Arun K. Pati, Samuel L. Braunstein
Published 2000-07-31Version 1
Unmeasureability of a quantum state has important consequences in practical implementation of quantum computers. Like copying, deleting of an unknown state from among several copies is prohibited. This is called no-deletion prinicple. Here, we present a no deleting principle for qudits. We obtain a bound on $N$-to-$M$ deleting and show that the quality of deletion drops exponentially with the number of copies to be deleted. In addition, we investigate conditional, state-dependent and approximate quantum deleting of unknown states. We prove that unitarity does not allow us to delete copies from an alphabet of two non-orthogonal states exactly. Further, we show that no-deleting principle is consistent with no-signalling.
Comments: Latex 4 pages, no-figures (Based on this a talk was presented in Benasque Science Center held from July 2-21, 2000)
Explicit form of the Bayesian posterior estimate of a quantum state under the uninformative prior
Verification of quantum-domain process using two non-orthogonal states
Feedback control for communication with non-orthogonal states
