The Japan Science and Technology Agency, the Institute of Physical and Chemical Research and electronics vendor NEC Corporation have developed new circuit technology said to be the world's first quantum bit (qubit) circuit that can control the strength of coupling between qubits. The new technology enables the coupling of qubits to be controlled by employing an additional qubit in between the coupled qubit pair. The additional qubit acts as a non-linear transformer that is able to turn on and off the magnetic coupling between the two coupled qubits. Using the new scheme, researchers have successfully employed a coupled two-qubit system to carry out a multi-quantum control experiment involving the turning on and off of the coupling.
Unlike the binary system used in current electronics (two states: on and off), information stored in qubits can exist in a much larger range of states. The coupling of qubits so far has been difficult to control: "It has hitherto been difficult to switch the movement of one bit and two bits in the same quantum bit, although the bit's movements in the state of one single bit and the coupling of two bits have been confirmed," explained researcher Jaw-Shen Tsai of NEC. Quantum computing is supposed to succeed today's most modern supercomputers due to its potential to perform functions exponentially faster than any classical computer. But there is still a long way to go before quantum computing becomes a reality, Tsai for example expects the development of a practical quantum computer to be more than 10 years away.
News source: ComputerWorld