Decoherence in crystal lattice quantum computation

Nuclear magnetic resonance (NMR) quantum computation in a crystal lattice h olds more promise for scalability than its solution NMR counterpart, but de phasing is a severe concern. Pulse sequence refocusing can help bring the q ubit dephasing time closer to the limit of the intrinsic decoherence time, but the intrinsic transverse relaxation time (T-2) and the longitudinal rel axation time (T-1) of the crystal must be sufficiently long for a successfu l implementation. We discuss these time scales and their relation to parame ters relevant to quantum computation for several crystal types, discussing in detail the examples of CaF2, MnF2. and CeP. Included in the calculation of coherence times for CeP is the development of spin-wave spectra in a typ e-1 antiferromagnetic FCC lattice. PACS: 03.67.Lx; 76.60.Es; 75.30.Ds.