|Title||Recycling of qubits|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Rapcan, P, Calsamiglia, J, Muñoz-Tapia, R, Bagan, E, Buzek, V|
We consider a finite number, N, of qubits that encode a pure single qubit state SU(2) covariantly. Given the N-qubit state has already been measured optimally to estimate the single-qubit state, we analyse the maximum information obtainable by a second, and subsequent observers ignorant of important details of the previous measurements. We quantify the information acquired by each observer as a function of N and of the number of independent observers that in succession have independently measured the same ensemble of qubits before him.