Montreal, Quebec, Canada
May 21, 2002 to May 24, 2002
Andris Ambainis , Institute for Advanced Study
Adam Smith , Massachusetts Institute of Technology
Ke Yang , Carnegie Mellon University
We study the problem of extracting EPR pairs from a general source of entanglement. Suppose Alice and Bob share a bipartite state R which is "reasonably close" to perfect EPR pairs. The only information Alice and Bob possess is a lower bound on the fidelity of R and a maximally entangled state. They wish to "purify" R using local operations and classical communication and output a state that is arbitrarily close to EPR pairs. We prove that on average, Alice and Bob cannot increase the fidelity of the input state significantly. On the other hand, there exist protocols that may fail with a small probability, and otherwise will output states arbitrarily close to EPR pairs with very high probability. These protocols come from the "purity-testing protocols" of Barnum et al.
Entanglement Purification, General Error Models, Quantum Cryptography, Purity-Testing
Andris Ambainis, Adam Smith, Ke Yang, "Extracting Quantum Entanglement", CCC, 2002, Proceedings of 17th IEEE Annual Conference on Computational Complexity, Proceedings of 17th IEEE Annual Conference on Computational Complexity 2002, pp. 0103, doi:10.1109/CCC.2002.1004345