Vertex-minor universal graphs for generating entangled quantum subsystems

Abstract

We study the notion of $k$-stabilizer universal quantum state, that is, an $n$-qubit quantum state, such that it is possible to induce any stabilizer state on any $k$ qubits, by using only local operations and classical communications. These states generalize the notion of $k$-pairable states introduced by Bravyi et al., and can be studied from a combinatorial perspective using graph states and $k$-vertex-minor universal graphs. First, we demonstrate the existence of $k$-stabilizer universal graph states that are optimal in size with $n=\Theta (k^2)$ qubits. We also provide parameters for which a random graph state on $\Theta (k^2)$ qubits is $k$-stabilizer universal with high probability. Our second contribution consists of two explicit constructions of $k$-stabilizer universal graph states on $n=O(k^4)$ qubits. Both rely upon the incidence graph of the projective plane over a finite field ${\mathbb{F}}_q$. This provides a major improvement over the previously known explicit construction of $k$-pairable graph states with $n=O(2^{3k})$, bringing forth a new and potentially powerful family of multipartite quantum resources.