7,553 research outputs found
High Current Matching over Full-Swing and Low-Glitch Charge Pump Circuit for PLLs
A high current matching over full-swing and low-glitch charge pump (CP) circuit is proposed. The current of the CP is split into two identical branches having one-half the original current. The two branches are connected in source-coupled structure, and a two-stage amplifier is used to regulate the common-source voltage for the minimum current mismatch. The proposed CP is designed in TSMC 0.18µm CMOS technology with a power supply of 1.8 V. SpectreRF based simulation results show the mismatch between the current source and the current sink is less than 0.1% while the current is 40 µA and output swing is 1.32 V ranging from 0.2 V to 1.52 V. Moreover, the transient output current presents nearly no glitches. The simulation results verify the usage of the CP in PLLs with the maximum tuning range from the voltage-controlled oscillator, as well as the low power supply applications
Scalable quantum information processing with atomic ensembles and flying photons
We present a scheme for scalable quantum information processing (QIP) with
atomic ensembles and flying photons. Using the Rydberg blockade, we encode the
qubits in the collective atomic states, which could be manipulated fast and
easily due to the enhanced interaction, in comparison to the single-atom case.
We demonstrate that our proposed gating could be applied to generation of
two-dimensional cluster states for measurement-based quantum computation.
Moreover, the atomic ensembles also function as quantum repeaters useful for
long distance quantum state transfer. We show the possibility of our scheme to
work in bad cavity or in weak coupling regime, which could much relax the
experimental requirement. The efficient coherent operations on the ensemble
qubits enable our scheme to be switchable between quantum computation and
quantum communication using atomic ensembles.Comment: 8 pages, 7 figure
Higher bottomonium zoo
In this work, we study higher bottomonia up to the , , , ,
multiplets using the modified Godfrey-Isgur (GI) model, which takes
account of color screening effects. The calculated mass spectra of bottomonium
states are in reasonable agreement with the present experimental data. Based on
spectroscopy, partial widths of all allowed radiative transitions, annihilation
decays, hadronic transitions, and open-bottom strong decays of each state are
also evaluated by applying our numerical wave functions. Comparing our results
with the former results, we point out difference among various models and
derive new conclusions obtained in this paper. Notably, we find a significant
difference between our model and the GI model when we study , and and
states. Our theoretical results are valuable to search for more
bottomonia in experiments, such as LHCb, and forthcoming Belle II.Comment: 40 pages, 4 figures and 40 tables. Accepted by Eur. Phys. J.
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