In a hybrid system consisting of two quantum dots (QDs) coupled to a superconductor (SC), zero-bias peaks in the differential conductance spectrum have been reported as potential signatures of Majorana fermions (MFs). However, such signatures are typically associated with modes that appear only at specific parameter values of the QDs—so-called sweet spots—and are referred to as the poor man's Majorana (PMM). To investigate whether these signatures can be conclusively attributed to genuine MFs emerging in the practical physical parameter values, we present an alternative approach that microscopically incorporates the superconducting effects into the QDs, rather than simply attributing them to two phenomenological parameters of QDs. This forms the dressed Majorana fermions (DMFs), which can be viewed as superpositions of quasiexcitations from both the QDs and the SC. We show that DMFs can localize at one end of a one-dimensional SC and emerge in a set of the practical physical parameters, thereby enhancing the feasibility of experimental detection. Our results provide a more accurate description of the PMM in such hybrid systems and offer practical guidance for observing end-localized PMM modes in continuous one-dimensional SC.

Surface acoustic waves (SAWs) provide a versatile platform for signal processing, sensing, and emerging quantum technologies, yet their functionality is often constrained by diffraction-induced spreading. Here we introduce perfect self-similar beams (PSSBs) into acoustics and develop a theoretical and numerical framework adapted for SAWs on $\mathrm{LiNb}{\mathrm{O}}_3$. Starting from the paraxial wave equation, we derive a closed-form error-function solution for an odd-symmetric 0/π entrance and design a dislocated interdigital transducer layout to encode the required phase distribution. To bridge the gap between ideal continuous apodization and practical implementation, we further introduce a multilevel voltage driving scheme to approximate the target transverse amplitude profile with high fidelity. Three-dimensional full-wave simulations confirm the hallmark properties of SAW PSSBs, including nondiffracting propagation, self-similar scaling, a robust central null, and self-healing after partial obstruction. This work establishes both a theoretical framework and a practical strategy for shaping diffraction-resilient SAW beams, with potential applications in micro/nano manipulation, phononic information processing, and acousto-optic or quantum coupling.

We investigate the inverse Edelstein effect in a nonhomogeneous system consisting of a ferromagnetic layer coupled to a Rashba two-dimensional electron gas. Within a semiclassical Boltzmann framework, we derive analytical expressions for the charge and spin currents and analyze their dependence on key parameters such as the chemical potential and the Rashba coupling strength. We show how interfacial exchange and spin-orbit interactions jointly control the efficiency of spin-to-charge conversion, leading to distinct regimes characterized by qualitatively different transport responses. A central outcome of our work is the availability of closed-form analytical results, which provide direct physical insight and enable a transparent and quantitative benchmarking with experiments on complex oxide interfaces, such as ${\mathrm{LaAlO}}_3/{\mathrm{SrTiO}}_3$.

Topological insulators represent a class of quantum materials exhibiting a host of unique physical properties. As an important category of topological insulators, quantum spin Hall insulators show one-dimensional topological helical edge states. Here, we report the successful growth of the high-quality ultrathin ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ film on a Nb-doped ${\mathrm{SrTiO}}_3$(001) substrate by molecular beam epitaxy. With a ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ island around one quintuple layer higher than the three quintuple layer thick film, one-dimensional edge states between even and odd quintuple layers (i.e., between the island and the film) are directly observed by scanning tunneling microscopy and spectroscopy. Combined with theoretical prediction, our work provides the signature of the existence of the quantum spin Hall phase in ultrathin ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ film, and offers a platform for exploring one-dimensional helical edge states and related quantum devices.

We propose a theoretical framework to engineer hybrid-order and higher-order topological phases in three-dimensional topological insulators by coupling to $d$-wave altermagnets (AMs). The presence of only a $d_{x^2-y^2}$-type AM drives the system into a hybrid-order topological phase where both first-order and second-order topological phases coexist. This phase is characterized by spectral analysis, low-energy surface theory, and dipolar and quadrupolar winding numbers, and its signature is further confirmed by two-terminal differential conductance calculations. Incorporation of the $d_{x^2-z^2}$-type AM drives the system into two second-order topological insulator phases hosting a distinct type of hinge modes. These two variants of second-order topological phases are also topologically characterized by spectral analysis, topological invariants, low-energy surface theory, and transport calculations. Importantly, the localization and direction of propagation of these one-dimensional hinge modes are controllable by tuning the relative strengths of the altermagnetic exchange orders. We utilize this feature to propose a tunable current switching behavior mediated via the hinge modes. Our results establish an AM-based hybrid structure as a versatile platform for controllable higher-order topology and hinge-mediated device applications.

The phenomenon of Hilbert space fragmentation, whereby dynamical constraints fragment Hilbert space into many disconnected sectors, provides a simple mechanism by which thermalization can be arrested. However, little is known about how thermalization occurs in situations where the constraints are not exact. To study this, we consider a situation in which a fragmented $1d$ chain with pair-flip constraints is coupled to an ergodicity-restoring thermal bath at its boundary. We numerically observe an exponentially long thermalization time in Hamiltonian dynamics, manifested in both entanglement dynamics and the relaxation of local observables. To understand this, we study an analogous model of random unitary circuit dynamics, whose thermalization time we prove scales exponentially with system size. Slow thermalization in this model is shown to be a consequence of strong bottlenecks in configuration space, which restrict how the system can explore Hilbert space, and demonstrate another way of producing anomalously slow thermalization dynamics.

In this paper we consider quantum Hamiltonians with time-dependent interaction strengths, and following the recently formulated generalized Bethe ansatz framework [Pasnoori, Phys. Rev. B 112, L060409 (2025)], we show that constraints imposed by integrability take the same form as the renormalization group flow equations corresponding to the respective Hamiltonians with constant interaction strengths. As a concrete example, we consider the anisotropic time-dependent Kondo model characterized by the time-dependent interaction strengths $J_{\parallel }\left(t\right)$ and $J_{\perp }\left(t\right)$. We construct an exact solution to the time-dependent Schrodinger equation, and by applying appropriate boundary conditions to the fermion fields we obtain a set of matrix difference equations called the quantum Knizhnik-Zamolodchikov equations corresponding to the XXZ $R$-matrix. The consistency of these equations imposes constraints on the time-dependent interaction strengths $J_{\parallel }\left(t\right)$ and $J_{\perp }\left(t\right)$, such that the system is integrable. Remarkably, the resulting temporal trajectories of the couplings are shown to coincide exactly with the renormalization group flow trajectories of the static Kondo model, establishing a direct and universal correspondence between integrability and renormalization group flow in time-dependent quantum systems.

Defect engineering of two-dimensional materials routinely produces local magnetic moments, yet itinerant half-metallic ferromagnetism remains elusive—experiments frequently yield paramagnetic insulators. We resolve this paradox for vacancy-doped monolayer $1T\text{−}{\mathrm{TiS}}_2$ by demonstrating that the insulator-to-half-metal transition is governed by universal geometric percolation of the defect network, extending the percolation framework established for three-dimensional diluted magnetic semiconductors into the 2D vacancy-doped regime. Half-metallicity emerges via a two-step mechanism: Crystal-field symmetry breaking ($O_h\to C_{4v}$) selectively stabilizes the Ti $3d_{z^2}$ orbital, generating robust local moments ($0.94{\mu }_B$), but spin-polarized transport requires these moments to form a spanning cluster. At critical vacancy concentration $x_c\approx 12.5\%$, a percolation transition drives the majority-spin impurity band from flat, localized levels ($W<0.1\mathrm{eV}$) to a dispersive 1.5-eV wide band with 100% spin polarization and a minority-spin gap of 1.0 eV. Finite-size scaling yields a Fisher exponent $\tau =2.09\pm 0.03$, confirmed by fractal scaling of ab initio charge densities (${\tau }_{\text{eff}}^{\text{DFT}}=1.87\pm 0.26$), placing the transition in the 2D percolation universality class. The percolation mechanism is independently corroborated by a striking supercell-size effect: at identical concentration, $2\times 2$ cells yield antiferromagnetic order while $4\times 4$ cells mandate ferromagnetism, reflecting the presence or absence of a spanning cluster. We estimate a Curie temperature exceeding 300 K from the exchange coupling, and identify a geometric jamming instability at $x>20\%$ that fragments the network. These results define a narrow functional window ($11\%<x<15\%$) for half-metallic operation and establish geometric connectivity as a quantitative design principle for defect-engineered 2D spintronics.

Strongly covalent-bonded metallic compounds have emerged as promising high-temperature superconductors since the discovery of record-holding 39 K superconductivity in ${\mathrm{MgB}}_2$. Yet, recent theoretically designed lightweight high-critical temperature ($T_{\text{c}}$) covalent superconductors lack thermodynamic stability, a key prerequisite for experimental validation. Herein, we propose an effective template-guided strategy, designing nine fully $\sigma$-bonded metal boride superconductors with $T_{\text{c}}$ exceeding ${\mathrm{MgB}}_2$. Machine-learning accelerated structure searches combined with anharmonic calculations confirm $F\overline{4}3m\text{−}{\mathrm{Sr}}_2{\mathrm{B}}_5$ to be thermodynamically stable at 38–54 GPa and retain dynamic stability at ambient conditions. The calculated $T_{\mathrm{c}}$ reaches around 90 K at 40 GPa, dominated by strong coupling between the metallized $\sigma$ electronic states and $E$ phonon modes of boron atoms. Our design concept may advance the development of high-$T_{\mathrm{c}}$ lightweight covalent superconductors that can survive at room pressure.

Understanding the storage forms of manganese during Earth's evolution is essential for elucidating the origin of large-scale manganese deposits associated with the Great Oxygenation Event. Here, in addition to known manganese oxides, we identify an unconventional Mn-rich compound, ${\mathrm{Mn}}_4\mathrm{O}$, which exhibits thermodynamic stability from ambient pressure up to at least 150 GPa—the highest pressure explored. Additionally, a high-pressure polymorph of ${\mathrm{Mn}}_3{\mathrm{O}}_4$ with monoclinic $Cc$ symmetry emerges as stable above 72 GPa. Ab initio molecular dynamics simulations confirm that both phases remain in the solid state across a wide pressure-temperature range relevant to deep-mantle conditions. We propose that ${\mathrm{Mn}}_4\mathrm{O}$ may form via redox reactions between manganese and oxidized species transported by subducted hydrated lithosphere, and subsequently be brought to the surface through mantle convection, where it oxidizes into conventional manganese ores in the presence of ${\mathrm{O}}_2$. Owing to their low sound velocities, these phases could contribute to the seismic anomalies observed in ultralow velocity zones near the core-mantle boundary. These findings suggest a previously unrecognized deep-mantle reservoir for manganese and offer insights into the deep-cycle behavior of this key transition metal.

The atomic-scale structure and melting curve of liquid mercury was measured using in situ synchrotron x-ray diffraction (SXRD) at pressure and temperature ($p\text{−}T$) conditions up to 9.44(2) GPa and 651(1) K. Ab initio molecular dynamics (AIMD) simulations were employed to obtain a detailed atomistic model of the liquid structure. The results reveal a pronounced flattening, and potential maximum, in the measured melting curve between 6 and 9 GPa. The structure factors $S_{\mathrm{HgHg}}\left(Q\right)$ and pair distribution functions $g_{\mathrm{HgHg}}\left(r\right)$ calculated from the AIMD simulations are in good overall agreement with the SXRD measurements under comparable reduced densities and temperatures, indicating that the atomistic structure of liquid Hg is well captured by AIMD. With increasing pressure, the principal peak in $S_{\mathrm{HgHg}}\left(Q\right)$ shifts to higher $Q$, with the subsidiary peak at $Q=2k_{\mathrm{F}}$ experiencing a concomitant shift consistent with the increased electron density. Considering the Evans $t$-matrix formulation of the Ziman theory of liquid metals, the structural $S\left(2k_{\mathrm{F}}\right)$ term is expected to have only a weak influence on the electrical resistivity under compression. In contrast, the pressure-induced broadening and shift of the $d$-projected density of states towards the Fermi level is consistent with enhanced near-resonant $d$-electron scattering, and a corresponding increase in resistivity, analogous to the behavior of first-row transition metals. Analysis of the measured $g_{\mathrm{HgHg}}\left(r\right)$ functions, and AIMD trajectories in real space, indicates that the liquid structure experiences a progressive development towards simple hard-sphere-like behavior at increasing $p\text{−}T$ along the melting curve. However, topological cluster classification analysis shows that while the structural fingerprint of liquid Hg strongly resembles an effective hard-sphere system, even at the highest pressures investigated it contains more many-body motifs than expected for this simple model.

Mobility edges commonly arise in one-dimensional quasiperiodic systems once exact self-duality is broken, yet their origin is typically understood only at the level of individual Hamiltonians. Here we show that mobility edge positions are not independent spectral features of individual Hamiltonians, but are structurally constrained across quasiperiodic Hamiltonians related by an isospectral duality. Using a bichromatic Aubry-André model as a minimal setting, we demonstrate that this constraint is encoded in an exact identity for Lyapunov exponents derived from the Thouless formula. As a consequence, the mobility edge positions are restricted to a reduced set of energies. In the self-dual limit, these mobility edge positions coincide at a single localization-delocalization transition. This structural constraint enforces a linear critical scaling of the physical Lyapunov spectrum near the self-dual point. Numerical results confirm a critical exponent consistent with the standard AubryAndré value of $\nu =1$, while simultaneously revealing a nonuniversal energy-dependent prefactor.

We study localization driven solely by interparticle interactions in moiré lattice systems without intrinsic disorder or externally imposed quasiperiodic potentials. We consider a one-dimensional bilayer with incommensurate lattice constants, described by a spin-dependent Fermi-Hubbard-type model with short-range interlayer interactions, where quasiperiodicity emerges only through interactions. Exact diagonalization shows that quenching hopping in one layer generates an interaction-induced mosaic potential with multiple mobility edges. When both layers are dynamical, increasing interlayer interactions drives transitions among ergodic, critical, and localized regimes, with energy-dependent coexistence in certain parameter ranges. An exact mapping to a noninteracting single-particle model on a higher-dimensional structured graph provides a unified interpretation of these results and suggests an experimentally accessible route to interaction-induced moiré physics and localization.

The non-Hermitian skin effect (NHSE) refers to the accumulation of an extensive number of eigenstates at system boundaries under open boundary conditions. As a dynamical consequence, wave packets in such systems drift and ultimately accumulate at a boundary, giving rise to the dynamical skin effect (DSE). While strong quasiperiodic potentials are known to suppress the DSE by inducing localization, we show that the introduction of Ornstein-Uhlenbeck noise unexpectedly restores it. Using perturbative analysis, we demonstrate that noise effectively maps the non-Hermitian Schrödinger dynamics onto a nonreciprocal master equation, whose complex spectrum develops a noise-induced point gap. This mechanism enables delocalization, reinstates directional transport, and revives the DSE even in regimes where the static NHSE is absent. Moreover, the relaxation dynamics exhibit a nonmonotonic dependence on noise strength, reflecting a competition between noise-assisted delocalization and noise-induced decoherence. Our results uncover a noise-enabled mechanism for resurrecting the DSE and suggest a new route for controlling transport in quasiperiodic, open quantum systems.

The synergistic interplay between spin correlations, spin-orbit coupling, and competing exchange interactions provides a promising route to realize exotic quantum states with nontrivial excitations in rare-earth-based frustrated magnets. Here, by using thermodynamic and local-probe measurements down to 16 mK, we demonstrate the exotic magnetism and spin dynamics in the distorted triangular lattice ${\mathrm{TbBO}}_3$. Thermodynamic experiments reveal the presence of dominant antiferromagnetic exchange and subdominant dipolar interactions. Despite sizable antiferromagnetic exchange interactions between the ${\mathrm{Tb}}^{3+}$ moments, the muon-spin relaxation experiment do not detect any signatures of long-range magnetic order or spin-freezing down to 16 mK, corroborating the specific heat and $ac$ magnetic susceptibility data down to 45 mK that suggests a persistent spin dynamics in this frustrated triangular lattice. The scaling of muon relaxation rate as a function of the characteristic energy scale for several spin-liquid candidates, including ${\mathrm{TbBO}}_3$, demonstrates that a common underlying mechanism is at play. The persistent dynamics in this frustrated triangular lattice antiferromagnet is reminiscent of a universal spin-liquid-like spin fluctuations, here attributed to dominant two dimensional (2D) antiferromagnetic short-range spin correlations, confirmed by the presence of a broad magnetic diffuse scattering in the elastic and low-energy inelastic neutron scattering channels at $Q\approx 1.03 {\text{Å}}^{-1}$ at low temperatures. Our results demonstrate that non-Kramers ion based triangular lattice hosts spin-liquid-like dynamics of local moments arising from the admixture of excited crystal electric field states into the ground state and intertwining of frustration and spin-orbit interaction.

Altermagnets enable nonrelativistic spin splitting without net magnetization, benefiting miniaturized and highly integrated spintronic devices. In this work, we investigate the physical mechanism by which ferroelectric substrates induce altermagnetism in antiferromagnetic materials through symmetry manipulation and magnetoelectric coupling effects. Using antiferromagnetic ${\mathrm{MnPSe}}_3$ and ferroelectric ${\mathrm{ReGeS}}_3$ as examples, we constructed both bilayer heterostructures and sandwich structures. Through multiple control strategies including twisting operations, optimizing stacking configurations, interlayer sliding, and polarization reversal, we achieved altermagnetic induction, antiferromagnetic-altermagnetic phase transitions, tunable spin-splitting level in band structures, and reversal of spin splitting in energy bands in the altermagnet. These results reveal the crucial role of interfacial charge transfer and lattice symmetry breaking in producing altermagnetism. Our findings demonstrate that the ferroelectric substrate breaks the $\mathcal{PT}$ symmetry while maintaining $[C_2\parallel M]$ symmetry in the antiferromagnetic layer, resulting in an alternating spin-splitting distribution in momentum space. Notably, in the sandwich structures, we successfully realize altermagnetism under strictly zero net polarization (antiferroelectric state). Furthermore, we achieve reversible switching between antiferromagnetic and altermagnetic phases as well as spin-splitting reversal in the altermagnet via twisting operations and polarization field control.

Two-dimensional Janus antiferromagnetic (AFM) materials provide a unique broken-symmetry environment to explore the interplay between spin, valley, and layer degrees of freedom. In this work, we investigate the Janus MXene bilayer ${\mathrm{Cr}}_2\mathrm{CHF}$, which maintains a robust AFM ground state with a high Néel temperature ($T_{\mathrm{N}}=475\mathrm{K}$), ensuring magnetic stability well above room temperature. To elucidate the underlying physics, we develop a low-energy $\mathbf{k}·\mathbf{p}$ model, demonstrating that the intrinsic vertical dipole of the Janus layers, in synergy with interlayer exchange coupling, plays a pivotal role in lifting the valley degeneracy. Our analysis reveals that the Janus-induced internal electric field acts as a persistent bias, facilitating substantial valley splitting and contrasting Berry curvature. Furthermore, we show that interlayer sliding and external electric fields are functionally equivalent knobs for tuning the valley properties. A sliding-mediated ferroelectriclike switching is identified to reverse the layer-resolved valley polarization, enabling nonvolatile electrical control of the anomalous valley Hall effect. These findings establish bilayer ${\mathrm{Cr}}_2\mathrm{CHF}$ as a promising platform for integrated, high-temperature valleytronic memory and logic devices.