RESUMEN
Superconductor-semiconductor-superconductor heterostructures are attractive for both fundamental studies of quantum phenomena in low-dimensional hybrid systems as well as for future high-performance low power dissipating nanoelectronic and quantum devices. In this work, ultrascaled monolithic Al-Ge-Al nanowire heterostructures featuring monocrystalline Al leads and abrupt metal-semiconductor interfaces are used to probe the low-temperature transport in intrinsic Ge (i-Ge) quantum dots. In particular, demonstrating the ability to tune the Ge quantum dot device from completely insulating, through a single-hole-filling quantum dot regime, to a supercurrent regime, resembling a Josephson field effect transistor with a maximum critical current of 10 nA at a temperature of 390 mK. The realization of a Josephson field-effect transistor with high junction transparency provides a mechanism to study sub-gap transport mediated by Andreev states. The presented results reveal a promising intrinsic Ge-based architecture for hybrid superconductor-semiconductor devices for the study of Majorana zero modes and key components of quantum computing such as gatemons or gate tunable superconducting quantum interference devices.
RESUMEN
Unprecedented attention is focused on global health, with a four-fold increase in development assistance in the last 15 years and the scope of global health expanding beyond infectious disease to include chronic disease and health systems strengthening. As the global impact of health is more widely understood, it has become a crucial element of international relations, economic development, and foreign affairs. At this potential leverage point in the global health movement, the application of grand strategy is of critical importance. Grand strategy, i.e., the development and implementation of comprehensive plans of action to achieve large ends with limited means, has been refined through centuries of international relations and the management of states but has been inadequately applied to global health policy and implementation. We review key principles of grand strategy and demonstrate their applicability to a central global health issue: maternal mortality. The principles include: start with the end in mind, take an ecological approach, recognize that tactics matter, use positive deviance to characterize practical solutions and foster scale-up, and integrate timely intelligence and data into health interventions and improvement efforts. We advocate for the greater use of grand strategy in global health.