Mejialindgaard3465

The manipulation of quantum states of light1 holds the potential to enhance searches for fundamental physics. Only recently has the maturation of quantum squeezing technology coincided with the emergence of fundamental physics searches that are limited by quantum uncertainty2,3. In particular, the quantum chromodynamics axion provides a possible solution to two of the greatest outstanding problems in fundamental physics the strong-CP (charge-parity) problem of quantum chromodynamics4 and the unknown nature of dark matter5-7. In dark matter axion searches, quantum uncertainty manifests as a fundamental noise source, limiting the measurement of the quadrature observables used for detection. Few dark matter searches have approached this limit3,8, and until now none has exceeded it. Here we use vacuum squeezing to circumvent the quantum limit in a search for dark matter. By preparing a microwave-frequency electromagnetic field in a squeezed state and near-noiselessly reading out only the squeezed quadrature9, we double the search rate for axions over a mass range favoured by some recent theoretical projections10,11. We find no evidence of dark matter within the axion rest energy windows of 16.96-17.12 and 17.14-17.28 microelectronvolts. Breaking through the quantum limit invites an era of fundamental physics searches in which noise reduction techniques yield unbounded benefit compared with the diminishing returns of approaching the quantum limit.Steels with sub-micrometre grain sizes usually possess high toughness and strength, which makes them promising for lightweighting technologies and energy-saving strategies. So far, the industrial fabrication of ultrafine-grained (UFG) alloys, which generally relies on the manipulation of diffusional phase transformation, has been limited to steels with austenite-to-ferrite transformation1-3. Moreover, the limited work hardening and uniform elongation of these UFG steels1,4,5 hinder their widespread application. Here we report the facile mass production of UFG structures in a typical Fe-22Mn-0.6C twinning-induced plasticity steel by minor Cu alloying and manipulation of the recrystallization process through the intragranular nanoprecipitation (within 30 seconds) of a coherent disordered Cu-rich phase. Selleck ICI-118551 The rapid and copious nanoprecipitation not only prevents the growth of the freshly recrystallized sub-micrometre grains but also enhances the thermal stability of the obtained UFG structure through the Zener pinning mechanism6. Moreover, owing to their full coherency and disordered nature, the precipitates exhibit weak interactions with dislocations under loading. This approach enables the preparation of a fully recrystallized UFG structure with a grain size of 800 ± 400 nanometres without the introduction of detrimental lattice defects such as brittle particles and segregated boundaries. Compared with the steel to which no Cu was added, the yield strength of the UFG structure was doubled to around 710 megapascals, with a uniform ductility of 45 per cent and a tensile strength of around 2,000 megapascals. This grain-refinement concept should be extendable to other alloy systems, and the manufacturing processes can be readily applied to existing industrial production lines.Accurate three-dimensional (3D) imaging is essential for machines to map and interact with the physical world1,2. Although numerous 3D imaging technologies exist, each addressing niche applications with varying degrees of success, none has achieved the breadth of applicability and impact that digital image sensors have in the two-dimensional imaging world3-10. A large-scale two-dimensional array of coherent detector pixels operating as a light detection and ranging system could serve as a universal 3D imaging platform. Such a system would offer high depth accuracy and immunity to interference from sunlight, as well as the ability to measure the velocity of moving objects directly11. Owing to difficulties in providing electrical and photonic connections to every pixel, previous systems have been restricted to fewer than 20 pixels12-15. Here we demonstrate the operation of a large-scale coherent detector array, consisting of 512 pixels, in a 3D imaging system. Leveraging recent advances in the monolithic integration of photonic and electronic circuits, a dense array of optical heterodyne detectors is combined with an integrated electronic readout architecture, enabling straightforward scaling to arbitrarily large arrays. Two-axis solid-state beam steering eliminates any trade-off between field of view and range. Operating at the quantum noise limit16,17, our system achieves an accuracy of 3.1 millimetres at a distance of 75 metres when using only 4 milliwatts of light, an order of magnitude more accurate than existing solid-state systems at such ranges. Future reductions of pixel size using state-of-the-art components could yield resolutions in excess of 20 megapixels for arrays the size of a consumer camera sensor. This result paves the way for the development and proliferation of low-cost, compact and high-performance 3D imaging cameras that could be used in applications from robotics and autonomous navigation to augmented reality and healthcare.Molecular self-assembly is the spontaneous association of simple molecules into larger and ordered structures1. It is the basis of several natural processes, such as the formation of colloids, crystals, proteins, viruses and double-helical DNA2. Molecular self-assembly has inspired strategies for the rational design of materials with specific chemical and physical properties3, and is one of the most important concepts in supramolecular chemistry. Although molecular self-assembly has been extensively investigated, understanding the rules governing this phenomenon remains challenging. Here we report on a simple hydrochloride salt of fampridine that crystallizes as four different structures, two of which adopt unusual self-assemblies consisting of polyhedral clusters of chloride and pyridinium ions. These two structures represent Frank-Kasper (FK) phases of a small and rigid organic molecule. Although discovered in metal alloys4,5 more than 60 years ago, FK phases have recently been observed in several classes of supramolecular soft matter6-11 and in gold nanocrystal superlattices12 and remain the object of recent discoveries13.