Extracting useful work from quantum systems is a fundamental problem in quantum thermodynamics. In scenarios where rapid protocols are desired—whether due to practical constraints or deliberate design choices—a fundamental trade-off between power and efficiency is yet to be established. Here, we investigate the problem of finite-time optimal work extraction from closed quantum systems, subject to a constraint on the magnitude of the control Hamiltonian. We first reveal the trade-off relation between power and work under a general setup, showing that these fundamental performance metrics cannot be maximized simultaneously. We then identify a solvable class of finite-time optimal work-extraction problems. This class includes nontrivial many-body models such as the Heisenberg model and the $\mathrm{SU}\left(n\right)$-Hubbard model. The key assumption is that the control Hamiltonian is optimized over a Lie algebra preserved by the uncontrolled dynamics. Within this class, the optimal work-extraction problem admits an exact reduction to a nonlinear self-consistent equation, circumventing extensive search over time-dependent control paths. The resulting optimal protocol turns out to be particularly simple: It suffices to use a time-independent control Hamiltonian in the interaction picture, determined by that equation. By exploiting the Lie-algebraic structure of the controllable terms, our approach is applicable to quantum many-body systems through efficient numerical computation. Our results highlight the necessity of rapid protocols to achieve the maximum power and provide an exact route to finite-time optimal work extraction in many-body quantum systems.

We present a framework for characterizing higher-order topological phases directly from the one-particle density matrix, without any reference to an underlying Hamiltonian. Our approach extends the mode-shell correspondence, originally formulated for single-particle Hamiltonians, to Gaussian states subject to chiral constraints. In this correspondence, the mode index counts topological boundary modes, while the shell index quantifies the bulk topology in a region surrounding the modes, providing a bulk-boundary diagnostic. In one-dimensional topological insulators, the shell index reduces to the local chiral marker, recovering the winding number in the translation-invariant limit. We apply the mode-shell correspondence to a $C_4$-symmetric higher-order topological insulator with a chiral constraint and show that a fractional shell index implies that the higher-order phase is intrinsic. The one-particle density matrix is formulated in real space, so the mode-shell correspondence also applies to models without translation invariance. By introducing structural disorder into the $C_4$-symmetric higher-order insulator, we show that the mode-shell correspondence remains a meaningful diagnostic in amorphous structures. The mode-shell correspondence generalizes to interacting states with a gapped bulk spectrum in the one-particle density matrix, providing a practical and diverse route to characterize higher-order topology from the quantum state itself.

Quantum self-oscillatory phases are ubiquitous in driven-dissipative systems. Classically, each phase is defined by its flow pattern and how stationary sets organize phase space (e.g., fixed points and limit cycles), with transitions triggered by local bifurcations or global basin rearrangements. In the quantum regime, these reorganizations are often blurred by density-matrix averaging, and spectral indicators such as the Liouvillian gap can miss changes that unfold mainly in the transients. Here, we develop a topological toolkit for flows with limit cycles, rooted in Morse-Smale dynamical-systems theory, to reveal and classify dynamical phase transitions in self-oscillating driven-dissipative systems. We formulate a graph invariant, the molecule, encoding the connectivity and chirality of fixed points and limit cycles and the resulting topological constraints on basin and flow-region rearrangements during phase transitions. Exploiting these constraints, we uncover a class of global dynamical phase transitions, marked by discrete changes of the molecule, that leave no clear trace in the Liouvillian spectrum (gap or excited eigenvalues) yet induce sharp qualitative changes in transient quantum dynamics and relaxation pathways. Our findings show that flow topology offers a clear and unified way to identify and classify dynamical phases beyond what Liouvillian spectra alone reveal.

Impulsive plasma dynamics in the laboratory are often driven by rising electric currents, yet their quantitative plasma response has not been well established. By means of fully kinetic particle-in-cell simulations and laser-driven capacitor-coil experiments, we show that a rising current expels plasma, forming an expanding magnetic bubble and accelerating particles. The expansion front velocity scales with the Alfvén speed determined by the magnetic field at its inner edge and the plasma density at its outer edge. This mechanism establishes impulsive current drive as a fundamental way that generates plasma flows and accelerates particles in laboratory plasmas, with potential relevance to astrophysics.

We investigate the behavior of interstitial ${}^8\mathrm{Li}^{+}$ implanted near the surface of $2H\text{−}{\mathrm{MoTe}}_2$ using $\beta$-detected nuclear magnetic resonance. We find that, unlike the muon, ${}^8\mathrm{Li}^{+}$ does not show any signature of induced magnetism. This result is consistent with density functional theory, which identifies the Li stopping site at the 2a Wyckoff position in the van der Waals gap and confirms the absence of detectable Li-induced electronic spin polarization. Both the spin-lattice relaxation and the resonance line shape show evidence of pronounced spin dynamics above $\sim 200\mathrm{K}$, reminiscent of local stochastic ${}^8\mathrm{Li}^{+}$ motion within a cage. The resonance line shape consists of quadrupolar satellites on top of a broad central peak. To better understand the interaction of ${}^8\mathrm{Li}^{+}$ with the host material, we employ a frequency-comb measurement by simultaneously exciting four frequencies corresponding to the first-order quadrupolar satellite transitions, ${\nu }_0\pm 3{\nu }_{\mathrm{comb}}$ and ${\nu }_0\pm {\nu }_{\mathrm{comb}}$, around the Larmor frequency ${\nu }_0$ as a function of ${\nu }_{\mathrm{comb}}$. This offers an enhanced sensitivity to the quadrupolar split portion of the line. Using this method, we find a small decrease in the quadrupolar frequency with increasing temperature, showing the typical behavior associated with thermally excited phonons and the absence of any magnetic response, in contrast to what was observed for other defects in $2H\text{−}{\mathrm{MoTe}}_2$.

This study probes how gas compression governs the morphodynamics of gas-liquid-grain displacement in confined granular systems, a process vital to many applications like air sparging and carbon sequestration. Combining experiments and theory, we find that facilitating compression yields effects analogous to decreasing the classic capillary number. This analogy arises from the diminished transient flow rates due to the underlying coupling between viscous liquid displacement and gas pressure buildup. A theoretical model is developed to resolve this coupling, accurately matching the reduced injection pressure and prolonged breakthrough time observed in experiments. We further introduce a compression-dependent capillary number $\mathrm{C}{\mathrm{a}}_C$ that effectively captures the pattern transitions. Our findings underscore the role of compressibility in gas-driven flows—typically neglected in laboratories yet becoming increasingly critical toward industrial relevance.

We present optimal control strategies for the dc transport across a Josephson junction. Specifically, we consider a junction in which the Josephson coupling is driven parametrically, with either a bichromatic or a trichromatic driving protocol, and optimize the prefactor of the $1/\omega$ divergence of the imaginary part of the conductivity, which we refer to as the effective Josephson coupling $J_{\mathrm{eff}}$. We demonstrate that for an optimal bichromatic protocol an enhancement of $J_{\mathrm{eff}}$ by a factor of 70 can be reached, and for an optimal trichromatic protocol an enhancement by a factor of 135. This is motivated by pump-probe experiments that have demonstrated light-enhanced superconductivity along the $c$ axis of underdoped ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{6+\delta }$ (YBCO), where the junction serves as a minimal model for the $c$-axis coupling of superconducting layers. Therefore, the significant enhancement of superconductivity that we show for multifrequency protocols demonstrates that the advancement of pump-probe technology toward these strategies is highly desirable.

Strong directional disorder in local magnetic moments coupled to a Chern insulator gives rise to topological phases that cannot be realized in any clean system and are therefore genuinely disorder driven. We demonstrate this in a spinful Qi-Wu-Zhang model of a two-dimensional Chern insulator coupled to disordered classical spins of unit length. The topological phase diagram is computed numerically using two complementary approaches: twisted boundary conditions and the topological Hamiltonian technique. Our results show that strong disorder can act as a fundamental topological mechanism rather than merely a perturbation. For strong exchange coupling, tuning the mass parameter reveals a transition between phases with different Chern numbers $C$. Remarkably, this transition is driven by zeros, rather than poles, of the disorder-averaged Green’s function crossing the chemical potential, and has no analog in any clean system. We further identify a strong-coupling phase with $C=0$ that is nonetheless topologically nontrivial, characterized by a distinct Chern number $C^{\left(\mathrm{S}\right)}\ne 0$ over the manifold of classical spin configurations. This phase is also disorder driven, as $C^{\left(\mathrm{S}\right)}=0$ in the clean limit.

The quantum dynamics of many-qubit systems is an outstanding problem that has recently driven significant advances in both numerical methods and programmable quantum processing units (QPUs). In this work, we employ a comprehensive toolbox of state-of-the-art numerical approaches to classically simulate the dynamics of the two-dimensional transverse-field Ising model. Our methods include three different tensor-network techniques—matrix product states, tree tensor networks, and two-dimensional tensor networks under the belief propagation approximation—as well as time-dependent variational Monte Carlo with neural quantum states. We focus on two paradigmatic dynamical protocols: (1) quantum annealing through a critical point and (2) postquench dynamics. Our extensive results show the quantitative predictions of various state-of-the-art numerical methods providing a benchmark for future numerical investigations and experimental studies with the aim to push the limitations on classical and QPUs. In particular, our work connects classical simulability to different regimes associated with quantum dynamics in Rydberg arrays—namely, quasiadiabatic dynamics, the Kibble-Zurek mechanism, and quantum quenches.

We propose a hybrid quantum system in which a magnet supporting nonreciprocal magnons, chiral magnons, or both mediates the dissipative and unidirectional coupling of spin qubits. By driving the qubits, the steady state of this qubit-qubit coupling scheme becomes the maximally entangled Bell state. We devise a protocol where the system converges to this entangled state and benchmark it including qubit decay and dephasing. The protocol is numerically tested on a hybrid system consisting of nitrogen-vacancy (NV) centers coupled to magnon surface modes of a yttrium iron garnet (YIG) film. We show that the dephasing time of the NV centers forms the bottleneck for achieving the entanglement of NV centers separated by a distance within the magnon coherence length. Our findings identify the key technological requirements and demonstrate a viable route toward steady-state entanglement of solid-state spins over distances of several microns using magnonic quantum networks, expanding the toolbox of magnonics for quantum information purposes.

We report the study of spin dynamics of ${\mathrm{Eu}}^{2+}$ in the antiferromagnetic axion topological insulator ${\mathrm{EuSn}}_2{\mathrm{As}}_2$ by means of antiferromagnetic resonance at 9.34 GHz. Below the Néel temperature ($T_{\mathrm{N}}$), two types of resonance modes, the conventional bulk antiferromagnetic resonance and additional surface ferromagnetic resonance, are observed. The latter turns out to be characteristic of the axion-insulating phase. Above $T_{\mathrm{N}}$, we prove the existence of a Kosterlitz-Thouless scenario that is relevant for the spin relaxation in the ${\mathrm{Eu}}^{2+}$ layers. The absence of Korringa relaxation indicates the strong confinement of the conduction electrons at the Fermi level to the SnAs layers.

We report the experimental discovery of bulk superconductivity in two kagome lattice compounds, ${\mathrm{YRu}}_3{\mathrm{B}}_2$ and ${\mathrm{LuRu}}_3{\mathrm{B}}_2$, which were predicted through machine-learning-accelerated high-throughput screening combined with first-principles calculations. These materials crystallize in the hexagonal ${\mathrm{CeCo}}_3{\mathrm{B}}_2$-type structure with planar kagome networks formed by Ru atoms. We observe superconducting critical temperatures of $T_c=0.81$ K for ${\mathrm{YRu}}_3{\mathrm{B}}_2$ and $T_c=0.95$ K for ${\mathrm{LuRu}}_3{\mathrm{B}}_2$, confirmed through magnetization, specific heat, and electrical transport measurements. Both compounds exhibit nearly 100% superconducting volume fractions, demonstrating bulk superconductivity. Compared with isostructural ${\mathrm{LaRu}}_3{\mathrm{Si}}_2, {\mathrm{YRu}}_3{\mathrm{B}}_2$ and ${\mathrm{LuRu}}_3{\mathrm{B}}_2$ show a more dispersive Ru local $d_{x^2-y^2}$ quasiflat band [and thus a reduced density of states (DOS) at $E_F$] together with an overall hardening of the phonon spectrum, both of which lower the electron-phonon coupling (EPC) constant $\lambda$. Meanwhile, the dominant real-space EPC between Ru local $d_{x^2-y^2}$ states and the low-frequency Ru in-plane local $x$ branch remains nearly unchanged, indicating that the reduction of $\lambda$ originates from the $d_{x^2-y^2}$ DOS reduction and the overall phonon hardening. Superfluid weight calculations show that conventional contributions dominate over quantum geometric effects due to the dispersive nature of bands near the Fermi level. This work demonstrates the effectiveness of integrating machine-learning screening, first-principles theory, and experimental synthesis for accelerating the discovery of new superconducting materials.

Ultracold Feshbach molecules are a crucial intermediate step for the creation of quantum degenerate gases of strongly dipolar molecules. After coherent transfer to the rovibrational ground state, these dimers can realize stable dipolar gases with strong, tunable long-range interactions. Here, we report the creation of bosonic ${}^{23}\mathrm{Na}{}^{41}\mathrm{K}$ Feshbach molecules by radio-frequency (RF) association. An RF pulse applied on the molecular side of an interspecies Feshbach resonance at 73.6(1) G associates up to $1.1\left(1\right)\times {10}^4$ molecules from a thermal mixture of ${}^{23}\mathrm{Na}$ and ${}^{41}\mathrm{K}$ atoms. Measurements of the binding energy reveal a broad resonance width of 5.1(2) G, facilitating robust control over interspecies interactions. The molecule lifetime in the presence of background atoms exceeds 2 ms and increases to approximately 7 ms after removal of ${}^{23}\mathrm{Na}$. These results constitute a key step toward the production of ultracold ${}^{23}\mathrm{Na}{}^{41}\mathrm{K}$ ground-state molecules and for pursuing shielded evaporative cooling in the dipolar regime.

We use a quantum extreme learning machine (QELM) for characterizing and estimating parameters of quantum dynamics generated by a tunable collision model. The input to the learning protocol consists of quantum states produced by successive system-environment interactions, while the reservoir is implemented as a disordered many-body quantum system evolving under a fixed Hamiltonian. We systematically explore how extending the QELM feature space, through the inclusion of temporal information and additional observables, affects estimation performance. Our results demonstrate that temporal extensions of the feature vector consistently and significantly enhance estimation accuracy relative to the baseline protocol. Notably, incorporating memory from earlier time steps yields the most substantial and robust improvements, whereas extensions based solely on additional observables offer only marginal gains. Crucially, the advantage conferred by temporal memory becomes increasingly pronounced as the dynamics become more strongly non-Markovian, indicating that environmental memory effects serve as a constructive resource for learning.

Stochastic renewal processes are ubiquitous across physics, biology, and the social sciences. Here, we show that continuous-time renewal dynamics can naturally produce a mixed discrete-continuous structure, with a macroscopic fraction of particles occupying a discrete state. For ensembles of continuous-time random walkers subject to Poissonian renewal resets, we develop an age-structured framework showing that this discrete component corresponds to localization at the reset configuration. We next show that collective interactions can retain memory although all reset events are memoryless. Remarkably, the transition to collective memory is discontinuous, and we identify a discontinuous dynamical phase transition from weak collective bias, where the dynamics are stationary, to strong collective bias, where the dynamics are nonstationary and display aging up to finite-size effects. We explicitly discuss ecological implications of our work, illustrating how continuous-time renewal dynamics shape macroscopic structure and collective organization with long-term memory.

Quantum simulation aims to recreate complex many-body phenomena in controlled environments, offering insights into dynamics that are otherwise difficult to model. Existing platforms, however, are often complex and costly to scale, typically requiring ultrapure vacuum or low temperatures. Here, we introduce a platform based on a thin, strongly interacting ${}^{13}\mathrm{C}$ nuclear spin layer in diamond that allows controlled exploration of many-body dynamics at room temperature. Nearby nitrogen-vacancy centers enable polarization, readout, and, combined with radio-frequency fields, coherent control of the nuclear spins. We demonstrate strong, tunable interactions among the nuclear spins and use the system to probe discrete time-crystalline order across varying interaction ranges. By combining ease of use with operation at ambient temperatures, our work opens new opportunities for investigating strongly correlated many-body effects.