Optimal conversion of Kochen-Specker sets into bipartite perfect quantum strategies

TL;DR

This paper develops an algorithm to convert Kochen-Specker sets into bipartite perfect quantum strategies with minimal inputs, advancing the understanding and construction of efficient quantum nonlocal strategies.

Contribution

It proves that minimal-input BPQS derived from generalized KS sets can be obtained from pure state KS sets and introduces an algorithm to find minimal-input BPQS from KS sets.

Findings

The algorithm recovers the best known BPQS in various dimensions.

It finds BPQS with fewer inputs than previously known in several cases.

The method applies to KS sets in dimensions 3 through 8.

Abstract

Bipartite perfect quantum strategies (BPQSs) allow two players isolated from each other to win every trial of a nonlocal game. BPQSs have crucial roles in recent developments in quantum information and quantum computation. However, only few BPQSs with a small number of inputs are known and only one of them has been experimentally tested. It has recently been shown that every BPQS has an associated Kochen-Specker (KS) set. Here, we first prove that any BPQS of minimum input cardinality that can be obtained from a generalized KS set can also be obtained from a KS set of pure states. Then, we address the problem of finding BPQSs of small input cardinality starting from KS sets. We introduce an algorithm that identifies the BPQS with the minimum number of settings for any given KS set. We apply it to many well-known KS sets of small cardinality in dimensions 3, 4, 5, 6, 7, and 8. In each dimension, the algorithm either recovers the best BPQS known or find one with fewer inputs.