Tomography of Quantum Operations. D 'ariano, G M & Presti, P L. 2000. arXiv: quant-ph/0012071v1
abstract   bibtex   
Quantum operations describe any state change allowed in quantum mechanics, including the evolution of an open sys-tem or the state change due to a measurement. In this letter we present a general method based on quantum tomography for measuring experimentally the matrix elements of an arbi-trary quantum operation. As input the method needs only a single entangled state. The feasibility of the technique for the electromagnetic field is shown, and the experimental setup is illustrated based on homodyne tomography of a twin-beam. The typical state change in quantum mechanics is the unitary evolution, where the final state is related to the initial one via the transformation ρ → E(ρ) ≡ U ρU , with U unitary operator on the Hilbert space H of the system. Unitary transformations describe only the evolu-tions of closed systems, and non-unitary transformations occur when the quantum system is coupled to an en-vironment or when a measurement is performed on the system. What is the most general possible state change in quantum mechanics? The answer is provided by the formalism of " quantum operations " by Kraus [1]. Here input and output states are connected via the map ρ → E(ρ) Tr E(ρ) . (1)
@article{d_ariano_tomography_2000,
	title = {Tomography of {Quantum} {Operations}},
	abstract = {Quantum operations describe any state change allowed in quantum mechanics, including the evolution of an open sys-tem or the state change due to a measurement. In this letter we present a general method based on quantum tomography for measuring experimentally the matrix elements of an arbi-trary quantum operation. As input the method needs only a single entangled state. The feasibility of the technique for the electromagnetic field is shown, and the experimental setup is illustrated based on homodyne tomography of a twin-beam. The typical state change in quantum mechanics is the unitary evolution, where the final state is related to the initial one via the transformation ρ → E(ρ) ≡ U ρU , with U unitary operator on the Hilbert space H of the system. Unitary transformations describe only the evolu-tions of closed systems, and non-unitary transformations occur when the quantum system is coupled to an en-vironment or when a measurement is performed on the system. What is the most general possible state change in quantum mechanics? The answer is provided by the formalism of " quantum operations " by Kraus [1]. Here input and output states are connected via the map ρ → E(ρ) Tr E(ρ) . (1)},
	urldate = {2017-09-11},
	author = {D 'ariano, G M and Presti, P Lo},
	year = {2000},
	note = {arXiv: quant-ph/0012071v1},
	keywords = {\#nosource},
}

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