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arXiv · 1410.6008

Deterministic superreplication of one-parameter unitary transformations

W. Dür·P. Sekatski·M. Skotiniotis
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Abstract

We show that one can deterministically generate out of $N$ copies of an unknown unitary operation up to $N^2$ almost perfect copies. The result holds for all operations generated by a Hamiltonian with an unknown interaction strength. This generalizes a similar result in the context of phase covariant cloning where, however, super-replication comes at the price of an exponentially reduced probability of success. We also show that multiple copies of unitary operations can be emulated by operations acting on a much smaller space, e.g., a magnetic field acting on a single $n$-level system allows one to emulate the action of the field on $n^2$ qubits.

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W. Dür, P. Sekatski, M. Skotiniotis. 2015-05-06. Deterministic superreplication of one-parameter unitary transformations. https://doi.org/10.1103/physrevlett.114.120503

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