Beating the Classical Limits of Information Transmission using a Quantum Decoder. (arXiv:1704.07036v2 [quant-ph] UPDATED)
Encoding schemes and error-correcting codes are widely used in information
technology to improve the reliability of data transmission over real-world
communication channels. Quantum information protocols can further enhance the
performance in data transmission by encoding a message in quantum states,
however, most proposals to date have focused on the regime of a large number of
uses of the noisy channel, which is unfeasible with current quantum technology.
We experimentally demonstrate quantum enhanced communication over an amplitude
damping noisy channel with only two uses of the channel per bit and a single
entangling gate at the decoder. By simulating the channel using a photonic
interferometric setup, we experimentally increase the reliability of
transmitting a data bit by greater than 20% for a certain damping range over
classically sending the message twice. We show how our methodology can be
extended to larger systems by simulating the transmission of a single bit with
up to eight uses of the channel and a two-bit message with three uses of the
channel, predicting a quantum enhancement in all cases.