Like the letters in the alphabet forming words, reusing components of a heterogeneous mixture is an efficient strategy for assembling a large number of target structures. Examples range from synthetic DNA origami to proteins self-assembling into complexes. The standard self-assembly paradigm views target structures as free-energy minima of a mixture. While this is an appealing picture, at high speed structures may be kinetically trapped in local minima, reducing self-assembly accuracy. How then can high speed, high accuracy, and combinatorial usage of components coexist? We propose to reconcile these three concepts not by avoiding kinetic traps, but by exploiting them to encode target structures. This can be achieved by sculpting the kinetic pathways of the mixture, instead of its free-energy landscape. We formalize these ideas in a minimal toy model, for which we analytically estimate the encoding capacity and kinetic characteristics, in agreement with simulations. Our results may be generalized to other soft-matter systems capable of computation, such as liquid mixtures or elastic networks, and pave the way for high-dimensional information processing far from equilibrium.

Krylov subspace methods in quantum dynamics identify the minimal subspace in which a process unfolds. To date, their use is restricted to time evolutions governed by time-independent generators. We introduce a generalization valid for driven quantum systems governed by a time-dependent Hamiltonian that maps the evolution to a diffusion problem in a one-dimensional lattice with nearest-neighbor hopping probabilities that are inhomogeneous and time dependent. This representation is used to establish a novel class of fundamental limits to the quantum speed of evolution and operator growth. We also discuss generalizations of the algorithm, adapted to discretized time evolutions and periodic Hamiltonians, with applications to many-body systems.

Quantum tomography approaches typically consider a set of observables that we wish to measure, designing a measurement scheme that measures each of the observables and then repeats the measurements as many times as necessary. We show that instead of considering only the simple set of observables, one should consider a multiset of the observables taking into account the required repetitions, to minimize the number of measurements. This leads to a graph theoretic multicoloring problem. We show that the multiset method offers at most quadratic improvement but it is achievable. Furthermore, despite the NP-hard optimal coloring problem, the multiset approach with greedy coloring algorithms already offers asymptotically quadratic improvement in test cases.

We calculate the complete next-to-leading order (NLO) QCD corrections to loop-induced $gg\to ZZ$ production including full top-quark mass effects. The two-loop virtual corrections are obtained by combining analytic results for the massless, Higgs-mediated, and one-loop factorizable contributions with numerically computed amplitudes containing the top-quark mass. We show that the choice of subtraction scheme for the virtual contribution impacts the precision with which the virtual contribution must be evaluated in order to obtain sufficiently precise phenomenological predictions. For direct production through a massive top-quark loop, we observe that the relative NLO corrections are large. The direct massive and Higgs-mediated contributions individually increase relative to the massless production at high diboson invariant mass, but interfere destructively with each other. At the Large Hadron Collider, the NLO corrections to the gluon channel give a sizable contribution to the $pp\to ZZ+X$ cross section at ${\mathrm{N}}^3\mathrm{LO}$.

In state-of-the-art optical lattice clocks, beyond-electric-dipole polarizability terms lead to a breakdown of magic wavelength trapping. In this Letter, we report a novel approach to evaluate lattice light shifts, specifically addressing recent discrepancies in the atomic multipolarizability term between experimental techniques and theoretical calculations. We combine imaging and multi-ensemble techniques to evaluate lattice light shift atomic coefficients, leveraging comparisons in a dual-ensemble lattice clock to rapidly evaluate differential frequency shifts. Further, we demonstrate application of a running wave field to probe both the multipolarizability and hyperpolarizability coefficients, establishing a new technique for future lattice light shift evaluations.

We demonstrate the existence of coexisting frequency combs in a harmonically mode-locked laser that we link to the splay phases of the Kuramoto model with short range interactions. These splay states are multistable and the laser may wander between them under the influence of stochastic forces. Consequently, the many pulses circulating in the cavity are not necessarily coherent with each other. As these partially disordered states for the phase of the field still feature regular intensity pulses, we term them as incoherent crystals of optical pulses. We provide evidence that the notion of coherence should be interpreted by comparing the duration of the measurement time with the Kramers’ escape time of each splay state. Our theoretical results are confirmed experimentally by performing high resolution spectral measurements via a heterodyne technique of a passively mode-locked vertical external-cavity surface-emitting laser.

Topological singularities, such as Weyl points (WPs) and Dirac points, can give rise to unidirectional propagation channels known as chiral zero modes (CZMs) when subject to a magnetic field. CZMs, as distinct zeroth Landau levels (bulk modes) with high degeneracy, are responsible for intriguing phenomena like the chiral anomaly in quantum systems. The propagation direction of each CZM is determined by both the applied magnetic field and the topological charge of the singularity point. While counterpropagating CZMs have been observed in 2D and 3D systems, the realization of copropagating CZMs has remained elusive. Here, we present the first experimental observation of copropagating CZMs in magnetic photonic crystals hosting a single pair of ideal Weyl points. By manipulating the crystal’s structural configuration and applying a uniform bias magnetic field, we spatially alter the locations of the WPs, creating pseudo-magnetic fields of opposite directions for different WPs. This arrangement results in a pair of CZMs that possess the same group velocity and copropagate. Our work opens up new possibilities for the topological manipulation of wave propagation and may lead to advancements in optical waveguides, switches, and various other applications.

We report the experimental realization of a new type of topology-controlled photonic cavities in valley photonic crystals by adopting judiciously oriented mirrors to localize the valley-polarized edge states along their propagation path. By using microwave frequency- and time-domain measurements, we directly observe the strong confinement of electromagnetic energy at the mirror surface due to the extended time delay required for the valley index flipping. Moreover, we experimentally demonstrate that both the degree of energy localization and quality factors of the topology-controlled photonic cavities are determined by the valley-flipping time which is controlled by the topology of the mirror. These results extend and complement the current design paradigm of topological photonic cavities.

Half metals, which are amenable to perfect spin filtering, can be utilized for high-magnetoresistive devices. However, available half metals are very limited. Here, we demonstrate that materials with intrinsic spin-valley-mismatched (SVM) states can be used to block charge transport, resembling half metals and leading to giant tunneling magnetoresistance. As an example, by using first-principles transport calculations, we show that ferromagnetic $1T\text{−}{\mathrm{VSe}}_2$, $1T\text{−}{\mathrm{VS}}_2$, and $2H\text{−}{\mathrm{VS}}_2$ are such spin-valley-mismatched metals, and giant magnetoresistance of more than 99% can be realized in spin-valve van der Waals (vdW) junctions using these metals as electrodes. Owing to the intrinsic mismatch of spin states, the central-layer materials for the vdW junctions can be arbitrary nonmagnetic materials, in principle. Our research provides clear physical insights into the mechanism for high magnetoresistance and opens new avenues for the search and design of high-magnetoresistance devices.

Intrinsic transparent conductors (ITCs) correspond to a unique class of TCs that do not need intentional doping. This character can provide ITCs significant advantages by avoiding severe “doping bottlenecks” and dopant scattering usually encountered in conventional transparent conducting oxides (TCOs). However, the realization of ITCs generally requires the minimization of photon absorption and reflection in metallic conductors, which is difficult due to the gapless nature of their band structures. Here, based on first-principles calculations, we illustrate a feasible strategy to design optical transparency in metallic conductors by a synergetic effect of symmetry and spatial-distribution forbidden transitions between their energy bands around the Fermi level. The validity of this design strategy is demonstrated in a zero-dimensional electride, ${\mathrm{K}}_4{\mathrm{Al}}_3{({\mathrm{SiO}}_4)}_3$, which exhibits both electrical conductivity and optical transparency in the ultraviolet spectrum. More interestingly, we find that this transmittance range can be tuned to the visible spectrum region by chemical substitutions in ${\mathrm{K}}_4{\mathrm{Al}}_3{({\mathrm{SiO}}_4)}_3$ with the elements that have either larger electronegativity or smaller atomic radius. By examining dozens of possible cation substitutions via high-throughput calculations, we identify several promising candidates that have the potential as ITCs.

We present a method for computing angle-resolved electron energy loss and gain spectroscopies for phonon and magnon excitations in transmission electron microscopy. Fractional scattering intensities are derived from the temperature-dependent time autocorrelation of the auxiliary electron beam wave function. This method captures both single and multiple scattering processes, as well as dynamical diffraction effects, while remaining computationally efficient and easy to parallelize.

The Luria-Delbrück model is a classic model of population dynamics with random mutations, that has been used historically to prove that random mutations drive evolution. In typical scenarios, the relevant mutation rate is exceedingly small, and mutants are counted only at the final time point. Here, inspired by recent experiments on DNA repair, we study a mathematical model that is formally equivalent to the Luria-Delbrück setup, with the repair rate $p$ playing the role of mutation rate, albeit taking on large values, of order unity per cell division. We find that although at large times the fraction of repaired cells approaches one, the variance of the number of repaired cells undergoes a phase transition: when $p>1/2$ the variance decreases with time, but, intriguingly, for $p<1/2$ even though the fraction of repaired cells approaches 1, the variance in the number of repaired cells increases with time. Analyzing DNA-repair experiments, we find that in order to explain the data the model should also take into account the probability of a successful repair process once it is initiated. Taken together, our work shows how the study of variability can lead to surprising phase transitions as well as provide biological insights into the process of DNA repair.

We use particle simulations to map comprehensively the shear rheology of dry and wet granular matter comprising particles of finite stiffness, in both fixed pressure and fixed volume protocols. At fixed pressure we find nonmonotonic constitutive curves that are shear thinning, whereas at fixed volume we find nonmonotonic constitutive curves that are shear thickening. We show that the presence of one nonmonotonicity does not imply the other. Instead, there exists a signature in the volume fraction measured under fixed pressure that, when present, ensures nonmonotonic constitutive curves at fixed volume. In the context of dry granular flow we show that gradient and vorticity bands arise under fixed pressure and volume, respectively, as implied by the constitutive curves. For wet systems our results are consistent with a recent experimental observation of shear thinning at fixed pressure. We furthermore predict discontinuous shear thickening in the absence of critical load friction.

The Lieb-Robinson bound (LRB) states that the range and strength of interactions between the constituents of a complex many-body system impose upper limits to how fast the signal can propagate. It manifests in a light conelike growth of correlation function connecting two distant subsystems. Here, we employ the techniques of quantum information to demonstrate that the LRB can be determined from local measurements performed on a single qubit that is connected to a many-body system. This formulation provides an operational recipe for estimating the LRB in complex systems, replacing the measurement of the correlation function with simple single-particle manipulations. We demonstrate the potency of this approach by deriving the upper limit to the speed of signal propagation in the $XY$ spin chain.