Edge transport serves as a powerful probe of remarkable low-energy properties of fractional quantum Hall states, including the anyonic character of their excitations. Here, we develop a theory of fractional quantum Hall edges driven out of equilibrium, which is based on the Keldysh action for the bosonized chiral Luttinger liquid. With this nonequilibrium FQH bosonization framework, we first consider a single-mode Laughlin edge and analyze the full counting statistics of charge, the quasiparticle Green's functions, and tunneling transport properties through a quantum point contact, allowing for generic edge excitations. We then extend the formalism to multimode edges with intermode interactions, and explore, with a focus on the $\nu =4/3$ and $\nu =2/3$ edges as paradigmatic examples, how interaction-induced fractionalization of anyons modifies the edge dynamics and the associated transport observables. While the full counting statistics probes the fractionalized charge of the excitations, the Green's functions and tunneling transport are governed by mutual braiding phases of fractionalized excitations and tunneling quasiparticles. We emphasize in particular the effect of interaction-induced fractionalization on the Fano factor $F$ and the differential Fano factor $F_d$, observables that can be measured experimentally. Our formalism, which provides a unified framework for nonequilibrium transport in FQH edges and Luttinger liquids, permits extracting anyonic braiding information from nonequilibrium edge-transport experiments, and paves the way to various extensions, including more involved experimental geometries and edge structures.

In superconductors with multiple pairing channels, Bardasis-Schrieffer modes and clapping modes arise as fluctuations in channels whose angular momenta differ from that of the pair condensate. Crystal symmetries often impose selection rules that keep these modes optically dark. We show that if pairing occurs around a single Fermi surface, trigonal warping renders both of these modes, as well as the quasiparticle excitation gap, visible in the longitudinal and Hall optical responses. Our results suggest that rhombohedral graphene multilayers, which are believed to host the required ingredients, might offer an ideal setting for the study of exotic superconducting collective modes.

We study the three-point equal-time correlations of the density in a weakly interacting spin-1/2 Fermi gas and present two results. First, we compute the three-point correlation $s_3^{\rho }({\mathbf{q}}_1,{\mathbf{q}}_2)$ for the total density $\rho ={\rho }_{\uparrow }+{\rho }_{\downarrow }$ exactly as a function of ${\mathbf{q}}_1$ and ${\mathbf{q}}_2$ to first order in a dimensionless interaction parameter $\mathcal{I}$. This generalizes a previous result that related the singularity in $s_3^{\rho }({\mathbf{q}}_1,{\mathbf{q}}_2)$ to the Landau Fermi liquid parameters $F_0^s$ and $F_0^a$ that applied in a certain long-wavelength collinear limit of ${\mathbf{q}}_1$ and ${\mathbf{q}}_2$. Second, we compute the leading order $\mathcal{O}\left({\mathcal{I}}^3\right)$ interaction correction to the same-spin three-point correlation function $s_3^{\uparrow }({\mathbf{q}}_1,{\mathbf{q}}_2)$ in the long-wavelength collinear limit. These results are directly relevant to current experiments on atomic Fermi gases using quantum gas microscopy.

We present a consistent continuum description of finite graphene nanoribbons within the Dirac Hamiltonian formalism, addressing the interplay between geometry and boundary conditions. Although effective Dirac models are widely used to describe low-energy electronic properties, their application to finite systems requires systematic treatment of boundary-condition compatibility. We show that boundary conditions associated with zigzag and armchair edges cannot, in general, be imposed independently in a finite geometry. Their simultaneous implementation introduces nontrivial constraints that define a well-posed spectral problem. Within the consistent framework developed here, we derive the complete set of admissible solutions, including both oscillatory and edge-localized states. We demonstrate that the spectrum organizes into valley-coupled modes with identical eigenenergies, and that the existence of edge-localized states is restricted to specific regions of the spectral parameter space, depending explicitly on the system size. Furthermore, we show that different but unitarily equivalent forms of the Dirac Hamiltonian become physically inequivalent once boundary conditions are imposed, as they induce distinct constraints on the wavefunction components. To validate our analytical framework, we perform extensive numerical comparisons with tight-binding calculations on the honeycomb lattice. The results obtained here confirm that our consistent boundary-condition implementation correctly captures the physics of both zigzag and armchair terminations, including the absence of topologically protected edge states in armchair geometries. Our results establish precise criteria for the consistent application of continuum models to finite graphene nanoribbons and clarify the role of boundary conditions in their electronic structure.

In semiconductor nanostructures, optical excitation typically creates bound electron-hole states, such as excitons, trions, and larger complexes. Their relative motion is described by the Wannier equation, which is valid only for spatially extended motion in the Coulomb-dominated, weak-confinement limit. Other small nanostructures, such as quantum dots, are in the confinement-dominated strong confinement regime, where the wave function factorizes into independent electron and hole parts. Nanoplatelets are in between the two regimes and require solving an unfactorized higher-dimensional Schrödinger equation, which is computationally expensive. This work demonstrates how tensor networks can partially overcome this problem, using CdSe nanoplatelets as an example. The method is also applicable to related two-dimensional systems. As a demonstration, we calculate the excitonic and trionic ground states, as well as several excited states, for nanoplatelets of varying sizes, including their energies and oscillator strengths. More importantly, overall strategies for using tensor networks in real space for systems under intermediate confinement have been developed.

We develop a theoretical framework for Landau levels in quasiperiodic twisted bilayer graphene at a ${30}^{\circ }$ twist angle, a system without translational symmetry but possessing 12-fold rotational symmetry. Using a quasiband formalism, we incorporate the magnetic field through a conventional momentum substitution in the zero-field Hamiltonian. This approach provides a transparent physical interpretation by directly relating the Landau levels to the quasiband structure, allowing them to be understood as quantized orbits of quasiband pockets. By using this method, we reveal distinctive spectral features, including nearly flat bands with weak magnetic-field dependence and highly degenerate levels arising from 12 off-center pockets. The resulting Landau levels are classified by two quantum numbers: the Landau-level index and the angular momentum associated with the underlying quasicrystalline symmetry. We also compute the magneto-optical conductivity and show that optical transitions follow angular-momentum selection rules enforced by the 12-fold symmetry. Our approach provides a symmetry-based and computationally efficient framework for bulk quantum magneto-optics in quasicrystalline van der Waals systems, predicting spectroscopic signatures accessible in high-field infrared and THz experiments.

Several photoemission spectroscopies and, in particular, Auger spectroscopy, involve double ionization processes. For the numerical simulation of these spectroscopies it is convenient to use the particle-particle channel of the two-body Green's functions since its poles correspond to excitation energies in which the final state has two more particles (holes or electrons) than the initial state. In standard approaches it is approximated within the random phase approximation. As a consequence only the quasiparticles of the photoemission spectrum are captured but none of the satellites features. In this work, we go beyond this approximation by employing the multichannel Dyson equation. By coupling the particle-particle two-body Green's function to the three-hole–one-electron and three-electron–one-hole channels of the four-body Green's function, the multichannel Dyson equation incorporates correlations beyond the random phase approximation in a straightforward way. We are thus able to describe both quasiparticles and satellites in the photoemission spectra.

We demonstrate how pump-probe techniques enable specific spectroscopic diagnostics of fracton phases of matter by studying lineon-planon braiding in the paradigmatic X-cube model. Our discussion builds on previous works probing anyonic exchange statistics in conventional spin liquids, but the extension to fracton phases reveals qualitatively different phenomena due to the restricted mobility of fractionalized excitations. A key feature is that nearby planons can form an emergent bound state by accessing different planes via alternative pairing configurations. We show that this bound state qualitatively modifies the long-time linear and nonlinear responses, leading to an asymptotic linear-in-$t$ behavior for the pump-probe signal ${\chi }_{\mathit{ZZX}}$. By contrast, swapping the pump and probe polarizations produces a nonlinear response ${\chi }_{\mathit{XXZ}}$ that is asymptotically $t$ independent. This asymmetry reflects the fact that the two species of fractionalized excitations live in different spatial dimensions. Thus the pump-probe signals studied here are sensitive to (i) nontrivial braiding statistics in three dimensions, (ii) the existence of bound states among fractionalized excitations, and (iii) the one-dimensional mobility of lineons. Our results therefore provide spectroscopic signatures that distinguish fracton phases from conventional topologically ordered spin liquids.

We compute high-resolution angle-resolved photoemission spectroscopy of the Hubbard model using the unbiased determinant quantum Monte Carlo algorithm, revealing an asymmetry between electron and hole doping. Electron doping exhibits more coherent quasiparticles and stronger antiferromagnetic correlations compared to hole doping. At low doping, a nodal-antinodal dichotomy on the Fermi surface is observed, similar to cuprate experiments. The dichotomy reflects the momentum dependence of the Mott gap, as manifested in both the spectral function and the self-energy. For hole doping, we observe a transition toward the pseudogap, without signature of pocket formation. The simulated nuclear magnetic resonance pseudogap temperatures do not necessarily agree with the temperature determined by spectroscopy. These findings collectively suggest the pseudogap is a smooth crossover driven by strong correlations.

Motivated by the recent interest in the criticality of open quantum many-body systems, we study nonlinear sigma models with complexified couplings as a general framework for nonunitary field theory. Applying the perturbative renormalization-group analysis to the tenfold symmetric spaces, we demonstrate that fixed points with complex scaling dimensions and critical exponents arise generically, without counterparts in conventional nonlinear sigma models with real couplings. We further clarify the global phase diagrams in the complex-coupling plane and identify both continuous and discontinuous phase transitions. Our work thus identifies nonlinear sigma models as a representative setting for studying complex critical points and elucidates universal aspects of critical phenomena in complexified field theory.

We revisit the derivation of the orbital magnetization formula for periodic crystals in current density functional theory (CDFT). Our derivation computes the linear response of the energy density to a periodic magnetic field in the long-wavelength limit. We unveil a Ward identity which connects the current vertex to the derivative of the Kohn-Sham self-energy. It is confirmed that the orbital magnetization of the interacting solid can be computed exactly (in principle) from the self-consistent eigenfunctions and eigenvalues of the Kohn-Sham equation of CDFT.

Recent experiments on graphene multilayers under displacement field have demonstrated a wide variety of electronically ordered phases, including valley and/or spin polarized phases as well as potentially unconventional superconducting phases. In addition, quantum oscillation measurements in Bernal bilayer graphene showed the presence of electronic nematic states. Here, we investigate the emergence of nematic order in this system within a self-consistent Hartree-Fock framework, using a realistic band structure with trigonal warping and a dual-gate screened Coulomb interaction. We compute the phase diagram as carrier density and displacement field are varied, and find a sequence of isospin (spin and valley) polarized states consistent with experiment, including partially polarized phases with a large Fermi pockets for isospin-majority carriers and smaller Fermi pockets for isospin-minority carriers. Within these partially isospin polarized states, we identify regions with three $C_3$-symmetric pockets for the minority carriers and regions with only one or two such pockets, implying that the system develops a spontaneous nematic order that breaks $C_3$ symmetry. We find numerically that nematicity emerges near the boundary between fully and partially polarized phases and is controlled by the strength of the screened interaction. We analytically derive a criterion for the nematic order, which agrees with our numerical results.

The temperature increase in the contact regions between solids in sliding contact can easily reach several hundred Kelvin and thereby dramatically affect friction and wear. The classical theories by Jaeger, Archard, and Greenwood, commonly used to estimate flash temperature, ignore the multiscale nature of real surfaces and instead approximate the frictional heat sources with circular or square shapes. Here, we present an analytical theory for the flash temperature valid for randomly rough surfaces with roughness across arbitrarily many decades in length scale. The theory extends established methods for stress correlation functions and peak stresses to temperature. Numerical results for rubber sliding on concrete, and granite on granite, are presented as illustrations. We show that classical theories for flash temperature fail severely for surfaces with multiscale roughness.

Spin defects in diamond are promising platforms for quantum sensing. The longest electron spin relaxation times ($T_1$) at room temperature for solid-state defects are observed in nitrogen vacancy centers in diamond, which can reach 6.67 ms, and substitutional nitrogen (“P1 centers”) in diamond, which exhibit a $T_1$ of 2 ms. No other solid-state defect has exhibited millisecond-scale spin relaxation times at room temperature thus far. Here, we characterize the spin properties of the WAR5 defect in diamond with pulsed electron spin resonance. The observed $T_1$ is one of the longest for solid-state spin defects: 0.97(27) ms at room temperature and 14.38(19) min at 4 K. The observed coherence time ($T_2$) is 246(7) $\mu \mathrm{s}$, which can be extended to 6.49(34) ms at 4 K with dynamical decoupling. Furthermore, we demonstrate optical spin polarization with a range of wavelengths from 405 to 500 nm and propose potential zero-phonon line candidates.

We report zero-field (ZF) and transverse-field (TF) muon-spin rotation/relaxation ($\mu \mathrm{SR}$) measurements on superconducting ${\mathrm{Li}}_{0.95}\mathrm{FeAs}$ ($T_{\mathrm{c}}\simeq 16.0\mathrm{K}$) grown by a high-pressure self-flux method. The ZF-$\mu \mathrm{SR}$ data show no detectable change of the electronic relaxation rate on cooling through $T_{\mathrm{c}}$, providing no evidence for time-reversal-symmetry breaking in the superconducting state. TF-$\mu \mathrm{SR}$ measurements reveal a well-developed vortex response with strong flux pinning and a negligible nonsuperconducting contribution, confirming that superconductivity is a bulk property of the sample. From the second moment of the internal field distribution we determine a low-temperature in-plane magnetic penetration depth ${\lambda }_{ab}=245\left(15\right)$ nm. The temperature dependence of the normalized superfluid density is well described by an effective two-gap model with ${\mathrm{\Delta }}_1=2.0\left(2\right)\mathrm{meV}$ and ${\mathrm{\Delta }}_2=0.7\left(2\right)\mathrm{meV}$. A quantitative comparison with band weights derived from angle-resolved photoemission spectroscopy shows that the $\mu \mathrm{SR}$ response is dominated by the Fermi-surface sheets carrying the intermediate and small superconducting gaps, whereas the band hosting the largest gap contributes only about 3% to the total superfluid density and is therefore not resolved in the present analysis. Taken together, these results provide an independent bulk confirmation of nodeless multigap superconductivity in ${\mathrm{Li}}_{0.95}\mathrm{FeAs}$ without detectable time-reversal-symmetry breaking and show how $\mu \mathrm{SR}$ reconciles the gap scales reported by bulk- and surface-sensitive probes in this multiband system.

The interplay among orbital-selective electron correlation, Hund's coupling, tunable structural motifs, and Kondo-like scattering establishes a compelling paradigm for understanding and engineering correlated multiorbital systems, as vividly exemplified by nickelate superconductors. Here, using high-resolution angle-resolved photoemission spectroscopy combined with theoretical calculations, we systematically investigate the electronic properties of trilayer nickelates. In ${\mathrm{La}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$, we observe pronounced interorbital hybridization, whereas in ${\mathrm{Pr}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$, the flat $d_{z^2}$ band becomes markedly incoherent and diminishes in spectral weight. By contrast, the dispersive $d_{x^2-y^2}$ bands retain coherence in both compounds. This striking incoherence/coherence dichotomy identifies an orbital differentiation modulated by the interlayer Ni-O-Ni bonding angle. The depletion of the $d_{z^2}$ orbitals further suppresses the interorbital hybridization and influences the density-wave transition in ${\mathrm{Pr}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$. Moreover, the density-wave gap is substantially reduced in ${\mathrm{Pr}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$, likely due to extra scattering channels provided by the local moments of $\mathrm{P}{\mathrm{r}}^{3+}$ cations. Our findings reveal a structural control parameter for the multiorbital correlated state in trilayer nickelates, providing important insights into the emergence of superconductivity under high pressure.

Accurate surface thermochemistry requires balanced error cancellation between extended slabs and molecular reference states. This balance can fail whenever the electronic-structure error is not transferable across the chemically distinct species entering a thermodynamic cycle. Here we examine this problem in single-determinant fixed-node diffusion Monte Carlo (SD-FNDMC) for oxygen-reduction intermediates on Pt(111) and selected CO-reduction intermediates on Cu(111). Gas-phase thermochemistry is used to diagnose the reference-state imbalance, and a hybrid cycle is introduced to separate slab-adsorbate binding from molecular formation. The hybrid cycle keeps the surface binding term at the SD-FNDMC level, where cancellation is expected to be most favorable, and replaces the molecular formation contribution with a benchmark coupled cluster reference. For Pt(111), the resulting correction is small for ${}^{*}\mathrm{O}$ and ${}^{*}\mathrm{OH}$ but larger for ${}^{*}\mathrm{OOH}$, while the geometry-matched refinement gives only a secondary correction. Applying the same cycle to ${}^{*}\mathrm{CHO}$ and ${}^{*}\mathrm{COH}$ adsorption on Cu(111) gives corrections of opposite sign, showing that the bias is controlled primarily by the electronic structure of the corresponding HCO and COH molecular references rather than by adsorbate geometry alone. This decomposition identifies molecular reference imbalance as a separable source of error in SD-FNDMC surface thermochemistry and reduces the corresponding bias without modifying the SD-FNDMC slab-binding contribution.

The crystallographic structure of iron under extreme conditions is a key benchmark for state-of-the-art experimental and computational methods. Moreover, it plays a crucial role in our understanding of planetary cores, as it strongly influences the interpretation of observational data and, consequently, our knowledge of their internal structure and dynamics. However, even the crystal structure of pure solid iron under Earth's core conditions remains uncertain, with the commonly expected hexagonal close-packed phase being energetically competitive with several cubic structures. In this study, iron was compressed in a diamond anvil cell to pressures exceeding 200 GPa and dynamically probed near its melting point using MHz-frequency x-ray pulses from the European X-ray Free-Electron Laser. In the pressure range between 120 and 160 GPa, the high temporal resolution of the structural snapshots at elevated temperatures revealed the face-centered cubic phase, extending its observed stability to higher pressures than previously reported. Brief appearances of intermediate or disordered phases, including body-centered cubic (bcc) and stacking-faulted structures, were also observed. Above 230 GPa, new diffraction reflections emerged at high temperatures and are interpreted as evidence for the nucleation of a previously unreported phase, which subsequently evolved into a powderlike diffraction pattern characteristic of the bcc structure. The unprecedented time resolution of the structural data acquired during rapid heating and cooling cycles provides insights into the kinetics and mechanisms of phase transformations in iron at these extreme pressures.

Quantum-electrodynamical density-functional theory (QEDFT) provides a first-principles framework for describing materials coupled to quantized electromagnetic fields. While QEDFT has successfully captured cavity-induced modifications of electronic structures in atoms and molecules, a fully self-consistent and accurate framework to simulate and predict the structural, phonon-related, polarization, and optical response of periodic solids in optical cavities has remained elusive. Here, we introduce a unified QEDFT approach that combines collective light-matter coupling parameter in the electronic ground state, density-functional perturbation theory for phonons, and real-time time-dependent QEDFT for optical excitations. This framework enables ab initio calculations of cavity-modified electronic and phononic dispersions, Born effective charges, dielectric tensors, and both resonant and nonresonant optical absorption spectra. Using wurtzite gallium nitride (GaN) in an optical cavity as a case study, we demonstrate that the quantized vacuum field reshapes electronic, phononic, and polarization properties, producing experimentally accessible signatures in the dielectric function and absorption spectra. These results establish QEDFT as a general first-principles platform for predicting and exploring cavity-modified quantum materials.

We introduce a mechanism that produces a Hall-like transverse response in time-reversal-invariant materials, driven entirely by geometric effects. Specifically, we demonstrate that a tilted potential interface causes electron wave packets to undergo a refractionlike deflection upon transmission through the barrier, leading to a finite transverse current and a corresponding Hall-like conductance. Our analytical framework captures the essential features of this refraction-driven charge transport, and the resulting transverse conductance profile is corroborated by numerical simulations across different lattice models and device geometries. We further visualize our predicted effect through real-time wave packet dynamics, which reveals its purely geometric origin and the robustness of the transverse response. These findings establish a fundamentally distinct class of Hall-like transport phenomena in mesoscopic systems that preserve time-reversal symmetry.