A site-resolved two-dimensional quantum simulator with hundreds of trapped ions.

A large qubit capacity and an individual readout capability are two crucial requirements for large-scale quantum computing and simulation1. As one of the leading physical platforms for quantum information processing, the ion trap has achieved a quantum simulation of tens of ions with site-resolved readout in a one-dimensional Paul trap2-4 and of hundreds of ions with global observables in a two-dimensional (2D) Penning trap5,6. However, integrating these two features into a single system is still very challenging. Here we report the stable trapping of 512 ions in a 2D Wigner crystal and the sideband cooling of their transverse motion. We demonstrate the quantum simulation of long-range quantum Ising models with tunable coupling strengths and patterns, with or without frustration, using 300 ions. Enabled by the site resolution in the single-shot measurement, we observe rich spatial correlation patterns in the quasi-adiabatically prepared ground states, which allows us to verify quantum simulation results by comparing the measured two-spin correlations with the calculated collective phonon modes and with classical simulated annealing. We further probe the quench dynamics of the Ising model in a transverse field to demonstrate quantum sampling tasks. Our work paves the way for simulating classically intractable quantum dynamics and for running noisy intermediate-scale quantum algorithms7,8 using 2D ion trap quantum simulators.

Data integration and inference of gene regulation using single-cell temporal multimodal data with scTIE.

Single-cell technologies offer unprecedented opportunities to dissect gene regulatory mechanisms in context-specific ways. Although there are computational methods for extracting gene regulatory relationships from scRNA-seq and scATAC-seq data, the data integration problem, essential for accurate cell type identification, has been mostly treated as a standalone challenge. Here we present scTIE, a unified method that integrates temporal multimodal data and infers regulatory relationships predictive of cellular state changes. scTIE uses an autoencoder to embed cells from all time points into a common space by using iterative optimal transport, followed by extracting interpretable information to predict cell trajectories. Using a variety of synthetic and real temporal multimodal data sets, we show scTIE achieves effective data integration while preserving more biological signals than existing methods, particularly in the presence of batch effects and noise. Furthermore, on the exemplar multiome data set we generated from differentiating mouse embryonic stem cells over time, we show scTIE captures regulatory elements highly predictive of cell transition probabilities, providing new potentials to understand the regulatory landscape driving developmental processes.

NorA efflux pump mediates Staphylococcus aureus response to Pseudomonas aeruginosa pyocyanin toxicity.

Endogenous transporters protect Staphylococcus aureus against antibiotics and also contribute to bacterial defense from environmental toxins. We evaluated the effect of overexpression of four efflux pumps, NorA, NorB, NorC, and Tet38, on S. aureus survival following exposure to pyocyanin (PYO) of Pseudomonas aeruginosa, using a well diffusion assay. We measured the PYO-created inhibition zone and found that only an overexpression of NorA reduced S. aureus susceptibility to pyocyanin killing. The MICPYO of the NorA overexpressor increased threefold compared to that of wild-type RN6390 and was reduced 2.5-fold with reserpine, suggesting that increased NorA efflux caused PYO resistance. The PYO-created inhibition zone of a ΔnorA mutant was consistently larger than that of a plasmid-borne NorA overexpressor. PYO also produced a modest increase in norA expression (1.8-fold at 0.25 µg/mL PYO) that gradually decreased with increasing PYO concentrations. Well diffusion assays carried out using P. aeruginosa showed that ΔnorA mutant was less susceptible to killing by PYO-deficient mutants PA14phzM and PA14phzS than to killing by PA14. NorA overexpression led to reduced killing by all tested P. aeruginosa. We evaluated the NorA-PYO interaction using a collection of 22 clinical isolates from adult and pediatric cystic fibrosis (CF) patients, which included both S. aureus (CF-SA) and P. aeruginosa (CF-PA). We found that when isolated alone, CF-PA and CF-SA expressed varying levels of PYO and norA transcripts, but all four CF-PA/CF-SA pairs isolated concurrently from CF patients produced a low level of PYO and low norA transcript levels, respectively, suggesting a partial adaptation of the two bacteria in circumstances of persistent co-colonization.

Phenazine-1 carboxylic acid of Pseudomonas aeruginosa induces the expression of Staphylococcus aureus Tet38 MDR efflux pump and mediates resistance to phenazines and antibiotics.

In this study, we showed that phenazine-1 carboxylic acid (PCA) of Pseudomonas aeruginosa induced the expression of Tet38 efflux pump triggering Staphylococcus aureus resistance to tetracycline and phenazines. Exposure of S. aureus RN6390 to supernatants of P. aeruginosa PA14 and its pyocyanin (PYO)-deficient mutants showed that P. aeruginosa non-PYO phenazines could induce the expression of Tet38 efflux pump. Direct exposure of RN6390 to PCA compound at 0.25× MIC led to a five-fold increase in tet38 transcripts. Expression of Tet38 protein was identified through confocal microscopy using RN6390(pRN-tet38p-yfp) that expressed YFP under control of the tet38 promoter by PCA at 0.25× MIC. The MICs of PCA of a Tet38-overexpressor and a Δtet38 mutant showed a three-fold increase and a two-fold decrease, respectively, compared with that of wild-type. Pre-exposure of RN6390 to PCA (0.25× MIC) for 1 hour prior to addition of tetracycline (1× or 10× MIC) improved bacteria viability of 1.5-fold and 2.6-fold, respectively, but addition of NaCl 7% together with tetracycline at 10× MIC reduced the number of viable PCA-exposed RN6390 of a 2.0-log10 CFU/mL. The transcript levels of tetR21, a repressor of tet38, decreased and increased two-fold in the presence of PCA and NaCl, respectively, suggesting that the effects of PCA and NaCl on tet38 production occurred through TetR21 expression. These data suggest that PCA-induced Tet38 protects S. aureus against tetracycline during coinfection with P. aeruginosa; however, induced tet38-mediated S. aureus resistance to tetracycline is reversed by NaCl 7%, a nebulized treatment used to enhance sputum mobilization in CF patients.

Staphylococcus aureus AbcA transporter enhances persister formation under ß-lactam exposure.

We evaluated the role of Staphylococcus aureus AbcA transporter in bacterial persistence and survival following exposure to the bactericidal agents nafcillin and oxacillin at both the population and single-cell levels. We show that AbcA overexpression resulted in resistance to nafcillin but not oxacillin. Using distinct fluorescent reporters of cell viability and AbcA expression, we found that over 6-14 hours of persistence formation, the proportion of AbcA reporter-expressing cells assessed by confocal microscopy increased sixfold as cell viability reporters decreased. Similarly, single-cell analysis in a high-throughput microfluidic system found a strong correspondence between antibiotic exposure and AbcA reporter expression. Persister cells grown in the absence of antibiotics showed neither an increase in nafcillin MIC nor in abcA transcript levels, indicating that survival was not associated with stable mutational resistance or abcA overexpression. Furthermore, persister cell levels on exposure to 1×MIC and 25×MIC of nafcillin decreased in an abcA knockout mutant. Survivors of nafcillin and oxacillin treatment overexpressed transporter AbcA, contributing to an enrichment of the number of persisters during treatment with pump-substrate nafcillin but not with pump-non-substrate oxacillin, indicating that efflux pump expression can contribute selectively to the survival of a persister population.

Picosecond laser filament-guided electrical discharges in air at 1 kHz repetition rate.

Laser-induced filaments have been shown to reduce the voltage necessary to initiate electrical discharges in atmospheric air and guide their propagation over long distances. Here we demonstrate the stable generation of laser filament-guided electrical discharge columns in air initiated by high energy (up to 250 mJ) 1030 nm wavelength laser pulses of 7 ps duration at repetition rates up to 1 kHz and we discuss the processes leading to breakdown. A current proportional to the laser pulse energy is observed to arise as soon as the laser pulse arrives, initiating a high impedance phase of the discharge. Full breakdown, characterized by impedance collapse, occurs 100 ns to several µs later. A record 4.7-fold reduction in breakdown voltage for dc-biased discharges, which remains practically independent of the repetition rate up to 1 kHz, is observed to be primarily caused by a single laser pulse that produces a large (∼80%) density depression. The radial gaps between the filamentary plasma channel and the hollowed electrodes employed are shown to play a significant role in the breakdown dynamics. A rapid increase of 3-4 orders of magnitude in current is observed to follow the formation of localized radial current channels linking the filament to the electrodes. The increased understanding and control of kHz repetition rate filament-guided discharges can aid their use in applications.

Vertebral fracture severity assessment on anteroposterior radiographs with a new semi-quantitative technique.

We developed a new tool to assess the severity of osteoporotic vertebral fracture using radiographs of the spine. Our technique can be used in patient care by helping to stratify patients with osteoporotic vertebral fractures into appropriate treatment pathways. It can also be used for research purposes. PURPOSE: The aim of our study was to propose a semi-quantitative (SQ) grading scheme for osteoporotic vertebral fracture (OVF) on anteroposterior (AP) radiographs. METHODS: On AP radiographs, the vertebrae are divided into right and left halves, which are graded (A) vertical rectangle, (B) square, (C) traverse rectangle, and (D) trapezoid; whole vertebrae are graded (E) transverse band or (F) bow-tie. Type A and B were compared with normal and Genant SQ grade 1 OVF, Type C and D with grade 2 OVF, and Type E and F with grade 3 OVF. Spine AP radiographs and lateral radiographs of 50 females were assessed by AP radiographs SQ grading. After training, an experienced board-certified radiologist and a radiology trainee assessed the 50 AP radiographs. RESULTS: The height-to-width ratio of the half vertebrae varied 1.32-1.48. On lateral radiographs, 84 vertebrae of the 50 patients had OVFs (38 grade 1, 24 grade 2, and 22 grade 3). On AP radiographs, the radiologist correctly assigned 84.2%, 91.7%, and 77.2% and the trainee correctly assigned 68.4%, 79.2%, and 81.8% of grade 1, 2, and 3 OVFs, respectively. Compared with lateral radiographs, the radiologist had a weighted Kappa of 0.944 including normal vertebrae and 0.883 not including normal vertebrae, while the corresponding Kappa values for the trainee were 0.891 and 0.830, respectively. CONCLUSION: We propose a new semi-quantitative grading system for vertebral fracture severity assessment on AP spine radiographs.

How much organic carbon could the soil store? The carbon sequestration potential of Australian soil.

Soil is a huge carbon (C) reservoir, but where and how much extra C can be stored is unknown. Current methods to estimate the maximum amount of mineral-associated organic carbon (MAOC) stabilized in the fine fraction (clay + silt, < 20 µm $$ <20\;\upmu \mathrm{m} $$ ) fit through the MAOC versus clay + silt relationship, not their maxima, making their estimates more uncertain and unreliable. We need a function that 'envelopes' that relationship. Here, using 5089 observations, we estimated that the uppermost 30 cm of Australian soil holds 13 Gt (10-18 Gt) of MAOC. We then fitted frontier lines, by soil type, to the relationship between MAOC and the percentage of clay + silt to estimate the maximum amounts of MAOC that Australian soils could store in their current environments, and calculated the MAOC deficit, or C sequestration potential. We propagated the uncertainties from the frontier line fitting and mapped the estimates of these values over Australia using machine learning and kriging with external drift. The maps show regions where the soil is more in MAOC deficit and has greater sequestration potential. The modelling shows that the variation over the whole continent is determined mainly by climate, linked to vegetation and soil mineralogy. We find that the MAOC deficit in Australian soil is 40 Gt (25-60 Gt). The deficit in the vast rangelands is 20.84 Gt (13.97-29.70 Gt) and the deficit in cropping soil is 1.63 Gt (1.12-2.32 Gt). Management could increase C sequestration in these regions if the climate allowed it. Our findings provide new information on the C sequestration potential of Australian soils and highlight priority regions for soil management. Australia could benefit environmentally, socially and economically by unlocking even a tiny portion of its soil's C sequestration potential.

Abnormal Bifurcation of the Double Binding Energy Differences and Proton-Neutron Pairing: Nuclei Close to N=Z Line from Ni to Rb.

The recently observed abnormal bifurcation of the double binding energy differences δV_{pn} between the odd-odd and even-even nuclei along the N=Z line from Ni to Rb has challenged the nuclear theories. To solve this problem, a shell-model-like approach based on the relativistic density functional theory is established, by treating simultaneously the neutron-neutron, proton-neutron, and proton-proton pairing correlations both microscopically and self-consistently. Without any ad hoc parameters, the calculated results well reproduce the observations, and the mechanism for this abnormal bifurcation is found to be due to the enhanced proton-neutron pairing correlations in the odd-odd N=Z nuclei, compared with the even-even ones. The present results provide an excellent interpretation for the abnormal δV_{pn} bifurcation, and provide a clear signal for the existence of the proton-neutron pairing correlations for nuclei close to the N=Z line.

Emergence of High-Order Deformation in Rotating Transfermium Nuclei: A Microscopic Understanding.

The rotational properties of the transfermium nuclei are investigated in the full deformation space by implementing a shell-model-like approach in the cranking covariant density functional theory on a three-dimensional lattice, where the pairing correlations, deformations, and moments of inertia are treated in a microscopic and self-consistent way. The kinematic and dynamic moments of inertia of the rotational bands observed in the transfermium nuclei ^{252}No, ^{254}No, ^{254}Rf, and ^{256}Rf are well reproduced without any adjustable parameters using a well-determined universal density functional. It is found for the first time that the emergence of the octupole deformation should be responsible for the significantly different rotational behavior observed in ^{252}No and ^{254}No. The present results provide a microscopic solution to the long-standing puzzle on the rotational behavior in No isotopes, and highlight the risk of investigating only the hexacontetrapole (ß_{60}) deformation effects in rotating transfermium nuclei without considering the octupole deformation.

Inertia Induces Strong Orientation Fluctuations of Nonspherical Atmospheric Particles.

The orientation of nonspherical particles in the atmosphere, such as volcanic ash and ice crystals, influences their residence times and the radiative properties of the atmosphere. Here, we demonstrate experimentally that the orientation of heavy submillimeter spheroids settling in still air exhibits decaying oscillations, whereas it relaxes monotonically in liquids. Theoretical analysis shows that these oscillations are due to particle inertia, caused by the large particle-fluid mass-density ratio. This effect must be accounted for to model solid particles in the atmosphere.

Realizing Synthetic Dimensions and Artificial Magnetic Flux in a Trapped-Ion Quantum Simulator.

Synthetic dimension is a potent tool in quantum simulation of topological phases of matter. Here we propose and demonstrate a scheme to simulate an anisotropic Harper-Hofstadter model with controllable magnetic flux on a two-leg ladder using the spin and motional states of a single trapped ion. We verify the successful simulation of this model by comparing the measured dynamics with theoretical predictions under various coupling strength and magnetic flux, and we observe the chiral motion of wave packets on the ladder as evidence of the topological chiral edge modes. We develop a quench path to adiabatically prepare the ground states for varying magnetic flux and coupling strength, and we measure the chiral current on the ladder for the prepared ground states, which allows us to probe the quantum phase transition between the Meissner phase and the vortex phase. Our work demonstrates the trapped ion as a powerful quantum simulation platform for topological quantum matter.

Voltage-Controlled Magnon Transistor via Tuning Interfacial Exchange Coupling.

Magnon transistors that can effectively regulate magnon transport by an electric field are desired for magnonics, which aims to provide a Joule-heating free alternative to the conventional electronics owing to the electric neutrality of magnons (the key carriers of spin-angular momenta in the magnonics). However, also due to their electric neutrality, magnons have no access to directly interact with an electric field and it is thus difficult to manipulate magnon transport by voltages straightforwardly. Here, we demonstrated a gate voltage (V_{g}) applied on a nonmagnetic metal and magnetic insulator (MI) interface that bent the energy band of the MI and then modulated the probability for conduction electrons in the nonmagnetic metal to tunnel into the MI, which can consequently enhance or weaken the spin-magnon conversion efficiency at the interface. A voltage-controlled magnon transistor based on the magnon-mediated electric current drag (MECD) effect in a Pt-Y_{3}Fe_{5}O_{12}-Pt sandwich was then experimentally realized with V_{g} modulating the magnitude of the MECD signal. The obtained efficiency (the change ratio between the MECD voltage at ±V_{g}) reached 10%/(MV/cm) at 300 K. This prototype of magnon transistor offers an effective scheme to control magnon transport by a gate voltage.

Heralded Three-Photon Entanglement from a Single-Photon Source on a Photonic Chip.

In the quest to build general-purpose photonic quantum computers, fusion-based quantum computation has risen to prominence as a promising strategy. This model allows a ballistic construction of large cluster states which are universal for quantum computation, in a scalable and loss-tolerant way without feed forward, by fusing many small n-photon entangled resource states. However, a key obstacle to this architecture lies in efficiently generating the required essential resource states on photonic chips. One such critical seed state that has not yet been achieved is the heralded three-photon Greenberger-Horne-Zeilinger (3-GHZ) state. Here, we address this elementary resource gap, by reporting the first experimental realization of a heralded 3-GHZ state. Our implementation employs a low-loss and fully programmable photonic chip that manipulates six indistinguishable single photons of wavelengths in the telecommunication regime. Conditional on the heralding detection, we obtain the desired 3-GHZ state with a fidelity 0.573±0.024. Our Letter marks an important step for the future fault-tolerant photonic quantum computing, leading to the acceleration of building a large-scale optical quantum computer.

Discovery of New Isotopes

Using the fusion-evaporation reaction ^{106}Cd(^{58}Ni,4n)^{160}Os and the gas-filled recoil separator SHANS, two new isotopes _{76}^{160}Os and _{74}^{156}W have been identified. The α decay of ^{160}Os, measured with an α-particle energy of 7080(26) keV and a half-life of 201_{-37}^{+58} µs, is assigned to originate from the ground state. The daughter nucleus ^{156}W is a ß^{+} emitter with a half-life of 291_{-61}^{+86} ms. The newly measured α-decay data allow us to derive α-decay reduced widths (δ^{2}) for the N=84 isotones up to osmium (Z=76), which are found to decrease with increasing atomic number above Z=68. The reduction of δ^{2} is interpreted as evidence for the strengthening of the N=82 shell closure toward the proton drip line, supported by the increase of the neutron-shell gaps predicted in theoretical models.

Dynamics of the Deformable Fluid Interface Interacting with an Approaching Solid under the Electrostatic Field.

A theoretical model was developed to describe the dynamics of a deformable fluid interface interacting with an approaching solid without contact by both the attractive electrostatic and van der Waals (i.e., vdW) interaction, analogous to the situation in the experiments by electric force microscopy (i.e., EFM) or electric-surface force apparatus (i.e., E-SFA) involved in the soft fluid interface. On the basis of this model, a numerical study of the deformation of the fluid interface, the force-vs-separation behavior, and the critical limiting conditions of contact has systematically been carried out. Our results show that the surface pressure induced by the electrostatic interaction plays a more prominent role in the deformation of the fluid interface than the vdW interaction does, and there exists a principal length scale associated with the relative strength of the electrostatic field to the surface tension, affecting the fluid interface shape under the electrostatic field. It was also shown that both the force-distance curves and the corresponding curves of fluid interface deformation peak versus distance for various electrostatic fields satisfy the universal scaling power law. Moreover, an analytical solution to the Euler-Lagrange differential equation governing the deformation of the fluid interface under the external electric field is obtained, and two extended formulas for explicitly describing the principal length scales that respectively characterize the lateral and longitudinal deformations of the fluid interface were determined.

Deciphering the in situ phonon evolution of potassium sodium niobate under varying temperature and electric fields.

The application of in situ Raman spectroscopy under multiple fields is widely recognized as an effective approach for investigating the physical mechanism of phase transitions in ferroelectrics, because it can directly provide the detailed information about the vibration evolution of various phonon modes within lattices, such as bond stretching and rotation. Based on this technique, our work aims to thoroughly probe the dynamics of phase transitions in traditional ferroelectric potassium sodium niobate [(K,Na)NbO3, KNN] under external fields, by analyzing the in situ dependence of wavenumber and intensity of phonon modes under the varying temperature and electric fields. The results indicate that different vibration modes respectively relating to the A-site ions and NbO6 octahedra in KNN exhibit distinct and abrupt distortion behavior during the orthorhombic-tetragonal and tetragonal-cubic transitions. Moreover, a certain degree of distortion can still be observed in the cubic phase above the Curie temperature. With an applied electric field, KNN presents quite different electrostriction in orthorhombic and tetragonal phases. Particularly, more than one kind of phonon mode undergoes non-linear variations under the varying electric fields, accompanied by the mutations at some fixed fields. These findings will be conducive to further understanding the phase transition mechanism in KNN from the perspective of phonon evolution. Simultaneously, it will also give crucial guidance for the design and development of KNN-based ferroelectrics as well as functional devices.

Molecular rectification induced by magnetization alignment in organic-ferromagnetic devices.

Spin-dependent transport in ferromagnet/organic-ferromagnet/ferromagnet junctions is investigated theoretically under different alignment of magnetization orientations. The results demonstrate a significant current rectification at low bias voltages, and the rectifying direction relies on the relative magnetization orientation in each component. The orbital analysis demonstrates two underlying mechanisms for the rectification, the slight structural asymmetry of the molecule from spin radicals and distinct spin match between conducting electrons and the magnetic molecule upon the reversal of bias. The latter is responsible for the strong low-bias rectification and relies on the magnetization alignment. The effects of parameter strength, temperature and size on the rectification are discussed. This work explores a new route to achieve high-performance molecular rectifiers operating at low bias with controlled rectifying direction.

Piloting a new cross-sector model of care to support parents with cancer: feasibility and acceptability of the Parent Support Worker role.

PURPOSE: A new Parent Support Worker (PSW) service was piloted in three Australian hospitals. This study assesses the feasibility and acceptability (including preliminary effectiveness) of the service in supporting cancer patients with children. METHODS: A multi-site, mixed-methods study collected quantitative and qualitative data on the effectiveness of the service (pre post-test, n = 36), qualitative and quantitative data on acceptability of the service (survey, n = 43), and qualitative data on acceptability (semi-structured interviews, n = 13). Feasibility was assessed through rates of service uptake amongst referred parents. RESULTS: Of 1133 parents referred, 810 (71%) accepted to receive the service, suggesting high interest in PSW support. Interviewees likewise reported that the service was accessible and facilitated further referrals, indicating good feasibility. Surveys completed three months after accessing PSW support showed high acceptability and satisfaction. Additionally, there was preliminary evidence of service impacts: parents' distress, parenting concerns, parenting efficacy, and stress about situations of concern improved significantly from pre- to post-service (all p < 0.005). Interviewees further described how their emotional coping and confidence to support and communicate with their children had improved through contact with the service. CONCLUSION: The PSW service, integrated into a novel cross-sector model of care, showed to be feasible and acceptable to parent patients and their partners and improved psychological and parenting outcomes. The study suggests refinements to the service and the need for future larger studies to explore the effectiveness of the service in improving parents' outcomes. This study complements previous evidence on the implementation of the PSW service in hospitals.

Optimisation of monoenergetic images to reduce banding artifacts in the lower cervical spine using dual-layer spectral computed tomography: a retrospective study.

AIM: To investigate the application value of dual-layer detector computed tomography (CT) single-energy spectral images for reducing artefacts in the lower cervical spine. MATERIALS AND METHODS: Sixty-three patients who underwent neck examination using spectral CT between March 2022 and January 2023 were selected as the participants. Conventional mixed-energy images and spectral imaging data at 40-200 KeV were obtained from the spectral CT scans. The standard deviation (SD), signal-to-noise ratio (SNR), |CTdifference| (the difference in CT value between the C6-7 and C3-4 artefact regions), and contrast-to-noise ratio (CNR) of the C6-7 spinal canal were measured. The image quality of the artefact region in the conventional and single images were compared. RESULTS: The SDintervertebral disc value was highest in the single-level 40 KeV images and lowest in the 120 KeV images (P<0.05). The SNR was lowest in the 40 KeV images (2.07 ± 2.74) and highest in the 120 KeV images (6.20 ± 5.26) (P<0.05). The CTdifference was highest in the 40 KeV images and lowest in the 120 KeV images (108.38 vs. 10.63 ± 8.58). The subjective image quality scores were lowest in the 40 KeV images and highest in the 120 KeV images. CONCLUSION: Our findings suggest that single-energy 120 KeV images may offer benefits such as low SDintervertebral disc, elevated SNR, higher CNR, and improved image quality.