Can experimentally-accessible measures of entanglement distinguish quantum spin liquids from disorder-driven "random singlet" phases ?

At the theoretical level, quantum spin liquids are distinguished from other phases of matter by their entanglement properties. However, since the usual measure of entanglement, entanglement entropy, cannot accessed in experiment, indentifying quantum spin liquids in candidate materials remains an acute problem. Here we show other, experimentally-accessible, measures of entanglement can be used to distinguish a quantum spin liquid from a competing disorder-driven “random singlet” phase, in a model of a disordered antiferromagnet on a triangular lattice. The application of these results to the triangular-lattice systems YbZnGaO${}_4$, YbZn${}_2$GaO${}_5$ and KYbSe${}_2$ is discussed.