Recent THz-pump second-harmonic-generation (SHG) probe measurements of quantum paraelectrics observed a significant long-lived nonoscillatory SHG component following an ultrafast resonant excitation of the soft mode, which was interpreted as a signature of THz-induced transient ferroelectric order. We propose that the THz-induced modulation of the SHG signal can be attributed solely to the dynamic variation of the dielectric environment associated with the lattice background, which reflects the coherent response of soft mode under THz pumping. We develop a temperature-dependent dynamic model incorporating the hot-phonon effect to simulate the soft-mode behaviors under ultrafast THz excitation. Its application to paraelectric ${\mathrm{KTaO}}_3$ produces quantitatively most of the features exhibited in our time-resolved SHG measurements and those in existing literature, including a long-lived nonoscillatory SHG response, SHG oscillations at twice the soft-mode frequency, SHG dampings, and temperature and field-strength dependencies. We conclude that the observed THz-induced nonoscillatory SHG response in quantum paraelectrics is a consequence of the nonequilibrium hot-phonon effect, offering an alternative to its existing interpretation as a signature of transient ferroelectric order.

Biological transport networks are highly optimized structures that ensure power-efficient distribution of fluids across various domains, including animal vasculature and plant venation. Theoretically, these networks can be described as space-embedded graphs, and rich structures that align well with observations emerge from optimizing their hydrodynamic energy dissipation. Studies on these models typically use regular grids and focus solely on edge width optimization. Here, we present a generalization of the hydrodynamic graph model that permits additional optimization of node positioning. We achieve this by defining sink regions, accounting for the energy dissipation of delivery within these areas, and optimizing by means of differentiable physics. In the context of leaf venation patterns, our method results in organic networks that adapt to irregularities of boundaries and node misalignment, as well as overall improved efficiency. We study the dependency of the emergent network structures on the capillary delivery conductivity and identify a transition in which the network collapses above a critical threshold. Our findings provide insights into the early formation of biological systems and the efficient construction of transport networks.

We study a nonstabilizerness resource theory for operators, which is dual to that describing states. We identify that the stabilizer Rényi entropy analog in operator space is a good magic monotone satisfying the usual conditions while inheriting efficient computability properties and providing a tight lower bound to the minimum number of non-Clifford gates in a circuit. Operationally, this measure quantifies how well an operator can be approximated by one with only a few Pauli strings—analogous to how entanglement entropy relates to tensor-network truncation. A notable advantage of operator stabilizer entropies is their inherent locality, as captured by a Lieb-Robinson bound. This feature makes them particularly suited for studying local dynamical magic resource generation in many-body systems. We compute this quantity analytically in two distinct regimes. First, we show that under random evolution, operator magic typically reaches near-maximal value for all Rényi indices, and we evaluate the Page correction. Second, harnessing both dual unitarity and ZX graphical calculus, we solve the operator stabilizer entropy for interacting integrable XXZ circuit, finding that it quickly saturates to a constant value. Overall, this measure sheds light on the structural properties of many-body nonstabilizerness generation and can inspire Clifford-assisted tensor network methods.

Three-qubit gates can be constructed using combinations of single-qubit and two-qubit gates, making their independent realization unnecessary. However, direct implementation of three-qubit gates reduces the depth of quantum circuits, streamlines quantum programming, and facilitates efficient circuit optimization, thereby enhancing overall performance in quantum computation. In this work, we propose and experimentally demonstrate a high-fidelity scheme for implementing a three-qubit controlled-controlled-z (ccz) gate in a flip-chip superconducting quantum processor with tunable couplers. This direct ccz gate is implemented by simultaneously leveraging two tunable couplers interspersed between three qubits to enable three-qubit interactions, achieving an average final state fidelity of 97.94% and a process fidelity of 93.54%. This high fidelity cannot be achieved through a simple combination of single- and two-qubit gate sequences from processors with similar performance levels. Our experiments also verify that multilayer direct implementation of the ccz gate exhibits lower leakage compared to decomposed gate approaches. As a showcase, we utilize the ccz gate as an oracle to implement the Grover search algorithm on three qubits, demonstrating high performance with the target probability amplitude significantly enhanced after two iterations. These results highlight the advantage of our approach, and facilitate the implementation of complex quantum circuits.

The first observation of the ${\mathrm{\Sigma }}^{+}\to p{\mu }^{+}{\mu }^{-}$ decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$, collected with the LHCb detector at a center-of-mass energy of 13 TeV. A yield of $237\pm 16{\mathrm{\Sigma }}^{+}\to p{\mu }^{+}{\mu }^{-}$ decays is obtained, where the uncertainty is statistical only. A branching fraction of $(1.08\pm 0.17)\times {10}^{-8}$ is measured, where the uncertainty includes statistical and systematic sources. No evidence of resonant structures is found in the dimuon invariant-mass distribution. All results are compatible with standard model expectations. This represents the rarest decay of a baryon ever observed.

We study the temporal, driven-dissipative dynamics of open photon Bose-Einstein condensates (BEC) in a dye-filled microcavity, taking the condensate amplitude and the noncondensed fluctuations into account on the same footing by means of a cumulant expansion within the Lindblad formalism. The fluctuations fundamentally alter the dynamics in that the BEC always dephases to zero for a sufficiently long time. However, a ghost attractor, although outside of the physically accessible configuration space, attracts the dynamics and leads to a plateaulike stabilization of the BEC for an exponentially long time, consistent with experiments. We also show that the photon BEC and the lasing state are separated by a true phase transition, since they are characterized by different fixed points. The ghost-attractor nonequilibrium stabilization mechanism is an alternative to prethermalization and may possibly be realized on other dynamical platforms as well.

We investigate the multipartite mutual information between $N$ discrete-state stochastic units interacting in a network that is invariant under unit permutations. We show that, when the system relaxes to fixed point attractors, multipartite correlations in the stationary state either do not scale extensively with $N$ or the extensive scaling is not robust to arbitrarily small perturbations of the system dynamics. In particular, robust extensive scaling cannot occur in thermodynamic equilibrium. In contrast, mutual information scales extensively when the system relaxes to time-dependent attractors (e.g., limit cycles), which can occur only far from equilibrium. This demonstrates the essential role of dissipation in the generation and maintenance of multipartite correlations. We illustrate our theory with the nonequilibrium Potts model.

The complex two-step yielding observed in some soft materials under oscillatory shearing is shown to result from two independent phenomena. The first step at small deformations corresponds to elastic softening, while the larger deformation feature corresponds to yielding. This interpretation is supported by experimental recovery rheology data and the construction of a rheo-physical model. Our findings elucidate the mechanisms governing complex yielding and underscore the insight afforded by recovery experiments, which decouple the underlying physics between recoverable and unrecoverable processes.

We propose to employ the amplification mechanism of Grover’s search algorithm to efficiently prepare entangled states of an ensemble of qubits. The conditional change of sign employed in the algorithm can be implemented by the phase shift of photons scattered on an optical cavity hosting an atomic ensemble. We show that collective Dicke states, Greenberger-Horne-Zeilinger states, and Schrödinger cat superpositions of $N$ atoms may be prepared deterministically by few ($\sim N^{1/4}$) photon scattering events without individual addressing of the atoms.

The nature of dark matter, which constitutes 27% of the Universe’s matter-energy content, remains one of the most challenging open questions in physics. Over the past two decades, the $\mathrm{DAMA}/\mathrm{LIBRA}$ experiment has reported an annual modulation in the detection rate of $\approx 250\mathrm{kg}$ of NaI(Tl) detectors operated at the Gran Sasso Laboratory, which the collaboration interprets as evidence of the galactic dark matter detection. However, this claim has not been independently confirmed and is refuted under certain dark matter particle and halo model scenarios. Therefore, it is crucial to perform an experiment with the same target material. The ANAIS experiment uses 112.5 kg of NaI(Tl) detectors at the Canfranc underground laboratory and it has been collecting data since August 2017 to model-independently test the $\mathrm{DAMA}/\mathrm{LIBRA}$ result. This Letter presents the results of the annual modulation analysis corresponding to six years of ANAIS-112 data. Our results, the most sensitive to date with the same target material, NaI(Tl), are incompatible with the $\mathrm{DAMA}/\mathrm{LIBRA}$ modulation signal at a $4\sigma$ confidence level. Such a discrepancy strongly challenges the $\mathrm{DAMA}/\mathrm{LIBRA}$ dark matter interpretation and highlights the need to address systematic uncertainties affecting the comparison, particularly those related to the response of detectors to nuclear recoils, which may require further characterization of the DAMA crystals.

Astrophysical black holes are open systems which, when perturbed, radiate quasinormal modes (QNMs) to infinity. By contrast, laboratory analogs are necessarily finite sized, presenting a potential obstacle to exciting QNMs in experiments. We explore how the QNM spectrum of a toy-model black hole changes when enclosed by a partially reflecting wall with adjustable reflectivity. Our results reveal a continuous connection between the QNM spectra of open and finite-sized systems. Additionally, we demonstrate that QNMs in this setup are easily excited by incoherent background noise. This Letter opens new avenues for studying QNMs of black holes and compact objects in laboratory settings, where finite-size effects and noise are unavoidable.

We investigate the behavior of the Efimov effect—a universal quantum few-body phenomenon—in the presence of an external driving field. Specifically, we consider up to three bosonic atoms, such as ${}^{133}\mathrm{Cs}$, interacting with a light atom, such as ${}^6\mathrm{Li}$, where the latter has two internal spin states $\{\uparrow ,\downarrow \}$ that are Rabi coupled. Assuming that only the spin-$\uparrow$ light atom interacts with the bosons, we find that the Rabi drive transposes the entire Efimov spectrum such that the Efimov trimers and tetramers are centered around the Rabi-shifted two-body scattering resonance. Crucially, we show that the Rabi drive preserves the trimers’ discrete scaling symmetry, while universally shifting the Efimov three-body parameter, leading to a log-periodic modulation in the spectrum as the Rabi drive is varied. Our results suggest that Efimov physics can be conveniently explored using an applied driving field, opening up the prospect of an externally tunable three-body parameter.

${\text{MoTe}}_2$, a promising material for flexible electronics and straintronics, exhibits rapid strain-induced conductivity changes. However, the underlying mechanisms remain poorly understood. Here, through deep-learning molecular dynamics and density-functional theory calculations, we identify a reversible phase transition between the semiconductive ${\mathrm{T}}_{\mathrm{b}}^{\prime }$ phase and the semimetallic ${\mathrm{T}}^{*}$ phase as the key mechanism driving this phenomenon. This transition, which is highly sensitive to the direction of applied strain, provides valuable insights for optimizing ${\text{MoTe}}_2$-based high-frequency nanoelectronic devices and reducing fabrication-related failures.

The observed fractional quantum Hall (FQH) plateaus follow a recurring hierarchical structure that allows an understanding of complex states based on simpler ones. Condensing the elementary quasiparticles of an Abelian FQH state results in a new Abelian phase at a different filling factor, and this process can be iterated ad infinitum. We show that condensing clusters of the same quasiparticles into an Abelian state can instead realize non-Abelian FQH states. In particular, condensing quasiparticle pairs in the $\nu =\frac{2}{3}$ Laughlin state yields the anti-Pfaffian phase at half filling. We moreover show that the successive condensation of Laughlin quasiparticles produces quantum Hall states whose fillings coincide with the most prominent plateaus in the first excited Landau level of GaAs. More generally, such condensation can realize any non-Abelian FQH state that admits a parton representation. This surprising result is supported by an exact analysis of explicit wave functions, field theory arguments, conformal-field theory constructions of trial states, and numerical simulations.

Magnetic kagome lattices have attracted much attention because the interplay of band topology with magnetism and electronic correlations give rise to various exotic quantum states. A common structural distortion in the kagome lattice is the breathing mode, which can significantly influence the magnetism and band characteristics. However, the control of breathing mode and the associated topological phenomena remain rarely explored. Here, we demonstrate that the coupling of breathing modes with ferroelectricity, magnetism, and band topology in the $M_3{X}_8$ monolayer system enables electric field manipulation of topological spin structure and electronic states. The breathing mode mainly occurs in materials containing early $4d/5d$ transition metal elements and can be reversed or even suppressed via ferroelectric switching in low-barrier materials. Importantly, electric field-induced switching of the breathing mode can alter the chirality of the topological spin structure, or trigger a transition from a topological trivial insulator to a Chern insulator. This work paves the way for exploring novel physical phenomena driven by breathing mode in kagome materials.

We present the first search for the lepton-flavor-violating decay modes $B^0\to K_S^0{\tau }^{\pm }{\ell }^{\mp }$ ($\ell =\mu ,e$) using the 711 and $365{\mathrm{fb}}^{-1}$ data samples recorded by the Belle and Belle II detectors, respectively. We use a hadronic $B$-tagging technique to fully reconstruct a $B$ meson and search for signal decays in the system recoiling against the tagged meson, considering $\tau$ decays to either light leptons, one charged hadron, or one charged hadron and a neutral pion. We find no evidence for $B^0\to K_S^0{\tau }^{\pm }{\ell }^{\mp }$ decays and set 90% confidence level upper limits on the branching fractions in the range of $[0.8,3.6]\times {10}^{-5}$.