Nuclear spin qubits in a pseudo-spin quantum chain

We analyze a quantum computer (QC) design based on nuclear spin qubits in a quasi-one-dimensional (1D) chain of non-Kramers doublet atoms. We explore the use of spatial symmetry breaking to obtain control over the local dynamics of a qubit. We also study the decoherence mechanisms at the single qubit level and the interactions mediated by the magnetic media. The design can be realized in $\textrm{PrBr}_{\textrm{3}-x}\textrm{F}_{x}$ with nuclear magnetic resonance (NMR) techniques.Comment: 7 pages, 3 figure

Analysis of neuropeptide gene expression by transfection of DNA into cell lines

The transcriptional regulation of neuropeptide genes by cAMP is often directed by a cAMP responsive enhancer (CRE) upstream to the promoter of the genes. The identity of the CRE was determined by transient transfection experiments and has the consensus sequence of 5′-TGACGTCA-3′. A large family of transcription factors have been identified which recognize the CRE. Transient transfection assays that employed expression of these factors driven by viral promoters have determined they can transactivate the neuropeptide gene promoters. Because of the large number of factors that have been identified as being able to recognize the CRE, it has been difficult to determine which factors mediate in vivo the transactivation of a particular CRE. Using a dominant negative mutant of one of these factors, CREB, it has been determined that both CREB as well as other factors which do not interact with CREB may mediate the cAMP response of the somatostatin gene.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43232/1/11022_2005_Article_BF01667368.pd

Joint densities and density matrices refinements: first attempts and first results

International audienceAlthough analysis of joint experimental data as diverse as x-rays structure factors, polarized neutron flipping ratios, neutron structure factors, CBED measurements, x-ray Compton magnetic (and non magnetic) profiles, among others, is theoretically feasible and desirable, to this day only few attempts have been made. We will remind some of the important strategies that have been elaborated in the past and we will propose a new possible way of combining and exploiting the richness of the diversity of experimental methods. We will show that as long as the data are issued from elastic coherent scattering experiments only marginal changes have to be made to the usual pseudo-atoms model. This will be illustrated with recent results obtained on magnetic compounds. We will finally address a critical discussion concerning the difficulties occurring in combining real and momentum space data