In this study, we investigate the manipulation of Weyl orbits in topological Dirac semimetals (DSMs) with surface doping using circularly polarized light (CPL). Our investigation reveals that surface impurities in topological DSMs can couple the Fermi arcs from different Weyl sectors, leading to the breakdown of intrinsic Weyl orbits. The application of CPL can effectively reduce the overlapping between the Fermi arcs, thereby restoring partial Fermi arcs of the topological DSMs. Subsequently, extrinsic Weyl orbits emerge between opposite Weyl sectors. These extrinsic Weyl orbits present an intriguing pathway to regulate the three-dimensional (3D) quantum Hall effect(QHE). The 3D QHE induced by the extrinsic Weyl orbits can be modulated through surface magnetic perturbations and light irradiation, resulting in observable quantized Hall plateaus in the parameter space of CPL. Our findings propose a promising approach for stabilizing Weyl orbits and manipulating the 3D QHE in topological semimetals.

The first quasiexact ab initio path integral Monte Carlo (PIMC) investigation of the dynamic local field correction $\tilde{G}(\mathbf{q},z_l;r_s,\mathrm{\Theta })$ in the imaginary Matsubara frequency domain is reported, focusing on the unpolarized uniform electron gas in the warm dense matter and strongly coupled regimes. The impact of dynamic exchange–correlation effects on the static structure factor is investigated. A straightforward explanation is provided for previously reported spurious effects in the so-called static approximation [Dornheim et al., Phys. Rev. Lett. 125, 235001 (2020)], where the frequency dependence of the local field correction is neglected. The comprehensive analysis of the asymptotic Matsubara order behavior, the density dependence, and the temperature dependence hints at the intriguing possibility of constructing an analytical four-parameter representation of $\tilde{G}(\mathbf{q},z_l;r_s,\mathrm{\Theta })$ valid for a substantial part of the uniform electron gas phase diagram, which would constitute key input for thermal density functional theory simulations.

We investigate how the dynamical fluctuations of many-body quantum systems out of equilibrium can be mitigated when they are opened to a dephasing environment. We consider the survival probability (spectral form factor with a filter) evolving under different kinds of random matrices and under a spin-1/2 model with weak and strong disorder. In isolated many-body quantum systems, the survival probability is non-self-averaging at any timescale, that is, the relative variance of its fluctuations does not decrease with system size. By opening the system, we find that the fluctuations are always reduced, but self-averaging can only be ensured away from critical points. Self-averaging is achieved for the long-time dynamics of full random matrices, power-law banded random matrices deep in the delocalized phase, and the Rosenzweig-Porter ensemble in all phases except at the localization transition point. For the spin model, the survival probability becomes self-averaging only in the chaotic regime provided the initial states are in the middle of the spectrum. Overall, a strongly non-self-averaging survival probability in open systems is an indicator of criticality.

We present the construction of a reciprocal electromagnetic field by extending the Berry curvatures into four-dimensional energy-momentum space. The resulting governing equations, termed Berry-Maxwell equations, are derived by incorporating Lorentz invariance to constrain the parameter space of energy-momentum. Notably, these Berry-Maxwell equations exhibit dual and self-dual structures compared to the Maxwell equations. The very existence of Berry-Maxwell equations is independent of the geometrical phase of matter waves, implying that they cannot be directly derived from the time-dependent Schrödinger equation. Indeed, we find that the physical reality of this reciprocal electromagnetic field is rooted in the fundamental principles of special relativity and Gauss's law of Weyl monopoles. To validate our theory experimentally, we outline three effects for verification: (i) Lorentz boost of a Weyl monopole, (ii) reciprocal Thouless pumping, and (iii) plane-wave solutions of Berry-Maxwell's equations.

High-pressure x-ray diffraction up to 30 GPa, in conjunction with resonant emission x-ray spectroscopy and partial fluorescence yield x-ray absorption spectroscopy up to 52 GPa, were used to study how the structural and electronic properties of ${\mathrm{UTe}}_2$ evolve with pressure at room temperature. An orthorhombic-to-tetragonal phase transition was observed to occur between 5 and 7 GPa, with a large volume collapse of nearly 10% and a nearest U-U distance increase by about 4%. This lower-to-higher symmetry transition suggests less $5f$ electron participation in bonding when the weakly correlated superconducting phase in the tetragonal structure of ${\mathrm{UTe}}_2$ appears. Beyond 7 GPa, no new structural transitions were found up to 30 GPa. The resonant x-ray emission spectra clearly demonstrate an intermediate valence of U, nearly +3.74 at 1.8 GPa and room temperature, and reveal that the U valence shifts towards 4+, passes through a peak at 2.8 GPa, then decreases towards 3+ and settles down to a nearly constant value above 15 GPa. These experiments reveal that some fundamental structural and valence changes occur in ${\mathrm{UTe}}_2$ at relatively low pressures, which could be responsible for the interplay between unconventional superconductivity, magnetic ordering, and weakly correlated superconductivity that is manifested in the temperature-pressure phase diagram of ${\mathrm{UTe}}_2$.

In crystalline systems, higher-order topology, characterized by topological states of codimension greater than one, usually arises from the mismatch between Wannier centers and atomic sites, leading to filling anomalies. However, this phenomenon is less understood in aperiodic systems, such as quasicrystals, where bulk Wannier centers are absent. In this study, we examine a modification of Fibonacci chains and squares derived from a typical higher-order topological model, the two-dimensional Su-Schrieffer-Heeger model, to investigate their higher-order topological properties. We discover that topological interfacial states, including corner states, can emerge at the interfaces between modified Fibonacci chains and squares derived from topologically distinct parent systems. These interfacial states can be characterized by a shift in the local Wannier center spectrum, which indicates filling anomalies in finite samples. We numerically validate these interfacial states using the finite element method in phononic and photonic Fibonacci quasicrystals. Our results provide insight into the higher-order topology of quasicrystals and open avenues for exploring novel topological phases in aperiodic structures.

Here, we present electronic structures of the topological nodal line semimetal ZrSiS along in-plane and out-of-plane directions using high-field torque magnetometry. The torque signal measured up to 35 T exhibited clear de Haas-van Alphen (dHvA) oscillations in both directions; however, the angular dependence of the frequencies along these directions is quite different. Our Berry phase (${\mathrm{\Phi }}_{\text{B}}$) calculations using the Landau level fan diagram show that ${\mathrm{\Phi }}_{\text{B}}\approx \pi$, confirming the nontrivial topology of ZrSiS. Using Lifshitz-Kosevich and Dingle temperature analyses on the temperature and field-dependent dHvA oscillations data, we calculated all relevant physical parameters. We found that Dirac fermions exhibit anisotropic transport properties along the in-plane and out-of-plane directions, with in-plane fermions having a longer scattering time, a higher mean free path, and greater quantum mobility. To explain the experimental results, we computed the electronic bands and Fermi surface of ZrSiS using ab initio density functional theory. The electronic bands revealed multiple Dirac cones near the Fermi level, displaying linear dispersion over an energy range of 2 eV. The possible dHvA frequencies were computed using Onsager's relation, and the calculated frequencies closely align with the experimental dHvA frequencies. The anisotropic quantum transport properties presented here provide valuable insights into the unique Dirac fermion physics inherent in ZrSiS.

Bipolar magnetic semiconductors (BMSs) enable controlled spin polarization for advanced spintronic applications. However, their applications are greatly hindered by the limited number of available BMS materials. We demonstrate a family of egg-tray graphene nanoribbons (EGNRs) featuring both zigzag edges and internal defects (pentagons and heptagons) constructed by slicing egg-tray graphene. First-principles calculations show that these EGNRs exhibit distinguished BMS behavior, along with other spintronic properties such as half-metallicity and spin-gapless semiconductivity (SGS). Most notably, when the width of EGNRs is small, the internal defect regions significantly influence the spin density distribution of the entire ribbon, resulting in spin polarization not only localized at the edge carbon atoms but also across the defect areas. The synergistic effect between these distinct regions promotes the formation of stable BMSs. The calculations also show a gradual transition from BMS to semiconductor or half-metal, controlled by the edge states while the width of EGNRs increases. Furthermore, including pentagons and heptagons at the edges of EGNRs compresses BMS behavior, transforming the material into an SGS. In this paper, we provide a route to achieve and control BMSs in a family of carbon nanoribbon materials based on the combination of edge cutting and topology control of graphene materials.

Entanglement of mixed quantum states can be quantified using the partial transpose and its corresponding entanglement measure, the logarithmic negativity. Recently, the notion of partial transpose has been extended to systems of anyons, which are exotic quasiparticles whose exchange statistics go beyond the bosonic and fermionic cases. Studying the fundamental properties of this anyonic partial transpose, we first reveal that when applied to the special case of fermionic systems, it can be reduced to the fermionic partial transpose or its twisted variant depending on whether or not a boundary Majorana fermion is present. Focusing on ground state properties, we find that the anyonic partial transpose captures both the correct entanglement scaling for gapless systems, as predicted by conformal field theory, and the phase transition between a topologically trivial and a nontrivial phase. For non-Abelian anyons and the bipartition geometry, we find a rich multiplet structure in the eigenvalues of the partial transpose, the so-called negativity spectrum, and reveal the possibility of defining both a charge- and an imbalance-resolved negativity.

We theoretically investigate the transport properties of a Josephson junction composed of superconductor/minimally twisted bilayer graphene/superconductor structures. In the presence of an out-of-plane electric field, the low-energy physics is best described by a network of domain-wall states. Depending on system parameters, they lead to the emergence of zigzag or pseudo-Landau-level modes with distinct transport characteristics. Specifically, we find zigzag modes feature linear dispersion of Andreev bound states, resulting in a $4\pi$-periodic Josephson current. In contrast, pseudo-Landau-level modes exhibit flat Andreev bound states and, consequently, a vanishing bulk Josephson current. Interestingly, edge states can give rise to $4\pi$-periodic Josephson response in the pseudo-Landau-level regime. We also discuss experimental signatures of such responses.

In this paper we propose an $S$-matrix approach to numerical simulations of network models and apply it to random networks that we proposed in a previous work [I. A. Gruzberg, A. Klümper, W. Nuding, and A. Sedrakyan, Phys. Rev. B 95, 125414 (2017)]. Random networks are modifications of the Chalker-Coddington (CC) model for the integer quantum Hall transition that more faithfully captures the physics of electrons moving in a strong magnetic field and a smooth disorder potential. This method has considerable advantages compared to the transfer matrix approach and gives the value $\nu \approx 2.4$ for the critical exponent of the localization length in a random network. This finding confirms our previous result and is surprisingly close to the experimental value ${\nu }_{\text{expt}}\approx 2.38$ observed at the integer quantum Hall transition but substantially different from the CC value ${\nu }_{\text{CC}}\approx 2.6$.

The topological charge Hall effect (TCHE) and the topological spin Hall effect (TSHE), arising from ferromagnetic (FM) and antiferromagnetic (AFM) skyrmions, respectively, can be elucidated through the emergence of spin-dependent Berry gauge fields that affect the adiabatic flow of electrons within the skyrmion texture. TCHE is absent in systems with parity-time (PT) symmetry, such as collinear AFM systems. In this paper, we theoretically study TCHE and TSHE in a canted antiferromagnet within the diffusive transport regime. Spin canting or weak ferromagnetism in canted AFMs, which break the PT symmetry, may arise, e.g., from strong homogeneous Dzyaloshinskii-Moriya interactions. Using a semiclassical Boltzmann approach, we obtain diffusion equations for the spin and charge accumulations in the presence of finite spin flip and spin-dependent momentum relaxation times. We show that the weak ferromagnetic moment stemming from spin canting and the subsequent breaking of PT symmetry, results in the emergence of both finite TCHE and TSHE in AFM systems.

We study a superconductor Josephson junction with a Bogoliubov Fermi surface, employing McMillan's Green's function technique. The low-energy degrees of freedom are described by spinless fermions (bogolons), where the characteristic feature appears as an odd-frequency pair potential. The differential equation of the Green's function is reduced to the eigenvalue problem of the non-Hermitian effective Hamiltonian. The physical quantities such as the density of states and pair amplitude are then extracted from the obtained Green's function. We find that the zero energy local density of states at the interface decreases as the relative phase of the Josephson junction increases. This decrease is accompanied by the generation of an even-frequency pair amplitude near the interface. We also clarify that the $\pi$-junction-like current phase relation is realized in terms of bogolons. In contrast to conventional $s\text{−}\mathrm{wave}$ superconductor junctions, where even-frequency pairs dominate in the bulk and odd-frequency pairs are generated near the interface, our findings illuminate the distinct behaviors of junctions with Bogoliubov Fermi surfaces. We further explore spatial dependencies of these physical quantities systematically using quasiclassical Green's functions.

We discuss a class of three-band non-Abelian topological insulators in three dimensions that carry a single bulk Hopf index protected by spatiotemporal ($\mathcal{PT}$) inversion symmetry. These phases may also host subdimensional topological invariants given by the Euler characteristic class, resulting in real Hopf-Euler insulators. Such systems naturally realize helical nodal structures in the three-dimensional Brillouin zone, providing a physical manifestation of the linking number described by the Hopf invariant. We show that, by opening a gap between the valence bands of these systems, one finds a fully-gapped “flag” phase, which displays a three-band multigap Pontryagin invariant. Unlike the previously reported $\mathcal{PT}$-symmetric four-band real Hopf insulator, which hosts a $\mathbb{Z}\oplus \mathbb{Z}$ invariant, these phases are not unitarily equivalent to two copies of a complex two-band Hopf insulator. We show that such uncharted phases can be obtained through dimensional extension of two-dimensional Euler insulators, and that they support (i) an optical bulk integrated circular shift effect quantized by the Hopf invariant, (ii) quantum-geometric breathing in the real-space Wannier functions, and (iii) surface Euler topology on boundaries. Consequently, our findings pave the way for novel experimental realizations of real-space quantum geometry, as these systems may be directly simulated by utilizing synthetic dimensions in metamaterials or ultracold atoms.

We demonstrate that the optical conductivity of a Fermi liquid (FL) in the absence of umklapp scattering is dramatically affected by the topology of the Fermi surface (FS). Specifically, electron-electron ($\mathit{ee}$) scattering leads to rapid current relaxation in systems with multiple, or multiply connected, FSs, provided that the valleys have different effective masses. This effect results from intervalley drag. We microscopically derive the optical conductivity of a two-valley system, both within the FL regime and near a quantum critical point (QCP) of the Ising-nematic type. In the FL regime, intervalley drag restores the Gurzhi-like scaling of the conductivity, $\mathrm{Re}\sigma \left(\omega \right)\sim {\omega }^0$. This dependence contrasts sharply with the previously identified subleading contribution to the conductivity of a two-dimensional FL with a single convex FS, where $\mathrm{Re}\sigma \left(\omega \right)\sim {\omega }^{2}ln\left|\omega \right|$. The vanishing of the leading term in the optical conductivity is a signature of geometric constraints on $\mathit{ee}$ scattering channels, which are lifted for a multiply connected FS. A large differential response, $d\mathrm{Re}\sigma /d\mu$ with $\mu$ being the chemical potential, is predicted at the Lifshitz transition from a single-valley to a multivalley FS, which should be observable within the experimentally accessible frequency range. Near a QCP, intervalley drag leads to a ${\left|\omega \right|}^{-2/3}$ scaling of $\mathrm{Re}\sigma \left(\omega \right)$ in two dimensions, thus providing a specific current-relaxing process for this long-standing conjecture.

We develop a percolation model for face centered cubic binary alloys with chemical short-range order (SRO) to account for chemical ordering/clustering that occurs in nominally random solid solutions. We employ a lattice generation scheme that directly utilizes the first nearest neighbor Warren-Cowley SRO parameter to generate the lattice. We quantify the effects of SRO on the first nearest neighbor three-dimensional (3D) site percolation threshold using the large cell Monte Carlo renormalization group method and find that the 3D site percolation threshold is a function of the SRO parameter. We analyze the effects of SRO on the distribution of the total number of distinct clusters in the percolated structures and find that short-ranged clustering promotes the formation of a dominant spanning cluster. Furthermore, we find that the scaling exponents of percolation are independent of SRO. We also examine the effects of SRO on the 2D–3D percolation crossover and find that the thickness of the thin film for percolation crossover is a function of the SRO parameter. We combine these results to develop a percolation crossover model to understand the electrochemical passivation behavior in binary alloys. The percolation crossover model provides a theoretical framework to understand the critical composition of passivating elements for protective oxide formation. With this model, we show that SRO can be used as a processing parameter to improve corrosion resistance.