Papers

We show that edge states in fractional quantum Hall effect samples can be selectively probed and excited with sub-terahertz optical spectroscopy. Using the composite fermion (CF) mean-field framework, which maps the strongly correlated fractional quantum Hall problem onto an effective integer quantum Hall problem, we calculate the absorbance spectrum for the Jain sequence of filling fractions including both bulk and edge states. The CF edge-state absorption peaks appear in the millimeter-wave to sub-terahertz range, e.g., 60-500 GHz at B = 10 T in GaAs, i.e. they are blueshifted with respect to the bulk CF cyclotron frequency but are well below the integer quantum Hall cyclotron frequency scale at the same magnetic fields. The number of resolved peaks in each series of the absorption spectrum counts the filled Lambda-levels and fingerprints the fraction. Inversion symmetry breaking near the edge activates optical transitions forbidden in the bulk and enables second-order nonlinear processes in electric-dipole approximation. The absolute frequency scale of the spectrum is set by the CF effective mass, which is generated entirely by electron-electron interactions, so the absorption spectrum provides a direct optical probe of this interaction-induced mass.

In swollen elastomers, elasticity can arrest macroscopic demixing between the polymer network and the solvent, producing stable domains of finite size. While previous theories have focused on isotropically swollen elastomers, anisotropy strongly influences the phase behavior of many related systems, such as gels and crosslinked polymer blends. Building on the approach developed in Part I of this two-part paper, we investigate the effects of two experimentally induced sources of anisotropy: uniaxial swelling and stiffness gradients. We show that uniaxial swelling can lead to the formation of stable lamellar microphases and modify phase behavior, while stiffness gradients can cause spatial variations in the characteristic microphase size.

The temperature-dependent band gap of solids is usually computed from the perturbative Allen-Heine-Cardona (AHC) electron-phonon self-energy evaluated on-shell. Extending AHC to arbitrary frequency $\omega$ to determine the full spectral function via the Dyson equation is known to fail, misplacing satellites and yielding no broadening at band extrema, while non-perturbative supercell (SC) methods have focused on eigenvalue averages rather than lineshapes, and approaches based on special displacements cannot describe the full lineshape, or the lineshift at degenerate bands. Here we use a non-perturbative Green's function method (NPG), stochastically sampling distorted SC configurations, from which the spectral function, including lineshift, linewidth, and asymmetry, follows directly, and we recover finite spectral weight at the renormalized band extrema. We prove that the perturbative self-energy, computed to any order with the bare propagator and introduced into the Dyson equation, has an imaginary part that vanishes within the bare gap, giving incorrect spectral functions: self-consistency of the propagator is essential to broaden the band edges. NPG satisfies this property by construction, and contains all non-bubble diagrams. We also give a simple explanation of why SC methods converge with much smaller SCs than the corresponding $\mathbf{q}$-grids required by perturbation theory. For the band gap shift itself, the NPG and on-shell AHC results are found to be comparable, demonstrating that higher-order terms do not significantly alter the resulting renormalization in diamond. When it comes to the spectral function though, our results show that going beyond bare perturbation theory is not merely more accurate, but necessary, and NPG provides a robust framework to capture spectral broadening and higher-order effects from first principles.

Complex hypergraphs (chygraphs) contain graphs, hypergraphs, multiplex and interacting networks as special cases, and the percolation threshold of all of them follows from one symbolic calculation: the spectrum of a tensor $A$ built from four matrices of first moments. That calculation stops at the threshold. Here I show that $A$ is the Jacobian, at its trivial fixed point, of a non-linear self-consistency map whose non-trivial fixed point is the giant component fraction, so threshold and order parameter are two orders of one object on one index set. Carrying the expansion one order further gives the critical amplitude $B$ in $S=B\Lambda+O(\Lambda^2)$ in closed form, and exposes a hierarchy: first moments fix the threshold, second moments the amplitude, and only the generating functions themselves the order parameter away from it. Dropping the assumption that a complex's participation in different layers is independent generalises the tensor again, replacing unconditional first moments by inclusion-biased second moments: distributions with identical marginals have different thresholds and different order parameters. Six constructions from the literature are then solved by substitution, among them AND- against OR-logic hypergraph percolation, which share a chygraph and differ in one generating function, and SIR epidemics with two levels of mixing, whose household reproduction number falls out of the tensor. A reported failure of mean-field theory on strongly clustered graphs is shown to be a failure of applying it to the wrong object: mapped onto the treelike backbone rather than the clustered graph, the same calculation reproduces the exact threshold, order parameter and critical exponents. Everything is implemented in one class, in which a chygraph is specified once by its generating functions and then returns all three, and validated against Monte Carlo simulation.

Impact craters relax over long timescales, and this process is commonly described by a diffusion model. The diffusion coefficient determines the relaxation rate, and it has been estimated from observed crater shapes. This coefficient, however, represents the combined effect of several physical mechanisms. Its physical basis has not been revealed yet. In this study, we isolate the contribution of seismic vibration in a controlled experiment. Using a quasi-two-dimensional setup, we first confirm that a linear diffusion equation reproduces the crater relaxation. We then measure the diffusion coefficient and obtain the scaling form through systematic experiments. We find that the diffusion coefficient is proportional to the crater diameter. This dependence is not expected for simple diffusion. We interpret this dependence as arising because the thickness of the vibro-fluidized granular layer scales with the crater depth. This scaling relation is the main result of this study. We then apply it to the Moon with a parameterized model of impact-driven seismic spreading in the regolith layer. Integrating over the impact flux yields a macroscopic coefficient nearly proportional to crater diameter for shallow-layer-like spreading. Its magnitude depends on uncertain model parameters but is consistent with observations for plausible values. These results indicate that vibration is a physically plausible contributor to crater relaxation on the Moon.

In a previous work [Masubuchi et al., Compos. Sci. Technol. 134, 43 (2016)], a fiber-length distribution function was proposed as the hypoexponential, or Erlang-type, convolution of two exponential waiting lengths, motivated by two independent Poisson processes for breakage and for blocking of adjacent breaks. The present paper further evaluates this hypoexponential form by introducing a finite initial length L_{0}, and by analyzing the mechanistic basis of the buckling-induced fiber breakage process. The obtained finite-L_{0} closed-form solution was compared to a glass fiber dataset to retroactively justify the infinite-length idealization in the earlier work for such systems while providing the complete form for processes in which fragments remain comparable to L_{0}. Concerning the mechanics of fiber fragmentation, a Mellin transform analysis of the fragmentation equation showed that scale-invariant cascades yield power laws and therefore cannot generate characteristic lengths; those lengths must instead arise from scale-breaking ingredients, particularly the cutoff region and the arrested processing history. Monte Carlo simulations of a phenomenological finite-opportunity cascade showed that the hypoexponential form does not reproduce the peak of the generated distribution but captures its exponential-like tail, implying that it serves as a useful two-parameter fitting model, although not an exact generative distribution.

Origami-inspired tubular structures provide a versatile platform for shape morphing, with multistability achieved predominantly through crease-network geometry. Expanding the range of morphing behaviors can therefore require increasingly intricate crease patterns that become more difficult to model and fabricate, ultimately constraining the realizable morphing landscape. Here, we expand the design space of origami-inspired structures beyond geometry by introducing localized instabilities within the crease network, thereby creating compliant multistable structures whose local fold architectures govern global deformation and stability through both constitutive mechanics and geometric constraints. To relate local fold architectures to global multistability, we develop and experimentally validate a modeling framework in which compliant folds are represented as continuous fields that capture spatially varying bistable mechanics. Force- and displacement-controlled design maps demonstrate that global deformation and stability can be programmed through the fold architecture's local parameters. Redistributing bistability within a fixed crease-network topology shifts the global response between compliant, spatially distributed deformation in semi-bistable architectures and discrete transitions within a hierarchically organized space of stable configurations in fully bistable architectures. These results establish a local-to-global design principle for programming both the stable configurations of a structure and the transition pathways connecting them, expanding the design space for multistable metamaterials, adaptive morphing structures, and soft robotic systems.

This paper presents a macroscopic, or continuum, theory aimed at describing when, where, and why cracks nucleate and propagate in nominally elastic brittle materials under monotonic, quasi-static, but otherwise arbitrary mechanical loads. Motivated by recent insights, the proposed sharp theory posits that: cracks nucleate and propagate exclusively in regions where the strength surface of the material is exceeded, with their evolution dictated by the minimization of the sum of the potential — the elastic energy minus the work done by the externally applied forces — and surface energies. While the theory applies to materials with any elasticity (linear or nonlinear) and any material symmetry (isotropic or anisotropic), attention is restricted here to the most basic case of isotropic elastic brittle materials. For demonstration purposes, the theory is confronted with a set of nine tests that span the entire range of well-settled experimental knowledge on fracture nucleation and propagation — the so-called “Nine Circles of Elastic Brittle Fracture” — on both a hard material (a silicate glass) and a soft material (a synthetic rubber).

In this work, we investigate the extent to which fluctuation–response relations emerge from coarse-grained stochastic dynamics alone, and which aspects instead depend on additional information about the system. To address this question, we study the rotating stochastic Landau model, an exactly solvable system describing an overdamped charged Brownian particle in a constant magnetic field, coupled dissipatively to a rotating environment, whose steady state supports circulating probability currents. Using the Martin–Siggia–Rose path integral, we show that there is an emergent $\mathbb{Z}_2$ symmetry transformation that implements the time-reversed dynamics and changes the action by a boundary term. Comparison with the Crooks fluctuation theorem identifies this term with the entropy associated with transitions between steady-state configurations. After coupling the theory to external sources, the same symmetry yields Ward identities relating fluctuations and response. These identities follow entirely from the coarse-grained stochastic theory and do not fix the noise strength. Finally, upon imposing the Einstein relation, we show that they coincide with the high-temperature fluctuation–dissipation relations implied by the rotating Kubo–Martin–Schwinger condition for a microscopic Gibbs ensemble.

Non-local constitutive theories have received increasing attention in continuum descriptions of granular flows. However, these models have not been systematically compared for silo discharge within a unified numerical framework. We address this gap with two-dimensional finite-volume method (FVM) simulations of silo discharge using the Basilisk platform. We first validate our FVM implementation of the dynamic non-local granular fluidity (NGF) model against the material point method results of Dunatunga & Kamrin (J. Fluid Mech., 2022, 940, A14), obtaining quantitative agreement. Second, we relate the discharge rate $Q$ to the outlet-to-particle size ratio $D/d$ and the non-local amplitude $A$. From the simulated $Q$, we then evaluate the clogging probability $J(D/d, A)$ within the probabilistic framework of Janda et al. (Europhys. Lett. 84 (4), 44002). The predicted $J$ decays exponentially with $D/d$, consistent with the experimental trend of Janda et al. (Europhys. Lett. 84 (4), 44002). Rather than directly predicting flow arrest, our approach captures the continuous probabilistic transition. Finally, within the same numerical framework and using identical values of $A$, we compare several non-local constitutive models, including several linearised variants that we derive. Almost all models predict a reduction in the discharge rate with increasing $A$, yet significant quantitative differences are observed among the models. The results are further classified into groups according to their predicted flow behaviour, revealing close correspondences among certain formulations. Notably, using the non-local amplitudes reported in the literature [Bouzid et al. (Phys. Rev. Lett. 111, 238301), Henann & Kamrin (Proc. Natl Acad. Sci. USA 110(17))] yields near-zero discharge rates. Ill-posed issues are discussed. The implementation of all models is open-sourced and computationally efficient.

We introduce and study (fermionic and bosonic) invertible quasi-local algebras over uniformly locally finite metric spaces $X$ with infinite-dimensional local von Neumann algebras. We show that the group of Brauer equivalence classes of such algebras is isomorphic to both the group of phases of invertible states and the group of stable equivalence classes of quantum cellular automata over $X\times \mathbb{Z}$. Using K-theory of the symmetric monoidal category of invertible quasi-local algebras and bounded spread isomorphisms, we propose a definition of an $\Omega$-spectrum of invertible phases as conjectured by Kitaev. We then show that the $c=\frac{1}{2}$ chiral Majorana fermion net and the $(E_{8})_{1}$ conformal net provide Brauer non-trivial invertible quasi-local algebras, thus providing explicit constructions of non-trivial invertible states and quantum cellular automata on $\mathbb{Z}^{2}$. In addition, we show that the time-slice nets of rational diagonal conformal field theories admit lattice degrees of freedom, which implies the discretization of any holomorphic conformal net is invertible.

AlGaAs/GaAs superlattices grown by Molecular Beam Epitaxy (MBE) are foundational for advanced optoelectronic devices, including Quantum Bragg Mirror (QBM) infrared detectors. The performance of these devices critically depends on achieving near-perfect periodicity and abrupt interfaces, however, intrinsic statistical fluctuations during MBE growth introduce nanoscale structural disorder that can degrade device efficiency. In this study, we present a comprehensive methodology for quantifying this disorder in a 203-layer QBM device. High-resolution structural characterization was performed using high-energy (25 keV) synchrotron X-ray diffraction. By coupling a recursive dynamical diffraction formalism with an ensemble simulated annealing refinement, we extracted statistically robust, layer-by-layer thickness profiles. Our analysis reveals highly systematic, material-specific deviations from the nominal design: all AlGaAs barrier layers were consistently thinner than nominal by 0.3-0.6 nm. Furthermore, the sequential thickness profile successfully identified a significant 35 nm deficit in the final macroscopic top contact layer and a 40 nm deficit in the first GaAs layer. Achieving a statistical precision of about 0.2 to 0.6 nm (approximately 1-2 atomic monolayers), this non-destructive diagnostic approach provides directly actionable feedback for MBE flux calibration protocols.

Nickel phosphorus trisulfide (NiPS$_3$) stands out as a Mott insulator exhibiting XY-type antiferromagnetic order. In this work, we investigate the electrodynamic response of single-crystalline NiPS$_3$ using Terahertz Time-Domain Spectroscopy (THz-TDS) as a function of temperature. In cases where the magnetic permeability cannot be approximated to unity, conventional THz transmission analysis is often restricted to the complex refractive index, hindering the distinction between magnetic and dielectric contributions. To overcome this limitation, we demonstrate an extraction methodology capable of decoupling the magnetic permeability from the electric permittivity. Assuming that the dielectric contribution remains invariant below the N'eel temperature (TN), we used data from the paramagnetic phase to isolate the intrinsic magnetic component at 13 K. The angular and thermal dependence of the spectra revealed a magnon mode near 1 THz (for 0$^\circ$ orientation) and, distinctively, a zone-folded phonon activated by symmetry breaking (at 90$^\circ$). The isolated magnetic permeability was successfully modeled using Drude-Lorentz oscillators, enabling the extraction of fundamental spin dynamics parameters in this material.

While thermal runaway occurs across diverse physical disciplines, its presence in subwavelength phase-change photonics remains unexplored because existing thermo-optical models break down near sharp optical transitions. Here, we introduce an iterative multiphysics framework coupling full-wave electrodynamics with heat transfer, and we discover optically induced thermal runaway in vanadium dioxide (VO2) nanostructures. The runaway switching threshold depends on the illumination wavelength, ambient temperature, and underlying substrate, with external thermal biasing significantly reducing the optical intensity required for runaway ignition. Our results push forward the modeling of sharp photothermal transitions and provide essential design principles for active metasurfaces, neuromorphic photonic devices, and nanoscale thermal management.

Bridging pyro-phototronic and ferroelectric properties in a single material not only gives rise to exotic physical phenomena but also provides strategy to build-up next-generation multi-functional energy harvesting devices. The layered halide perovskites are emerging class of synergetic 2D-materials of exceptional light-induced functionalities. Here, we report synthesis of a lead-free perovskite (3-fluorobenzylamine)2CuCl4 of partially fluorinated aromatic rings. Molecular chains are chiral in helicoids so to render flexibility, energy-transfer, and freedom to tailor tunable pyro-phototronics on light illumination. The fluorinated framework promotes ferroelectric-to-paraelectric transition point (TC), as high as \textasciitilde 412 K of wide range of workably. A giant pyro-photronic response is distinctly evident even upon UV-visible light-illuminations. A significantly high pyro-photronic current of 60 nA was achieved under an illumination of {\lambda}ex\textasciitilde 365 nm (27 mW) in a self-powered configuration. Consequently, an intricate coupling of the spontaneous polarization to the optical properties is visualized from the piezo response force microscopy (PFM) responses. In particular, the polar domains get diminished reversibly in on-off steps of the light irradiations. It indicates, the light provides another degree of the freedom to control the features for the applications of optoelectronic devices, optical memories, photo/thermo-chromic systems, and energy-harvesters.

Wireless communication via propagating magnetic fields is a communication modality that has recently garnered significant interest for short-to-medium range communication in conductive mediums, such as underwater and underground, where existing approaches utilizing electric fields are highly inefficient. Typical implementations of magnetic communication make use of loop antennas as both the transmitter and receiver, with the sensitivity and frequency response scaling with and inversely with the loop cross-sectional area, respectively. Here, we explore an alternative hybrid magnetic communication system consisting of an highly radiation efficient and compact acoustically actuated magnetoelectric resonator as the transmitter, and a highly sensitive micrometer scale quantum magnetometer based on nitrogen-vacancy centers in diamond as the receiver, with their core properties unconstrained by size. We demonstrate amplitude and phase-encoded transmission and reception of AC magnetic fields at $f_{\mathrm{AC}}$ = 20 kHz, achieving a sensitivity of 50 pT/$\sqrt{\mathrm{Hz}}$ and 1.2 mrad/$\sqrt{\mathrm{Hz}}$, respectively. This work establishes the use of hybrid magnetoelectric resonator and quantum diamond magnetometer communication system as a viable alternative to existing loop-based approaches.

We consider a non-interacting Bose gas governed by a general one-particle Hamiltonian in the canonical ensemble. Our main results are large-deviation estimates for the number of particles in the Bose–Einstein condensate. We show that the left- and right-tail probabilities decay at different exponential rates as the number of particles tends to infinity.

The multiferroic semiconductor GeMnTe exhibits ferroelectricity, strong Rashba spin-orbit coupling, and carrier-mediated magnetic order, making it a unique platform for exploring the interplay among electronic, structural, and magnetic degrees of freedom. In this study, we investigate the ultrafast magnetization dynamics of Ge0.85Mn0.15Te using time-resolved magneto-optical spectroscopy. By separating magnetic and nonmagnetic contributions in the transient response, we identify two distinct laser-induced magnetic phenomena, both resulting from photoinduced effective spin-orbit torque. Coherent magnetization precession arises from a laser-induced increase in hole concentration, which modifies the occupation of Rashba-split spin-locked valence band states and alters the magnetic easy axis. The transient change in magnetic ordering, observed as variations in the coercive field, is attributed to laser-induced modifications of the ferroelectric sublattice displacement, which affect the ferroelectric polarization and the associated Rashba spin-orbit interaction. While the first type of optical spin-orbit torque has already been observed in the diluted magnetic semiconductor (Ga,Mn)As, the second effect is unique to the multiferroic Rashba semiconductor (Ge,Mn)Te, opening new opportunities for all-optical manipulation of magnetic order and spin-orbit torque generation in spin-orbitronic devices.

We study the ground-state properties and dynamical response of the Heisenberg model on the sawtooth chain in and away from the exactly solvable valence-bond-solid (VBS) point. We employ U(1)-symmetric density-matrix renormalization group (DMRG) and time-dependent variational principle (TDVP) methods to compute equilibrium diagnostics and the zero-temperature dynamical structure factor (DSF) $S^{zz}(q,\omega)$ across the dimerized phase, a valence-bond-ordered state in which the two symmetry-equivalent apex–base bonds of each triangle develop unequal spin correlations, probing the approach to the continuous lower phase boundary, the exact VBS point, and the approach to the first-order upper boundary. In every regime, the DSF is a broad continuum dominated by a bright band at its lower edge, with the intensity at the one-triplon energy $\omega \simeq J_{AB}$ suppressed. We identify the spectrum as a deconfined two-spinon continuum of kink and antikink domain walls between the two degenerate singlet coverings. Closed-form spinon dispersions fix the continuum edges and track the dominant band across the zone in all three regimes, while an explicit finite-separation two-kink calculation in a constrained Hilbert space reproduces the measured intensity distribution. Our results provide a microscopic picture of fractionalized excitations in the dimerized sawtooth chain and are relevant to the recently discovered Ti$^{3+}$ kagome fluorides, where strongly anisotropic exchange interactions can generate sawtooth-chain building blocks.

We present a theoretical study of the quantum transport through a nanoscale system in which a central quantum dot (QD) is coupled asymmetrically to normal leads and to two Majorana bound states (MBSs) localized at the ends of a topological superconducting nanowire threaded by a tunable magnetic flux. The effects of the leads–QD coupling asymmetry parameter $\alpha$ and the bias voltage asymmetry parameter $q$ on the system's linear conductance are considered for the case of unhybridized and hybridized MBSs. In the zero-temperature limit, for unhybridized MBSs the system's linear conductance is finite only when the magnetic flux phase $\phi = (2n+1)\pi$ ($n\in\mathbb{Z}$) and it scales as $\mathcal{G}=2q\alpha e^2/[h(\alpha+1)]$, while for hybridized MBSs it presents a complicated dependence on the system's parameters. At finite temperature, for unhybridized MBSs, the system's linear conductance oscillates as a function of the magnetic flux phase $\phi$ with a period of $2\pi$, and the position of the linear conductance maxima can be shifted from $\phi=2n\pi$ to $\phi=(2n+1)\pi$ by simply varying the value of the bias voltage asymmetry parameter $q$. For hybridized MBSs, the conductance exhibits a similar behavior when the energy level of the central QD, $\varepsilon_d$, is tuned at the leads' Fermi level ($\varepsilon_d=\varepsilon_F$), although when $\varepsilon_d\neq\varepsilon_F$ the oscillation period changes to $4\pi$, and the position of the linear conductance maxima depends on the actual value of $\varepsilon_d$ and other parameters in the system. Our results highlight the experimental importance of the leads-QD and bias voltage asymmetry parameters, which are often present in realistic experimental setups, and can strongly affect the identification and observation of MBSs transport signatures.

The Traveling Salesman Problem (TSP) asks for the shortest route to visit a set of cities exactly once. It combines a simple local rule - each city must be visited once - with a hard, global constraint- all cities must be traversed within a single cycle. We cast the problem within a probabilistic, information-theoretic framework. The coexistence of local and global constraints is precisely what makes the problem difficult to address in this framework: the local rule can be enforced through vertex-level constraints, whereas the global constraint cannot be captured by independent edge probabilities. We show that this obstacle can be overcome by defining a maximum-entropy probability distribution over graphs, in which edge costs and degree constraints generate an assignment-like ensemble, and a global term, describing the hard constraint, tilts this ensemble toward Hamiltonian cycles. To make the construction tractable, we derive a mean-field approximation in terms of edge occupancies and implement a differentiable cycle penalty that suppresses sub-tours. This leads to a self-consistent numerical procedure whose output is not only a candidate tour but also a probability matrix encoding competing edges and degenerate solutions. We test the method on synthetic ensembles and on TSPLIB instances. The algorithm converges to connected tours in polynomial time, matching the best-known solution in the majority of instances and remaining within a small relative gap otherwise. Beyond its competitive performance, the proposed framework offers a general approach for handling hard constraints while reducing hard combinatorial optimization problems to simpler ones.

Mechanochemical milling is regarded as a scalable, solvent-free method that makes halide perovskites that solution processing cannot. Its deeper promise, though, is that mechanical force could become a new axis of synthetic control to turn milling from an empirical method into a predictive science. Halide perovskites are the ideal platform to establish this: their soft lattices and low formation energies make them intrinsically responsive to mechanical activation. Realising this requires settling what milling actually makes, and how: can a milled phase genuinely be trapped outside equilibrium, or is it just a convenient way to the equilibrium phase, and by what atomistic pathway does it work? These questions are mostly answered by assumption, while the in-situ and computational tools that resolved them for other material classes already exist. Closing this gap will unlock two design capabilities: mechanical energy used as a synthetic variable to tune phase selection, and metastability made programmable, producing trapped phases, specific intermediates, and compositions that have no possible solution route. Finally, two tests decide whether that control reaches practice: the state engineered during milling must survive into a working device, and the method must prove genuinely greener across the full device life cycle, rather than just solvent-free.

We study an assembly of $N$ scalar fields coupled via a quenched random interaction, equivalent to a spin glass whose spins are promoted to $d$-dimensional fields. When $N$ is large, the random coupling matrix produces a family of Gaussian universality classes whose critical exponents are determined by the behavior of the eigenvalue density near the spectral edge. For a Wigner matrix, the correlation length diverges at criticality but the susceptibility remains finite, and one-loop replica analysis supports an upper critical dimension of unity. In an exactly solvable spherical variant, the heat capacity jumps at the transition in $d>1$, and correlations remain pinned to their critical form throughout the glass phase, giving generic scale invariance despite the absence of a Goldstone mode.

Periodically driven quantum systems provide a powerful route to engineer novel states of matter by controlling their effective Hamiltonians through external fields. However, most treatments are usually simplified by considering the high-frequency limit, and do not account for the processes taking place in the transient regime during the onset of the drive. In this work, we introduce a time and momentum resolved tunneling spectroscopy protocol to probe the instantaneous energy spectrum of Floquet-driven systems beyond the high-frequency regime, capturing both emergent effects and non-adiabatic phenomena without requiring explicit reconstruction of the full time-dependent Green's function. We benchmark the method on driven non-interacting fermionic models, and then generalize the approach to strongly correlated systems with the aid of time-dependent density matrix renormalization group techniques. We also provide a microscopic description to the emergence of in-gap states under resonant driving, and briefly explore its finite temperature analog.

The quantum geometric tensor - the Berry curvature together with the quantum metric - now underlies a long list of observables, from the anomalous Hall effect to the superfluid weight of a flat band. We ask which of these observables actually require quantum mechanics. To answer this question, we study a purely classical system: a point particle carrying a classical magnetic moment $\boldsymbol{\ell}$ that precesses in a momentum-dependent magnetic field $\mathbf{B}(\mathbf{p})$. Within Hamiltonian classical mechanics, the component of $\boldsymbol{\ell}$ along the field reproduces the Berry-curvature phenomena, while its precessing transverse component reproduces the quantum-metric phenomena. The particle acquires a position spread whose second moment is the metric, an orbital magnetic moment, and - most strikingly - an inertial mass generated by a position-dependent force, and with it a nonzero Drude weight in a system that is nominally dispersionless.

Quantum anomalies strongly constrain the possible behavior of many-body systems. A prime example is the Lieb-Schultz-Mattis (LSM) theorem, which relates UV symmetry and filling constraints to IR features of the energy spectrum and ground-state structure. Here, we ask how LSM constraints shape dynamical signatures and temporal correlations in open quantum systems. Using a spacetime duality, we show that the Liouvillian of a $d$-dimensional repeated quantum channel with a mixed anomaly between strong $S$ and weak $G$ symmetry can be mapped to a $(d{+}1)$-dimensional mixed-state symmetry-protected topological (mSPT) phase. Under this correspondence, the initial and steady states of the channel are identified with boundary states of the higher-dimensional mSPT in the presence of bulk projection. We further introduce the twisted Renyi-$N$ correlator (TRNC) as a probe of temporal correlations in the channel and demonstrate that it is dual to the mSPT strange correlator, providing a direct bulk-boundary route to diagnose long-range temporal order implied by the LSM anomaly. Finally, we identify the Liouvillian singular spectrum, rather than the Liouvillian spectrum itself, as a more fundamental diagnostic of quantum anomalies, and show that it is dual to the operator entanglement spectrum of the mSPT.

The non-Abelian statistics of Majorana zero modes has inspired numerous proposals for their detection and manipulation in topological superconductors. Implementations based on magnetic adatoms deposited on superconductors draw particular attention due to their capabilities for precise atomic manipulation and the control over disorder. Here, we propose a scheme for detecting changes in the ground state parity of a topologically non-trivial adatom system by passing supercurrent through their low-energy modes. We unravel characteristic discontinuities in the critical current driven by zero-energy level crossings. We apply these findings to a setup where the Majorana coupling is mediated by a single control magnetic adatom hosting a Yu-Shiba-Rusinov state, and test the robustness of our results against finite temperatures and different tunneling regimes. Our findings introduce a non-invasive approach for reading out and controlling the ground state parity of Majorana states in Shiba-Majorana hybrid systems.

How does the Bose or Fermi statistics of microscopic particles survive when confinement binds them into emergent bosonic composites? We address this question in the strong-coupling limit of a $2+1$D $\mathbb{Z}_2$ lattice gauge theory, where charges are confined into tightly bound pairs that can be described by an effective dimer model. We find that the statistics of the underlying matter is encoded entirely in a single local hopping phase $\varphi$ -$0$ for bosons, $\pi$ for fermions. Treating $\varphi$ as a continuous parameter that interpolates between the two, we map the ground-state phase diagram with the help of tensor-network methods. The angle $\varphi$ itself drives a transition between a dimer-superfluid and a dimer-charge density wave state, while the magnetic coupling binds neighboring dimers into resonating pairs, in competition with the inter-dimer repulsion. We identify a novel gapped phase in which dimer pairs crystallize into an ordered pattern of resonating plaquettes. Finally, we propose a quench protocol under which identical dimer configurations evolve in markedly different ways depending on the statistics of their constituents. This provides a dynamical probe of the internal structure of dimers, and allows to detect ordered phases through real-time signatures, within reach of simulators that natively realize bosonic degrees of freedom.

We show that a magnet can remain perfectly collinear while its quantum vacuum circulates. In a centrosymmetric altermagnet, a symmetry-allowed locally staggered Dzyaloshinskii-Moriya coupling imprints a gauge-irremovable vortex-antivortex pair into the anomalous magnon pair correlations at high-symmetry points in momentum space. In real space, these hidden vortices produce an antiferrochiral array of equilibrium spin currents circulating oppositely around neighboring plaquettes. Gauge-irremovable frustration therefore survives despite classical collinearity: it exists entirely in the quantum correlations. Our results show that complex pairing, gauge-invariant fluxes, and equilibrium loop currents - structures encountered across electronic flux phases, spin liquids, and frustrated quantum magnets - can be encoded in the squeezed vacuum of a collinear magnet.

Magic-angle helical trilayer graphene—three graphene layers sequentially twisted in the same direction by $\sim1.8^\circ$—relaxes into a mosaic of domains that, at zero field, carry opposite valley-resolved Chern numbers, with boundaries hosting a network of gapless conducting modes. Charge transport through this network depends sensitively on how the modes connect and scatter, making well-quantized transport unlikely. Contrary to this expectation, we observe a field-induced Chern gap with Chern number $C=-6$ emanating from charge neutrality; in this gap, the Hall resistance is quantized to within $2\%$ of the expected value, $-h/6e^2$, at 4.6 K. We explain this behavior using both Hofstadter and orbital Zeeman calculations, which show that a moderate magnetic field drives a valley-selective topological transition. Above the transition, the total Chern number of the occupied states in each spin-valley flavor becomes identical across neighboring domains, and the domain-wall modes can become gapped. Though the central valence-band Chern numbers still differ between the two domain types, the observed quantized transport attests to a global gap.