1,654 research outputs found
Kondo resonance in a nanotube quantum dot coupled to a normal and a superconducting lead
We report on electrical transport measurements through a carbon nanotube
quantum dot coupled to a normal and a superconducting lead. The ratio of Kondo
temperature and superconducting gap is identified to govern the
transport properties of the system. In the case of the
conductance resonance splits into two resonances at . For the
opposite scenario the conductance resonance persists, however
the conductance is not enhanced compared to the normal state due to a relative
asymmetry of the lead-dot couplings. Within this limit the data is in agreement
with a simple model of a resonant SN-interface.Comment: 4 pages, 2 figures. submitted to the Proc. Rencontres de Moriond on
Quantum Information and Decoherence in Nanosystems 200
Conserved spin and orbital phase along carbon nanotubes connected with multiple ferromagnetic contacts
We report on spin dependent transport measurements in carbon nanotubes based
multi-terminal circuits. We observe a gate-controlled spin signal in non-local
voltages and an anomalous conductance spin signal, which reveal that both the
spin and the orbital phase can be conserved along carbon nanotubes with
multiple ferromagnetic contacts. This paves the way for spintronics devices
exploiting both these quantum mechanical degrees of freedom on the same
footing.Comment: 8 pages - minor differences with published versio
Shot noise in carbon nanotube based Fabry-Perot interferometers
We report on shot noise measurements in carbon nanotube based Fabry-Perot
electronic interferometers. As a consequence of quantum interferences, the
noise power spectral density oscillates as a function of the voltage applied to
the gate electrode. The quantum shot noise theory accounts for the data
quantitatively. It allows to confirm the existence of two nearly degenerate
orbitals. At resonance, the transmission of the nanotube approaches unity, and
the nanotube becomes noiseless, as observed in quantum point contacts. In this
weak backscattering regime, the dependence of the noise on the backscattering
current is found weaker than expected, pointing either to electron-electron
interactions or to weak decoherence
Coherent coupling of a single spin to microwave cavity photons
Electron spins and photons are complementary quantum-mechanical objects that
can be used to carry, manipulate and transform quantum information. To combine
these resources, it is desirable to achieve the coherent coupling of a single
spin to photons stored in a superconducting resonator. Using a circuit design
based on a nanoscale spin-valve, we coherently hybridize the individual spin
and charge states of a double quantum dot while preserving spin coherence. This
scheme allows us to achieve spin-photon coupling up to the MHz range at the
single spin level. The cooperativity is found to reach 2.3, and the spin
coherence time is about 60ns. We thereby demonstrate a mesoscopic device
suitable for non-destructive spin read-out and distant spin coupling.Comment: minor differences with published versio
The role of concussion history and biological sex on baseline concussion clinical profile symptoms in adolescent rugby players
BackgroundAccurate concussion monitoring requires access to preinjury baseline data. This is particularly important in adolescent athletes who have a high risk of concussion and are prone to prolonged recovery. As Rugby Union is governed by similar laws for men and women, it is also an ideal population to rigorously examine the impact of biological sex on concussion symptoms.AimsTo evaluate self-reported concussion symptoms at baseline in adolescent rugby union players, and examine if subtype-specific symptoms are affected by concussion history and biological sex.MethodsAdolescent rugby union players aged 16–18 years were recruited during the 2022–2023 playing season. Participants completed a series of questionnaires covering post-concussion symptoms, concussion clinical profiles, anxiety, depression and fear avoidance behaviours. Independent variables of interest in analysis were biological sex and concussion history.Results149 participants (75% male) were included. 42% (63/149) reported at least one previous concussion (average time since concussion: 18.7 months, range 1–72). Adolescents with a concussion history reported significantly higher scores than those with no history, across two clinical profiles (ocular and sleep), concussion symptom severity, and depression, all based on medium effect sizes (SMD 0.3–0.5). Females had significantly higher scores across cognitive/fatigue, ocular and sleep clinical profiles, concussion symptoms, anxiety and depression, each with large effect sizes (SMD > 0.5).ConclusionsConcussion history and sex are associated with higher baseline scores on specific concussion clinical profile, concussion symptom severity, and anxiety symptoms. These findings highlight the importance of considering baseline differences when interpreting post-injury clinical profile symptoms in adolescent rugby players. (Trial registration: ACTRN12622000931774)
More Than One Personal Risk Factor is Associated with Worse Clinical Outcomes Among Adolescents Following Concussion
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