English

Quantum interactive proofs and the complexity of separability testing

Quantum Physics 2015-03-27 v2 Computational Complexity

Abstract

We identify a formal connection between physical problems related to the detection of separable (unentangled) quantum states and complexity classes in theoretical computer science. In particular, we show that to nearly every quantum interactive proof complexity class (including BQP, QMA, QMA(2), and QSZK), there corresponds a natural separability testing problem that is complete for that class. Of particular interest is the fact that the problem of determining whether an isometry can be made to produce a separable state is either QMA-complete or QMA(2)-complete, depending upon whether the distance between quantum states is measured by the one-way LOCC norm or the trace norm. We obtain strong hardness results by proving that for each n-qubit maximally entangled state there exists a fixed one-way LOCC measurement that distinguishes it from any separable state with error probability that decays exponentially in n.

Keywords

Cite

@article{arxiv.1308.5788,
  title  = {Quantum interactive proofs and the complexity of separability testing},
  author = {Gus Gutoski and Patrick Hayden and Kevin Milner and Mark M. Wilde},
  journal= {arXiv preprint arXiv:1308.5788},
  year   = {2015}
}

Comments

v2: 43 pages, 5 figures, completely rewritten and in Theory of Computing (ToC) journal format

R2 v1 2026-06-22T01:15:32.795Z