermore, as the intensity of social influence increases, the system undergoes a Hopf bifurcation leading to periodic oscillations, which reflects a vicious cycle of recurrent epidemic waves. Finally, we confirm the robustness of this NPI-abandonment dilemma in networked populations. Our work illustrates rich emergent dynamics, challenging traditional perspectives on behavioral epidemiology.

We introduce a two-dimensional model of spin-$1/2$ Dirac fermions in graphene subjected to a highly tunable electric field, which exhibits super-Klein tunneling. The electric field can be continuously interpolated between two limiting configurations: a uniform electrostatic Lorentzian barrier with translational invariance and a chain of well-separated electrostatic scatterers. We demonstrate that super-Klein tunneling arises naturally as a direct consequence of the intrinsic connection of the model to free-particle dynamics, a relation that is established through methods of supersymmetric quantum mechanics, which provide an elegant and analytically tractable framework. Besides the mentioned super-Klein tunneling, scale invariance of the model and invisibility of the potential for particles of specific energy are revealed, and possible routes toward experimental realization are discussed.

We study a ${\mathbb{Z}}_3$-symmetric Rabi model that describes a three-level system coupled to two bosonic modes. We derive a mapping of the two-mode ${\mathbb{Z}}_3$ Rabi model onto a qubit-boson ring. This mapping allows us to formulate a realistic implementation of the ${\mathbb{Z}}_3$ Rabi model based on superconducting qubits. It also provides context for the previously proposed optomechanical implementation of the ${\mathbb{Z}}_3$ Rabi model. In addition, we propose a physical implementation of the ${\mathbb{Z}}_3$ Potts model via a coupled chain of ${\mathbb{Z}}_3$ Rabi models.

We present a technique to observe the optical manipulation of individual quantum states of ${\mathrm{H}}_3^{+}$ ions stored inside a heavy-ion storage ring, where the excitation is detected by electron-beam-assisted action spectroscopy. The transitions addressed here are chosen to enable multicolor spectroscopy of states far above the energetic barrier, where this molecule—with a triangular ground state—can sample linear geometries. This region of the spectrum has so far been inaccessible due to extremely weak direct transition strengths from the ground vibrational level. Our experiments pave the way for spectroscopy of the simplest polyatomic molecule in a previously unexplored energetic territory, which would benchmark theoretical data crucial for the understanding of this fundamental molecular system. Our results also demonstrate laser pumping to vibrationally and rotationally excited states of ${\mathrm{H}}_3^{+}$, gaining model-dependent access to their relative dissociative electron recombination rates.

The emerging field of quantum magnonics seeks to understand and harness the quantum properties of magnons—quantized collective spin excitations in magnets. Squeezed magnon states arise naturally as the equilibrium ground states of anisotropic ferromagnets and antiferromagnets, representing an important class of nonclassical magnon states. In this work, we show how a qubit-conditioned quantum quench of an anisotropic ferromagnet can be used for Heisenberg-limited parameter estimation based on measurements of the qubit only. In the presence of ground-state squeezing, the protocol yields information about the eigenmode frequency of the coupled magnon-qubit system, whereas no information is gained in the absence of such squeezing. The protocol therefore leverages genuine quantum correlations in the form of magnonic squeezing while simultaneously relying on the equilibrium character of this squeezing—a feature distinctive to magnetic systems.

Spin shuttling has crystalized as a powerful and promising tool for establishing intermediate-range connectivity in semiconductor spin-qubit devices. Although experimental demonstrations have performed exceptionally well on different materials platforms, the question of how to handle areas of low valley splitting in silicon during shuttling remains unresolved. In this work, we explore the possibility of utilizing the valley degree of freedom, particularly in regions of low valley splitting, to allow mobile spin qubits to be shuttled through an occupied stationary quantum dot, thereby leapfrogging over the stationary electron. This not only grants a more enriched mobility for shuttled electrons, as it opens new possible routing paths, but also enables the implementation of an entangling swap${}^{\gamma }$ two-qubit gate operation in the process. Simulating this process for different sets of parameters, we demonstrate the feasibility of such an operation and offer a unique use case for otherwise precarious regions of a quantum processor chip and propose a possible extension to the set of possible operations for silicon spin-qubit devices.

We numerically investigate how particle surface roughness affects the static and dynamic properties of a hard-particle fluid across a wide range of densities, $\rho$. These simulations of a simple model of granular systems reveal that, although the amplitude and coverage of surface corrugation significantly influence the $\rho$ dependence of system properties, the qualitative behavior of this dependence remains unchanged. These findings can be described quantitatively by introducing an effective particle size, which enables a direct mapping of the rough particle systems to equivalent hard-disk systems. Analytical calculations provide an explicit form of this mapping and allow us to predict the static and dynamic properties of rough particles using standard liquid-state theories for hard disks.

An avoided crossing is a familiar spectral signature of interaction between nearby modes, but the eigenvalue trajectory alone does not establish whether their modal identities are exchanged. We examine this question in a deformed microwave billiard by comparing finite element eigenvalues and fields. Across 21 screened adjacent level events, the spectral slope is compared with the boundary response obtained from the fields at the event center. For the 11 events whose rotation width can be resolved within the sampled interval, the boundary-derived and overlap-derived widths agree to within about 11%. One event behaves differently: The spectral model predicts substantial modal rotation, while the computed fields change very little and are instead reproduced by the boundary response. Another event shows that the mode that improves the eigenvalue model is not the mode that best restores the field subspace. Spectral repulsion alone is therefore not sufficient to determine modal exchange or the reference subspace required over a finite parameter range.

Biomolecular machines operate as stochastic flows on networks. Here, we develop a principled approach to network design where local transition rates are systematically tuned to achieve global dynamical objectives. Based on the fluctuation-response duality in caliber force theory, our formalism unifies existing nonequilibrium response relations under a single conjugate structure. Topologically, a force-rate Jacobian yields response symmetries that establish a local orthogonal control protocol for network flows. Analytically, it parses covariance to diagnose noise mechanisms, revealing the transition from timing to branching fluctuations in a kinesin motor. With algebraic closure streamlining multiobjective gradient evaluations, this framework provides a unified blueprint for designing stochastic dynamics.

We derive the characteristic equation governing the linear stability of the incoherent state in delayed noisy Kuramoto-Daido oscillator ensembles with general periodic coupling. The calculation is formulated for arbitrary normalized delay kernels and natural-frequency distributions. For a Lorentzian frequency distribution and first-harmonic coupling, the characteristic equation reduces to a closed dispersion relation in which phase diffusion and frequency heterogeneity enter through the damping combination $D+\mathrm{\Delta }$, while the delay kernel enters through its Laplace transform. The neutral conditions recover the established fixed- and distributed-delay limits and are evaluated explicitly for Gamma-distributed delays. We then derive the reduced phase dynamics of an overdamped Josephson-junction array coupled through a delayed common load. A finite-dc-load admittance produces a uniform drift that corresponds to the constant Fourier component of the reduced coupling function. When the ac coupling and dc-induced drift vary with the same load parameter, the resulting effective-frequency shift displaces the neutral stability boundary. Finite-$N$ simulations of the reduced phase equations agree with the continuum prediction over the parameter range considered.

Microscopic heat engines operate in regimes where thermodynamic quantities fluctuate strongly, making stochastic effects an essential aspect of their performance. However, existing geometric formulations of finite-time thermodynamics primarily characterize average dissipation and do not systematically capture its fluctuations. Here, we develop a unified geometric framework that consistently describes both the mean dissipated availability and its fluctuations. In the linear-response regime, we show that these quantities are governed by metric tensors constructed from equilibrium correlation functions, providing a common geometric structure for dissipation and its fluctuations. This framework yields geometric bounds on both the mean and variance of the dissipated availability, and thereby on the efficiency and its fluctuations. The formalism applies broadly to stochastic systems, including Markov jump processes and overdamped and underdamped Brownian dynamics, establishing a unified geometric description across microscopic heat engines.

We investigate the performance of large language models (LLMs) on repetitive deterministic prediction tasks and study how the sequence accuracy rate (SAR) scales with output length. Each such task involves the repetition of the same operation $N$ times. Examples of such tasks include letter replacement in letter strings following a given rule, integer addition, and multiplication of string operators in many-body quantum mechanics. If the LLM performs the task by a simple repetition algorithm, the success rate would follow an exponential decay with sequence length. In contrast, our experiments on leading LLMs reveal a crossover that is sharper than exponential: $-log\mathrm{SAR}$ grows superlinearly with $N$, and accuracy collapses around a characteristic length $N_{*}$, the accuracy cliff that separates reliable from unreliable generation. The hypothesis of independent per-step errors is rejected for every model and task we studied. The crossover is well described by a double-exponential accumulation law, $\mathrm{SAR}=exp(-{\beta }_{0}N{\alpha }^{N-1})$, whose crossover scale $N_{*}$ does not depend on the functional form chosen to fit it. To interpret this behavior, we introduce a minimal effective model in which step-correctness variables interact through dense random couplings and compete with an external field set by the prompt. Solved by direct enumeration, the model reproduces the superlinear error accumulation and the accuracy cliff qualitatively, and it assigns to each model-task pair two interpretable parameters, an intrinsic error rate and an error-accumulation factor.

We investigate how quantum correlations in squeezed driving fields determine scaling laws in dissipative multiphoton quantum sensing. Independently squeezed fields yield factorized scaling, with separate absorption and emission contributions and nonlinear thresholds that suppress exponential scaling in linear processes. In contrast, jointly squeezed fields generate collective scaling governed by the total nonlinear photon order of the dissipative interaction. Remarkably, we show that normally ordered observables do not inherit the full nonlinear scaling of the underlying multiphoton fluctuations. Instead, they exhibit asymptotic behavior with an effective nonlinear order reduced by one. This arises because normally ordered observables probe only part of the underlying multiphoton fluctuation structure. These findings reveal how multiphoton fluctuations, quantum correlations, and measurement structure jointly determine the experimentally accessible sensitivity of nonlinear dissipative quantum sensors and establish design principles for quantum sensing protocols based on structured squeezed light.

Using both simulation and experiment, we investigate the robustness of dynamical decoupling sequences to pulse errors: rotation errors and detuning errors. Whereas prior work examined the effect of errors on coherence times, here we show that quantum sensing can be affected by pulse errors in dramatically different ways than coherence times alone. We also explore the effects of qubit leakage: off-resonant coupling to other quantum levels. We find order-of-magnitude differences between commonly used dynamical decoupling sequences in both their sensitivity to pulse errors and leakage.

Scattering theory has long established that wave packets can experience time delays and advances, while developments in attosecond interferometry have made such temporal shifts experimentally accessible. They are encoded in the spectral phase of the emitted electron wave packet and are commonly accessed through interferometric techniques. Here, we report an intensity-driven reversal of the angular phase of a threshold photoelectron sideband in helium. By varying the intensity of an infrared dressing field, we control the direction of the phase change at large emission angles, which is associated with interference between partial waves near angular nodes. Solving the time-dependent Schrödinger equation within the single-active-electron approximation confirms the existence of an angular phase inversion. Our results reveal a mechanism for manipulating the angular phase structure of photoelectron wave packets over a large range via laser-induced interference.