Strong NP-hardness of the quantum separability problem

  • Authors:
  • Sevag Gharibian

  • Affiliations:
  • School of Computer Science and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada

  • Venue:
  • Quantum Information & Computation
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

Given the density matrix ρ of a bipartite quantum state, the quantum separability prob-lem asks whether ρ is entangled or separable. In 2003, Gurvits showed that this problemis NP-hard if ρ is located within an inverse exponential (with respect to dimension) dis-tance from the border of the set of separable quantum states. In this paper, we extendthis NP-hardness to an inverse polynomial distance from the separable set. The resultfollows from a simple combination of works by Gurvits, Ioannou, and Liu. We applyour result to show (1) an immediate lower bound on the maximum distance between abound entangled state and the separable set (assuming P ≠ NP), and (2) NP-hardnessfor the problem of determining whether a completely positive trace-preserving linearmap is entanglement-breaking.