We investigate the dynamics of multimode optical systems driven by two-photon processes and subject to nonlocal losses, incorporating quantum noise at the Gaussian level. Our findings show that the statistics retrieved from a single Gaussian quantum trajectory exhibits emergent thermal equilibrium governed by an Ising Hamiltonian, encoded in the dissipative coupling between modes. The system’s effective temperature is set by the driving strength relative to the oscillation threshold. Given the ultrashort timescales typical of all-optical devices, our Letter demonstrates that such multimode optical systems can operate as ultrafast Boltzmann samplers, paving the way toward the realization of efficient hardware for combinatorial optimization, with promising applications in machine learning and beyond.

We report the achievement of single-qubit gates with sub-part-per-million error rates, in a trapped-ion ${}^{43}{\mathrm{Ca}}^{+}$ hyperfine clock qubit. We explore the speed and fidelity trade-off for gate times $4.4\le t_g\le 35\mathrm{\mu }\mathrm{s}$, and benchmark a minimum error per Clifford gate of $1.5(4)\times {10}^{-7}$. Calibration errors are suppressed to $<{10}^{-8}$, leaving qubit decoherence ($T_2\approx 70\mathrm{s}$), leakage, and measurement as the dominant error contributions. The ion is held above a microfabricated surface-electrode trap that incorporates a chip-integrated microwave resonator for electronic qubit control; the trap is operated at room temperature without magnetic shielding.

When a gravitational wave (GW) passes through a dc magnetic field, it couples to the conducting wires carrying the currents which generate the magnetic field, causing them to oscillate at the GW frequency. The oscillating currents then generate an ac component through which the GW can be detected—thus forming a resonant mass detector or a magnetic Weber bar. We quantify this claim and demonstrate that magnets can have exceptional sensitivity to GWs over a frequency range demarcated by the mechanical and electromagnetic resonant frequencies of the system; indeed, we outline why a magnetic readout strategy can be considered an optimal Weber bar design. The concept is applicable to a broad class of magnets, but can be particularly well exploited by the powerful magnets being deployed in search of axion dark matter, for example, by DMRadio and ADMX-EFR. Explicitly, we demonstrate that the MRI magnet that is being deployed for ADMX-EFR can achieve a broadband GW strain sensitivity of $\sim {10}^{-20}/\sqrt{\mathrm{Hz}}$ from a few kHz to about 10 MHz, with a peak sensitivity down to $\sim {10}^{-22}/\sqrt{\mathrm{Hz}}$ at a kHz exploiting a mechanical resonance.

We investigate the low energy regime of BFSS quantum mechanics using its holographic dual. We identify three distinct thermodynamic phases (black holes) and analyze their thermodynamic properties extensively, including phase transitions amongst the several phases. While the properties of the canonical ensemble aligns with existing conjectures on BFSS thermodynamics, we uncover intriguing and unexpected behavior in the microcanonical ensemble. Specifically, for sufficiently low energies, we observe the dominance of the localized phase. Surprisingly, we also identify an energy range where the non-uniform phase becomes dominant. The transition between these phases is mediated by a Kol-type topology-changing phenomenon.

A new effective theory framework for fluctuating hydrodynamics in the relativistic regime is derived using standard thermodynamical principles and general properties of nonequilibrium stochastic dynamics. For the first time, we establish clear and concise conditions for ensuring that the resulting effective theories are causal, stable, and well-posed within general relativity. These properties are independent of spacetime foliation and are valid in the full nonlinear regime. Out-of-equilibrium fluctuations are constrained by a relativistically covariant version of the Crooks fluctuation theorem, which determines how the entropy production is distributed even when the system is driven by an external force. This leads to an emerging ${\mathbb{Z}}_2$ symmetry responsible for imposing fluctuation-dissipation relations for n-point correlation functions, which matches the standard constraints for the Schwinger-Keldysh effective action.

The spectroscopic studies of very neutron-rich nucleus ${}^{128}\mathrm{Ag}$ have been performed for the first time at the Radioactive Isotope Beam Factory of RIKEN. A new seniority isomer with a half-life of $1.60(7)\mathrm{\mu }\mathrm{s}$ has been identified and is proposed to have a spin-parity of ${16}^{-}$ with a maximally aligned configuration comprising three proton holes in the $g_{9/2}$ orbital and one neutron hole in the $h_{11/2}$ orbital. The new level structure in ${}^{128}\mathrm{Ag}$ is quite well described by shell model calculations without invoking excitations across the $Z=50$ and $N=82$ shell gaps, and presents a good case of seniority scheme in odd–odd nuclei in the south vicinity of the double-magic nucleus ${}^{132}\mathrm{Sn}$. With a classification of various components of the proton–neutron interaction, the inversion of lowest-lying $9^{-}$ and ${10}^{-}$ states between ${}^{128}\mathrm{Ag}$ and its neighboring isotone ${}^{130}\mathrm{In}$ is found to be dynamically ascribed to the seniority-nonconserving proton–neutron interaction components. The structure above ${10}^{-}$ up to the ${16}^{-}$ isomer in ${}^{128}\mathrm{Ag}$ shows remarkable similarities to seniority structures in the semimagic nuclei ${}^{128}\mathrm{Pd}$ and ${}^{130}\mathrm{Cd}$. These spectroscopic features in ${}^{128}\mathrm{Ag}$ indicate that the $N=82$ shell closure is still robust in silver isotopes.

We present a new scale decomposition method to investigate turbulence in wavenumber-frequency space. Using 3D magnetohydrodynamic turbulence simulations, we show that magnetic fluctuations with time scales longer than the nonlinear time exhibit an inverse cascade toward even smaller frequencies. Low frequency magnetic fluctuations support turbulence, acting as an energy reservoir that is converted into plasma kinetic energy, the latter cascading toward large wavenumbers and frequencies, where it is dissipated. Our results shed new light on the spatiotemporal properties of turbulence, potentially explaining the origin and role of low frequency turbulent fluctuations in the solar wind.

The coherent x-ray diffraction imaging (CXDI) technique offers unique insights into the nanoscale world, enabling the reconstruction of 3D structures with a nanoscale resolution achieved through computational phase reconstruction from measured scattered intensity maps. However, the computational demands of 3D coherent x-ray diffraction imaging limit its real-time application in experimental settings. This Letter presents a carousel phase retrieval algorithm (CPRA) that enables the real-time, high-resolution reconstruction of computationally complex 3D objects. CPRA is based on representing the 3D reconstruction problem as a set of 2D reconstructions of projected images corresponding to different experimentally collected angles via the Fourier slice theorem. The consistency between the 2D reconstructed images is based on an iterative procedure in which each 2D reconstruction accounts for the adjacent 2D reconstructed images in a periodic (carousel) manner. Demonstrations on complex systems, including a lithium-rich layered oxide particle and a biological cell of Staphylococcus aureus, demonstrate that CPRA significantly enhances the reconstruction quality and enables the reconstruction process to be completed in real time during the experiment.

One-dimensional Coulomb drag has been an essential tool to probe the physics of interacting Tomonaga-Luttinger liquids. To date, most experimental work has focused on the linear regime while the predictions for Luttinger liquids beyond the linear response theory remain largely untested. In this Letter, we report measurements of reciprocal momentum transfer induced Coulomb drag between vertically coupled quasi-one-dimensional quantum wires in the nonlinear regime. Measurements were performed at ultralow temperatures between wires only 15 nm apart. Our results reveal a nonlinear dependence of the drag voltage as a function of the drive current superimposed with an oscillatory contribution, in agreement with theoretical predictions for Coulomb drag between Tomonaga-Luttinger liquids. Additionally, the observed current-voltage characteristics exhibit a nonmonotonic temperature dependence, further corroborating the presence of non-Fermi-liquid behavior in our system. These findings are observed both in the single and in the multiple subband regimes and in the presence of disorder, extending the onset of this behavior beyond the clean single channel Tomonaga-Luttinger regime where the predictions were originally formulated.

Square lattice Hubbard model with tunable hopping ratio $t^{\prime }/t$ is highly promising for realizing a variety of quantum phases, including higher-temperature superconductivity. We show that twisted square lattice homobilayers offer such tunability when the flat bands originate from the corner of the Brillouin zone. An emergent symmetry, generically present at low twist angles, enforces $t=0$ for these bands. Breaking it with interlayer displacement field or in-plane magnetic field introduces $t$ and anisotropy, tunable in a wide range for correlated electrons on the moiré square lattice.

Supersymmetry (SUSY) proposed as an elementary symmetry for physics beyond the standard model has found important applications in various areas outside high-energy physics. Here, we systematically implement supersymmetric quantum mechanics—exhibiting fundamental SUSY properties in the simple setting of quantum mechanics—into a wide range of topological semimetals, where the broken translational symmetry, e.g., by a magnetic field, is effectively captured by a SUSY potential. We show that the dynamical SUSY breaking via the instanton effect over the SUSY potential valleys works as the underlying mechanism for the gap opening of the topological semimetallic phases, and the magnitude of the instanton effect is proportional to the energy gap. This instanton mechanism provides a simple criterion for determining whether the energy gap has been opened, without resorting to detailed calculations, i.e., a finite energy gap is opened if and only if the SUSY potential has an even number of zeros. Our theory leads to previously unexpected results: even an infinitesimal magnetic field can open a gap in topologically robust Dirac, Weyl, and nodal-line semimetallic phases due to the dynamical SUSY breaking. Overall, the revealed connection between SUSY quantum mechanics and nonuniform topological semimetals can elucidate previously ambiguous phenomena, provide guidance for future investigations, and open a new avenue for exploring topological semimetals.

The superconducting diode effect (SDE), where zero-resistance states appear nonreciprocally during current injection, is receiving tremendous interest in both fundamental and applied physics because the SDE is a novel manifestation of symmetry breaking and enables the creation of a novel diode. In particular, magnetic-field-free SDEs have been extensively investigated because of their potential to serve as building blocks for superconducting circuit technology. In this Letter, we report the field-free SDE in a layered superconductor, FeSe. Its underlying physics is clarified by systematic controlled experiments to be an interplay of a large thermoelectric response and geometrical asymmetry in FeSe. Our findings can pave a new avenue for the construction of novel material and device platforms utilizing SDEs.

We use femtosecond pump-probe spectroscopy to study the coherent interaction of excited exciton states in ${\mathrm{WSe}}_2$ and ${\mathrm{MoSe}}_2$ monolayers via the optical Stark effect. For cocircularly polarized pump and probe, we measure a blueshift that points to a repulsive interaction between the $2s$ and $1s$ exciton states. The determined $2s\text{−}1s$ interaction strength is on par with that of the $1s\text{−}1s$ in agreement with the semiconductor Bloch equations. Furthermore, we demonstrate the existence of a $2s\text{−}1s$ biexciton bound state in the cross-circular configuration in both materials and determine their binding energy.

Quantum effects in metrology can in principle enhance measurement precision from the so-called standard quantum limit to the Heisenberg limit. Further advancements in quantum metrology largely rely on innovative metrology protocols that can avoid a number of known obstacles, including the challenge of preparing entangled states with sufficient fidelity, the readout noise in measuring highly entangled states, and no-go theorems for quantum metrology under noisy environments. In this Letter, exploiting some peculiar but experimentally feasible dynamical features of a collection of spins with all-to-all time-periodic interactions, we propose a metrology protocol that can circumvent all three mentioned obstacles and yet still make good use of time as a resource for metrology. Specifically, by mapping the dynamics of such a periodically driven spin system to that of a paradigm of quantum chaos but tuned to some high-order quantum resonance, it is shown that a simple SU(2) coherent state can, after evolving to highly entangled states in the ensuing dynamics, be dynamically brought back to the same initial coherent state. The associated quantum Fisher information is found to exhibit quadratic scaling with both the number of spins and the duration of the metrology protocol. The achieved Heisenberg scaling can also largely survive in the presence of Markovian noise. Representing a previously unknown strategy for quantum metrology, the protocol proposed here can be tested on available experimental platforms.

The STAR Collaboration presents measurements of the semi-inclusive distribution of charged-particle jets recoiling from energetic direct-photon (${\gamma }_{\mathrm{dir}}$) and neutral-pion (${\pi }^0$) triggers in $p+p$ and central $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200\mathrm{GeV}$ over a broad kinematic range, for jet resolution parameters $R=0.2$ and 0.5. Medium-induced jet yield suppression is observed to be larger for $R=0.2$ than for 0.5, reflecting the angular range of jet energy redistribution due to quenching. The predictions of model calculations incorporating jet quenching are not fully consistent with the observations. These results provide new insight into the physical origins of jet quenching.

We investigate the ground-state phases of ultracold gases composed of bosonic microwave-shielded polar molecules (MSPMs). Using a translational symmetry-breaking variational ansatz with Jastrow correlations, we characterize the many-body correlations arising from the large shielding core of the two-body potential in a dense gas. We show that the molecular gases are always stabilized by the shielding potential and support a self-bound gas phase and an expanding gas phase. Furthermore, we find that, analogous to liquid ${}^4\mathrm{He}$, the condensate fraction is significantly reduced when the size of the shielding core of the two-body potential becomes comparable to the intermolecular distance. For experimental detection, we also identify a bimodal feature in the momentum distribution. Our work invalidates the application of the Gross-Pitaevskii equation to molecular gases and establishes a universal framework to reveal the many-body correlations in dense molecular gases.

Because of the inherently probabilistic nature of quantum mechanics, each experimental realization of a dynamical quantum system can produce distinct measurement outcomes, particularly when coupled to a dissipative environment. Although quantum trajectories that lead to exotic, highly entangled states are possible in principle, their observation is typically hindered by extremely low probabilities. In this Letter, we present a method to significantly enhance the probability of generating highly entangled states in an ensemble of atoms undergoing collective superradiant decay on timescales much shorter than the individual atomic spontaneous emission rate. By analyzing an effective non-Hermitian Hamiltonian governing the dynamics between photon emission events, we identify the conditions necessary for these rare no-click trajectories to occur with higher likelihood. Crucially, our method relies on initializing the system in a nonclassical state, whose entanglement is amplified via the non-Hermitian superradiant dynamics. This approach provides a new route to creating highly entangled macroscopic states such as atomic Schrödinger cat states, paving the way for advancements in quantum metrology and other quantum technologies.