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论文类型：期刊论文

发表时间：2017-05-01

发表刊物：QUANTUM INFORMATION PROCESSING

收录刊物：SCIE、EI

卷号：16

期号：5

ISSN号：1570-0755

关键字：Quantum uncertainty relation; Standard deviation; Quantum superposition principle

摘要：The quantum superposition principle is used to establish improved upper and lower bounds for the Maccone-Pati uncertainty inequality, which is based on a "weighted-like" sum of the variances of observables. Our bounds include free parameters that not only guarantee nontrivial bounds but also effectively control the bounds' tightness. Significantly, these free parameters depend on neither the state nor the observables. A feature of our method is that any nontrivial bound can always be improved. In addition, we generalize both bounds to uncertainty relations with multiple (three or more) observables, maintaining the uncertainty relations' tightness. Examples are given to illustrate our improved bounds.