Memory cost of quantum protocols

Bibliographic Details
Title: Memory cost of quantum protocols
Authors: Bisio, Alessandro, D'Ariano, Giacomo Mauro, Perinotti, Paolo, Sedlak, Michal
Source: Phys. Rev. A 85, 032333 (2012)
Publication Year: 2011
Collection: Quantum Physics
Subject Terms: Quantum Physics
More Details: In this paper we consider the problem of minimizing the ancillary systems required to realize an arbitrary strategy of a quantum protocol, with the assistance of classical memory. For this purpose we introduce the notion of memory cost of a strategy, which measures the resources required in terms of ancillary dimension. We provide a condition for the cost to be equal to a given value, and we use this result to evaluate the cost in some special cases. As an example we show that any covariant protocol for the cloning of a unitary transformation requires at most one ancillary qubit. We also prove that the memory cost has to be determined globally, and cannot be calculated by optimizing the resources independently at each step of the strategy.
Comment: 9 pages
Document Type: Working Paper
DOI: 10.1103/PhysRevA.85.032333
Access URL: http://arxiv.org/abs/1112.3853
Accession Number: edsarx.1112.3853
Database: arXiv
More Details
DOI:10.1103/PhysRevA.85.032333