Superconducting chiral domains associated with a time-reversal symmetry-breaking order parameter have garnered significant attention in kagome systems. In this Letter, we demonstrate both the intrinsic direct-current and alternating-current Josephson effects in the nanoplates of the vanadium-based kagome material ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$, as evidenced by Fraunhofer-like patterns and Shapiro steps. Moreover, both the Fraunhofer-like patterns and Shapiro steps are modulated by thermal cycling, suggesting that the Josephson effects arise from dynamic superconducting domains. These findings may provide new insights into chiral superconductivity in ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ and highlight the potential of these intrinsic Josephson junctions for applications in chiral superconductor-based quantum devices.

Effective thermal regulation is increasingly vital in numerous technological applications. The recent progress on topological diffusion in thermal materials offers promising potential. A distinct feature of diffusive systems is that their anti-Hermitian characteristics ensure purely imaginary eigenvalues representing decay rates, where higher decay rates imply better heat dissipation efficiency. Although research on higher-order topology has been extensive across various systems, investigations specifically of diffusive systems are just beginning. In particular, the few studies on the corner states are limited in their controllability. In this Letter, inspired by the concepts of the atomic $p$ orbital and higher-orbital topology, we introduce multipolar thermal modes in the domain wall between two thermal kagome lattices to achieve multiple corner states. Diverging from traditional research on kagome lattices, we discovered higher-decay-rate corner states above the third band and linked their properties to multipolar modes localized at the domain wall. This approach not only enables higher-decay-rate corner states but also explores new dimensions of control over them. We theoretically identify and experimentally observe various corner states in a two-dimensional diffusive system. It is also demonstrated that simple thermal pulses can trigger transitions between different corner states, thereby dynamically enhancing the decay rate. This study further reveals the potential of topological approaches in heat dissipation, paving the way for the development of thermal management and related fields.

Chiral magnetic textures are of fundamental interest for studying exotic spin behavior, but also promising for the development of energy-efficient memory and logic devices. Recent computational work has suggested that in contrast to well-studied static chiral textures like skyrmions, there exists dynamic fluctuation-driven magnetic chirality even in the absence of long-range magnetic order. Here, we present definitive magnetotransport signatures of fluctuation-driven chirality in a model material system of $\mathrm{Pt}/{\mathrm{Li}}_{0.5}{\mathrm{Al}}_{1.0}{\mathrm{Fe}}_{1.5}{\mathrm{O}}_4$ (LAFO) bilayers, where LAFO is a ferromagnetic insulator. We establish a fluctuation-driven origin for the magnetic chirality by observing a strong correlation between the onset of the topological Hall effect and the destruction of magnetic order. Corroborated by Monte Carlo simulations, we develop a rigorous analytical framework to gain a first-principles understanding of scaling behaviors in the transport data. Our results bring novel insights to fluctuation-driven chirality and analysis of magnetotransport data.

Conventional methods to measure the dispersion relations of collective spin excitations involve probing bulk samples with particles such as neutrons, photons, or electrons, which carry a well-defined momentum. Open-ended finite-size spin chains, on the contrary, do not have a well-defined momentum due to the lack of translation symmetry, and their spin excitations are measured with an eminently local probe, using inelastic electron tunneling spectroscopy (IETS) with a scanning tunneling microscope (STM). Here, we discuss under what conditions STM-IETS spectra can be Fourier-transformed to yield dispersion relations in these systems. We relate the success of this approach to the degree to which spin excitations form standing waves. We show that STM-IETS can reveal the energy dispersion of magnons in ferromagnets and triplons in valence bond crystals, but not that of spinons, the spin excitations in Heisenberg spin-$1/2$ chains. We compare our theoretical predictions with state-of-the-art measurements on nanographene chains that realize the relevant spin Hamiltonians.

Bayes’ rule, which is routinely used to update beliefs based on new evidence, can be derived from a principle of minimum change. This principle states that updated beliefs must be consistent with new data, while deviating minimally from the prior belief. Here, we introduce a quantum analog of the minimum change principle and use it to derive a quantum Bayes’ rule by minimizing the change between two quantum input-output processes, not just their marginals. This is analogous to the classical case, where Bayes’ rule is obtained by minimizing several distances between the joint input-output distributions. When the change maximizes the fidelity, the quantum minimum change principle has a unique solution, and the resulting quantum Bayes’ rule recovers the Petz transpose map in many cases.

Quark stars are challenging to confirm or exclude observationally because they can have similar masses and radii as neutron stars. By performing the first calculation of the nonequilibrium equation of state of decompressed quark matter at finite temperature, we determine the properties of the ejecta from binary quark-star or quark star–black hole mergers. We account for all relevant physical processes during the ejecta evolution, including quark nugget evaporation and cooling, and weak interactions. We find that these merger ejecta can differ significantly from those in neutron star mergers, depending on the binding energy of quark matter. For relatively high binding energies, quark star mergers are unlikely to produce $r$-process elements and kilonova signals. We propose that future observations of binary mergers and kilonovae could impose stringent constraints on the binding energy of quark matter and the existence of quark stars.

Quasinormal modes play a prominent role in the relaxation of diverse physical systems to equilibria, ranging from astrophysical black holes to tiny droplets of quark-gluon plasma at the RHIC and LHC accelerators. We propose that a novel kind of quasinormal mode governs the direct approach to self-similar time evolution of nonthermal fixed points, whose relevance ranges from high-energy physics to cold atom gases. We utilize black hole perturbation theory techniques to compute the spectrum of these far-from-equilibrium quasinormal modes for a kinetic theory with a Fokker-Planck collision kernel in isotropic and homogeneous states. Our conclusion is that quasinormal modes of nonthermal fixed points give rise to a tower of progressively more decaying power-law contributions. A by-product of our analysis is a precise determination and improved understanding of the distribution function characterizing nonthermal fixed points.

Altermagnets represent a recently discovered class of collinear magnets, characterized by antiparallel neighboring magnetic moments and an alternating-sign spin polarization in momentum space ($\mathit{k}$ space). However, experimental methods for probing the $\mathit{k}$-space spin polarization in altermagnets remain limited. In this Letter, we propose an approach to address this challenge by interfacing an altermagnet with the surface of a topological insulator. We show that the altermagnet’s unique $\mathit{k}$-space spin polarization imprints a momentum-dependent, sign-alternating Dirac mass onto the otherwise massless surface states of the topological insulator, a direct consequence of breaking time-reversal symmetry. This engineered Dirac mass results in a unique, alternating half-quantized anomalous Hall effect. By measuring the Hall conductance, we can extract the local $\mathit{k}$-space magnetic moment. Moreover, we can map the global magnetic moment distribution by tuning the Dirac point position using an in-plane magnetic field, thereby revealing the $\mathit{k}$-space spin density of the altermagnet. This Letter establishes the Dirac fermion on the topological insulator surface as a sensitive probe for unveiling spin characters of altermagnets and those of other unconventional antiferromagnets.

Non-Abelian anyons in quantum spin liquids (QSLs) provide a promising route to fault-tolerant topological quantum computation. In the exactly solvable Kitaev honeycomb model, such anyons of the QSL state can be bound to nonmagnetic spin vacancies and endowed with non-Abelian statistics by an infinitesimal magnetic field. Here, we investigate how this approach for stabilizing non-Abelian anyons extends to a finite magnetic field represented by a proper Zeeman term. Through large-scale density-matrix renormalization group simulations, we compute the vacancy-anyon binding energy as a function of magnetic field for both the ferromagnetic and antiferromagnetic Kitaev models. We find that anyon binding remains robust within the entire QSL phase for the ferromagnetic Kitaev model but breaks down already inside this phase for the antiferromagnetic Kitaev model. To compute a binding energy several orders of magnitude below the magnetic energy scale, we introduce both a refined definition and an extrapolation scheme based on carefully tailored perturbations.

Optimal control of levitated nanoparticles subjected to thermal fluctuations is a challenging problem, both theoretically and experimentally. In this Letter, we compute the time-dependent harmonic confining potential that steers, in a prescribed time and with the minimum energetic cost, a Brownian particle between two assigned equilibrium states. We take full account of inertial effects, thus addressing the general underdamped dynamics, and, to address actual experimental conditions, the stiffness of the confining potential is required to be bounded. We carry out an experiment realizing the described protocol for an optically confined nanoparticle, which is shown to reach the target state within accuracy—while spending less energy than other protocols with the same duration, significantly shorter than the characteristic relaxation time. The results presented here are expected to have relevant applications in the design of optimal devices, such as engines at the nanoscale.

Quantum many-body scarred systems exhibit atypical dynamical behavior, evading thermalization and featuring periodic state revivals. In this Letter, we investigate the impact of projective measurements on the dynamics in the scar subspace for the paradigmatic PXP model, revealing that they can either disrupt or enhance the revivals. Local measurements performed at random times rapidly erase the system’s memory of its initial conditions, leading to fast steady state relaxation. In contrast, a periodic monitoring amplifies recurrences and preserves the coherent dynamics over extended timescales. We identify a measurement-induced phase resynchronization, countering the natural dephasing of quantum scars, as the key mechanism underlying this phenomenon.

The Kibble-Zurek scaling reveals the universal dynamics when a system is linearly ramped across a symmetry-breaking phase transition. However, in reality, inevitable finite-size effects or symmetry-breaking perturbations can often smear out the critical point and render the phase transition into a smooth crossover. In this Letter, we show experimentally that the precise Kibble-Zurek scaling can be retained in the near-critical crossover regime, not necessarily crossing the critical point strictly. The key ingredient to achieving this near-critical Kibble-Zurek scaling is that the system size and the symmetry-breaking field must be appropriately scaled following the variation of ramping speeds. The experiment is performed in a reconfigurable Rydberg atom array platform, where the Rydberg blockade effect induces a $Z_2$ symmetry-breaking transition. The atom array platform enables precise control of the system size and the zigzag geometry as a symmetry-breaking field. Therefore, we can demonstrate notable differences in the precision of the Kibble-Zurek scaling with or without properly scaling the system size and the zigzag geometry. Our results strengthen the Kibble-Zurek scaling as an increasingly valuable tool for investigating phase transition in quantum simulation platforms.

Moiré potential formed in van der Waals heterostructures is predicted to feature multiple local minima functioning as orbital degree of freedom, which is an important ingredient for understanding intriguing strong correlation phenomena. However, an experimental demonstration of this moiré-orbital enabled quantum state engineering is still unexplored. Here, we report clear evidence of moiré-orbital resolved excitonic Mott insulating states in multiannealing H-type ${\mathrm{WSe}}_2/{\mathrm{WS}}_2$ heterobilayers and demonstrate their application in generating spatially ordered excitonic quantum phases. This moiré orbital is evidenced by interlayer exciton emissions with an energy separation of $\sim 65\mathrm{meV}$ and further supported by our multiple field-dependent characterizations. Remarkably, the moiré orbital allows a sequential formation of correlated Mott insulating states, with the extracted onsite Hubbard interaction reaching $\sim 30\mathrm{meV}$. A combined optical and electric doping allows control of strongly correlated quantum phases with various spatially ordered fermionic-bosonic orbital components.

Recent studies have shown that a soliton can be fractionally transported by slowly varying a system parameter over one period in a nonlinear system. This phenomenon is attributed to the nontrivial topology of the corresponding energy bands of a linear Hamiltonian. Here we find the occurrence of fractional Thouless pumping of solitons in a nonlinear off-diagonal Aubry-André-Harper model. Surprisingly, this happens despite the fact that all the energy bands of the linear Hamiltonian are topologically trivial, indicating that nonlinearity can induce fractional Thouless pumping of solitons. Specifically, our results show that a soliton can be pumped across one unit cell over one, two, three, or four pump periods, implying an average displacement of 1, $1/2$, $1/3$, or $1/4$ unit cells per cycle, respectively. We attribute these behaviors to changes in on-site potentials induced by a soliton solution, leading to the nontrivial topology for the modified linear Hamiltonian. Given that our model relies solely on varying nearest-neighbor hoppings, it is readily implementable on existing state-of-the-art photonic platforms.

Giant number fluctuations (GNFs), whereby the standard deviation $\mathrm{\Delta }N$ in the local number of particles $⟨N⟩$ grows faster than $\sqrt{⟨N⟩}$, are a hallmark property of dry active matter systems with orientational order, such as a collection of granular particles on a vibrated plate. This contrasts with momentum-conserving (“wet”) active matter systems, such as suspensions of swimming bacteria, where no theoretical prediction of GNFs exist, although numerous experimental observations of such enhanced fluctuations have been reported. In this Letter, we numerically confirm the emergence of super-Gaussian number fluctuations in a three-dimensional suspension of pusher microswimmers undergoing a transition to collective motion. These fluctuations emerge sharply above the transition, but only for sufficiently large values of the bacterial persistence length ${\ell }_p=v_s/\lambda$, where $v_s$ is the bacterial swimming speed and $\lambda$ the tumbling rate. Crucially, these “pseudo-GNFs” differ from true GNFs, as they only occur on length scales shorter than the typical size $\xi$ of nematic patches in the collective motion state, which is in turn proportional to the single-swimmer persistence length ${\ell }_p$. Our results thus suggest that observations of enhanced density fluctuations in biological active matter systems actually represent transient effects that decay away beyond mesoscopic length scales and raises the question to what extent “true” GNFs with universal properties can exist in the presence of fluid flows.

Bell’s theorem is often considered the most stringent notion of nonclassicality. The generalization of Bell’s theorem to causal networks offers interesting new perspectives on the phenomenon of quantum nonclassicality and prompts us with a fundamental inquiry: what is the simplest scenario leading to the incompatibility between quantum correlations and the classical theory of causality? Here, we demonstrate that quantum nonclassicality is possible in an entanglement swapping network consisting of only three dichotomic variables, without the need for the locality assumption or external measurement choices. We also show that interventions, a central tool in the field of causal inference, significantly improve the noise robustness of this new kind of nonclassical behavior, making it feasible for experimental tests with current technology.