  Quantum error correction plays an important role in fault-tolerant quantum
information processing. It is usually difficult to experimentally realize
quantum error correction, as it requires multiple qubits and quantum gates with
high fidelity. Here we propose a simple quantum error-correcting code for the
detected amplitude damping channel. The code requires only two qubits. We
implement the encoding, the channel, and the recovery on an optical platform,
the IBM Q System, and a nuclear magnetic resonance system. For all of these
systems, the error correction advantage appears when the damping rate exceeds
some threshold. We compare the features of these quantum information processing
systems used and demonstrate the advantage of quantum error correction on
current quantum computing platforms.
