Spin-squeezed states provide a seminal example of how the structure of quantum mechanical correlations can be controlled to produce metrologically useful entanglement1-7. These squeezed states have been demonstrated in a wide variety of quantum systems ranging from atoms in optical cavities to trapped ion crystals8-16. By contrast, despite their numerous advantages as practical sensors, spin ensembles in solid-state materials have yet to be controlled with sufficient precision to generate targeted entanglement such as spin squeezing. Here we report the experimental demonstration of spin squeezing in a solid-state spin system. Our experiments are performed on a strongly interacting ensemble of nitrogen-vacancy colour centres in diamond at room temperature, and squeezing (-0.50 ± 0.13 dB) below the noise of uncorrelated spins is generated by the native magnetic dipole-dipole interaction between nitrogen-vacancy centres. To generate and detect squeezing in a solid-state spin system, we overcome several challenges. First, we develop an approach, using interaction-enabled noise spectroscopy, to characterize the quantum projection noise in our system without directly resolving the spin probability distribution. Second, noting that the random positioning of spin defects severely limits the generation of spin squeezing, we implement a pair of strategies aimed at isolating the dynamics of a relatively ordered sub-ensemble of nitrogen-vacancy centres. Our results open the door to entanglement-enhanced metrology using macroscopic ensembles of optically active spins in solids.

The doughnut-shaped framework of social and planetary boundaries (the 'Doughnut') provides a concise visual assessment of progress towards the goal of meeting the needs of all people within the means of the living planet1-3. Here we present a renewed Doughnut framework with a revised set of 35 indicators that monitor trends in social deprivation and ecological overshoot over the 2000-2022 period. Although global gross domestic product (GDP) has more than doubled, our median results show a modest achievement in reducing human deprivation that would have to accelerate fivefold to meet the needs of all people by 2030. Meanwhile, the increase in ecological overshoot would have to stop immediately and accelerate nearly two times faster towards planetary boundaries to safeguard Earth-system stability by 2050. Disaggregating these global findings shows that the richest 20% of nations, with 15% of the global population, contribute more than 40% of annual ecological overshoot, whereas the poorest 40% of countries, with 42% of the global population, experience more than 60% of the social shortfall. These trends and inequalities reaffirm the case for overcoming the dependence of nations on perpetual GDP growth4,5 and reorienting towards regenerative and distributive economic activity-within and between nations-that assigns priority to human needs and planetary integrity.

The application of biocatalysis in synthesis has the potential to offer streamlined routes towards target molecules1, tunable catalyst-controlled selectivity2, as well as processes with improved sustainability3. Despite these advantages, biocatalysis is often a high-risk strategy to implement, as identifying an enzyme capable of performing chemistry on a specific intermediate required for a synthesis can be a roadblock that requires extensive screening of enzymes and protein engineering to overcome4. Strategies for predicting which enzyme and small molecule are compatible have been hindered by the lack of well-studied biocatalytic reaction datasets5. The underexploration of connections between chemical and protein sequence space constrains navigation between these two landscapes. Here we report a two-phase effort relying on high-throughput experimentation to populate connections between productive substrate and enzyme pairs and the subsequent development of a tool, CATNIP, for predicting compatible α-ketoglutarate (α-KG)/Fe(II)-dependent enzymes for a given substrate or, conversely, for ranking potential substrates for a given α-KG/Fe(II)-dependent enzyme sequence. We anticipate that our approach can be readily expanded to further enzyme and transformation classes and will derisk the investigation and application of biocatalytic methods.

Electronic spins of nitrogen-vacancy centres in diamond constitute a promising system for micro- and nanoscale magnetic sensing1-4, because of their operation under ambient conditions5, ease of placement in close proximity to sensing targets6 and biological compatibility7. At high densities, the electronic spins interact through dipolar coupling, which typically limits8 but can also potentially enhance9 sensing performance. Here we report the experimental demonstration of many-body signal amplification in a solid-state, room-temperature quantum sensor. Our approach uses time-reversed two-axis-twisting interactions, engineered through dynamical control of the quantization axis and Floquet engineering10 in a two-dimensional ensemble of nitrogen-vacancy centres. We observe that optimal amplification occurs when the backward evolution time equals twice the forward evolution time, in sharp contrast to the conventional Loschmidt echo11,12. These observations can be understood as resulting from an underlying time-reversed mirror symmetry of the microscopic dynamics, providing key insights into signal amplification and opportunities for practical entanglement-enhanced quantum sensing.

The art of kirigami allows programming a sheet to deform into a particular manner with a pattern of cuts, endowing it with exotic mechanical properties and behaviours1-17. Here we program discs to deform into stably falling parachutes as they deploy under fluid-structure interaction. Parachutes are expensive and delicate to manufacture, which limits their use for humanitarian airdrops or drone delivery. Laser cutting a closed-loop kirigami pattern18 in a disc induces porosity and flexibility into an easily fabricated parachute. By performing wind tunnel testing and numerical simulations using a custom flow-induced reconfiguration model19, we develop a design tool to realize kirigami-inspired parachutes. Guided by these results, we fabricate parachutes from the centimetre to the metre scale and test them in realistic conditions. We show that at low load-to-area ratios, kirigami-inspired parachutes exhibit a comparable terminal velocity to conventional ones. However, unlike conventional parachutes that require a gliding angle for vertical stability20 and fall at random far from a target, our kirigami-inspired parachutes always fall near the target, regardless of their initial release angle. These kinds of parachutes could limit material losses during airdropping as well as decrease manufacturing costs and complexity.