99 research outputs found
Improved scaling of the entanglement entropy of quantum antiferromagnetic Heisenberg systems
In this paper, we derive corrections to the subleading logarithmic term of
the entanglement entropy in systems with spontaneous broken continuous
symmetry. Using quantum Monte Carlo simulations, we show that the improved
scaling formula leads to much better estimations of the number of Goldstone
modes in the two-dimensional square lattice spin-1/2 Heisenberg model and
bilayer spin-1/2 Heisenberg model in systems of rather small sizes, compared
with previous results. In addition, the universal geometry-dependent finite
constant in the entanglement entropy scaling is also obtained in good agreement
with the theoretical value.Comment: 7 pages, 4 figure
Patient classification of hypertension in Traditional Chinese Medicine using multi-label learning techniques
Shape evolution and bubble formation of acoustically levitated drops
In this study, we investigated the shape evolution and bubble formation of acoustically levitated drops upon increasing the sound intensity. Here, a levitated liquid drop evolves progressively from an oblate spheroidal shape to a flattened film to a thin bowl-shaped film, eventually forming a closed bubble. Through systematic experiments, numerical simulation, and scaling analysis, we demonstrate that the buckled geometry of the liquid film can drastically enhance the suction effect of acoustic radiation pressure at its rim, forming a significant pressure gradient inside the film which causes an abrupt area expansion and bubble formation. Our results provide the mechanical origin responsible for the shape evolution and bubble formation of acoustically levitated drops, and highlight the role of buckled geometry in the levitation and manipulation of liquid films in an ultrasound field
Mode conversion enables optical pulling force in photonic crystal waveguides
We propose a robust scheme to achieve optical pulling force using the guiding modes supported in a hollow core double-mode photonic crystal waveguide instead of the structured optical beams in free space investigated earlier. The waveguide under consideration supports both the 0th order mode with a larger forward momentum and the 1st order mode with a smaller forward momentum. When the 1st order mode is launched, the scattering by the object inside the waveguide results in the conversion from the 1st order mode to the 0th order mode, thus creating the optical pulling force according to the conservation of linear momentum. We present the quantitative agreement between the results derived from the mode conversion analysis and those from rigorous simulation using the finite-difference in the time-domain numerical method. Importantly, the optical pulling scheme presented here is robust and broadband with naturally occurred lateral equilibriums and has a long manipulation range. Flexibilities of the current configuration make it valuable for the optical force tailoring and optical manipulation operation, especially in microfluidic channel systems
Synthesis and Gas-Sensing Property of Highly Self-assembled Tungsten Oxide Nanosheets
We report the synthesis of tungsten oxide (WO3) nanosheets using a simple yet efficient hydrothermal technique free of surfactantand template. The WO3 nano-sheets are self-assembled as well to form ordered one-dimensional chain nanostructure. A comprehensive microscopic characterization reveals that the nano-sheets have triangular and circular two different shape edges, dislocation and stacking faults are also observed, which should have implications for our understanding of catalytic activity of ceria. We also propose a growth mechanism for the nano-sheets. As a result of this unique morphology, this WO3 nano-sheets are found to show excellent gas-sensing properties which can use as promising sensor materials detecting ethanol with low concentration
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