  Entanglement and coherence are two essential quantum resources for quantum
information processing. A natural question arises of whether there are direct
link between them. And by thinking about this question, we propose a new
measure for quantum state that contains concurrence and is called intrinsic
concurrence. Interestingly, we discover that the intrinsic concurrence is
always complementary to coherence. Note that the intrinsic concurrence is
related to the concurrence of a special pure state ensemble. In order to
explain the trade-off relation more intuitively, we apply it in some composite
systems composed by a single-qubit state coupling four typical noise channels
with the aim at illustrating their mutual transformation relationship between
their coherence and intrinsic concurrence. This unified trade-off relation will
provide more flexibility in exploiting one resource to perform quantum tasks
and also provide credible theoretical basis for the interconversion of the two
important quantum resources.
