# Computing quantum discord is NP-complete

@article{Huang2014ComputingQD,
title={Computing quantum discord is NP-complete},
author={Yichen Huang},
journal={New Journal of Physics},
year={2014},
volume={16}
}
• Yichen Huang
• Published 25 May 2013
• Computer Science, Physics
• New Journal of Physics
We study the computational complexity of quantum discord (a measure of quantum correlation beyond entanglement), and prove that computing quantum discord is NP-complete. Therefore, quantum discord is computationally intractable: the running time of any algorithm for computing quantum discord is believed to grow exponentially with the dimension of the Hilbert space so that computing quantum discord in a quantum system of moderate size is not possible in practice. As by-products, some…
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