The Furusawa-Yoshikawa Laboratory is conducting researches on optical quantum computers toward realizing fault-tolerant universal quantum computers based on quantum teleportation.

Quantum computers perform calculations by utilizing the unique properties of quantum mechanics such as quantum superposition and quantum entanglement. It is known that computations by the quantum computers can be overwhelmingly faster than the ones by currently used computers ("classical computers" in comparison to the quantum computers), and its realization in a wide variety of fields has been desired. However, a practical quantum computer has not yet been realized due to many remaining issues; in particular, the realizations of (1) “universality” that the quantum computer can be used for any calculation and (2) “fault-tolerance” that it can correct errors in the calculation process are major issues.

Currently, quantum computers are being studied in various ways (superconducting qubits, ion traps, etc.). We are particularly focusing on photonic computers that perform calculations with information on traveling light waves. By using light, not only can we realize the above (1) and (2), but also do noise resistance, large-scale calculation, and increase of the clock frequency in principle.

In our laboratory, we are conducting not only proof-of-principle experiments but also research on optical circuit integration for practical applications./p>