Quantum computers are computers with a new operating principle that are said to solve calculations that take an enormous amount of time even in modern supercomputers in an instant.Its applications are wide-ranging, such as speeding up database searches, simulating natural phenomena, and developing functional materials and pharmaceuticals, and general-purpose quantum computers are being developed in various systems around the world.However, increasing the scale of any system has been a long-standing issue, and even now, only calculations of several tens of qubits have been realized.

　Under such circumstances, Professor Furusawa and Assistant Professor Takeda invented a new method using an optical circuit with a loop structure.It utilizes the idea of ​​performing large-scale quantum calculations by using one quantum teleportation circuit, which is the basic unit of calculation, repeatedly without limit.

　The strength of this method is that it is possible to execute even a large-scale calculation by circulating an optical pulse in a loop and repeatedly using it while switching the function of one quantum teleportation circuit.In principle, it is expected to be able to process more than 1 million qubits.Moreover, since it requires only the smallest optical circuit, it can significantly reduce the resources and costs required for implementing a large-scale quantum computer, and is expected to bring innovation to the development of optical quantum computers.

　In the future, we will actually work on the development of a large-scale quantum computer using this method while proceeding with the analysis of the calculation accuracy and the implementation method of various algorithms in the photon computer of this method.

Paper information:[Physical Review Letters] Universal quantum computing with measurement-induced continuous-variable gate sequence in a loop-based architecture