We perform a differential resistance study in the hydrodynamic regime of an electron liquid in GaAs/AlGaAs quantum wells. At zero magnetic field $\left(B\right)$ a Lorentzian profile occurs in the nonlinear transport driven by a U-turn (ac) current loop, in $(\mathrm{ac}+\mathrm{dc})$ measurements a minimum deepens with the external dc current bias $\left(j_{\text{dc}}\right)$. Our analysis shows that the observed electronic transport valley induced by $j_{\text{dc}}$ is attributed to the Joule heating effect on the electron temperature $\left(T_e\right)$ of the electron liquid. Quantitatively, we demonstrate that the viscosity resistivity $\left(\mathrm{\Delta }\rho \right)$ is proportional to $T^{-2}$ and is consistent with the dc-current-induced electronic Gurzhi effect in various configurations of measurement.

Non-Abelian topological charges, characterized by their noncommutative algebra, offer a framework for describing multigap topological phases beyond conventional Abelian invariants. Although higher-order topological phases (HOTPs) host boundary states at corners or hinges, their characterization has largely relied on Abelian invariants such as winding and Chern numbers. Here, we propose a coupled-wire scheme for constructing non-Abelian HOTPs and analyze in detail a two-dimensional model as its minimal realization. The resulting Hamiltonian supports hybridized corner modes, protected by parity-time reversal $\left(\mathcal{PT}\right)$ plus sublattice symmetries, and described by a topological vector that unites a non-Abelian quaternion charge with an Abelian winding number. Corner states emerge only when both invariants are nontrivial, whereas weak topological edge states of non-Abelian origin arise when the quaternion charge is nontrivial, enriching the bulk-edge-corner correspondence. The system further exhibits topological phase transitions of both non-Abelian and Abelian characteristics, providing a unified platform that bridges these two distinct topological classes. Our work thus extends the study of HOTPs into non-Abelian regimes and suggests feasible experimental realizations in synthetic quantum matter.

We study Andreev-mediated transport and current fluctuations in interacting normal-superconducting quantum-dot systems. Using a generalized master equation based on real-time diagrammatics and full counting statistics, we compute the steady-state current, zero-frequency noise, and rate of entropy production in the large superconducting-gap limit. We show how Coulomb interactions modify Andreev-mediated transport by renormalizing resonant conditions and suppressing superconducting coherence, leading to a pronounced reduction of current precision even when average currents are only weakly affected. These effects are particularly evident at high temperatures, where conventional Coulomb-blockade features are thermally smeared while fluctuation properties remain highly sensitive. By analyzing thermodynamic uncertainty relations, we demonstrate that violations of the quantum bound present in the noninteracting regime are progressively reduced and eventually suppressed as interactions increase, whereas the recently proposed hybrid bound remains satisfied. Our results clarify how Coulomb interactions and nonequilibrium fluctuations jointly determine transport properties in hybrid superconducting devices, and establish current precision as a robust benchmark for interacting Andreev transport beyond the noninteracting limit.

We introduce a one-dimensional non-Hermitian Kitaev chain with staggered imbalance in the $p$-wave superconducting pairing. By tuning the chemical potential and the pairing imbalance, we find that the eigenenergy spectrum undergoes real-to-complex transitions, and the spectral gap can change from a real line gap to an imaginary one. The pairing imbalance significantly enlarges the parameter region supporting a topological superconducting phase. Remarkably, we show that a topologically nontrivial phase hosting Majorana zero modes can be induced by varying the pairing imbalance, even in the regime of strong chemical potential. The gap-closing points and phase boundaries are determined analytically, and the resulting phase diagrams are presented with the nontrivial phase characterized by a nonzero topological invariant. Furthermore, we identify the coexistence of Majorana zero modes and finite-energy Majorana edge modes in this system. Our results reveal exotic phenomena arising from imbalanced pairing and establish a platform for exploring topological superconductivity in non-Hermitian systems.

We propose a theoretical framework in which a one-dimensional (1D) tight-binding model incorporating unconventional magnetic order together with Rashba and Ising spin-orbit couplings are considered to realize two key phenomena in condensed matter systems: topological superconductivity and the superconducting diode effect (SDE). We first elucidate the underlying band topology of the normal-state Hamiltonian and subsequently introduce an on-site attractive Hubbard interaction. Performing a a self-consistent mean-field analysis, we establish superconducting order parameters in both the conventional Bardeen-Cooper-Schrieffer (BCS) and finite-momentum Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing channels. Intriguingly, both pairing states can support topological superconductivity, characterized by a nontrivial winding number, and lead to the emergence of four zero-energy Majorana modes localized at the ends of the 1D chain. The FFLO state further gives rise to an intrinsic field-free SDE, manifested as a nonreciprocal supercurrent and quantified by the diode efficiency $\eta$. Notably, our model yields a large diode efficiency $\eta \sim 65\%$, highlighting its potential for realizing topological superconductivity and highly efficient superconducting devices.

In this theoretical work, we propose an all-optical method for fast and precise manipulation of twist angle in two-dimensional multilayer by transferring orbital angular momentum from phase-structured light (e.g., vortex beams) to a 2D material flake. We model the light-matter interaction, analyze the twist dynamics, and develop a phase diagram for optical twists by mapping the system onto an impulsively forced nonlinear pendulum. Our findings reveal rich dynamical responses spanning single- and multipulse twist angle control to (quasi)stable dynamical trajectories, and suggest a pathway for all-optical measurement of the twist potential energy. Aided by classical potential estimates for the interlayer energy and numerical simulations, we demonstrate the feasibility of this approach with hexagonal boron nitride (hBN) bilayers and extend the results to transition metal dichalcogenides (TMDs) with first-principles calculations. These results can be generalized to other 2D multilayers, paving the way for customizable moiré electronics and photonics.

We present a numerical study of the two-dimensional quantum percolation model, revealing that a critical region with multifractal eigenstates mediates the transition from localized to delocalized states. By analyzing the mean level ratio and participation entropy, we identify two distinct transitions: a Berezinskii-Kosterlitz-Thouless (BKT) transition at the classical percolation threshold, separating the localized and critical phases, and a power-law-like transition at a larger concentration, marking the onset of full delocalization. The critical phase is characterized by multifractal eigenstates, as evidenced by the generalized fractal dimension and multifractal spectrum. We present a detailed discussion of the results for a spectral window $E/t=0.60\pm 0.05$. The analyses were repeated for energy windows centered at different values of $E/t$, and the results are displayed in the form of a phase diagram as a function of energy; the outcome highlights the robustness of both the multifractal phase and the BTK transition. Altogether, our results establish that in the marginal two-dimensional case, the Anderson impurity model and the quantum percolation model belong to different universality classes.

The study of many-body localized phases intrinsically links spectral properties with eigenstate characteristics: localized systems exhibit Poisson level statistics and area-law entanglement entropy, while ergodic systems display volume-law entanglement and follow random matrix theory predictions, including level repulsion. Here, we introduce the interacting Anderson Quantum Sun model, which significantly deviates from these conventional expectations. In addition to standard localized and ergodic phases, we identify a regime that exhibits volume-law entanglement coexisting with intermediate spectral statistics. We also identify another nonstandard regime marked by Poisson level statistics, subvolume entanglement growth, and rare-event-dominated correlations, indicative of emerging ergodic instabilities. These results highlight unconventional routes of ergodicity breaking and offer fresh perspectives on how Anderson localization may be destabilized.

Quasi-one-dimensional bismuth halides offer an exceptional platform for exploring diverse topological phases, yet the nature of the room-temperature topological phase transition in ${\mathrm{Bi}}_4{\mathrm{I}}_4$ remains unresolved. While theory predicts the high-temperature $\beta$ phase to be a strong topological insulator (TI), experiments observe a weak TI. Here we resolve this discrepancy by revealing the critical role of electron-phonon coupling. Using our ab initio scheme for phonon-induced band renormalization, we show that thermal phonons alone drive $\beta –{\mathrm{Bi}}_4{\mathrm{I}}_4$ from the strong TI predicted by static-lattice calculations to a weak TI at temperatures where $\beta –{\mathrm{Bi}}_4{\mathrm{I}}_4$ is stable, with calculated surface states in close agreement with experiments. We further reveal that high-energy states shape the low-energy topology in $\beta –{\mathrm{Bi}}_4{\mathrm{I}}_4$ via phonon-mediated processes. Our work establishes the critical role of electron-phonon coupling in driving the topological phase transition and provides a broadly applicable approach for predicting topological electronic structure at finite temperatures.

Relaxor ferroelectrics can be categorized into single-phase relaxors, reentrant relaxors, and polymorphic relaxors in terms of domain structure features. Among these, polymorphic relaxors with nanodomains in at least two different phases exhibit superior energy storage/electrocaloric properties compared with the other two types of relaxors. However, it has remained unclear how polymorphic relaxors form because of limitations in characterization techniques and, more importantly, a lack of theoretical models. In this work, we develop a phase-field model of polymorphic relaxors based on a perovskite-structured binary ferroelectric system with a cubic (C) to tetragonal (T) transition at one end and a C to rhombohedral (R) transition at the other, incorporating both the nanoscale compositional heterogeneity arising from the random distribution of substituted ions and the local electric fields generated by heterovalent ion substitution. Based on this model, we reproduce the domain structure features as well as the dielectric permittivity behavior and construct a complete phase diagram for polymorphic relaxors, all of which are consistent with experimental observations. Further analysis shows that composition near the morphotropic phase boundary (MPB) and strong local electric fields are the critical dual factors driving the formation of polymorphic relaxors. Once the two necessary conditions are not simultaneously satisfied, either single-phase relaxors or reentrant relaxors occur. This work unravels the origin of polymorphic relaxor formation by developing a phase-field model of polymorphic relaxors, which provides a theoretical foundation for the design of relaxors with enhanced performance.

We demonstrate a nonzero twist-angle stabilization mechanism in lattice-mismatched 2D heterobilayers, which results from the geometric alignment between the flake edges and the vectors determining the moiré pattern supercell. Using atomistic simulations of graphene flakes on hexagonal boron nitride, with diameters of up to $\sim 2500\AA$, we identify twist angles corresponding to global minima in the twist-angle dependence of the interlayer interaction energy at $\sim 0.{61}^{\circ }$ for armchair and $\sim 1.{89}^{\circ }$ for zigzag-edged flakes, tunable via in-plane strain. This locking mechanism, which relies on energy barriers that are an order of magnitude larger than those of nearby metastable twist angles, provides a geometric route to precision twist-angle control of two-dimensional heterostructures and to understand the self-orientation of macroscopic flakes.

We study the low-energy excitation spectra of a spin-1/2 quantum Heisenberg model with a monoaxial Dzyaloshinskii-Moriya interaction. Using the density matrix renormalization group method, our analysis reveals a degeneracy between skyrmion and antiskyrmion states, enabling the formation of a Schrödinger cat state, a quantum superposition of these topologically distinct textures. To characterize this nontrivial state, we compute two-point spin correlation functions, highlighting signatures accessible via neutron scattering experiments. Furthermore, we demonstrate that applying a magnetic field gradient induces a coherent time evolution of the cat state, offering a controllable mechanism for its manipulation. These findings provide a framework for the detection of skyrmionic Schrödinger cat states in quantum magnets.

We perform nanosecond-resolution multiplexed readout on six same-chip superconducting microwave resonators. This allows us to pinpoint the position of ionizing radiation impacts on the chip by measuring the differential time-of-flight of the generated phonons, inducing correlated errors in the device, thereby implementing an on-chip seismic array. We correlate the phase response of each resonator—a proxy for the absorbed energy—to the distance from the impact point to uncover a millimetric characteristic length for the phonon-mediated radiation poisoning.

The germanium vacancy in diamond (GeV) is a promising candidate for color center based quantum networking. Yet, like for other group-IV vacancy defects in diamond, achieving fast, high-fidelity qubit operations using traditional magnetic resonance techniques is experimentally challenging due to a weak magnetic dipole and susceptibility to thermally induced decoherence. Here, we perform all-optical control of the GeV and realize Rabi frequencies exceeding $\sim 20$ MHz. We do so by driving the two $\mathrm{\Lambda }$-systems of the GeV simultaneously and apply this to probe the spin coherence ($T_2^{*}=224\pm 14$ ns, $T_2^{\mathrm{H}}=11.9\pm 0.3 \mu \text{s}$). Our control scheme is applicable to other color centers and particularly, other group-IV defects for which the scheme may be optimized to improve all-optical control in these systems.

Motivated by transition-metal trihalides, we study the strong-coupling model of $d^1$ honeycomb lattice systems in the large spin-orbit coupled limit. By considering different possible hopping pathways, SU(4) symmetry is found to emerge at multiple points in the parameter space of the hopping parameters. The resultant Dirac spin-orbital liquids, within the parton mean-field description, provide distinct realizations of symmetry fractionalization. The calculated dynamical spin-structure factor fingerprints this distinctive nature, measurable in experiments. The conclusions are found to be perturbatively robust upon inclusion of low-energy gauge fluctuations.

The acoustic coupled-cavity system offers a versatile platform for exploring novel topological phenomena such as topological pumping and beyond, wherein long-range coupling, as an emerging modulation strategy, is typically introduced via extrinsic connection elements or moving fluids, resulting in increased systemic complexity or unwanted fluid-induced noise. Here, we exploit intrinsic next-nearest-neighbor (NNN) couplings within coupled-cavity systems as a controllable degree of freedom and, based on it, demonstrate a remarkable effect of asymmetric topological pumping in a compact spatially modulated acoustic lattice without extra coupling tubes and moving fluids. Through a higher-order approximation, we theoretically reveal and experimentally demonstrate that the intrinsic long-range coupling, which is commonly overlooked in previous designs, can be significantly amplified and independently modulated via rationally designing the structural parameters. As the NNN coupling increases, asymmetric band compression leads to highly uneven spectral spacings, ultimately triggering the directional breakdown of pump channels. Simulation results confirm the asymmetric pumping of sound in the spatially modulated lattices irrespective of whether nonparaxial or paraxial conditions are applied. Our findings may advance the exploration of topological phases enriched by NNN coupling and provide a design paradigm for compact acoustic devices enabling direction-selective wave control.

We propose to incorporate grain boundary (GB) anisotropy in phase-field modeling by extending the standard partial differential equations (PDEs) formulation to include a nonlocal functional of an orientation field. Regardless of the number of grains in the simulation, the model uses a single orientation field and incorporates grain misorientation and inclination information obtained from sampling the orientation field at optimized locations in the vicinity of the GB. The formalism enables simple and precise tuning of GB energy anisotropy while avoiding an extensive fitting procedure. The functional includes explicit GB functions to control the GB energy as a function of both misorientation and inclination. The model is validated by reproducing the linear grain growth rate, Wulff shapes with varying misorientations and anisotropic coefficients, and analytical equilibrium dihedral angles at triple junctions. Polycrystalline simulations further demonstrate grain growth, coalescence, triple junction behavior, and the influence of anisotropy on grain morphology.