10,103 research outputs found
K-quantum Nonlinear Jaynes-Cummings Model in Two Trapped Ions
A k-quantum nonlinear Jaynes-Cummings model for two trapped ions interacting
with laser beams resonant to k-th red side-band of center-of-mass mode, far
from Lamb-Dicke regime, has been obtained. The exact analytic solution showed
the existence of quantum collapses and revivals of the occupation of two atoms.Comment: 8 pages, 3 figure
Bounds on the multipartite entanglement of superpositions
We derive the lower and upper bounds on the entanglement of a given
multipartite superposition state in terms of the entanglement of the states
being superposed. The first entanglement measure we use is the geometric
measure, and the second is the q-squashed entanglement. These bounds allow us
to estimate the amount of the multipartite entanglement of superpositions. We
also show that two states of high fidelity to one another do not necessarily
have nearly the same q-squashed entanglement.Comment: 4 pages, 2 figure. few typos correcte
Semi-Supervised Self-Taught Deep Learning for Finger Bones Segmentation
Segmentation stands at the forefront of many high-level vision tasks. In this
study, we focus on segmenting finger bones within a newly introduced
semi-supervised self-taught deep learning framework which consists of a student
network and a stand-alone teacher module. The whole system is boosted in a
life-long learning manner wherein each step the teacher module provides a
refinement for the student network to learn with newly unlabeled data.
Experimental results demonstrate the superiority of the proposed method over
conventional supervised deep learning methods.Comment: IEEE BHI 2019 accepte
Investigating the micromechanics of soil reinforced with recycled tyres using the Discrete Element Method
This PhD program aims to provide insights into the behaviour of tyre reinforced sand, and to further the understanding of the reinforcement mechanisms. The discrete element method (DEM) using the software PFC3D version 5.0, is used to investigate the micro- mechanics of tyre-reinforced sand based on pull-out tests. A series of numerical direct shear tests have been performed. A full investigation of the individual particle shape descriptors (e.g., elongation index, flatness index, convexity and roundness) is presented, highlighting their influence on the macroscopic behaviour (e.g., failure mode and volumetric response). MorphologI G3 at UCL helps to obtain the quantitative particle shape information on Fujian Standard Sand. The sand information is incorporated in the results of particle shape studies to propose a representative particle shape for Fujian Standard Sand to model direct shear tests, leading to the calibration of pure sand. Then, a new three-dimensional DEM model for tyre rubber is developed based on uniaxial tensile tests. The model can capture the key volume change characteristics of tyres with a Poisson’s ratio of 0.5 independent of the tyre dimensions. Tyre rubber is modelled using body-centred-cubic (BCC) packing with linear inter-particle bonds. Next, a systematic parametric study is presented, which includes the effects of different packings, particle overlapping, particle radii and sample aspect ratios on the mechanical response of the tyre model using Young’s modulus and Poisson’s ratio. The DEM parameters are set to match corresponding experimental Young’s modulus data, completing the calibration of tyre. Lastly, the tyre – sand interface coefficient friction is calibrated from numerical and laboratory interface direct shear tests. All DEM parameters are used in tyre reinforced sand pull-out tests simulations. Micro analyses (such as particle displacement, velocity, contact force) presented in simulations show that the DEM tyre-sand pullout test simulation can capture the progress failure of tyre rubber during the pull-out process, and the intrusive capabilities of the discrete element method are used to gain insight into the reinforcement mechanisms between tyre and sand
Quantum-State Engineering of Multiple Trapped Ions for Center-of-Mass Mode
We propose a scheme to generate a superposition with arbitrary coefficients
on a line in phase space for the center-of-mass vibrational mode of N ions by
means of isolating all other spectator vibrational modes from the
center-of-mass mode. It can be viewed as the generation of previous methods for
preparing motional states of one ion. For large number of ions, we need only
one cyclic operatin to generate such a superposition of many coherent states.Comment: 14 pages, revte
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