arXiv subjects

C. S. Yu

Publications and source records attributed to C. S. Yu.

4 recordsLinked to original sources

arXiv2017

The influence of localization transition on dynamical properties for an extended Aubry-Andr\'e-Harper model

We show the localization transition and its effect on two dynamical processes for an extended Aubry-Andr\'e-Harper model with incommensurate on-site and hopping potentials. After specifying an extended Aubry-Andr\'e-Harper model, we check the localization transition for all the eigenstates and eigenenergy band splitting behavior versus a system parameter. To examine the effect of localization transition on dynamical processes, firstly, the slowly pumping of the edge states are examined. In the dynamical processes, the system acts as conductor for the excitation in the nonlocal region and insulator in the localized region. Then by quantum Lyapunov control method with different control Hamiltonians, we prepare an edge localized state which exists in the nonlocal region. Compared to that in the nonlocal region, the control effect is suppressed in the localized region. Then we employ the entropy and occupation imbalance between even and odd sites to indicate the localization transition further. Finally, the experimental schemes based on cold atoms trapped quasiperiodic optical lattice and coupled optical waveguide arrays are suggested.

cond-mat.dis-nn↗

arXiv2017

Effect of loss on the topological features of dimer chain described by the extended Aubry-Andr\'e-Harper model

By introducing loss to one sublattice of a dimer chain described by the extended Aubry-Andr\'e or Harper (AAH) model, we study the topological features including the edge states, spectrum and winding number of the chain. We find that the parameter region for the system to have real band-gap-closing is increased due to the loss, and the average displacement of the single excitation can still witness the topological features of the chain in the presence of loss. The robustness of the zero energy eigenstate against four kinds of disorders is also examined. A feasible experiment setup based on coupled waveguides to observe the prediction of this paper is proposed.

cond-mat.quant-gas↗

arXiv2008

Investigation of Micro Porosity Sintered wick in Vapor Chamber for Fan Less Design

Micro Porosity Sintered wick is made from metal injection molding processes, which provides a wick density with micro scale. It can keep more than 53 % working fluid inside the wick structure, and presents good pumping ability on working fluid transmission by fine infiltrated effect. Capillary pumping ability is the important factor in heat pipe design, and those general applications on wick structure are manufactured with groove type or screen type. Gravity affects capillary of these two types more than a sintered wick structure does, and mass heat transfer through vaporized working fluid determines the thermal performance of a vapor chamber. First of all, high density of porous wick supports high transmission ability of working fluid. The wick porosity is sintered in micro scale, which limits the bubble size while working fluid vaporizing on vapor section. Maximum heat transfer capacity increases dramatically as thermal resistance of wick decreases. This study on permeability design of wick structure is 0.5 - 0.7, especially permeability (R) = 0.5 can have the best performance, and its heat conductivity is 20 times to a heat pipe with diameter (Phi) = 10mm. Test data of this vapor chamber shows thermal performance increases over 33 %.

physics.gen-ph↗

arXiv2003

Noise-assisted preparation of entangled atoms

We discuss the generation of entangled states of two two-level atoms inside an optical cavity. The cavity mode is supposed to be coupled to a white noise with adjustable intensity. We describe how the entanglement between the atoms inside the cavity arise in such a situation. The entanglement is maximized for intermediate values of the noise intensity, while it is a monotonic function of the spontaneous rate. This resembles the phenomenon of stochastic resonance and sheds more light on the idea to exploit white noise in quantum information processing.

quant-ph↗