Quantum computer architectures: An idea whose time is not far away

Current day computers are increasingly getting limited in hardware due to deep sub-micron effects which may prevent finer gate widths. Parallel computing methods with a large number of cores can only give a linear speed up. Quantum computing is an attempt to unite Quantum mechanics and information science together to achieve next generation computation. Quantum computers have simultaneity and parallelism built inherently. Building a Quantum computer has some difficulties associated with it which involves criteria such as hardware architecture, coherence and fidelity. Quantum computing promises interesting possibilities. Many laboratories in the world are doing research on building Quantum computers which promise exponential speed up. In this article we have given a brief introduction to Quantum mechanics and examine Quantum computing possibilities using few architectures which are being investigated for Quantum computing. We compare three different architectures, namely, Trapped ion architecture, Quantum computing using superconducting Qubits and Quantum computing with Nitrogen Vacancy center in diamonds with various factors such as temperature requirements, coherence time of superposition states, fidelity, error correction, power dissipation and noise.