Resurrection of Schr\"{o}dinger Cat

The most striking difference between quantum and classical systems is the ability of quantum objects to be in a superposition state. A system in a superposition of macroscopically distinct states (\textit{alive} and \textit{dead} states of the ``Schr\"{o}dinger cat'') would demonstrate highly unusual behavior. Cat states are the central elements in recent proposals on high-precision spectroscopy, amplified quantum detection and measurement. Quantum decoherence is the major obstacle in building practical devices which could revolutionize high-precision measurements or information processing. Here we experimentally demonstrate that quantum state of a system can be recovered after the state is destroyed by uncontrollable natural decoherence. The physical system used in this experiment is a cluster of seven dipolar-coupled nuclear spins of single-labeled $^{13}$C-benzene oriented in liquid crystal. After decoherence of the cat state, superposition of states with all spins up (\textit{alive}) and all spins down (\textit{dead}), information stored in a single ancillary spin ($^{13}$C) is used to bring the protons subsystem into the \textit{alive} state, while the excess entropy produced by decoherence is transferred to the ancillary spin.