Quantum Dot Quantum Computation

Within the last few years, quantum computation has developed into a truly interdisciplinary field involving the contributions of physicists, engineers, and computer scientists. There have been several experimental studies in order to find the proper physical realization of qubits to perform quantum computation. One of the most promising candidates for qubits is the spin state of the electrons, confined in quantum-dots. Different configurations are possible for the electron spins. Control over these spins would allow performing different operations, gating and entangling. However, this is not sufficient for realization of quantum computing. The elementary requirements of any physically feasible quantum computer are specified by five DiVincenzo criteria. In order to consider all these criteria, a broad understanding of material properties, physical phenomenology, technological feasibility, and the quantum mechanical time evolution of these systems are required. The promising proposal for quantum computers that satisfies these criteria is quantum dot proposal, which is founded on electron spins as qubits. Electron spin quantum dots, spin-cluster quantum dots, silicon semiconductor quantum dots, and hybrid quantum dots are some of alternate solid-state quantum dot proposals. In order to implement these proposals in the real world, several fabrication methods such as molecular beam epitaxy, rapid thermal process, and lithography are studied. Gated quantum dots, vertical quantum dots, and self-assembled quantum dots, three major structures of quantum dots, which are proposed by different research groups, are also reviewed. There are also various methods for performing the initialization and measurement on a qubit. In spite of all the advantages of quantum dots, there are also some obstacles in these proposals that should be addressed. These problems include entanglement, gating error, and coherence. In addition to the problem of implementing the quantum dot quantum computing, communication using the electron spins is another fundamental issue that should be addressed. Entangled electrons are the basic elements in quantum communication that should be generated and detected using proper feasible methods. By considering all these aspect, it can be concluded that quantum dots are the best candidates for implementing future quantum computing.