Quantum Information Processing, Vol. 5, No. 5, October 2006 (© 2006)
Programmable Quantum Processors
Received May 12, 2005; accepted December 21, 2005; Published online July 12, 2006
A quantum processor is a device with a data register and a program register.
The input to the program register determines the operation, which is a completely
positive linear map, that will be performed on the state in the data register. We
develop a mathematical description for these devices. We generalize the concept
of quantum programmable processors and we propose programmable measurement
KEY WORDS: Quantum program registers; programmable quantum processor;
positive operator-valued measurements.
PACS: 03.67.-a; 03.67.Lx; 03.65.Ta.
The coherent control of individual quantum systems is one of the most
exciting achievements in physics in the last decade.
The possibility of
controlling quantum dynamics has far reaching consequences for quantum
technologies, in particular, for quantum computing.
One of the best-
known applications of coherent control in quantum physics is the state
preparation of an individual quantum system. For example, a particular
state of the vibrational motion of a trapped ion can be prepared by using
We dedicate this paper to Anton Zeilinger on the occasion of his 60th birthday.
Research Center for Quantum Information, Institute of Physics, Slovak Academy of Sci-
a cesta 9, 845 11 Bratislava, Slovakia.
ur Quantenphysik, Universit
at Ulm, 89069 Ulm, Germany.
udolie 116, 841 04 Bratislava, Slovakia.
Department of Physics, Hunter College of CUNY, 695 Park Avenue, New York, NY 10021,
Faculty of Informatics, Masaryk University, Botanick
a 68a, 602 00 Brno, Czech Republic.
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