The substantial increase in the number of quantum bits, also called qubits, and structural dimensions of logic gates have made the fidelity and connectivity of qubits highly critical.

Taking into consideration Taiwan's solid foundation and large number of experts in the semiconductor chip manufacturing and IC design and packaging technology sectors, Taiwan's Ministry of Science and Technology (MOST) believes solid-state quantum technology should be a priority investment for Taiwan.

With a long coherence time and high fidelity, qubits are the cornerstones of quantum computer operations, according to an academic research report. Coherence time and fidelity are also closely related to the material and interface quality of qubits.

In terms of solid-state qubits, material technology includes superconducting material manufacturing technology, high purity silicon synthesis technology and precursor development, and low impurity insulating layer manufacturing technology, as well as other materials and component technologies that could raise the coherence time and fidelity of qubits.

The MOST 2022 plan includes a clear outline of the "Taiwan Quantum Next Generation Key Technology Development Plan." Comprised of seven main points, five of which the MOST is involved in, these points include developing key technologies for the core components of quantum computers and communications hardware, establishing a quantum software research and development (R&D) platform, establishing an industry exchange and cooperation platform, cultivating R&D talent for quantum generation technology, and promoting quantum science education.

The MOST's strategy is to first integrate R&D capabilities by forming an interdisciplinary national team for the R&D of key technologies for quantum technology hardware, which will form the foundation of Taiwan's quantum industry. Next is to set up a software technology R&D platform for quantum theory to develop application technologies for quantum computing and cryptography. The third is to bridge industry-government-academic cooperation by establishing an industry exchange and cooperation platform. Additionally, it must recruit talent to expand the team and encourage young students to get involved in quantum technology research.

In the future, the MOST will work with Academia Sinica and other inter-academic research units to establish a quantum core facility base. It will also cooperate with the Ministry of Economic Affairs on quantum subsystem hardware technology.

Taiwan first commissioned an academic research team to carry out a quantum computer development plan for Taiwan in 2017. The quantum computer project plan was formally launched in mid-April 2018.

At present, significant progress has been made globally in low-temperature superconductors, quantum light sources, photonic circuits, and single-photon photodetector systems for optical computing.

The main advantages of optical computing include room temperature operation, less susceptibility to interference (low noise), no need for a vacuum environment, and direct connection to fiber-optic networks. The fact that photonic qubits are difficult to store in a fixed place and photons do not directly carry out interactions are its main obstacles.

From a scientific classification point of view, quantum light sources include photon source, entangled photon source, and photonic state production source (squeezed coherent state, continuous variable state). Photonic circuits are designed according to different algorithms; they need to be integrated with photonic chips and are reconfigurable optical components. Single-photon detectors must have high efficiency, low noise, and high response speed.

Experts say that quantum states are easily interrupted by the environment and cause quantum decoherence. Moreover, it is difficult to achieve perfect quantum logic gate operation, which will generate more noise.

If a quantum computer is to realize a meaningful quantum computation, for example, a factorization algorithm, the error rate of each logic gate must be significantly lower than 10 to the minus 10 power. Achieving this level of error rate is still extremely challenging when only relying on physical methods. Therefore it is necessary to utilize quantum error correction code technology to protect the quantum state so that the quantum calculation can approximate the ideal fault-tolerant quantum computation.

As the number of qubits gradually increases, using quantum circuits to describe quantum calculations will become too complex and not feasible. A higher level of quantum programming language will need to be further developed.

In the future, the quantum computer structure and quantum operating system fields can be expected to slowly take shape. As such, the MOST also plans to invest in the development of quantum programming language to attract more researchers.

In terms of the quantum applications that most interest the outside world, academic circles have proposed the optimization of quantum circuits, quantum chemical energy level structure analysis, quantum finance, quantum machine learning, quantum new drugs and material simulation, quantum transportation management, quantum reversible circuit synthesis algorithms, quantum annealing, and other quantum-inspired application calculations.

By DIGITIMES