Additivity of decoherence measures for multiqubit quantum systems
- 作者：Fedichkin ; Leonid ; Fedorov ; Arkady ; Privman ; Vladimir
- 关键词：03.67.Lx ; 03.65.Yz ; Decoherence ; Fault tolerance ; Spin-boson ; Qubit ; Quantum computer
- 刊名：Physics Letters A
- 出版年：2004
- 期刊代码：57_03759601
- 类别：ph
- 出版时间：July 26, 2004
- 卷：328
- 期：2-3
- 页码：87-93
- 文件大小：216 K
摘要
We introduce new measures of decoherence appropriate for evaluation of quantum computing designs. Environment-induced deviation of a quantum system's evolution from controlled dynamics is quantified by a single numerical measure. This measure is defined as a maximal norm of the density matrix deviation. We establish the property of additivity: in the regime of the onset of decoherence, the sum of the individual qubit error measures provides an estimate of the error for a several-qubit system. This property is illustrated by exact calculations for a spin-boson model.