Interpolatability distinguishes LOCC from separable von Neumann measurements

TL;DR

This paper identifies that the ability to interpolate measurements distinguishes LOCC from separable operations in quantum mechanics, providing a new operational principle to understand their differences.

Contribution

It introduces the concept of interpolatability of von Neumann measurements as a criterion to differentiate LOCC from separable operations.

Findings

Interpolatability characterizes LOCC but not separable operations.

Separable operations are strictly more powerful than LOCC.

Interpolatability offers a new operational perspective on quantum measurement classes.

Abstract

Local operations with classical communication (LOCC) and separable operations are two classes of quantum operations that play key roles in the study of quantum entanglement. Separable operations are strictly more powerful than LOCC, but no simple explanation of this phenomenon is known. We show that, in the case of von Neumann measurements, the ability to interpolate measurements is an operational principle that sets apart LOCC and separable operations.