arXiv subjects

Yee-Mou Kao

Publications and source records attributed to Yee-Mou Kao.

5 recordsLinked to original sources

arXiv2021

Analytical Studies of the Magnetic Domain Wall Structure in the presence of Non-uniform Exchange Bias

The pinning phenomena of the domain wall in the presence of exchange bias is studied analytically. The analytic solution of the domain wall spin configuration is presented. Unlike the traditional solution which is symmetric, our new solution could exhibit the asymmetry of the domain wall spin profile. Using the solution, the domain wall position, its width, its stability, and the depinning field are discussed analytically.

cond-mat.mes-hall↗

arXiv2017

Ehrenfest urn model with interaction

We studied the Ehrenfest urn model in which particles in the same urn interact with each other. Depending on the nature of interaction, the system undergoes a first-order or second-order phase transition. The relaxation time to the equilibrium state, the Poincare cycles of the equilibrium state and the most far-from-equilibrium state, and the duration time of the states during first-order phase transition are calculated. It was shown that the scaling behavior of the Poincare cycles could be served as an indication to the nature of phase transition, and the ratio of duration time of the states could be a strong evidence of the metastability during first-order phase transition.

cond-mat.stat-mech↗

arXiv2003

Drifting diffusion on a circle as continuous limit of a multiurn Ehrenfest model

We study the continuous limit of a multibox Erhenfest urn model proposed before by the authors. The evolution of the resulting continuous system is governed by a differential equation, which describes a diffusion process on a circle with a nonzero drifting velocity. The short time behavior of this diffusion process is obtained directly by solving the equation, while the long time behavior is derived using the Poisson summation formula. They reproduce the previous results in the large $M$ (number of boxes) limit. We also discuss the connection between this diffusion equation and the Schr$\ddot{\rm o}$dinger equation of some quantum mechanical problems.

physics.atom-ph↗

arXiv2002

Poincaré cycle of a multibox Ehrenfest urn model with directed transport

We propose a generalized Ehrenfest urn model of many urns arranged periodically along a circle. The evolution of the urn model system is governed by a directed stochastic operation. Method for solving an $N$-ball, $M$-urn problem of this model is presented. The evolution of the system is studied in detail. We find that the average number of balls in a certain urn oscillates several times before it reaches a stationary value. This behavior seems to be a peculiar feature of this directed urn model. We also calculate the Poincaré cycle, i.e., the average time interval required for the system to return to its initial configuration. The result can be easily understood by counting the total number of all possible microstates of the system.

cond-mat.stat-mech↗

arXiv2002

Reflection of matter waves by a moving wall

Reflection of a normal incident matter wave by a perfectly reflecting wall moving with a constant velocity is investigated. A surprising phenomenon is found-that if the the wall moves faster than the phase velocity of the incident wave, both the reflected and incident waves propagate in the same direction. This counter-intuitive result is an example which shows that common sense is not always credible when one deals with quantum problems.

quant-ph↗