Landau levels have been central to the discovery of exotic quantum phases and their unprecedentedly deep roots in geometry and topology. A powerful concept called “vortexability” extends this framework to moiré systems. In this Letter, we show that vortexable systems support not only Landau-level-like flat bands but also entirely new types with distinct topological properties. Notably, while $n_b$ Landau levels have total Chern number $C=n_b$, vortexable moiré systems can host $n_b$ flat bands with $C=1\ne n_b$. We provide a complete classification of such exact flat bands in single and bilayer systems with Dirac or quadratic band crossings, identifying the symmetry conditions that govern their number and topology. Up to six flat bands can be symmetry protected. We construct explicit wave functions, showing that sublattice-polarized states always sum to Chern number $\pm 1$ and satisfy ideal non-Abelian quantum geometry. When the Berry curvature is sharply peaked, we show that a topological heavy-fermion description remains valid—even for bands with high degeneracy.

Altermagnets break time-reversal symmetry, and their spin-orbit coupling (SOC) allows for an anomalous Hall effect (AHE) that depends on the direction of the Néel ordering vector. The AHE and the ferromagnetic spin moment share the same symmetry and hence are usually proportional. However, density functional theory (DFT) calculations find that the AHE exists with negligible ferromagnetic spin moment for some compounds, whereas it reaches sizable values for other altermagnets. By examining realistic minimal models for altermagnetism in which the DFT phenomenology is captured, we uncover a general SOC-enabled quasisymmetry, the uniaxial spin space group, that provides a natural explanation for the amplitude of the ferromagnetic spin moment across the vast range of different altermagnetic materials. Additionally, we derive analytic expressions for the magnetic anisotropy energy, providing a simple means of identifying the preferred Néel vector orientation for altermagnets.

Phyllotactic patterns, where elements such as leaves, seeds, or droplets arrange along alternate spirals, are fascinating examples of complex structures encountered in nature. In botany, their symmetries develop when a new primordium periodically grows in the largest gap left between the previous one and the apex. Experiments using ferrofluid droplets have shown that phyllotactic patterns can also spontaneously form when identical elements repulsing each other are periodically released at a given distance from an injection center and are advected radially at a constant speed. Here, we show that phyllotactic structures can also genuinely develop in the large class of spatial symmetry breaking systems with an intrinsic wavelength in the case of radial growth. The constraint of maintaining a fixed wavelength between spots while expanding radially either diffusively or advectively generalizes the concept of temporal release of repulsing agents in botany to new classes of systems. We explore this on three different systems: numerically on two models describing reaction-driven phase transitions and spatial Turing patterns, respectively, and experimentally on chemical precipitation patterns. This paves the way to engineer new complex self-organized structures in a panoply of different systems, ranging from spinodal decomposition, chemical, biological or optical Turing structures, and Liesegang patterns, to name a few.

Recent work on quantum reference frames (QRFs) has demonstrated that superposition and entanglement are properties that change under QRF transformations. Given their utility in quantum information processing, it is important to understand how a mere change of perspective can produce or reduce these resources. Here we prove the existence of a QRF invariant which can be decomposed such that it captures the trade-off between entanglement and subsystem coherence: we demonstrate the invariance of the sum of entanglement and subsystem coherence for two pairs of resource quantifiers. Moreover, we find a weaker trade-off that holds for any possible pair of measures. Finally, we discuss the implications of this interplay for violations of Bell’s inequalities, clarifying that for any choice of QRF, there is a quantum resource responsible for the violation. These findings contribute to a better understanding of the quantum information theoretic aspects of QRFs, offering a foundation for future exploration in both quantum theory and quantum gravity.

The simultaneous estimation of multiple unknown parameters is the most general scenario in quantum sensing. Quantum multiparameter estimation theory provides fundamental bounds on the achievable precision of simultaneous estimation. However, these bounds can become singular (no finite bound exists) in multiparameter sensing due to parameter interdependencies, limited probe accessibility, and insufficient measurement outcomes. Here, we address the singularity issue in quantum sensing through a simple mechanism based on a sequential measurement strategy. This sensing scheme overcomes the singularity constraint and enables the simultaneous estimation of multiple parameters with a local and fixed measurement throughout the sensing protocol. This is because sequential measurements, involving consecutive steps of local measurements followed by probe evolution, inherently produce correlated measurement data that grows exponentially with the number of sequential measurements. Finally, through two different examples, namely a strongly correlated probe and a light-matter system, we demonstrate how such singularities are reflected when inferring the unknown parameters through Bayesian estimation.

We prove the Penrose-Wall singularity theorem in the full semiclassical gravity regime, significantly expanding its range of validity. To accomplish this, we modify the definition of quantum-trapped surfaces without affecting their genericity. Our theorem excludes controlled “bounces” in the interior of a black hole and in a large class of cosmologies.

We calculate the spatial Wilson line correlator for $2+1$ flavor QCD using highly improved staggered quark discretization for fermions and in quenched QCD for a wide range of temperatures, from the chiral crossover temperature $T_{\mathrm{pc}}\simeq 156\mathrm{MeV}$ or the deconfinement temperature $\simeq 300\mathrm{MeV}$, respectively, up to 2 GeV. Extracting the spatial string tension for different lattice cutoffs and by performing a continuum extrapolation of this observable, we show that the soft (magnetic) gluons interact nonperturbatively even at temperatures $\gtrsim 1\mathrm{GeV}$. We provide incriminating evidences to demonstrate that dimensionally reduced effective theories can describe these soft quark and gluon quasi-particles for both quenched and $2+1$ flavor QCD, at temperatures $T\gtrsim 5T_{\mathrm{pc}}$. We also show for the first time the imprints of the nonperturbative pseudopotential in the properties of mesonic screening masses for temperatures ranging from 0.8 to 164 GeV in the quark-gluon plasma.

We numerically verify and analytically prove a winding number invariant that correctly predicts the number of edge states in one-dimensional, nearest-neighbor (between unit cells), two-band models with any complex couplings and open boundaries. Our winding number uses analytical continuation of the wave-vector into the complex plane and involves two special points on the full Riemann surface band structure that correspond to bulk eigenvector degeneracies. Our winding number is invariant under unitary or similarity transforms. We emphasize that the topological criteria we propose here differ from what is traditionally defined as a topological or trivial phase in symmetry-protected classification studies. It is a broader invariant for our model that supports non-zero energy edge states and its transition does not coincide with the gap closing condition. When the relevant symmetries are applied, our invariant reduces to well-known Hermitian and non-Hermitian symmetry-protected topological invariants.

Switching magnetism using only electricity is of great significance for industrial applications but remains challenging. We find that altermagnetism, as a newly discovered unconventional magnetism, may open an avenue along this effort. Specifically, to have deterministic switching, i.e., reversing current direction must reverse magnetic structure, parity symmetry has to be broken. We discover that, due to their symmetry, which depends on chemical environments, altermagnet devices may naturally carry the parity symmetry breaking required for deterministic electrical switching of magnetism. More importantly, we identify MnTe bilayers (Te-Mn-Te-Mn-Te) as candidate devices, with the help of symmetry analysis, first-principles calculations, and magnetic dynamics simulations. This scheme will inspire further explorations on unconventional magnetism.

Interfaces play a pivotal role in various physical, chemical, and biological processes. In polymer crystallization, nucleation often occurs at solid interfaces due to the reduced barrier for heterogeneous nucleation, with the chain conformations and dynamics deviating significantly from their undisturbed (bulk) state. In this Letter, we employed a nanopore-confined system to differentiate between two nucleation scenarios: surface nucleation and homogeneous nucleation, through comprehensive crystal orientation analysis. Experimental findings reveal that surface-induced nucleation in polymers is predominantly driven by an entropic effect, arising from the loss of conformational entropy as polymer chains flatten at weakly interacting solid interfaces. Homogeneous nucleation is, instead, predominant in cases of strong interfacial interactions.

The system of polymers dissolved in a mixture of different solvents is a widely used coarse-grained model to represent biomolecular condensates in intracellular environments. Here, we apply a variational theory to simultaneously control the center of mass of two polymers and perform the first quantification of their interactions in a mixture of solvent and cosolvent. While the polymer can completely dissolve in both solvents, strong polymer-cosolvent affinity induces the occurrence of polymer-assisted cosolvent condensation. Even though all the molecular interactions are soft, the potential of mean force between two polymer-cosolvent condensates exhibits an anomalous feature of hard-wall repulsion upon contact, which cannot be categorized into any existing types of interchain interactions. This repulsion is enhanced as either the affinity or the bulk cosolvent fraction increases. The underlying mechanism is cosolvent regulation manifested as a discontinuous local condensation of cosolvent as two condensates approach. The hard-wall repulsion provides a kinetic barrier to prevent coalescence of condensates and hence highlights the intrinsic role of proteins as a cosolvent in stabilizing biomolecular condensates.

As quantum devices continue to grow in size but remain affected by noise, it is crucial to determine when and how they can outperform classical computers on practical tasks. A central piece in this effort is to develop the most efficient classical simulation algorithms possible. Among the most promising approaches are Pauli backpropagation algorithms, which have already demonstrated their ability to efficiently simulate certain classes of parameterized quantum circuits—a leading contender for near-term quantum advantage—under random circuit assumptions and depolarizing noise. However, their efficiency was not previously established for more realistic nonunital noise models, such as amplitude damping, that better capture noise on existing hardware. Here, we close this gap by adapting Pauli backpropagation to nonunital noise, proving that it remains efficient even under these more challenging conditions. Our proof leverages a refined combinatorial analysis to handle the complexities introduced by nonunital channels, thus strengthening Pauli backpropagation as a powerful tool for simulating near-term quantum devices.

We propose a method to perform an exact calculation of one-loop quantum corrections to black hole entropy in terms of Virasoro semiclassical blocks. We analyze in detail a four-dimensional Kerr black hole and show that in the near-extremal limit a branch of long-lived modes arises. We prove that the contribution of these modes accounts for a $(s-1/2)\log T_{\text{Hawking}}$ correction to the entropy for massless particles of spin $s=1$, 2. We show that in the full calculation performed in the exact Kerr background the leading contribution actually is sourced by the near-horizon region only, and as such has a universal validity for any asymptotic behavior at infinity.

Worldtube excision is a method of reducing computational burden in numerical relativity simulations of binary black holes in situations where there is a good analytical model of the geometry around (one or both of) the objects. Two such scenarios of relevance in gravitational-wave astronomy are (1) the case of mass-disparate systems, and (2) the early inspiral when the separation is still large. Here we illustrate the utility and flexibility of this technique with simulations of the fully self-consistent radiative evolution in the model problem of a scalar charge orbiting a Schwarzschild black hole under the effect of scalar-field radiation reaction. We explore a range of orbital configurations, including inspirals with large eccentricity (which we follow through to the final plunge and ringdown) and hyperbolic scattering.

Recent interest in orbital angular momentum has led to a rapid expansion of research on spin-orbit coupling effects in solids, while also highlighting significant technical challenges. The breaking of rotational symmetry renders the orbital angular momentum operator ill defined, causing conceptual and computational issues in describing orbital motion. To address these issues, here we propose an alternative framework. Based on the Bloch representation of the full relativistic interaction, we derive a field that directly couples to electron spins while preserving discrete translational symmetry, thereby eliminating the need for the position operator. Our approach is fully compatible with existing first-principles computational frameworks for both static and time-dependent density functional theory. We demonstrate that this method offers a more effective description of the Edelstein and spin Hall effects compared to conventional orbital angular momentum formalisms.