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Bound states in the continuum (BICs) hold significant promise in manipulating electromagnetic fields and reducing losses in optical structures, leading to advancements in fundamental research and practical applications. Despite their observation in various optical systems, the behavior of BIC in whispering-gallery-modes (WGMs) optical microcavities, essential components of photonic integrated chips, has yet to be thoroughly explored. In this study, we propose and experimentally identify a robust mechanism for generating quasi-BIC in a single deformed microcavity. By introducing boundary deformations, we construct stable unidirectional radiation channels as leaking continuum shared by different resonant modes and experimentally verify their external strong mode coupling. This results in drastically suppressed leaking loss of one originally long-lived resonance, manifested as more than a threefold enhancement of its quality (Q) factor, while the other short-lived resonance becomes more lossy, demonstrating the formation of Friedrich–Wintgen quasi-BICs as corroborated by the theoretical model and experimental data. This research will provide a practical approach to enhance theQ-factor of optical microcavities, opening up potential applications in the area of deformed microcavities, nonlinear optics, quantum optics, and integrated photonics. 

Abstract Entanglement has been known to boost target detection, despite it being destroyed by lossy-noisy propagation. Recently, Zhuang and Shapiro (2022Phys. Rev. Lett.128010501) proposed a quantum pulse-compression radar to extend entanglement’s benefit to target range estimation. In a radar application, many other aspects of the target are of interest, including angle, velocity and cross section. In this study, we propose a dual-receiver radar scheme that employs a high time-bandwidth product microwave pulse entangled with a pre-shared reference signal available at the receiver, to investigate the direction of a distant object and show that the direction-resolving capability is significantly improved by entanglement, compared to its classical counterpart under the same parameter settings. We identify the applicable scenario of this quantum radar to be short-range and high-frequency, which enables entanglement’s benefit in a reasonable integration time. 

Manipulating gene expression in the host genome with high precision is crucial for controlling cellular function and behavior. Here, we present a precise, non-invasive, and tunable strategy for controlling the expression of multiple endogenous genes both in vitro and in vivo, utilizing ultrasound as the stimulus. By engineering a hyper-efficient dCas12a and effector under a heat shock promoter, we demonstrate a system that can be inducibly activated through thermal energy produced by ultrasound absorption. This system allows versatile thermal induction of gene activation or base editing across cell types, including primary T cells, and enables multiplexed gene activation using a single guide RNA array. In mouse models, localized temperature elevation guided by high-intensity focused ultrasound effectively triggers reporter gene expression in implanted cells. Our work underscores the potential of ultrasound as a clinically viable approach to enhance cell and gene-based therapies via precision genome and epigenome engineering. 

The memory allocator plays a key role in the performance of applications, but none of the existing profilers can pinpoint performance slowdowns caused by a memory allocator. Consequently, programmers may spend time improving application code incorrectly or unnecessarily, achieving low or no performance improvement. This paper designs the first profiler—MemPerf—to identify allocator-induced performance slowdowns without comparing against another allocator. Based on the key observation that an allocator may impact the whole life-cycle of heap objects, including the accesses (or uses) of these objects, MemPerf proposes a life-cycle based detection to identify slowdowns caused by slow memory management operations and slow accesses separately. For the prior one, MemPerf proposes a thread-aware and type-aware performance modeling to identify slow management operations. For slow memory accesses, MemPerf utilizes a top-down approach to identify all possible reasons for slow memory accesses introduced by the allocator, mainly due to cache and TLB misses, and further proposes a unified method to identify them correctly and efficiently. Based on our extensive evaluation, MemPerf reports 98% medium and large allocator-reduced slowdowns (larger than 5%) correctly without reporting any false positives. MemPerf also pinpoints multiple known and unknown design issues in widely-used allocators. 

The NUMA architecture accommodates the hardware trend of an increasing number of CPU cores. It requires the coop- eration of memory allocators to achieve good performance for multithreaded applications. Unfortunately, existing allo- cators do not support NUMA architecture well. This paper presents a novel memory allocator – NUMAlloc , that is de- signed for the NUMA architecture. NUMAlloc is centered on a binding-based memory management. On top of it, NUMAl- loc proposes an “origin-aware memory management” to ensure the locality of memory allocations and deallocations, as well as a method called “incremental sharing” to balance the performance benefits and memory overhead of using transparent huge pages. According to our extensive evalua- tion, NUMAlloc hasthebestperformanceamongallevaluated allocators, running 15.7% faster than the second-best allo- cator (mimalloc), and 20.9% faster than the default Linux allocator with reasonable memory overhead. NUMAlloc is also scalable to 128 threads and is ready for deployment. 

The NUMA architecture accommodates the hardware trend of an increasing number of CPU cores. It requires the cooperation of memory allocators to achieve good performance for multithreaded applications. Unfortunately, existing allocators do not support NUMA architecture well. This paper presents a novel memory allocator – NUMAlloc, that is designed for the NUMA architecture. is centered on a binding-based memory management. On top of it, proposes an “origin-aware memory management” to ensure the locality of memory allocations and deallocations, as well as a method called “incremental sharing” to balance the performance benefits and memory overhead of using transparent huge pages. According to our extensive evaluation, NUMAlloc has the best performance among all evaluated allocators, running 15.7% faster than the second-best allocator (mimalloc), and 20.9% faster than the default Linux allocator with reasonable memory overhead. NUMAlloc is also scalable to 128 threads and is ready for deployment.