Physics of quantum coherence in spin systems

Quantum computation provides a great speedup over its classical counterpart in solving some hard problems. The advantages of quantum computation come from the coherent superposition principle of quantum mechanics. Spin system is one of the most significant candidates to realize quantum computation. In this review, we focus on the recent experimental progress related to quantum coherence and some fundamental concepts such as the uncertainty principle in the spin systems. We shall first briefly introduce the quantum description of qubit, coherence, and decoherence. Based on this picture, preserving quantum coherence and detection of weak magnetic fields are presented. We also discuss the realization of precise quantum coherent control, adiabatic quantum factorization algorithm, and two aspects of uncertainty relations.