A bug of quantum computing is introduced into scientists’ heads in the early 1980s, and is frustrating them ever since. The venture proved to be very complex. For some this technology always seems to be around the corner, while in fact, once you make that turn, there are miles and miles to go.
Many find this elusive technology so alluring because computers of the future, based on quantum computing, will have a potential to take artificial intelligence beyond the frontiers of human knowledge.
Quantum computers use quantum properties of micro particles. Their basic units are qubits, or quantum bits, which unlike ordinary bits can simultaneously have the value of 0 and 1. When in their working quantum state, it takes a millionth of a second for the processing of hundreds of operations. A computer having just 500 qubits could contain more bits (information) then there are particles in the known universe.
Since it is finally official that D-Wave quantum annealing computer is not in fact truly quantum, researchers are back to drawing board, trying to explore other architectures of quantum computing. Although there are many advancements in this field, notably because of the increased number of researchers and engineers who are specializing in quantum computing and huge funds at their disposal, the biggest problems have remained the same since the beginning: prolonging the quantum state of qubits long enough for an information to be stored and read with precision, and decreasing the rate of errors under 1% in order for algorithms, which can then be used for additional corrections of errors as they occur, can be applied.
Now that all major players in the technological arena, like Google, IBM, and Microsoft, along with numerous academic groups, are participating in this game, chances for finding the holy grail of computing are greater than ever.
Researchers at University of New South Wales reported in October 2014 to have created a qubit that was able to preserve its coherence of quantum information for more than 30 seconds. „Half a minute is an eternity in the quantum world “said Professor Andrea Morello, one of the researchers. How fascinating this information is testifies the statement of his colleague, Professor Andrew Dzurak, who pointed out that, “In solid-state systems these times are typically measured in nano of micro seconds before the information gets lost.” They have also managed to achieve accuracy of processing data close to 99.99 percent with one of the qubits (the nucleus) in the phosphorous atom. On top of all that, they have been working with silicone in the creation of two different types of qubits, demonstrating that quantum computers might not require esoteric materials and special conditions, like cryogenic temperatures, for their operations.
However, silicone-based quantum computers are still lagging behind quantum computer technologies such as atomic ion traps and superconducting circuits.
Atomic ion trap is probably the most promising system for building a quantum computer. The fact that research in this field is supported by IARPA (Intelligence Advance Research Projects Activity) speaks enough for itself. It works on a principle of confining ions (atoms which have lost or gained one or more electrons, thus becoming electrically charged) and controlling them with electromagnetic fields. Once their kinetic energy is reduced they can be manipulated by applying lasers and microwave radiation. Qubits are embodied in the internal energy of these ions.
Superconducting qubits are the key components of superconducting circuits, and they are the promising building blocks of a fully functional quantum computer. They can be manipulated by electromagnetic pulses which control the electric charge, magnetic pulse and phase difference across Josephson junction (two superconducting electrodes separated by a non-superconducting material). In April 2014 at the University of California, Santa Barbara, this type of computer was reported to be functioning with an accuracy of 99.4 % for a quantum logic gate involving two qubits, which paves the way for a practical error correction research.
Now it’s just a matter of making large number of cubits work together without errors. It sounds so simple…