We introduce a multirobust quantum control strategy designed to suppress multilevel leakage outside the computational qubit space while simultaneously ensuring robustness against unknown inhomogeneities in control parameters. It is based on a reformulation of the derivative removal by adiabatic gate (DRAG) technique which allows for the full incorporation of control pulses originally designed for two-level models by using the iterative quantum Kolmogorov-Arnold-Moser (KAM) algorithm. We apply it for optimal robust control designed by inverse optimization (RIO), referred to as RDK pulses. We analyze the performance of RDK pulses on various durations, iterations, and robustness types. We show that the two-level robustness is restored after only a few iterations with an asymptotic exponential approximation (i.e., as a superasymptotic series), even for relatively short pulse durations, and that the resulting pulses are near optimal in terms of energy compared to the optimal RIO pulses defined in the qubit subspace. Such pulses are well suited for superconducting transmons as well as other forms of qubits embedded in a multilevel structure. By effectively reproducing a two-level dynamics within a multilevel system, this approach is versatile thanks to its compatibility with two-level control strategies under conditions (smoothness, duration) that are analyzed.

We report the first experimental realization of a synthetic Hall torus using a spinor Bose-Einstein condensate confined in a ring-shaped trap with in situ imaging. By cyclically coupling three hyperfine spin states via Raman and microwave fields, we impose a periodic boundary condition in the synthetic dimension, which, together with a real-space ring trap, realizes a toroidal geometry with synthetic magnetic flux penetrating the surface. This flux induces azimuthal density modulations whose periodicity is uniquely determined by the quantized toroidal flux, a hallmark of the Hall torus. We then implement a topological charge pump by adiabatically varying an axial flux through the torus, inducing quantized azimuthal transport of the atoms. We further investigate the onset of these modulations as the system transitions from cylindrical to toroidal topology. Our results establish a versatile platform for exploring quantum Hall physics and topological phenomena in synthetic curved spaces.

The Kondo effect in strongly correlated systems arises from the antiferromagnetic coupling between itinerant conduction electrons and localized magnetic moments, giving rise to a variety of exotic quantum phenomena. Two-dimensional moiré superlattice systems provide a highly tunable platform featuring topological flat bands, where Wannier orbitals are spatially confined by the periodic moiré potential and serve as localized magnetic moments, enabling the observable Kondo effect. Here, we experimentally demonstrate Kondo interactions in hexalayer rhombohedral graphene moiré superlattices through magnetotransport and temperature-dependent measurements. With increasing magnetic field, the magnetoresistance exhibits an increase-decrease transition across a critical field $B_c$, while the Hall resistance $R_{xy}$ undergoes a sign reversal near $B_c$. Moreover, as temperature decreases, the longitudinal resistance $R_{xx}$ first increases logarithmically and then decreases following a $T^2$ behavior, indicating a transition to heavy fermion liquid. These behaviors can be consistently explained by the breakdown of Kondo singlets induced by either magnetic field or temperature, which liberates carriers previously bound to localized moments, thereby enhancing conductivity and altering the dominant carrier type. Furthermore, our results demonstrate that the Kondo interaction can be continuously tuned by both carrier density $n$ and displacement electric field $D$, and suggest the emergence of a Kondo insulating state. Our findings provide deep insight into the Kondo effect in moiré engineered flat-band systems, paving the path for exploring exotic correlated quantum phases.

Hopf bifurcations are a universal route to self-sustained oscillations in driven systems. Despite the absence of any singular stationary state, we show that time-averaged observables generically exhibit singularities at the onset of oscillations. The origin of this behavior is geometric: phase averaging over the emergent periodic attractor eliminates odd powers of the oscillation amplitude, while the squared amplitude varies smoothly with the distance from the bifurcation. Consequently, the excess of a time-averaged observable admits an integer-power expansion; observables remain finite but display discontinuities in finite-order derivatives. This yields an Ehrenfest-like hierarchy of Hopf singularities, in which the first nonanalytic derivative is determined by the lowest-order coupling between the observable and the limit-cycle waveform that survives phase averaging. The time averages of generic observables therefore exhibit kink singularities, while symmetry or geometric cancellations can suppress lower-order couplings and shift nonanalyticity to higher derivatives. We demonstrate this mechanism in chemical, electronic, and climate oscillators. Our results identify supercritical Hopf bifurcations as a universal mechanism for nonanalytic observable behavior, where singular yet nondiverging features emerge without any underlying singular stationary state.

Rotating a nonspherical object introduces rich and surprising dynamics to a classical mechanics problem. It has been shown that a rolling ellipse in air can rock, roll, or jump along a flat surface. Even for a rolling sphere, deformability can significantly alter its mobility compared to a rigid counterpart. Here, we experimentally examine both transitions between motion modes and the role of deformability using a driven ellipsoid that can be either rigid or soft. Using a geometric framework, we successfully model the motion of the rigid ellipsoid and identify the critical angular velocity for the rolling-to-jumping transition. Since shape strongly influences motion modes, we further explore the role of deformability using a soft ellipsoid. By modifying the soft ellipsoid’s shape, we tune the rolling-to-jumping transition in situ, and observe that soft ellipsoids move more efficiently along ramps than their rigid counterparts.

Simulation of open quantum systems is an area of active research in quantum algorithms. In this Letter, we revisit the connection between Markovian open-system dynamics and averages of Hamiltonian real-time evolutions, which we refer to as Hamiltonian twirling channels. By applying the Lévy-Khintchine representation theorem, we clarify when and how dissipative dynamics can be realized using Hamiltonian twirling channels. Guided by the general theory, we explore Hamiltonian twirling with Gaussian, compound Poisson, and symmetric stable distributions and their algorithmic implications. These give Lindbladian families whose expected Hamiltonian simulation time ranges from $\mathrm{\Theta }(\sqrt{t})$ for Gaussian dephasing to $\mathrm{\Theta }(t)$ for compound-Poisson jumps, and $\mathrm{\Theta }(t^{1/\alpha })$ for symmetric $\alpha$-stable laws with $1<\alpha \le 2$. Moreover, we prove that these time complexities are asymptotically optimal for the classes studied here using an information-theoretic approach, establishing fundamental lower bounds on fast-forwarding quantum simulation algorithms for the first time to the best of our knowledge.

Fluctuations are intrinsic to microscopic systems and impose fundamental limits on nonequilibrium precision, as captured by the thermodynamic uncertainty relation (TUR), which links current fluctuations to entropy production. While feedback control is expected to further suppress fluctuations, its role within the TUR framework has remained unclear, particularly in quantum systems where control is inherently information driven. In this Letter, we consider open quantum systems weakly coupled to a thermal environment, in which quantum jumps are continuously monitored, and Markovian feedback is applied. Using quantum mutual information to quantify the information contribution induced by feedback, we derive a finite-time TUR for arbitrary time-integrated currents in terms of entropy production and mutual information. Our results uncover how feedback control suppresses fluctuations together with thermodynamic cost and establish a fundamental precision bound imposed by information-based control. As an application, we analyze a quantum clock model and demonstrate that the clock precision can be enhanced by feedback control in the presence of a single thermal reservoir.

A doublet-band structure consisting of two $\mathrm{\Delta }I=1$ bands connected by multiple interband transitions was identified in ${}^{112}\mathrm{Sb}$, with an average energy difference of only 36 keV between the two bands. It represents the most degenerate doublet-band structure observed so far in nuclear systems. The experimental fingerprints and theoretical calculations indicate that the doublet-band structure arises from chiral symmetry breaking. This result provides the first example in which a pure high-$j$ particle-hole configuration and triaxial rotational behavior emerge simultaneously, giving rise to exceptionally strong chiral degeneracy.

We experimentally demonstrate a coherent-control scheme for precompensation of centrifugal distortion using shaped femtosecond laser pulses. By imposing a cubic spectral phase on the excitation pulse [Y. Huang et al., Phys. Rev. A 107, 053108 (2023)], rotational revivals that would otherwise become temporally broadened, multicycle, and overlap with neighboring rotational contributions are compressed into near single-cycle structures. An analytic expression derived from molecular rotational constants enables predictive pulse design and is validated experimentally. As a stringent demonstration of this control scheme, we achieve transient alignment of distinct $l$-doubling populations in ${\mathrm{CO}}_2$. More broadly, the demonstrated control scheme enables the selective preparation of closely spaced molecular components in controlled anisotropic angular distributions, with direct relevance to molecular-frame spectroscopies and advanced coherent control.

Patchy alignment pervades magnetohydrodynamic (MHD) turbulence, yet its role in the turbulent cascade remains unclear. Using net- and no-net-flux compressible simulations with up to $10,368^3$ grid cells, we uncover two distinct alignment laws. Our constant-flux model of departures from locally aligned states predicts the measured velocity-magnetic and velocity-vorticity angle scalings, ${\lambda }^{1/8}$ and ${\lambda }^{1/16}$, over resolved inertial scales $\lambda$. These laws change the predicted shapes of turbulent eddies and raise the theoretical threshold for magnetic reconnection to control the flow of energy across scales.

The effective interaction between composite fermions, set entirely by the Coulomb potential and the underlying electronic Landau level orbitals, can stabilize exotic fractional quantum Hall states. In particular, half-filled Landau levels with different orbital character can host either metallic or paired phases of composite fermions. Here, we leverage experimental control over the orbital composition to realize a composite-fermion pairing transition in the first excited Landau level of bilayer graphene. Transport measurements at filling factors $\nu =\frac{9}{2}$ and $(11/2)$ reveal conductive states giving way to well-developed plateaus with increasing displacement fields. These states are insensitive to an in-plane magnetic field, indicating single-component ground states and thus pointing at non-Abelian orders. Our numerical study, based on displacement-field-dependent Landau-level wave functions, supports the orbital origin of the pairing transition and suggests Moore-Read or anti-Pfaffian ground states.

In two dimensions a Chern insulator can be tuned from a topological state to an ordinary band insulator without breaking any symmetry, offering a clean example of “beyond-Landau” criticality. We show that electron interactions drive this transition to the Gross-Neveu-Yukawa (GNY) fixed point, a benchmark problem of broad interest across high-energy and condensed-matter physics. By solving the minimal Dirac model on the surface of a sphere, we obtain the full spectrum of critical excitations from systems containing only a few electrons. The leading critical exponents match state-of-the-art bootstrap bounds, and several previously unseen collective modes appear. Our results demonstrate that placing a Dirac cone on a curved geometry provides a surprisingly simple and accurate setup for strongly interacting topological transitions.

From the formation of social ties to the budding quantum internet, growing networks often exhibit local flexibility upon new nodes attaching to an existing network. In our proposed model, a new node connects uniformly at random to a node within the proximity of the intended target, including, but not restricted to, the target itself. Through numerical simulations and rigorous stochastic analysis, we find this local flexibility to qualitatively change the global network behavior of nonlinear preferential attachment. Depending on whether the preferential attachment is superlinear or (sub)linear, two distinct classes of complex network architectures emerge. The superlinear phase leads to a layered hierarchy, with no stationary degree distribution. Although there is a stationary degree distribution in the linear and sublinear cases, it decays strictly faster than for the Barabási-Albert model. We interpret our results within a two-dimensional phase diagram of network growth models incorporating redirection, with broad implications.

Preparing algebraically correlated ground states of quantum many-body systems is an important, yet challenging task for quantum simulation. We introduce a protocol that employs local projective measurements and unitary feedback for frustration-free gapless systems. Our approach prepares a priori unknown ground states in time that scales polynomially with system size. We analytically show the performance of our protocol for the dynamics of a single particle; we argue the same mechanism generalizes to many-body systems based on the physics of quasiparticles. Our theory predicts that the transient cooling dynamics directly reveals the system’s universal critical properties. In particular, the state preparation time is linear in the inverse of the finite-size gap (up to log correction) when the system’s dynamical critical exponent is larger than or equal to the effective spatial dimension explored by the quasiparticles. We verify these predictions in numerical simulations of ferromagnetic Heisenberg models in one and two dimensions, a Fredkin spin chain, and a two-dimensional model of resonating valence bond states. Our protocol stabilizes gapless many-body ground states fully digitally without requiring analog rotations, enabling access to high-fidelity states beyond conventional adiabatic approaches in near-term experiments.

Quantum subspace expansion (QSE) offers promising avenues to perform spectral calculations on quantum processors but comes with a large measurement overhead. Informationally complete measurements, such as classical shadows, were recently proposed to overcome this bottleneck. Here, we report the first large-scale implementation of QSE with informationally complete measurements. In particular, we probe the quantum phase transition of a spin model with three-body interactions, for which we observe accurate ground state energy recovery and mitigation of local order parameters across system sizes of up to 80 qubits. We achieve this by reformulating QSE as a constrained optimization problem, obtaining rigorous statistical error estimates and avoiding numerical ill conditioning. With over $3\times {10}^4$ measurement basis randomizations per circuit and the evaluation of $\mathcal{O}({10}^{14})$ Pauli traces, this represents one of the most significant realizations of classical shadows to date.

Understanding flux string dynamics can provide insight into quark confinement and hadronization. First-principles quantum and numerical simulations have mostly focused on toy-model Abelian lattice gauge theories (LGTs). With the advent of state-of-the-art quantum simulation experiments, it is timely to study string dynamics in non-Abelian LGTs beyond one spatial dimension. Using tensor network methods, we simulate the real-time string dynamics of a $2+1\mathrm{D}$ SU(2) Yang-Mills LGT with dynamical matter. In the strong-coupling regime and at resonance, string breaking occurs via a sharp Casimir reduction, along with meson and baryon-antibaryon formation, a distinctively non-Abelian feature. At finite baryon density, we discover a baryon blockade mechanism that delays string breaking. Away from resonance, the magnetic term drives purely non-Abelian fluctuations: glueball-like excitations and self-crossed strings that resolve two SU(2) intertwiners with distinct dynamics. For higher-energy strings, we uncover representation-dependent tension-reduction resonances. Our findings serve as a guide for upcoming quantum simulators of non-Abelian LGTs.

We establish interaction cross sections as a quantitative structural observable for hypernuclei. Using the hypertriton, ${}_{\mathrm{\Lambda }}{}^3\mathrm{H}$, as the most stringent benchmark, microscopic three-body wave functions are combined with a finite-range coupled-channel Glauber calculation and Bayesian inversion. For ${}_{\mathrm{\Lambda }}{}^3\mathrm{H}+{}^{12}\mathrm{C}$ at $1.5\mathrm{GeV}/\mathrm{nucleon}$, the interaction cross section decreases from about 1150 to 750 mb as the $\mathrm{\Lambda }$ separation energy $B_{\mathrm{\Lambda }}$ increases from 0.1 to 0.5 MeV, while propagated reaction-model uncertainties remain near 5%. A measurement therefore supplies a direct inversion ${\sigma }_I\to r_m\to B_{\mathrm{\Lambda }}$, constraining both the matter radius and the $\mathrm{\Lambda }$ separation energy. The framework provides the missing quantitative link between proposed interaction-cross-section measurements and the spatial structure of an already formed hypernucleus. Although demonstrated for the hypertriton, the methodology is readily extendable to other weakly bound hypernuclei.

From coating curved parts to creeping lava, thin-film gravitational drainage over complex surfaces can produce abrupt accumulation, usually associated with sharp edges or defects. Here, experiments, simulations, and asymptotics show that a smooth saddle alone generates a logarithmically singular ridge, regularized within a dynamic region where drainage balances hydrostatic pressure and capillarity. In a Newtonian lubrication picture, this mechanism can inform redistribution in manufacturing and geophysics, motivating extensions to complex rheology and interacting geometric features.

The occurrence of magnetic reconnection is of pivotal importance regarding the evolution of many magnetized astrophysical systems. Among others, the mechanism known as “diamagnetic suppression” can prevent reconnection from developing. Over the last decade, many studies evidenced a statistical correlation of the magnetic shear and plasma beta for current sheets interpreted as reconnecting or not, consistent with predictions of the diamagnetic suppression theory. The strength of the observed correlations has suggested that diamagnetic suppression is the dominant mechanism controlling whether reconnection occurs or not, in many space plasma environments, from planetary magnetospheres to the solar wind and heliopause. Here, we show that there exists a possible observational bias, operating at least in the context of the Earth’s magnetopause, that can lead to a similar statistical correlation because outflow speeds expected from magnetic reconnection strongly depend on both the magnetic shear and plasma $\beta$. Low velocity jets become increasingly difficult to observe when they become comparable to the surrounding flow fluctuation level. We conclude that the role of diamagnetic suppression at the Earth’s magnetopause remains unclear.