5 papers
Quantum homogenization
M. Ziman, P. Stelmachovic, V. Buzek +3
We design a universal quantum homogenizer, which is a quantum machine that takes as an input a system qubit initially in the state and a set of N reservoir qubits initially pre…
Optimal Manipulations with Qubits: Universal NOT Gate
V. Buzek, M. Hillery, R. Werner
It is not a problem to complement a classical bit, i.e. to change the value of a bit, a 0 to a 1 and vice versa. This is accomplished by a NOT gate. Complementing a qubit in an unk…
Controlling the flow of information in quantum cloners: Asymmetric cloning
V. Buzek, M. Hillery, R. Bednik
We show that the distribution of information at the output of the quantum cloner can be efficiently controlled via preparation of the quantum cloner. We present a universal cloning…
Universal optimal cloning of qubits and quantum registers
Vladimir Buzek, Mark Hillery
We review our recent work on the universal (i.e. input state independent) optimal quantum copying (cloning) of qubits. We present unitary transformations which describe the optimal…
Direct and indirect strategies for phase measurement
Marcia T. Fontenelle, Samuel L. Braunstein, Wolfgang P. Schleich +1
Recently, Torgerson and Mandel [Phys. Rev. Lett. 76, 3939 (1996)] have reported a disagreement between two schemes for measuring the phase difference of a pair of optical fields. W…