TY - JOUR
T1 - Universal control induced by noise
AU - Arenz, Christian
AU - Burgarth, Daniel
AU - Facchi, Paolo
AU - Giovannetti, Vittorio
AU - Nakazato, Hiromichi
AU - Pascazio, Saverio
AU - Yuasa, Kazuya
N1 - Funding Information:
D.B. acknowledges support from the EPSRC Grant No. EP/M01634X/1. K.Y. was supported by the Grant-in-Aid for Scientific Research (C) (No. 26400406) from the Japan Society for the Promotion of Science and by the Waseda University Grants for Special Research Projects (No. 2015K-202 and No. 2016K-215). This work was also supported by the Top Global University Project from the Ministry of Education, Culture, Sports, Science and Technology, Japan, by the Italian National Group of Mathematical Physics, by INFN through the project QUANTUM, and by PRIN Grant No. 2010LLKJBX.
Publisher Copyright:
© 2016 American Physical Society.
PY - 2016/6/6
Y1 - 2016/6/6
N2 - On the basis of the quantum Zeno effect, it has been recently shown [D. K. Burgarth, Nat. Commun. 5, 5173 (2014)2041-172310.1038/ncomms6173] that a strong-amplitude-damping process applied locally on a part of a quantum system can have a beneficial effect on the dynamics of the remaining part of the system. Quantum operations that cannot be implemented without the dissipation become achievable by the action of the strong dissipative process. Here we generalize this idea by identifying decoherence-free subspaces (DFSs) as the subspaces in which the dynamics becomes more complex. Applying methods from quantum control theory, we characterize the set of reachable operations within the DFSs. We provide three examples that become fully controllable within the DFSs while the control over the original Hilbert space in the absence of dissipation is trivial. In particular, we show that the (classical) Ising Hamiltonian is turned into a Heisenberg Hamiltonian by strong collective decoherence, which provides universal quantum computation within the DFSs. Moreover, we perform numerical gate optimization to study how the process fidelity scales with the noise strength. As a by-product, a subsystem fidelity that can be applied in other optimization problems for open quantum systems is developed.
AB - On the basis of the quantum Zeno effect, it has been recently shown [D. K. Burgarth, Nat. Commun. 5, 5173 (2014)2041-172310.1038/ncomms6173] that a strong-amplitude-damping process applied locally on a part of a quantum system can have a beneficial effect on the dynamics of the remaining part of the system. Quantum operations that cannot be implemented without the dissipation become achievable by the action of the strong dissipative process. Here we generalize this idea by identifying decoherence-free subspaces (DFSs) as the subspaces in which the dynamics becomes more complex. Applying methods from quantum control theory, we characterize the set of reachable operations within the DFSs. We provide three examples that become fully controllable within the DFSs while the control over the original Hilbert space in the absence of dissipation is trivial. In particular, we show that the (classical) Ising Hamiltonian is turned into a Heisenberg Hamiltonian by strong collective decoherence, which provides universal quantum computation within the DFSs. Moreover, we perform numerical gate optimization to study how the process fidelity scales with the noise strength. As a by-product, a subsystem fidelity that can be applied in other optimization problems for open quantum systems is developed.
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U2 - 10.1103/PhysRevA.93.062308
DO - 10.1103/PhysRevA.93.062308
M3 - Article
AN - SCOPUS:84973655811
VL - 93
JO - Physical Review A
JF - Physical Review A
SN - 2469-9926
IS - 6
M1 - 062308
ER -