ScholarBank@NUShttps://scholarbank.nus.edu.sgThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 28 Nov 2021 21:45:06 GMT2021-11-28T21:45:06Z5021- One-dimensional quantum walk with a moving boundaryhttps://scholarbank.nus.edu.sg/handle/10635/115214Title: One-dimensional quantum walk with a moving boundary
Authors: Kwek, L.C.; Setiawan
Abstract: Quantum walks are interesting models with potential applications to quantum algorithms and physical processes such as photosynthesis. In this paper, we study two models of one-dimensional quantum walks, namely, quantum walks with a moving absorbing wall and quantum walks with one stationary and one moving absorbing wall. For the former, we calculate numerically the survival probability, the rate of change of average position, and the rate of change of standard deviation of the particle's position in the long time limit for different wall velocities. Moreover, we also study the asymptotic behavior and the dependence of the survival probability on the initial particle's state. While for the latter, we compute the absorption probability of the right stationary wall for different velocities and initial positions of the left wall boundary. The results for these two models are compared with those obtained for the classical model. The difference between the results obtained for the quantum and classical models can be attributed to the difference in the probability distributions. © 2011 American Physical Society.
Thu, 15 Sep 2011 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/1152142011-09-15T00:00:00Z
- Effects of reduced measurement independence on bell-based randomness expansionhttps://scholarbank.nus.edu.sg/handle/10635/112425Title: Effects of reduced measurement independence on bell-based randomness expansion
Authors: Koh, D.E.; Hall, M.J.W.; Setiawan; Pope, J.E.; Marletto, C.; Kay, A.; Scarani, V.; Ekert, A.
Abstract: With the advent of quantum information, the violation of a Bell inequality is used to witness the absence of an eavesdropper in cryptographic scenarios such as key distribution and randomness expansion. One of the key assumptions of Bell's theorem is the existence of experimental "free will," meaning that measurement settings can be chosen at random and independently by each party. The relaxation of this assumption potentially shifts the balance of power towards an eavesdropper. We consider a no-signaling model with reduced "free will" and bound the adversary's capabilities in the task of randomness expansion. © 2012 American Physical Society.
Thu, 18 Oct 2012 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/1124252012-10-18T00:00:00Z