Início
Agenda 

 07 de maio de 2014
16h30 Sala F210 

Fernando de Melo

CBPF
The
Power of Noisy Fermionic Quantum Computation
We
consider the realization of universal quantum computation
through braiding of Majorana fermions supplemented by
unprotected preparation of noisy ancillae. It has been shown by
Bravyi [Phys. Rev. A 73, 042313 (2006)] that under the
assumption of perfect braiding operations, universal quantum
computation is possible if the noise rate on a particular
4fermion ancilla is below 40%. We show that above a noise rate
of 89% on this ancilla the quantum computation can be
efficiently simulated classically: we explicitly show that the
noisy ancilla is a convex mixture of Gaussian fermionic states
in this region. On the other hand, for noise rates below 53% we
prove that the state is not a mixture of Gaussian states. These
results are obtained by generalizing concepts in entanglement
theory to the setting of fermionic Gaussian states and their
convex mixtures. In particular we develop a complete set of
criteria, namely the existence of a Gaussiansymmetric
extension, which determine whether a state is a convex mixture
of Gaussian states. 




