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