Relating the Resource Theories of Entanglement and Quantum Coherence

Quantum coherence and quantum entanglement represent two fundamental features of nonclassical systems that can each be characterized within an operational resource theory. In this Letter, we unify the resource theories of entanglement and coherence by studying their combined behavior in the operational setting of local incoherent operations and classical communication (LIOCC). Specifically, we analyze the coherence and entanglement trade-offs in the tasks of state formation and resource distillation. For pure states we identify the minimum coherence-entanglement resources needed to generate a given state, and we introduce a new LIOCC monotone that completely characterizes a state’s optimal rate of bipartite coherence distillation. This result allows us to precisely quantify the difference in operational powers between global incoherent operations, LIOCC, and local incoherent operations without classical communication. Finally, a bipartite mixed state is shown to have distillable entanglement if and only if entanglement can be distilled by LIOCC, and we strengthen the well-known Horodecki criterion for distillability.

Figure 1

(a) A LIOCC formation protocol asymptotically generates an arbitrary state ${\rho }^{AB}$ from an initial supply of local coherent bits (${\mathrm{\Phi }}_A/{\mathrm{\Phi }}_B$) and shared entanglement bits (${\mathrm{\Phi }}_{A^{\prime }{B}^{\prime }}$). (b) A LIOCC dilution protocol performs the reverse transformation.