Classicalcommunication cost in distributed quantuminformation processing: A generalization of quantumcommunication complexity
Abstract
We study the amount of classical communication needed for distributed quantuminformation processing. In particular, we introduce the concept of ``remote preparation'' of a quantum state. Given an ensemble of states, Alice's task is to help Bob in a distant laboratory to prepare a state of her choice. We find several examples of an ensemble with an entropy S where the remote preparation can be done with a communication cost lower than the amount (2S) required by standard teleportation. We conjecture that, for an arbitrary Ndimensional pure state, its remote preparation requires 2 log_{2}N bits of classical communication, as in standard teleportation.
 Publication:

Physical Review A
 Pub Date:
 July 2000
 DOI:
 10.1103/PhysRevA.62.012313
 arXiv:
 arXiv:quantph/9912009
 Bibcode:
 2000PhRvA..62a2313L
 Keywords:

 03.67.Hk;
 Quantum communication;
 Quantum Physics
 EPrint:
 Revised Version. Accepted on March 31 for publication in Physical Review A. Proof of Theorem 3 clarified. A Proviso added to the statement of Conjecture 4. Related results on randomization and private quantum channel noted