Full reconstruction of a 14-qubit state within four hours

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Author(s)
Hou, Zhibo
Zhong, Han-Sen
Tian, Ye
Dong, Daoyi
Qi, Bo
Li, Li
Wang, Yuanlong
Nori, Franco
Xiang, Guo-Yong
Li, Chuan-Feng
Guo, Guang-Can
Year published
2016
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Full quantum state tomography (FQST) plays a unique role in the estimation of the state of a quantum
system without a priori knowledge or assumptions. Unfortunately, since FQST requires
informationally (over)complete measurements, both the number of measurement bases and the
computational complexity of data processing suffer an exponential growth with the size of the
quantum system. A 14-qubit entangled state has already been experimentally prepared in an ion trap,
and the data processing capability for FQST of a 14-qubit state seems to be far away from practical
applications. In this paper, the computational capability of ...
View more >Full quantum state tomography (FQST) plays a unique role in the estimation of the state of a quantum system without a priori knowledge or assumptions. Unfortunately, since FQST requires informationally (over)complete measurements, both the number of measurement bases and the computational complexity of data processing suffer an exponential growth with the size of the quantum system. A 14-qubit entangled state has already been experimentally prepared in an ion trap, and the data processing capability for FQST of a 14-qubit state seems to be far away from practical applications. In this paper, the computational capability of FQST is pushed forward to reconstruct a 14-qubit state with a run time of only 3.35 hours using the linear regression estimation (LRE) algorithm, even when informationally overcomplete Pauli measurements are employed. The computational complexity of the LRE algorithm is first reduced from∼1019 to∼1015 for a 14-qubit state, by dropping all the zero elements, and its computational efficiency is further sped up by fully exploiting the parallelism of the LRE algorithm with parallel Graphic Processing Unit (GPU) programming. Our result demonstrates the effectiveness of using parallel computation to speed up the postprocessing for FQST, and can play an important role in quantum information technologies with large quantum systems.
View less >
View more >Full quantum state tomography (FQST) plays a unique role in the estimation of the state of a quantum system without a priori knowledge or assumptions. Unfortunately, since FQST requires informationally (over)complete measurements, both the number of measurement bases and the computational complexity of data processing suffer an exponential growth with the size of the quantum system. A 14-qubit entangled state has already been experimentally prepared in an ion trap, and the data processing capability for FQST of a 14-qubit state seems to be far away from practical applications. In this paper, the computational capability of FQST is pushed forward to reconstruct a 14-qubit state with a run time of only 3.35 hours using the linear regression estimation (LRE) algorithm, even when informationally overcomplete Pauli measurements are employed. The computational complexity of the LRE algorithm is first reduced from∼1019 to∼1015 for a 14-qubit state, by dropping all the zero elements, and its computational efficiency is further sped up by fully exploiting the parallelism of the LRE algorithm with parallel Graphic Processing Unit (GPU) programming. Our result demonstrates the effectiveness of using parallel computation to speed up the postprocessing for FQST, and can play an important role in quantum information technologies with large quantum systems.
View less >
Journal Title
New Journal of Physics
Volume
18
Copyright Statement
©2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 Unported (CC BY 3.0) License (https://creativecommons.org/licenses/by/3.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Subject
Physical Sciences not elsewhere classified
Physical Sciences