A method for performing quantum state tomography for quadrupole nuclei is presented in this paper. First, it is shown that upon appropriate phase cycling, the nuclear-magnetic-resonance (NMR) intensities of quadrupole nuclei depend only on diagonal elements of the density-matrix. Thus, a method for obtaining the density-matrix elements, which consists of dragging off-diagonal elements into the main diagonal using fine phase-controlled selective radio-frequency pulses, was derived. The use of the method is exemplified through 23 Na NMR (nuclear spin I =3/2) in a lyotropic liquid crystal at room temperature, in three applications: (a) the tomography of pseudopure states, (b) the tomography of the quadrupole free evolution of the density matrix, and (c) the unitary state evolution of each qubit in the system over the Bloch sphere upon the application of a Hadamard gate. Further applications in the context of pure NMR and in the context of quantum information processing, as well as generalizations for higher spins, are discussed.The 23 Na NMR experiments described in this paper were performed using a 9.4 T VARIAN INOVA spectrometer in a lyotropic liquid-crystal system prepared with 35 . 9 wt. % of sodium decyl sulfate (Fluka), 7 . 2 wt. % of decanol (Su-*

The effect of activators on the hydration of granulated blast‐furnace slag (gbfs) was studied through compressive strength measurements, 29Si, 27Al, and 23Na high‐resolution nuclear magnetic resonance, and X‐ray diffraction. Four different activations containing sodium hydroxide, sodium silicate, and/or calcium hydroxide (CH) were considered, at fixed amounts of alkali: 5% Na2O, 5% Na2O‐2.5% CH, 5% Na2O‐7.5% SiO2, and 5% Na2O‐2.5% CH‐7.5% SiO2. Silicate‐activated gbfs cements have greater compressive strength than Portland cements over the whole period of study (1 yr). Also, silicate‐free activated gbfs cements have poorer mechanical strength than silicate‐activated cements. In fact, substantial structural differences were observed between hydration products in both kinds of activations. In silicate‐activated pastes there exists an intimate mixture of C‐S‐H layers and AFm‐like arrangements containing Al in octahedral sites bonded to the silicate layers, originated either from phase intergrowths or from a high density of Ca‐Al incorporation in the interlayer spaces of C‐S‐H. In pastes obtained from silicate‐free activation of gbfs there is a better chemical and structural definition among C‐S‐H and calcium aluminate hydrate domains (AFm and hydrogarnet).

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We report a detailed study of the longitudinal relaxation of several coherent states on the nuclear-magneticresonance ͑NMR͒ two-qubit quadrupole system, 23 Na ͑spin 3/2͒ in a lyotropic liquid-crystal system at room temperature. Relaxation of pseudopure states, simulated pseudo-Bell states and Hadamard states were investigated. The coherence of superposition states was verified by applying the respective quantum ''reading'' operators and comparing the recovered state with the original one. The degree of recovery varies between Ϸ70% and Ϸ100%, depending on the time length of the gate, as compared to relaxation times. Spin-lattice relaxation results follow a recently proposed multiexponential model that includes mixed magnetic dipolar and electric quadrupolar interactions. Relaxation curves are governed by initial conditions, and from the experimental curves individual transition rates are derived. The transverse relaxation time constant T 2 is found not to depend on the initial distribution of populations. This is a systematic study of relaxation in the context of NMR quantum computing.