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The global quantum internet will require long-lived, telecommunications-band photon–matter interfaces manufactured at scale 1 . Preliminary quantum networks based on photon–matter interfaces that meet a subset of these demands are encouraging efforts to identify new high-performance alternatives 2 . Silicon is an ideal host for commercial-scale solid-state quantum technologies. It is already an advanced platform within the global integrated photonics and microelectronics industries, as well as host to record-setting long-lived spin qubits 3 . Despite the overwhelming potential of the silicon quantum platform, the optical detection of individually addressable photon–spin interfaces in silicon has remained elusive. In this work, we integrate individually addressable ‘T centre’ photon–spin qubits in silicon photonic structures and characterize their spin-dependent telecommunications-band optical transitions. These results unlock immediate opportunities to construct silicon-integrated, telecommunications-band quantum information networks. Individually addressable ‘T centre’ photon-spin qubits are integrated in silicon photonic structures and their spin-dependent telecommunications-band optical transitions characterized, creating opportunities to construct silicon-integrated, telecommunications-band quantum information networks.

Quantum computing technologies are advancing, and the class of addressable problems is expanding. Together with the emergence of new ventures and government-sponsored partnerships, these trends will help to lower the barrier for adoption of new technology and provide stability in an uncertain market. Until then, quantum computing presents an exciting testbed for different strategies in an emerging market.Quantum computing technologies are advancing, and the class of addressable problems is expanding. What market strategies are quantum computing companies and start-ups adopting?

Quantum memories capable of storing and retrieving coherent information for extended times at room temperature would enable a host of new technologies. Electron and nuclear spin qubits using shallow neutral donors in semiconductors have been studied extensively but are limited to low temperatures (<̰10 kelvin); however, the nuclear spins of ionized donors have the potential for high-temperature operation. We used optical methods and dynamical decoupling to realize this potential for an ensemble of phosphorous-31 donors in isotopically purified silicon-28 and observed a room-temperature coherence time of over 39 minutes. We further showed that a coherent spin superposition can be cycled from 4.2 kelvin to room temperature and back, and we report a cryogenic coherence time of 3 hours in the same system.

Low-cost private schools (LCPS) are widespread in Kenya, particularly in urban areas. This study examines the reasons that parents send children to fee-charging schools in a context of free public primary education. Drawing on parent survey and interview data, as well as interviews with national policy makers, we found that parents who chose LCPS for their children were more driven by quality concerns than were public school parents. We also present data on the costs of the school types, compared to household income. Despite being termed 'low cost', the fees charged by schools primarily serving the poor were often a heavy burden on families. We conclude with recommendations for maximising the impact of LCPS on educational access and quality.

State of the art qubit systems are reaching the gate fidelities required for scalable quantum computation architectures. Further improvements in the fidelity of quantum gates demands characterization and benchmarking protocols that are efficient, reliable and extremely accurate. Ideally, a benchmarking protocol should also provide information on how to rectify residual errors. Gate set tomography (GST) is one such protocol designed to give detailed characterization of as-built qubits. We implemented GST on a high-fidelity electron-spin qubit confined by a single 31P atom in 28Si. The results reveal systematic errors that a randomized benchmarking analysis could measure but not identify, whereas GST indicated the need for improved calibration of the length of the control pulses. After introducing this modification, we measured a new benchmark average gate fidelity of 99.942 ( 8 ) % , an improvement on the previous value of 99.90 ( 2 ) % . Furthermore, GST revealed high levels of non-Markovian noise in the system, which will need to be understood and addressed when the qubit is used within a fault-tolerant quantum computation scheme.

Background The COVID-19 pandemic has exacerbated struggles for youth living in poor households. Youth in rural Tanzania are particularly vulnerable given widespread poverty, lack of formal sector employment opportunities, and health risks. We examine influences of the pandemic on economic insecurity and mental health and explore the coping strategies employed by youth and their households. Methods We conducted mixed-method data collection with youth ( N  = 760 quantitative and N  = 44 qualitative interviews) and households ( n  = 542) via mobile phone among a sub-set of a cohort from an on-going longitudinal sample in two rural regions in Tanzania. In addition to phone interviews, we collected data bi-weekly via SMS messaging. We present mixed-methods, descriptive analysis of the outcomes and longitudinally compare quantitative outcomes pre- and post-COVID-19, within the same individuals. Results Adverse economic impacts were most salient, and to cope, youth engaged in more labor and domestic chores. Compared to prior the COVID-19 pandemic, youth reported spending more time caring for elderly or sick household members and gathering firewood or nuts. Conclusions These findings underscore the potential opportunity to promote policies and programs which address risks youth face. Recommended measures include expansion and adaptation of social protection policies, strengthened food and nutrition surveillance and referral systems, and scaling up community-based mental health programming.

The diploblastic cnidarian body plan comprising the epidermis and gastrodermis has remained largely unchanged since it evolved roughly 600 Ma. The origin of muscle from the mesoderm in triploblastic lineages is a central evolutionary question in higher animals. Triploblasts have three embryonic germ layers: the endoderm, mesoderm, and ectoderm, which develop into organs, muscle, and skin, respectively. Diploblasts lack the mesoderm, the layer thought to give rise to the skeletomuscular system. However, phyla such as Cnidaria and Ctenophora, which are typically classified as diploblasts, possess striated musculature. Within phylum Cnidaria, class Cubozoa includes carnivorous box jellyfish, which are capable of extending and contracting their tentacles for predation and defense mechanisms, thus suggesting a well-organized system of muscles. Here, the tentacle musculature of the cubomedusae Carybdea marsupialis is investigated using transmission electron microscopy in conjunction with light microscopy to further understand the arrangement of musculature in these primitive animals. Cross sections of tentacles confirmed that the gastrodermis is separated from the epidermis by a collagenous mesogleal layer containing numerous longitudinal muscle cells arranged in fascicles. Longitudinal muscles permit the tentacle to retract toward the bell during fast tentacle shortening and crumpling behavioral responses. Circular muscle cells were found in the gastrodermis and epidermis, encircling the layer of longitudinal muscle. These circular muscles likely enable the elongation process that allows the tentacles to return to a resting state after contraction. The presence of a definitive muscle cell layer within the mesoglea suggests that C. marsupialis has an advanced muscle morphology that is similar to triploblastic animals .

Nuclear spin is seen as a robust qubit. Electrons can be used to ‘read’ to the nuclear state, but their presence causes decoherence. Researchers now show that this problem can be circumvented using a temporary spin state, thus enabling entanglement of the nuclear state at unprecedented speeds. The representation of information within the spins of electrons and nuclei has been a powerful method in the ongoing development of quantum computers 1 , 2 . Although nuclear spins are advantageous as quantum bits (qubits) because of their long coherence lifetimes (exceeding seconds 3 ), they exhibit very slow spin interactions and have weak thermal polarization. A coupled electron spin can be used to polarize the nuclear spin 4 , 5 , 6 and create fast single-qubit gates 7 , 8 , however, the permanent presence of electron spins is a source of nuclear decoherence. Here we show how a transient electron spin, arising from the optically excited triplet state of C 60 , can be used to hyperpolarize, manipulate and measure two nearby nuclear spins. Implementing a scheme that uses the spinor nature of the electron 9 , we performed an entangling gate in hundreds of nanoseconds: five orders of magnitude faster than the liquid-state J coupling. This approach can be widely applied to systems comprising an electron spin coupled to multiple nuclear spins, such as nitrogen–vacancy centres in diamond 10 , while the successful use of a transient electron spin motivates the design of new molecules able to exploit photoexcited triplet states.

Nuclear spin registers in the vicinity of electron spins in solid state systems offer a powerful resource to address the challenge of scalability in quantum architectures. We investigate here the properties of 29Si nuclear spins surrounding donor atoms in silicon, and consider the use of such spins, combined with the donor nuclear spin, as a quantum register coupled to the donor electron spin. We find the coherence of the nearby 29Si nuclear spins is effectively protected by the presence of the donor electron spin, leading to coherence times in the second timescale-over two orders of magnitude greater than the coherence times in bulk silicon. We theoretically investigate the use of such a register for quantum error correction (QEC), including methods to protect nuclear spins from the ionisation/neutralisation of the donor, which is necessary for the re-initialisation of the ancillae qubits. This provides a route for multi-round QEC using donors in silicon.