Data transmission by quantum matter-wave modulation*

Classical communication schemes exploiting wave modulation are the basis of our information era. Quantum information techniques with photons enable future secure data transfer in the dawn of decoding quantum computers. In this presentation we demonstrate that also matter-waves can be applied for secure data transfer. Our technique allows the transmission of a message by a quantum modulation of coherent electrons in a biprism interferometer. The data is encoded in the superposition state by a Wien filter introducing a longitudinal shift between separated matter-wave-packets. The transmission receiver is a delay line detector performing a dynamic contrast analysis of the fringe pattern. Our method relies on the Aharonov-Bohm effect and has no light optical analog since it does not shift the phase. We demonstrate that an eavesdropping attack will terminate the data transfer by disturbing the quantum state and introducing decoherence. Furthermore, the security limitations of our multi-particle scheme are discussed and a key distribution protocol is presented that prevents active eavesdropping.