Bardasis-Schrieffer-like phase mode in a superconducting bilayer

We theoretically study the low-lying collective modes of an even-parity spin-singlet superconducting bilayer, where strong spin-orbit coupling leads to a closely competing odd-parity parity pairing state. We develop a gauge-invariant theory for the coupling of phase fluctuations to an external electromagnetic field and show that the competing odd-parity pairing state gives rise to a Bardasis-Schrieffer-like phase mode within the excitation gap. Accounting for the long-range Coulomb interaction, however, we find that this mode hybridizes with an antisymmetric plasmon and is likely pushed into the quasiparticle continuum

Subsistence Strategy and Tibial Shape: Identifying Variation in Activity Across the Sudanese Landscape

The growing human tibia is uniquely responsive to repeated activities, resulting in identifiable morphological patterns that can be applied to ancient populations. Much of the bioarchaeological research in this area focuses on the transition to agriculture, noting a decline in bone strength and robusticity with increasing levels of sedentism. However, not all human groups adopted agriculture simultaneously or uniformly, and there continues to be variation in subsistence strategy based on climate, resource availability, and cultural practice. In Sudan, groups have continued to practice nomadic pastoralism alongside agriculture, although sedentary agricultural societies tend to be the focus of most archaeological research in the region. This work examines the difference in tibial morphology between groups utilising different subsistence practices within the same geographic region and archaeological period to explore activity-based changes to the tibia, using both cross-sectional geometry and geometric morphometrics to quantify the difference between tibial cross-sectional shapes at midshaft. The results suggest that while clear differences exist in midshaft tibial shape between the Sudanese groups practicing differing subsistence strategies, there is no one shape that is indicative of nomadism or sedentism; rather, there are general trends indicating higher mobility among more members of the nomadic group and more local movement among the members of the sedentary groups. Further, there is more similarity between females of all groups than males, problematising the idea that all individuals respond to bone remodeling activity in the same way. The conclusions presented here recommend that more research needs to be conducted on tibial shape variation in Sudan and worldwide using geometric morphometrics, as it presents a more nuanced approach than cross-sectional geometry, and that bone remodeling in response to activity must continue to be explored in light of differences in age, sex, and musculature

Low Power High Speed CMOS Interface for MOS Gas Sensors

AbstractA universal CMOS integrated MOS gas sensor interface for application development and sensor research is presented. Three different integrated heater sources with a maximum output range of 20V and 40mA and the possibility to operate an external transistor as current source with an output range of several hundred mA allow the operation of nearly all kinds of hotplates. Two different readout electronics for the sensor's resistance work within a range of 1 kΩ up to 10 MΩ with a constant voltage or constant current sensor bias. All measurements are digitized with two free configurable high speed low noise analog channels which allow fast and low power measurements. The configuration of the chip and the readout of the measurements are done with a register based SPI interface

Bound states around impurities in a superconducting bilayer

We theoretically study the appearance of bound states around impurities in a superconducting bilayer. We focus our attention on $s$-wave pairing, which includes unconventional odd-parity states permitted by the layer degree of freedom. Utilizing numerical mean-field and analytical $T$-matrix methods, we survey the bound state spectrum produced by momentum-independent impurity potentials in this model. For even-parity $s$-wave pairing bound states are only found for impurities which break time-reversal symmetry. For odd-parity $s$-wave states, in contrast, bound states are generically found for all impurity potentials, and fall into six distinct categories. This categorization remains valid for nodal gaps. Our results are conveniently understood in terms of the ``superconducting fitness'' concept, and show an interplay between the pair-breaking effects of the impurity and the normal-state band structure

Fast responding ephedrine detection with miniaturized surface ionization gas sensors

AbstractWe report on novel kinds of miniaturized gas sensors whose operation is based on the principle of surface ionization (SI). In SI gas sensing adsorbed analyte species are ionized at a heated solid surface and the formed ions are extracted towards an oppositely charged collector electrode positioned a short distance from the emitting surface. Here, we show that SI sensors allow for a fast, sensitive and selective detection of illicit drugs in the presence of large concentrations of solvent water