Quasiprobability Representations of Quantum Mechanics with Minimal Negativity

Huangjun Zhu
Phys. Rev. Lett. 117, 120404 – Published 14 September 2016
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Abstract

Quasiprobability representations, such as the Wigner function, play an important role in various research areas. The inevitable appearance of negativity in such representations is often regarded as a signature of nonclassicality, which has profound implications for quantum computation. However, little is known about the minimal negativity that is necessary in general quasiprobability representations. Here we focus on a natural class of quasiprobability representations that is distinguished by simplicity and economy. We introduce three measures of negativity concerning the representations of quantum states, unitary transformations, and quantum channels, respectively. Quite surprisingly, all three measures lead to the same representations with minimal negativity, which are in one-to-one correspondence with the elusive symmetric informationally complete measurements. In addition, most representations with minimal negativity are automatically covariant with respect to the Heisenberg-Weyl groups. Furthermore, our study reveals an interesting tradeoff between negativity and symmetry in quasiprobability representations.

  • Received 9 May 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.120404

© 2016 American Physical Society

Physics Subject Headings (PhySH)

General PhysicsQuantum Information, Science & Technology

Authors & Affiliations

Huangjun Zhu*

  • Institute for Theoretical Physics, University of Cologne, Cologne 50937, Germany

  • *hzhu1@uni-koeln.de, zhuhuangjun@gmail.com

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Issue

Vol. 117, Iss. 12 — 16 September 2016

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