We analytically and numerically investigate an Aharonov-Bohm interferometer with two superconducting terminals and a strongly correlated quantum dot in one arm. Through a rigorous derivation, we prove that this double-path interferometer is spectrally equivalent to a simpler system: an interacting quantum dot coupled to a noninteracting side-coupled proximitized mode and a semiconductor lead. This equivalence reveals a simple interpretation of the interferometer's behavior through the competition of a geometric factor $\chi$, a key parameter characterizing the anomalous part of the hybridization function, with the properties of the side-coupled mode. We identify the conditions for the formation of doublet chimney in the phase diagrams in more general setting. Moreover, we show how the obtained Andreev bound state spectra clearly indicate the presence of Josephson diode effect generated by interferometric phenomena.

A central feature of many van der Waals (vdW) materials is the ability to precisely control their charge doping, $n$, and electric displacement field, $D$, using top and bottom gates. For devices composed of only a few layers, it is commonly assumed that $D$ causes the layer-by-layer potential to drop linearly across the structure. Here, we show that this assumption fails for a broad class of crystalline and moiré vdW structures based on Bernal- or rhombohedral-stacked multilayer graphene. We find that the electronic properties at the Fermi level are largely dictated by special layer-polarized states arising at Bernal-stacked crystal faces, which typically coexist in the same band with layer-delocalized states. We uncover a mechanism by which the layer-delocalized states completely screen the layer-polarized states from the bias applied to the remote gate. This screening mechanism leads to an unusual scenario where voltages on either gate dope the band as expected, yet the band dispersion and associated electronic properties remain primarily (and sometimes exclusively) governed by the gate closer to the layer-polarized states. Our results reveal an electronic mechanism underlying the atypical single-gate-controlled transport characteristics observed across many flat-band graphitic structures, and provide key theoretical insights essential for accurately modeling these systems.

We investigate the influence of nonzero magnetization on the ground state phase diagram of the two-component Bose-Hubbard model. Employing a mean-field theoretical framework both analytically and numerically, we demonstrate that the positions and sizes of specific phases on the diagram are magnetization dependent. In particular, nonzero magnetization introduces different Mott insulator phase boundaries for each of the two components. This effect leads to the emergence of a hybrid phase characterized by the coexistence of a superfluid in one of the components and a Mott insulator in the other one. Our findings highlight the important role of conserved quantities, which is magnetization here, in reshaping the phase landscape, significantly influencing the stability and emergence of distinct quantum phases.

Organic light-emitting diodes (OLEDs) can show a remarkable spatial anisotropy in the strength of magnetoelectroluminescence (MEL) at geomagnetic field strengths, serving as models of the electron-hole radical-pair process invoked to explain some forms of biological magnetoreception. We examine this effect in dual singlet-triplet-emitting devices by quantifying the modifications to both the fluorescence and phosphorescence intensity. Although the changes in the yields of singlet and triplet excitations with magnetic-field strength are generally anticorrelated, with an increase in singlet population accompanied by a decrease in triplet population, and vice versa, we find that, unexpectedly, MELs in the singlet and triplet channels display strikingly different anisotropies with respect to the orientation of the magnetic field. By deuterating the OLED compounds, we control the strength of the anisotropic hyperfine interactions, providing insight into the underlying magnetic-field effects. We examine magnetoresistance and MEL in the ultralow field regime of below a few hundred microtesla, comparing the behavior of protonated and deuterated compounds. The functional form of the anisotropy differs markedly between singlet and triplet channels, which we rationalize quantitatively by means of quantum-stochastic simulations of the spin dynamics.

Landau level (LL) engineered photonic spin Hall effect (PSHE) holds great promise for nanoscale manipulation and steering of magneto-optical transport in two-dimensional atomic systems. Herein, we theoretically investigate PSHE modulated by LL transitions $\delta n=n^{\prime }-n=0, \pm 2$ (where $n$ and n' indicate the LL indexes of valence and conduction bands, respectively) in monolayer $\mathrm{WT}{\mathrm{e}}_2$. Results show that PSHE tuned by $\delta n=0, \pm 2$ has completely different dependent behaviors on LLs, incident angle of incident photons, and magnetic induction intensity. These discrepancies are ascribed to Hall-conductivity-incurred Hall angle Θ because the variation tendency of photonic spin Hall shifts is similar to that of Θ with changing the LL index. Giant PSHE with the largest in-plane displacement of more than 400 times of incident wavelength is obtained at the transition $|n=55\rangle \to |n^{\prime }=57\rangle$. Remarkably enhanced PSHE occurs at near-zero Hall angles. In-plane and transverse spin-dependent displacements give their respective extremum values at the same incident angles when the Θ is near to zero, and their incident-angle deviation will become larger and larger as the $\left|\mathrm{\Theta }\right|$ increases. This unambiguously confirms the strong influence of Hall angle in the PSHE, shedding important insights into the fundamental properties of spin-orbit interaction of light in time-reversal symmetry breaking quantum systems.

The low-energy carriers governed by a massive Dirac Hamiltonian in two-dimensional materials offer exciting opportunities for electronic and optoelectronic applications, but they are typically isotropic in nature. In this study, we explore massive Dirac fermions in monolayer ${\mathrm{MoS}}_2$ subject to a one-dimensional periodic electronic potential. We demonstrate these tailored massive Dirac fermions exhibit flat bands along one direction while preserving parabolic dispersion in the orthogonal direction. This anisotropy results in strongly inhomogeneous electromagnetic interactions, leading to the emergence of hyperbolic plasmons characterized by hourglass-shaped isofrequency contours. Moreover, these plasmons facilitate the formation hyperbolic surface plasmon polaritons at the ${\mathrm{MoS}}_2$-vacuum interfaces, giving rise to unique optical scenarios, such as directional wave propagation and negative refraction. This work highlights the potential for developing advanced optical devices based on ${\mathrm{MoS}}_2$ through tailored surface patterns and establishes a promising approach for engineering the electronic structure of two-dimensional materials.

While methods based on density-functional perturbation theory have dramatically improved our understanding of electron-phonon contributions to transport in materials, methods for accurately capturing electron-electron scattering relevant to low temperatures have seen significantly less development. The case of high-conductivity, moderately correlated materials characterized by low scattering rates is particularly challenging, since exquisite numerical precision of the low-energy electronic structure is required. Recent methodological advancements to density-functional theory combined with dynamical mean-field theory ($\mathrm{DFT}+\mathrm{DMFT}$), including adaptive Brillouin-zone integration and numerically precise self-energies, enable a rigorous investigation of electron-electron scattering in such materials. In particular, these tools may be leveraged to perform a robust scattering-rate analysis on both real- and imaginary-frequency axes. Applying this methodology to a subset of ${\mathrm{ABO}}_3$ perovskite oxides—${\mathrm{SrVO}}_3, {\mathrm{SrMoO}}_3, {\mathrm{PbMoO}}_3$, and ${\mathrm{SrRuO}}_3$—we demonstrate its ability to obtain quantitative convergence of the local electron-electron contributions to the temperature-dependent direct-current resistivity. This combination of numerical techniques offers fundamental insight into the role of electronic correlations in transport phenomena and provides a predictive tool for identifying materials with potential for technological applications.

We investigate the interplay between frustration and quantum dissipation in cyclic tight-binding Hamiltonians with three, four or five sites, which form the basic blocks of common frustrated lattices. The system-bath coupling is representative of interaction between excited electronic states and phonons, thus the models are relevant to exciton transfer. Four of the five model systems are electronically frustrated when the exciton coupling parameter is positive. We show analytically and numerically that the frustrated systems have positive and negative Boltzmann elements, which lead to destructive interference and give rise to a severe sign problem in the Monte Carlo evaluation of the imaginary-time path integral. We use quadrature-based, real- and imaginary-time small matrix path integral (SMatPI) methods, which circumvent the sign problem, to obtain the time evolution of the reduced density matrix and calculate thermodynamic properties. Coupling to dissipative baths dramatically slows down the relaxation of the frustrated systems. Our calculations show that the von Neumann entropy of frustrated Hamiltonians is minimally affected by the strength of system-bath coupling, in sharp contrast to systems that do not exhibit frustration. We find that the severity of the sign problem, the dynamical slowdown, and the phonon bath effects on the evolution of the purity and the equilibrium entropy correlate perfectly with a simple measure of frustration. We discuss the dynamical consequences of electronic frustration in terms of geometric phases associated with conical intersections in the multidimensional system-bath space and also through the sign flipping of coherences, which are severely quenched in frustrated systems, and present coherence maps that illustrate the dynamical bottlenecks to relaxation. These intriguing behaviors are absent in frustrated systems that lack dissipative environments and in conventional quantum dissipative systems that do not exhibit frustration.

We present a machine learning (ML) method for efficient computation of vibrational thermal expectation values of physical properties from first principles. Our approach is based on the nonperturbative frozen phonon formulation in which stochastic Monte Carlo algorithm is employed to sample configurations of nuclei in a supercell at finite temperatures based on a first-principles phonon model. A deep-learning neural network is trained to accurately predict physical properties associated with sampled phonon configurations, thus bypassing the time-consuming ab initio calculations. To incorporate the point-group symmetry of the electronic system into the ML model, group-theoretical methods are used to develop a symmetry-invariant descriptor for phonon configurations in the supercell. We apply our ML approach to compute the temperature dependent electronic energy gap of silicon based on density functional theory (DFT). We show that, with less than a hundred DFT calculations for training the neural network model, an order of magnitude larger number of sampling can be achieved for the computation of the vibrational thermal expectation values. Our work highlights the promising potential of ML techniques for finite temperature first-principles electronic structure methods.

Polarization singularities, such as bound states in the continuum (BICs) and circular polarization points ($C$ points), are central to advanced light manipulation in photonic systems. Although the evolution and splitting of these singularities have been widely studied, the underlying dynamics of the polarization nodal lines that dictate their birth, motion, and annihilation remain inadequately explored. Here, using polarization graphs, we reveal that two families of closed nodal lines with orthogonal orientations successively emanate from the Γ point in Dirac semimetal slabs and expand outward. Their rich interlacing configurations—intersection, tangency, separation, and concentric contraction—fully govern the trajectories of accidental BICs and the generation, merging, and topological charge conversion of general BICs. These intricate configurations can be achieved not only through conventional geometric adjustments, but also through active Fermi-energy tuning of Dirac semimetal, enabling dynamic reconfiguration of general BICs and their topological charges. Under mirror-symmetry breaking, we identify two distinct mechanisms—polarization nodal-line generation and splitting/anticrossing—that govern $C$-point formation. These mechanisms are also observed in two-dimensional Dirac semimetal systems. We further reveal that $k$-space loops encircling $C$-point pairs exhibit sharply different coverage patterns on the Poincaré sphere—broad for nodal-line generation and confined for splitting—offering promising avenues for polarization manipulation. Our findings provide insights into the dynamics of polarization singularities, with potential applications in chiral photonics, nonlinear optics, and tunable light-matter interactions.

Direct-current resistivity is a key probe for the physical properties of materials. In metals, Fermi liquid (FL) theory serves as the basis for understanding transport. A $T^2$ behavior of the resistivity is often taken as a signature of FL electron-electron scattering. However, the presence of impurity and phonon scattering as well as material-specific aspects such as Fermi surface geometry can complicate this interpretation. We demonstrate how density-functional theory combined with dynamical mean-field theory can be used to elucidate the FL regime. We take as examples ${\mathrm{SrVO}}_3$ and ${\mathrm{SrMoO}}_3$, two moderately correlated perovskite oxides, and establish a precise framework to analyze the FL behavior of the self-energy at low energy and temperature. Reviewing published low-temperature resistivity measurements, we find agreement between our calculations and experiments performed on samples with exceptionally low residual resistivity. This comparison emphasizes the need for further theoretical, synthesis, and characterization developments in these and other FL materials.

Twisted ${\mathrm{WSe}}_2$ hosts superconductivity, metal-insulator phase transitions, and field-controllable Fermi-liquid to non-Fermi-liquid transport properties. In this work, we use dynamical mean-field theory to provide a coherent understanding of the electronic correlations shaping the twisted ${\mathrm{WSe}}_2$ phase diagram. We find a correlated metal competing with three distinct site-polarized correlated insulators; the competition is controlled by interlayer potential difference and interaction strength. The insulators are characterized by a strong differentiation between orbitals with respect to carrier concentration and effective correlation strength. Upon doping, a strong particle-hole asymmetry emerges, resulting from a Zaanen-Sawatzky-Allen-type charge-transfer mechanism. The associated charge-transfer physics and proximity to a van Hove singularity in the correlated metal sandwiched between two site-polarized insulators naturally explains the interlayer potential-driven metal-to-insulator transition, particle-hole asymmetry in transport, and the coherence-incoherence crossover in $3.{65}^{\circ }$ twisted ${\mathrm{WSe}}_2$.

Quantum synchronization (QS) in open many-body systems offers a promising route for controlling collective quantum dynamics, yet existing manipulation schemes often rely on dissipation engineering, which distorts limit cycles, lacks scalability, and is strongly system-dependent. Here, we propose a universal and scalable method for continuously tuning QS—from maximal synchronization under isotropic interactions to complete synchronization blockade (QSB) under fully anisotropic coupling in spin oscillator networks. Our approach preserves intrinsic limit cycles and applies to both few-body and macroscopic systems. Using two spin-1 oscillators as an example, we analytically show that QS arises solely from spin flip-flop processes and their higher-order correlations, while anisotropic interactions induce nonsynchronizing coherence. However, unlike in finite spin-1 systems, in macroscopic spin networks we find that QSB can occur even when spin flip-flop processes are present. In this regime, anisotropic interactions actively suppress synchronization, demonstrating that the emergence of QSB is not merely a trivial consequence of the absence of synchronizing channels. The proposed mechanism is experimentally feasible using XYZ interactions and optical pumping and provides a general framework for programmable synchronization control in complex quantum networks and dynamical phases of matter.

Intense quantum fluctuations arising from geometrical frustrations in kagome lattice magnets provide a feasible approach to exotic quantum states. Here, we document an unexpected isosymmetric first-order magnetic transition in the recently synthesized frustrated kagome lattice antiferromagnet $\mathrm{N}{\mathrm{d}}_3\mathrm{ScB}{\mathrm{i}}_5$, which is characterized by significant latent heat and a pronounced magnetocaloric effect, as well as discontinuous Raman shifts and negligible hysteresis. Employing the magnetocaloric effect as a detection method, in conjunction with systematical field-dependent physical properties, we uncover a distinctive 1/2 magnetization plateau phase with significant quantum fluctuations. Our study unveils $\mathrm{N}{\mathrm{d}}_3\mathrm{ScB}{\mathrm{i}}_5$ as a prototypical model with an emerging phase of enhanced quantum fluctuations triggered by first-order magnetic transitions.

Hexagonal ${\mathrm{YMnO}}_3$ is an intensively studied representative of materials exhibiting the coexistence of magnetic and electric order, called multiferroicity. Nevertheless, a controversy about its antiferromagnetic order remains. Initial reports suggested space-group symmetry $P{6}_3{c}^{\prime }{m}^{\prime }$ with ${\mathrm{Mn}}^{3+}$ spins along the crystallographic $y$ axis and antiparallel orientation of corresponding spins in adjacent $xy$ planes. However, subsequent experiments increasingly supported $P{6}_3^{\prime }c{m}^{\prime }$ symmetry with spins aligned along the crystallographic $x$ axis and parallel orientation of corresponding spins in adjacent $xy$ planes. Despite accumulating evidence for this structure, a neutron polarimetry study revealed an order according to space-group symmetry $P{6}_3^{\prime }$, where the ${\mathrm{Mn}}^{3+}$ spins are rotated by ${11}^{\circ }$ from the $x$ toward the $y$ axis. Here we report experiments by optical second harmonic generation that point to $P{6}_3^{\prime }c{m}^{\prime }$ symmetry and no evidence for spin rotation within a noise-inflicted upper limit of $\lesssim 1^{\circ }$. We suggest that the discrepancy could be resolved by an expansion of the configurations measured by neutron polarimetry and the use of samples with enlarged domains to prevent domain-wall-related contributions.

As the most common type of waves, light is an indispensable tool in our daily lives. Our understanding and management of light diffraction give rise to precise microfabrication and optical microscopy. Here we unveil that the evolution of magnetic moments in two-dimensional (2D) magnetic systems can be mapped into a spatiotemporal diffraction process, similar to the spatial diffraction of a light beam along its propagating axis. Based on this mapping, we show it is possible to encode the time evolution of magnetic moments into their initial spatial distribution, and show how to harness this principle for the generation and manipulation of spin structures in a precise way, as the analogy of laser microfabrication. Moreover, we illustrate how the spin structure in a 2D magnetic system can be made to spontaneously reemerge through phase alignment, which is the magnetic analogy of optical microscopy. These results unlock an unprecedented control over magnetic moments and are expected to open new avenues in the study of magnetic materials and the development of next-generation spintronic devices.

We consider the spin-$\frac{1}{2}$ XXZ chain with diagonal boundary fields and solve it exactly using the Bethe ansatz in the gapped antiferromagnetic regime, and we obtain the complete phase boundary diagram. Depending on the values of the boundary fields, the system exhibits several phases that can be categorized based on the ground state exhibited by the system and also on the number of bound states localized at the boundaries. We show that the Hilbert space is comprised of a certain number of towers, depending on the number of boundary bound states exhibited by the system. The system undergoes boundary phase transitions when boundary fields are varied across certain critical values. There are two types of phase transitions. In the first type, the ground state of the system undergoes a change. In the second type, named the “eigenstate phase transition,” the number of towers of the Hilbert space changes, which is again associated with the change in the number of boundary bound states exhibited by the system. We use the density matrix renormalization group and exact diagonalization techniques to probe the signature of the eigenstate phase transition and the ground-state phase transition by analyzing the spin profiles in each eigenstate.

We present a comprehensive first-principles investigation of the structural stability, vibrational characteristics, and superconducting properties of the Janus ${\mathrm{Ti}}_2\mathrm{CSH}$ monolayer. Janus MXene (JMXene) materials, such as ${\mathrm{Ti}}_2\mathrm{CSH}$, have attracted significant attention because of their intrinsic two-dimensional structure and the absence of out-of-plane symmetry, which give rise to novel physical phenomena. Phonon calculations confirm the dynamical stability of the monolayer, while electronic structure and electron-phonon coupling analyses reveal a strong phonon-mediated pairing mechanism. Anisotropic Migdal-Eliashberg theory predicts a single-gap superconducting state, with gap values between 4.29 and 4.71 meV at 10 K and a critical temperature ($T_c$) of 22.6 K. These findings demonstrate that hydrogenation of ${\mathrm{Ti}}_2{\mathrm{CS}}_2$ into ${\mathrm{Ti}}_2\mathrm{CSH}$ significantly enhances superconductivity, thereby establishing ${\mathrm{Ti}}_2\mathrm{CSH}$ as a promising two-dimensional superconductor with potential applications in quantum and nanoscale technologies.

We investigate the interplay of nonreciprocity and nonlinearity in a one-dimensional nonlinear Klein-Gordon chain of classical oscillators coupled by asymmetric springs, akin to a mechanical analog of the Hatano-Nelson model with on-site nonlinearity. Using multiple-scale analysis, we show that families of nonlinear skin breathing modes—time-periodic, boundary-localized oscillations—emerge from their linear counterparts at any nonreciprocal strength. We derive an explicit nonlinear frequency shift for these families of nonlinear breathing modes, showing its dependence on amplitude, nonlinearity type, lattice size, and nonreciprocity, and we predict the emergence of genuine skin end breathers at the boundary once their oscillation frequency and higher harmonics enter the spectral gaps of the linear spectrum. Numerical pseudo-arclength continuation confirms full families of solutions for both hardening and softening nonlinearities. Furthermore, the Floquet analysis shows that these modes can be either linearly stable or unstable, with Floquet eigenvectors exhibiting skin localization inherited from the asymmetric couplings. Our results extend the nonlinear non-Hermitian skin effect from stationary modes to intrinsically time-periodic excitations, providing a pathway to engineer and control breathing modes in nonreciprocal mechanical metamaterials.