Ballistic one-dimensional holes with strong g-factor anisotropy in germanium

We report experimental evidence of ballistic hole transport in one-dimensional quantum wires gate-defined in a strained SiGe/Ge/SiGe quantum well. At zero magnetic field, we observe conductance plateaus at integer multiples of 2e2/h. At finite magnetic field, the splitting of these plateaus by Zeeman effect reveals largely anisotropic g-factors with absolute values below 1 in the quantum-well plane, and exceeding 10 out-of-plane. This g-factor anisotropy is consistent with a heavy-hole character of the propagating valence-band states, which is in line with a predominant confinement in the growth direction. Remarkably, we observe quantized ballistic conductance in device channels up to 600 nm long. These findings mark an important step toward the realization of novel devices for applications in quantum spintronics

Le destin des manuscrits catholiques d’Isaac Papin après sa mort : convoitise et mystère autour de la dépouille intellectuelle d’un sympathisant janséniste

Isaac Papin (1657-1709), né calviniste, est passé à la postérité pour sa conversion au catholicisme. Après avoir été le fer de lance des pajonistes au sein du Refuge, il se convertit entre les mains de Bossuet, en 1690. La seconde partie de sa vie est beaucoup moins connue. Deux dossiers de la collection Port-Royal d’Utrecht permettent de lever le voile sur un aspect totalement inédit de son parcours : ses relations avec le milieu janséniste. Si les traces sont peu nombreuses, ses relations avec Pasquier Quesnel sont attestées. Après sa mort, ses manuscrits sont convoités et finalement récupérés par les jansénistes. Les textes qu’ils contiennent sont publiés par les soins de Quesnel, en 1713, sous le titre Les deux voies opposées en matière de religion

A CMOS silicon spin qubit

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot (QD) encoding a hole spin qubit, the second one a QD used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. Our result opens a viable path to qubit up-scaling through a readily exploitable CMOS platform.Comment: 12 pages, 4 figure

Establised and experimental treatments for sickle cell disease

Sickle cell disease (SCD) is characterized by the presence of sickle hemoglobin (HbS), which has the unique property of polymerizing when deoxygenated. The sickling process is markedly accelerated when intracellular concentration of HbS is increased. Due to the unique dependence of HbS polymerization on its cell concentration, a slight reduction in HbS concentration is likely to have a beneficial effect on the kinetic of polymerization and on the generation of dense, dehydrated red cells. The pathophysiology of acute and chronic clinical manifestations of SCD is strictly related to the hemoglobin cyclic polymerization, to the generation of dense, dehydrated red cells and to the interaction between sickle red cells and abnormal activated vascular endothelial cells. In the present paper we have reviewed the principal therapeutic strategies and we have explored the future treatment options for sickle cell disease. Therapy of sickle cell disease is based on two major goals. The first one is the decrease in intracellular HbS concentration obtained with agents activating fetal hemoglobin synthesis, such as hydroxyurea (HU) or with erythrocyte-active agents blocking different red cell membrane ion pathways and preventing sickle cell dehydration. The second one is based on therapeutic strategies, which may reduce sickle cell-endothelial adhesive events

Pauli spin blockade in CMOS double quantum dot devices

Silicon quantum dots are attractive candidates for the development of scalable, spin-based qubits. Pauli spin blockade in double quantum dots provides an efficient, temperature independent mechanism for qubit readout. Here we report on transport experiments in double gate nanowire transistors issued from a CMOS process on 300 mm silicon-on-insulator wafers. At low temperature the devices behave as two few-electron quantum dots in series. We observe signatures of Pauli spin blockade with a singlet-triplet splitting ranging from 0.3 to 1.3 meV. Magneto-transport measurements show that transitions which conserve spin are shown to be magnetic-field independent up to B = 6 T.Comment: 5 pages , 4 figure

TRANSMIT: Training Research and Applications Network to Support the Mitigation of Ionospheric Threats

TRANSMIT is an initiative funded by the European Commission through a Marie Curie Initial Training Network (ITN). Main aim of such networks is to improve the career perspectives of researchers who are in the first five years of their research career in both public and private sectors. In particular TRANSMIT will provide a coordinated program of academic and industrial training, focused on atmospheric phenomena that can significantly impair a wide range of systems and applications that are at the core of several activities embedded in our daily life. TRANSMIT deals with the harmful effects of the ionosphere on these systems, which will become increasingly significant as we approach the next solar maximum, predicted for 2013. Main aim of the project is to develop real time integrated state of the art tools to mitigate ionospheric threats to Global Navigation Satellite Systems (GNSS) and several related applications, such as civil aviation, marine navigation and land transportation. The project will provide Europe with the next generation of researchers in this field, equipping them with skills developed through a comprehensive and coordinated training program. Theirs research projects will develop real time integrated state of the art tools to mitigate these ionospheric threats to GNSS and several applications that rely on these systems. The main threat to the reliable and safe operation of GNSS is the variable propagation conditions encountered by GNSS signals as they pass through the ionosphere. At a COST 296 MIERS (Mitigation of Ionospheric Effects on Radio Systems) workshop held at the University of Nottingham in 2008, the establishment of a sophisticated Ionospheric Perturbation Detection and Monitoring (IPDM) network (http://ipdm.nottingham.ac.uk/) was proposed by European experts and supported by the European Space Agency (ESA) as the way forward to deliver the state of the art to protect the range of essential systems vulnerable to these ionospheric threats. Through a set of carefully designed research work packages TRANSMIT will be the enabler of the IPDM network. The goal of TRANSMIT is therefore to provide a concerted training programme including taught courses, research training projects, secondments at the leading European institutions, and a set of network wide events, with summer schools, workshops and a conference, which will arm the researchers of tomorrow with the necessary skills and knowledge to set up and run the proposed service. TRANSMIT will count on an exceptional set of partners, encompassing both academia and end users, including the aerospace and satellite communications sectors, as well as GNSS system designers and service providers, major user operators and receiver manufacturers. TRANSMIT's objectives are: A. Develop new techniques to detect and monitor ionospheric threats, with the introduction of new prediction and forecasting models, mitigation tools and improved system design; B. Advance the physical modeling of the underlying processes associated with the ionospheric plasma environment and the knowledge of its influences on human activity; C. Establish a prototype of a real time system to monitor the ionosphere, capable of providing useful assistance to users, which exploits all available resources and adds value for European services and products; D. Incorporate solutions to this system that respond to all end user needs and that are applicable in all geographical regions of European interest (polar, high and mid-latitudes, equatorial region). TRANSMIT will pave the way to establish in Europe a system capable of mitigating ionospheric threats on GNSS signals in real tim

Care of patients with hemoglobin disorders during the COVID-19 pandemic: An overview of recommendations.

The outbreak of Coronavirus Disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a global health emergency.1 Compared to the general population, patients with hemoglobin disorders such as sickle cell disease (SCD) or thalassemia are expected to be more severely affected by COVID-19 due to their preexisting chronic morbidities.2 The Centers for Disease Control and Prevention does not report any specific indications for patients with hemoglobinopathies. However, it can be hypothesized that the rapid spread of the virus may render these patients fragile when fighting the infection. SCD, a hematological condition with functional asplenia, puts patients at a greater risk to develop acute pulmonary complications, including viral infections.2 A study by Hussain et al reported four SCD cases that tested positive for COVID-19.3 These cases initially presented to the emergency department for a typical vaso-occlusive crisis (VOC), and the clinical course of their SARS-CoV-2 infection was rather mild. Patients had a history of respiratory complications, such as acute chest syndrome (ACS), asthma, or pulmonary embolism, which may be potential risk factors for progressive COVID-19 pulmonary disease in patients with SCD.3 A series of isolated cases of ACS in SCD patients positive for COVID-19 has been recently reported.4,5 Therefore, very little clinical experience of infected patients with SCD currently exists. For this reason, we believe that certain recommendations must be followed by healthcare professionals treating any SCD patient infected with SARS-CoV-2