Multicomponent droplets are pertinent to diverse applications ranging from 3D printing to fabrication of electronic devices to medical diagnostics and are typically inherent with the occurrence of the phase transition in the manifestation of evaporation and solidification. Indeed, the versatile transformations and fascinating morphologies of the droplets have been identified, which primarily arise from the evaporation-induced flow. Here, we report the self-lifting behavior of a frozen binary droplet, resulting in a nearly doubling in height, in a fashion that defies against the gravitational effect. This counterintuitive observation is attributed to an internal solutal Marangoni flow up to $1\mathrm{mm}/\mathrm{s}$, which is driven by the enriched solute concentration locally in the vicinity of the solidification front. Moreover, we perform theoretical analysis by incorporating the propagation of solidification front, and the calculated spatiotemporal evolution of droplet shape agrees with experiments excellently. The effects of several key physical parameters on self-lifting are elucidated quantitatively, providing guidance to control the self-lifting. These results will further advance our understanding of underlying physicochemical hydrodynamics in the multicomponent liquid systems subjected to heat transfer and phase change, consequently shedding light on the relevant technological applications.

We show that 2D ${}^2\mathrm{H}$ NMR spectra enable valuable insights into the nature of an ice-water equilibrium in nanoscale confinement, which extends over a broad temperature range. In particular, 2D ${}^2\mathrm{H}$ NMR line-shape analysis allows us to determine the timescale on which the coexisting ice and water phases exchange molecules. For ${\mathrm{D}}_2\mathrm{O}$ in a silica nanopore with a diameter of 5.4 nm, we find that the residence time of a water molecule in either phase is characterized by an NMR exchange time of ${\tau }_{\mathrm{X}}=5.7\mathrm{ms}$ at 220 K. Thus, the ice-water equilibrium is highly dynamic, which is an important aspect for an understanding of deeply cooled confined and, possibly, bulk waters.

The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order $1\mathrm{\mu }{\mathrm{m}}^{-3}$, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.

Non-Hermitian (NH) extension of quantum-mechanical Hamiltonians represents one of the most significant advancements in physics. During the past two decades, numerous captivating NH phenomena have been revealed and demonstrated, but all of which can appear in both quantum and classical systems. This leads to the fundamental question: what NH signature presents a radical departure from classical physics? The solution of this problem is indispensable for exploring genuine NH quantum mechanics, but remains experimentally untouched so far. Here, we resolve this basic issue by unveiling distinct exceptional entanglement phenomena, exemplified by an entanglement transition, occurring at the exceptional point of NH interacting quantum systems. We illustrate and demonstrate such purely quantum-mechanical NH effects with a naturally dissipative light-matter system, engineered in a circuit quantum electrodynamics architecture. Our results lay the foundation for studies of genuinely quantum-mechanical NH physics, signified by exceptional-point-enabled entanglement behaviors.

We report on the experimental and numerical observations of synchronization and desynchronization of bound states of multiple breathing solitons (breathing soliton molecules) in an ultrafast fiber laser. In the desynchronization regime, although the breather molecules as wholes are not synchronized to the cavity, the individual breathers within a molecule are synchronized to each other with a delay (lag synchronization). An intermediate regime between the synchronization and desynchronization phases is also observed, featuring self-modulation of the synchronized state. This regime may also occur in other systems displaying synchronization. Breathing soliton molecules in a laser cavity open new avenues for the study of nonlinear synchronization dynamics.

Starting from the classical formulation of the weak turbulence theory in a density stratified fluid, we derive a simplified version of the kinetic equation of internal gravity wave turbulence. This equation allows us to uncover scaling laws for the spatial and temporal energy spectra of internal wave turbulence which are consistent with typical scaling exponents observed in the oceans. The keystone of our description is the assumption that the energy transfers are dominated by a class of nonlocal resonant interactions, known as the “induced diffusion” triads, which conserve the ratio between the wave frequency and vertical wave number. Our analysis remarkably shows that the internal wave turbulence cascade is associated to an apparent constant flux of wave action.

Single-component fractional quantum Hall states (FQHSs) at even-denominator filling factors may host non-Abelian quasiparticles that are considered to be building blocks of topological quantum computers. Such states, however, are rarely observed in the lowest-energy Landau level, namely at filling factors $\nu <1$. Here, we report evidence for an even-denominator FQHS at $\nu =1/4$ in ultra-high-quality two-dimensional hole systems confined to modulation-doped GaAs quantum wells. We observe a deep minimum in the longitudinal resistance at $\nu =1/4$, superimposed on a highly insulating background, suggesting a close competition between the $\nu =1/4$ FQHS and the magnetic-field-induced, pinned Wigner solid states. Our experimental observations are consistent with the very recent theoretical calculations that predict that substantial Landau level mixing, caused by the large hole effective mass, can induce composite fermion pairing and lead to a non-Abelian FQHS at $\nu =1/4$. Our results demonstrate that Landau level mixing can provide a very potent means for tuning the interaction between composite fermions and creating new non-Abelian FQHSs.

I report on the experimental confirmation that critical percolation statistics underlie the ordering kinetics of twisted nematic phases in the Allen-Cahn universality class. Soon after the ordering starts from a homogeneous disordered phase and proceeds toward a broken ${\mathbb{Z}}_2$-symmetry phase, the system seems to be attracted to the random percolation fixed point at a special timescale $t_{\mathrm{p}}$. At this time, exact formulas for crossing probabilities in percolation theory agree with the corresponding probabilities in the experimental data. The ensuing evolution for the number density of hull-enclosed areas is described by an exact expression derived from a percolation model endowed with curvature-driven interface motion. Scaling relation for hull-enclosed areas versus perimeters reveals that the fractal percolation geometry is progressively morphed into a regular geometry up to the order of the classical coarsening length. In view of its universality and experimental possibilities, the study opens a path for exploring percolation keystones in the realm of nonequilibrium, phase-ordering systems.

Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent $J/\psi$ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon ($W_{\gamma \mathrm{N}}^{\mathrm{Pb}}$) over a wide range of $40<W_{\gamma \mathrm{N}}^{\mathrm{Pb}}<400\mathrm{GeV}$. Results are obtained using data at the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of $1.52{\mathrm{nb}}^{-1}$. The cross section is observed to rise rapidly at low $W_{\gamma \mathrm{N}}^{\mathrm{Pb}}$, and plateau above $W_{\gamma \mathrm{N}}^{\mathrm{Pb}}\approx 40\mathrm{GeV}$, up to $400\mathrm{GeV}$, entering a new regime of small Bjorken-$x$ ($\approx 6\times {10}^{-5}$) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models.

The excited states of unstable ${}^{20}\mathrm{O}$ were investigated via $\gamma$-ray spectroscopy following the ${}^{19}\mathrm{O}(d,p){}^{20}\mathrm{O}$ reaction at $8A\mathrm{MeV}$. By exploiting the Doppler shift attenuation method, the lifetimes of the $2_2^{+}$ and $3_1^{+}$ states were firmly established. From the $\gamma$-ray branching and $E2/M1$ mixing ratios for transitions deexciting the $2_2^{+}$ and $3_1^{+}$ states, the $B(E2)$ and $B(M1)$ were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of $\gamma$-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.

Spin textures with various topological orders are of great theoretical and practical interest. Hopfion, a spin texture characterized by a three-dimensional topological order was recently realized in electronic spin systems. Here, we show that monochromatic light can be structured such that its photonic spin exhibits a hopfion texture in the three-dimensional real space. We also provide ways to construct spin textures of arbitrary Hopf charges. When extending the system to four dimensions by introducing a parameter dimension, a new type of topological defect in the form of a monopole loop in photonic spin is encountered. Each point on the loop is a topological spin defect in three dimensions, and the loop itself carries quantized Hopf charges. Such photonic spin texture and defect may find application in control and sensing of nanoparticles, and optical generation of topological texture in motions of particles or fluids.

The Grüneisen parameter ($\gamma$) is crucial for determining many thermal properties, including the anharmonic effect, thermostatistics, and equation of state of materials. However, the isentropic adiabatic compression conditions required to measure the Grüneisen parameter under high pressure are difficult to achieve. Thus, direct experimental Grüneisen parameter data in a wide range of pressures is sparse. In this work, we developed a new device that can apply pressure (up to tens of GPa) with an extremely short time of about 0.5 ms, confidently achieving isentropic adiabatic compression. Then, we applied our new technique to sodium chloride and measured its Grüneisen parameter, which conforms to previous theoretical predictions. According to our obtained sodium chloride Grüneisen parameters, the calculated Hugoniot curve of the NaCl B1 phase appears up to 20 GPa and 960 K, which compares very well with the shock compression experimental data by Fritz et al. and other calculation works. Our results suggest that this new method can reliably measure the Grüneisen parameter of even more materials, which is significant for researching the equation of state in substances.

Topological defects in active polar fluids can organize spontaneous flows and influence macroscopic density patterns. Both of them play an important role during animal development. Yet the influence of density on active flows is poorly understood. Motivated by experiments on cell monolayers confined to disks, we study the coupling between density and polar order for a compressible active polar fluid in the presence of a $+1$ topological defect. As in the experiments, we find a density-controlled spiral-to-aster transition. In addition, biphasic orientational phases emerge as a generic outcome of such coupling. Our results highlight the importance of density gradients as a potential mechanism for controlling flow and orientational patterns in biological systems.

Energy can be transferred between two quantum systems in two forms: unitary energy—that can be used to drive another system—and correlation energy—that reflects past correlations. We propose and implement experimental protocols to access these energy transfers in interactions between a quantum emitter and light fields. Upon spontaneous emission, we measure the unitary energy transfer from the emitter to the light field and show that it never exceeds half the total energy transfer and is reduced when introducing decoherence. We then study the interference of the emitted field and a coherent laser field at a beam splitter and show that the nature of the energy transfer quantitatively depends on the quantum purity of the emitted field.

We present a lattice-QCD based analysis of the nucleon sigma terms using gauge ensembles with $N_f=2+1$ flavors of $\mathcal{O}(a)$-improved Wilson fermions, with a complete error budget concerning excited-state contaminations, the chiral interpolation as well as finite-size and lattice spacing effects. We compute the sigma terms determined directly from the matrix elements of the scalar currents. The chiral interpolation is based on SU(3) baryon chiral perturbation theory using the extended on-mass shell renormalization scheme. For the pion nucleon sigma term, we obtain ${\sigma }_{\pi N}=(43.7\pm 3.6)\mathrm{MeV}$, where the error includes our estimate of the aforementioned systematics. The tension with extractions based on dispersion theory persists at the $2.4\text{−}\sigma$ level. For the strange sigma term, we obtain a nonzero value, ${\sigma }_s=(28.6\pm 9.3)\mathrm{MeV}$.

Nuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The $\beta$-decaying isomer ${}^{128\mathrm{m}}\mathrm{Sb}$ was identified as potentially impactful since the $\beta$-decay pathway along the $A=128$ isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the ${}^{128}\mathrm{Sb}$ isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of $-84564.8(25)\mathrm{keV}$ and $-84608.8(21)\mathrm{keV}$, respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of ${}^{128\mathrm{m}}\mathrm{Sb}$ in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process.

In this work, we investigate a two-dimensional system of ultracold bosonic atoms inside an optical cavity, and show how photon-mediated interactions give rise to a plaquette-ordered bond pattern in the atomic ground state. The latter corresponds to a 2D Peierls transition, generalizing the spontaneous bond dimerization driven by phonon-electron interactions in the 1D Su-Schrieffer-Heeger (SSH) model. Here the bosonic nature of the atoms plays a crucial role to generate the phase, as similar generalizations with fermionic matter do not lead to a plaquette structure. Similar to the SSH model, we show how this pattern opens a nontrivial topological gap in 2D, resulting in a higher-order topological phase hosting corner states, that we characterize by means of a many-body topological invariant and through its entanglement structure. Finally, we demonstrate how this higher-order topological Peierls insulator can be readily prepared in atomic experiments through adiabatic protocols. Our work thus shows how atomic quantum simulators can be harnessed to investigate novel strongly correlated topological phenomena beyond those observed in natural materials.

We perform calculations of the energy shift of the nuclear clock transition frequency ${}^{229}\mathrm{Th}$ as a function of the number of electrons in Th ion. We demonstrate that the dependence of the nuclear frequency on electron configuration is significant, for example, removing one electron from the atom leads to relative shift of the nuclear frequency $\sim {10}^{-7}$, which is 12 orders of magnitude larger than the expected relative uncertainty of the nuclear clock transition frequency ($\sim {10}^{-19}$). This leads to the difference of the nuclear clock frequencies in Th IV, Th III, Th II, and Th I. The relative change of the nuclear frequency between neutral Th and its bare nucleus is 1%. We also calculate the field shift constants for isotopic and isomeric shifts of atomic electron transitions in Th ions.

We present the first exact theory and analytical formulas for the large-scale phase fluctuations in the sine-Gordon model, valid in all regimes of the field theory, for arbitrary temperatures and interaction strengths. Our result is based on the ballistic fluctuation theory combined with generalized hydrodynamics, and can be seen as an exact “dressing” of the phenomenological soliton-gas picture first introduced by Sachdev and Young [Phys. Rev. Lett. 78, 2220 (1997)], to the modes of generalized hydrodynamics. The resulting physics of phase fluctuations in the sine-Gordon model is qualitatively different, as the stable quasiparticles of integrability give coherent ballistic propagation instead of diffusive spreading. We provide extensive numerical checks of our analytical predictions within the classical regime of the field theory by using Monte Carlo methods. We discuss how our results are of ready applicability to experiments on tunnel-coupled quasicondensates.