Tuning spatial entanglement in interacting two-electron quantum dots

作     者：Dung N. Pham Sathwik Bharadwaj L. R. Ram-Mohan 

作者机构：Department of Physics Worcester Polytechnic Institute Worcester Massachusetts 01609 USA Center for Computational NanoScience Worcester Polytechnic Institute Worcester Massachusetts 01609 USA Department of Electrical and Computer Engineering Worcester Polytechnic Institute Worcester Massachusetts 01609 USA Department of Mechanical Engineering Worcester Polytechnic Institute Worcester Massachusetts 01609 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2020年第101卷第4期

页      面：045306-045306页

核心收录：

基　　金：Academic and Research Computing Group Worcester Polytechnic Institute, WPI 

主　　题：Entanglement entropy Quantum dots Quantum wells Semiconductors Variational wave functional methods 

摘      要：Confined geometries such as semiconductor quantum dots are promising candidates for fabricating quantum computing devices. When several quantum dots are in proximity, spatial correlation between electrons in the system becomes significant. In this paper, we employ a variational formulation for calculating accurate two-electron wavefunctions in configuration space, irrespective of potential geometry. To evaluate the Coulomb integrals with high accuracy, a numerical integration method using multiple Gauss quadratures is used. With this approach, we investigate the confinement of two electrons in double quantum dots, and evaluate the spatial entanglement. We investigate the dependence of spatial entanglement on various geometrical parameters. We derive the two-particle wavefunctions in the asymptotic limit of the separation distance between quantum dots and obtain universal saturation values for the spatial entanglement. Resonances in the entanglement values due to avoided level crossings of states are observed. We also demonstrate the formation of electron clusters and show that the entanglement value is a good indicator for the formation of such clusters. Further, we show that a precise tuning of the entanglement values is feasible with applied external electric fields.