7,757 research outputs found
Single-shot single-gate RF spin readout in silicon
For solid-state spin qubits, single-gate RF readout can help minimise the
number of gates required for scale-up to many qubits since the readout sensor
can integrate into the existing gates required to manipulate the qubits
(Veldhorst 2017, Pakkiam 2018). However, a key requirement for a scalable
quantum computer is that we must be capable of resolving the qubit state within
single-shot, that is, a single measurement (DiVincenzo 2000). Here we
demonstrate single-gate, single-shot readout of a singlet-triplet spin state in
silicon, with an average readout fidelity of at a
measurement bandwidth. We use this technique to measure a triplet to
singlet relaxation time of in precision donor quantum
dots in silicon. We also show that the use of RF readout does not impact the
maximum readout time at zero detuning limited by the to decay,
which remained at approximately . This establishes single-gate
sensing as a viable readout method for spin qubits
On-board demux/demod
To make satellite channels cost competitive with optical cables, the use of small, inexpensive earth stations with reduced antenna size and high powered amplifier (HPA) power will be needed. This will necessitate the use of high e.i.r.p. and gain-to-noise temperature ratio (G/T) multibeam satellites. For a multibeam satellite, onboard switching is required in order to maintain the needed connectivity between beams. This switching function can be realized by either an receive frequency (RF) or a baseband unit. The baseband switching approach has the additional advantage of decoupling the up-link and down-link, thus enabling rate and format conversion as well as improving the link performance. A baseband switching satellite requires the demultiplexing and demodulation of the up-link carriers before they can be switched to their assigned down-link beams. Principles of operation, design and implementation issues of such an onboard demultiplexer/demodulator (bulk demodulator) that was recently built at COMSAT Labs. are discussed
Consumer Preferences for Fresh Citrus: Impacts of Demographic and Behavioral Characteristics
Fresh citrus, consumer preference, attitude, cluster analysis, market segmentation, Consumer/Household Economics, Crop Production/Industries, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing, Q13,
Perceptions of knowledge sharing among small family firm leaders: a structural equation model
Small family firms have many unique relational qualities with implications for how knowledge is passed between individuals. Extant literature posits leadership approach as important in explaining differences in knowledge-sharing climate from one firm to another. This study investigates how leadership approaches interact with family influence to inform perceptions of knowledge sharing. We utilize survey data (n = 110) from owner-managers of knowledge-intensive small family firms in Scotland. Our findings present a choice in leadership intention, contrasting organization-focused participation against family-influenced guidance. Insight is offered on the implications of this leadership choice at both organizational and familial level
Single-charge detection by an atomic precision tunnel junction
We demonstrate sensitive detection of single charges using a planar tunnel junction 8.5 nm wide and 17.2 nm long defined by an atomically precise phosphorus doping profile in silicon. The conductance of the junction responds to a nearby gate potential and also to changes in the charge state of a quantum dot patterned 52 nm away. The response of this detector is monotonic across the entire working voltage range of the device, which will make it particularly useful for studying systems of multiple quantum dots. The charge sensitivity is maximized when the junction is most conductive, suggesting that more sensitive detection can be achieved by shortening the length of the junction to increase its conductance
The stellar metallicity distribution of disc galaxies and bulges in cosmological simulations
By means of high-resolution cosmological hydrodynamical simulations of Milky
Way-like disc galaxies, we conduct an analysis of the associated stellar
metallicity distribution functions (MDFs). After undertaking a kinematic
decomposition of each simulation into spheroid and disc sub-components, we
compare the predicted MDFs to those observed in the solar neighbourhood and the
Galactic bulge. The effects of the star formation density threshold are visible
in the star formation histories, which show a modulation in their behaviour
driven by the threshold. The derived MDFs show median metallicities lower by
0.2-0.3 dex than the MDF observed locally in the disc and in the Galactic
bulge. Possible reasons for this apparent discrepancy include the use of low
stellar yields and/or centrally-concentrated star formation. The dispersions
are larger than the one of the observed MDF; this could be due to simulated
discs being kinematically hotter relative to the Milky Way. The fraction of low
metallicity stars is largely overestimated, visible from the more negatively
skewed MDF with respect to the observational sample. For our fiducial Milky Way
analog, we study the metallicity distribution of the stars born "in situ"
relative to those formed via accretion (from disrupted satellites), and
demonstrate that this low-metallicity tail to the MDF is populated primarily by
accreted stars. Enhanced supernova and stellar radiation energy feedback to the
surrounding interstellar media of these pre-disrupted satellites is suggested
as an important regulator of the MDF skewness.Comment: 20 pages, 14 figures, MNRAS, accepte
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