  Counterfactual quantum communication is unique in its own way that allows
remote parties to transfer information without sending any message carrier in
the channel. Although no message carrier travels in the channel at the time of
successful information transmission, it is impossible to transmit information
faster than the speed of light, thus without an information carrier. In this
paper, we address an important question What carries the information in
counterfactual quantum communication? and optimize the resource efficiency of
the counterfactual quantum communication in terms of the number of channels
used, time consumed to transmit 1-bit classical information between two remote
parties, and the number of qubits required to accomplish the counterfactual
quantum communication.
