Operational effects of the UNOT gate on classical and quantum correlations

Journal article

The NOT gate that flips a classical bit is ubiquitous in classical information processing. However its quantum analogue, the universal NOT (UNOT) gate that flips a quantum spin in any alignment into its antipodal counterpart is strictly forbidden. Here we explore the connection between this discrepancy and how UNOT gates affect classical and quantum correlations. We show that while a UNOT gate always preserves classical correlations between two spins, it can non-locally increase or decrease their shared discord in ways that allow violation of the data processing inequality. We experimentally illustrate this using a multi-level trapped 171Yb+ ion that allows simulation of anti-unitary operations.

Authors: Zhang, K; Ma, J; Zhang, X; Thompson, J; Vedral, V

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Science Bulletin
• Volume: 63
• Issue: 12
• Pages: 765-770
• Publication date: 2018-05-18
• Acceptance date: 2018-05-08
• DOI: 10.1016/j.scib.2018.05.011
• EISSN: 2095-9281
• ISSN: 2095-9273
• Language: English
• Keywords: ion trap; data processing inequality; quantum discord; quantum correlations; embedding quantum simulation; quantum information; universal NOT gate; FFR