2001/06/06 by J. Dziarmaga, Jacek Dziarmaga, D. A. R. Dalvit +6
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph) #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0106036
4 pages, 2 .eps figures
arxiv created 2001/06/06 · openalex publication_date 2001/06/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Many observers can simultaneously measure different parts of an environment of a quantum system in order to find out its state. To study this problem we generalize the formalism of conditional master equations to the multiple observer case. To settle some issues of principle which arise in this context (as the state of the system and of the environment are ultimately correlated), we consider an example of a system qubit interacting through controlled nots (CNOTs) with environmental qubits. The state of the system is the easiest to find out for observers who measure in a basis of the environment which is most correlated with the pointer basis of the system. In this case the observers agree the most. Furthermore, the more predictable the pointers are, the easier it is to find the state of the system, and the better is the agreement between different observers.