Probabilistic quantum multimeters

The programmable quantum devices are described which determines von Neumann measurements on single qubit. The quantum state of program register selects the desired measurement. The phase-covarinat multimeters for large class of programs and universal multimeters for special choice of program are analyzed. The error-prone devices are used which never make mistake but provide an inconclusive result from time to time. The multimeters are optimized with respect to minimum probability of an inconclusive result for given type of program.SCOPUS: ar.j