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Single nitrogen vacancy (NV) centers in diamond have been used extensively for high-sensitivity nanoscale sensing, but conventional approaches use confocal microscopy to measure individual centers sequentially, limiting throughput and access to nonlocal physical properties, where simultaneous, high-fidelity measurement of multiple centers is required. Here, we design and implement a multiplexed NV sensing platform that allows us to read out many single NV centers simultaneously using a low-noise camera. Using this platform, we coherently manipulate and read out the spin states of hundreds of individual NV centers in parallel, achieving comparable magnetic field sensitivity to confocal measurements. We also implement a parallelized version of spin-to-charge-conversion readout for low NV center spin state readout noise and use it to demonstrate multiplexed covariance magnetometry, in which we measure ten two-point magnetic field correlators from five NV centers simultaneously. From these measurements, we demonstrate the quantitative reconstruction of spatially varying magnetic correlations arising from a current-carrying wire. The number of correlators we can measure is limited only by the available laser power, opening the door to massively multiplexed covariance magnetometry. In contrast to scanning probes for imaging spatially varying magnetic fields, our approach measures the temporal dynamics of the magnetic field at many precisely defined positions simultaneously, from which the local noise spectrum and nonlocal properties such as correlation functions can be computed. This high-fidelity readout platform will find immediate applications in studying condensed matter phenomena that are characterized by the noise spectrum or correlation functions, including quantum phase transitions, dynamics far from equilibrium, magnetic order, and correlated electron phenomena. 

ABSTRACT Deploying nitrogen vacancy (NV) centers in diamond as nanoscale quantum sensors for condensed matter and materials physics requires placing the NV centers close to the sensing target. One solution is to fabricate diamond nanostructures and integrate them with materials and devices. However, diamond etching and ion milling can introduce subsurface damage and surface defects that degrade the charge stability and spin coherence of NV centers near the surface. Here, we report a procedure for fabricating low‐damage free‐standing diamond micromembranes, and we show that this fabrication scheme preserves the optical and spin properties of state‐of‐the‐art shallow NV center quantum sensors, within nanometers of the diamond surface, while providing significant photonic enhancement. Furthermore, we demonstrate a pick‐and‐place transfer method, which enables integration with diverse sensing targets. 

The climate simulation frontier of a global storm-resolving model (GSRM; or k-scale model because of its kilometer-scale horizontal resolution) is deployed for climate change simulations. The climate sensitivity, effective radiative forcing, and relative humidity changes are assessed in multiyear atmospheric GSRM simulations with perturbed sea-surface temperatures and/or carbon dioxide concentrations. Our comparisons to conventional climate model results can build confidence in the existing climate models or highlight important areas for additional research. This GSRM’s climate sensitivity is within the range of conventional climate models, although on the lower end as the result of neutral, rather than amplifying, shortwave feedbacks. Its radiative forcing from carbon dioxide is higher than conventional climate models, and this arises from a bias in climatological clouds and an explicitly simulated high-cloud adjustment. Last, the pattern and magnitude of relative humidity changes, simulated with greater fidelity via explicitly resolving convection, are notably similar to conventional climate models. 

Abstract Changes in tropical deep convection with global warming are a leading source of uncertainty for future climate projections. A comparison of the responses of active sensor measurements of cloud ice to interannual variability and next-generation global storm-resolving model (also known ask-scale models) simulations to global warming shows similar changes for events with the highest column-integrated ice. The changes reveal that the ice loading decreases outside the most active convection but increases at a rate of several percent per Kelvin surface warming in the most active convection. Disentangling thermodynamic and vertical velocity changes shows that the ice signal is strongly modulated by structural changes of the vertical wind field towards an intensification of strong convective updrafts with warming, suggesting that changes in ice loading are strongly influenced by changes in convective velocities, as well as a path toward extracting information about convective velocities from observations. 

Although the importance of using static taint analysis to detect taint-style vulnerabilities in Linux-based embedded firmware is widely recognized, existing approaches are plagued by following major limitations: (a) Existing works cannot properly handle indirect call on the path from attacker-controlled sources to security-sensitive sinks, resulting in lots of false negatives. (b) They employ heuristics to identify mediate taint source and it is not accurate enough, which leads to high false positives. To address issues, we propose EmTaint, a novel static approach for accurate and fast detection of taint-style vulnerabilities in Linux-based embedded firmware. In EmTaint, we first design a structured symbolic expression-based (SSE-based) on-demand alias analysis technique. Based on it, we come up with indirect call resolution and accurate taint analysis scheme. Combined with sanitization rule checking, EmTaint can eventually discovers a large number of taint-style vulnerabilities accurately within a limited time. We evaluated EmTaint against 35 real-world embedded firmware samples from six popular vendors. The result shows EmTaint discovered at least 192 vulnerabilities, including 41 n-day vulnerabilities and 151 0-day vulnerabilities. At least 115 CVE/PSV numbers have been allocated from a subset of the reported vulnerabilities at the time of writing. Compared with state-of-the-art tools such as KARONTE and SaTC, EmTaint found significantly more vulnerabilities on the same dataset in less time. 

This work demonstrates a novel junction termination extension (JTE) with a graded charge profile for vertical GaN p-n diodes. The fabrication of this JTE obviates GaN etch and requires only a single-step implantation. A bi-layer photoresist is used to produce an ultra-small bevel angle (~0.1°) at the sidewall of a dielectric layer. This tapered dielectric layer is then used as the implantation mask to produce a graded charge profile in p-GaN. The fabricated GaN p-n diodes show a breakdown voltage ( BV ) of 1.7 kV (83% of the parallel-plane limit) with positive temperature coefficient, as well as a high avalanche current density over 1100 A/cm 2 at BV in the unclamped inductive switching test. This robust avalanche is ascribed to the migration of the major impact ionization location from the JTE edge to the main junction. This single-implant, efficient, avalanche-capable JTE can potentially become a building block of many vertical GaN devices, and its fabrication technique has wide device and material applicability. 

Medium-voltage (MV) power electronic devices are widely used in renewable energy processing, electric grids, pulse power systems, etc. Current MV devices are mainly made of Si and SiC. This paper presents our recent efforts in developing a new generation of MV devices based on the multi-channel AlGaN/GaN platform and many new device designs involving charge balance, fin, and Cascode. The specific on-resistance of our 10 kV-class GaN Schottky barrier diodes and normally-OFF transistors is ~40 mΩ•cm 2 , rendering a Baliga’s figure of merit exceeding the 1-D unipolar SiC limits. We show the great promise of GaN in medium and high-voltage power applications. 

We report the first experimental demonstration of a vertical superjunction device in GaN. P-type nickel oxide (NiO) is sputtered conformally in 6μm deep n-GaN trenches. Sputter recipe is tuned to enable 1017 cm −3 level acceptor concentration in NiO, easing its charge balance with the 9×1016 cm −3 doped n-GaN. Vertical GaN superjunction p-n diodes (SJ-PNDs) are fabricated on both native GaN and low-cost sapphire substrates. GaN SJ-PNDs on GaN and sapphire both show a breakdown voltage (BV) of 1100 V, being at least 900 V higher than their 1-D PND counterparts. The differential specific on-resistance (RON,SP) of the two SJ-PNDs are both 0.3mΩ⋅ cm 2 , with the drift region resistance (RDR,SP) extracted to be 0.15mΩ⋅ cm 2 . The RON,SP∼BV trade-off is among the best in GaN-on-GaN diodes and sets a new record for vertical GaN devices on foreign substrates. The RDR,SP∼BV trade-off exceeds the 1-D GaN limit, fulfilling the superjunction functionality in GaN.