Research Highlights

Prof. Yoon-Ho Kim Demonstrates Decoherence Suppression Using Qubit Transduction

2015-10-30 737
 Prof. Yoon-Ho Kim and his team of researchers

Coherence and entanglement are the most essential resources for implementation of various quantum informational protocols, such as quantum teleportation or quantum cryptography. Prof. Yoon-Ho Kim and his team of researchers have provided an experimental demonstration of a decoherence suppression scheme using ‘qubit-transduction’ and report successful entanglement distribution over a decoherence channel. The research results were published in Scientific Reports.
Classical information can be expressed in binary numbers using “bit” that can represent either a state of 0 or 1. For example, classical computers do the information processing using a TTL (Transistor-Transistor Logic) signal as a physical system that encodes a bit state 0 with 0V, state 1 with 5V. Meanwhile, quantum information needs to be encoded in “qubit” instead of classical “bit”.
For a physical system to work as a quantum information carrier “qubit”, coherence and entanglement (the quantum properties) in the physical system should be protected. However, coherence or entanglement in a quantum state can be easily degraded and lost during interactions with environments (decoherence) so that suppressing decoherence has been an interesting topic in quantum information science.
Qubit-transduction switches the physical system that the qubit is initially encoded to another. By transducing the qubit that is sensitive to a particular form of decoherence the team has demonstrated that it is possible to avoid the effect of decoherence completely. As proof-of-principle experiments, the team has shown the decoherence suppression against two types of decoherence, amplitude damping decoherence and polarization-mode dispersion decoherence, via qubit transduction between polarization qubits and dual-rail qubits. Because the protocol is input-state independent, requires no ancillary photons and symmetries, and has near-unity success probability, the team expects the results to present a significant breakthrough in quantum communication over decoherence channels.