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Variational quantum eigensolvers (VQEs) combine classical optimization with efficient cost function evaluations on quantum computers. We propose a new approach to VQEs using the principles of measurement-based quantum computation. This strategy uses entangled resource states and local measurements. We present two measurement-based VQE schemes. The first introduces a new approach for constructing variational families. The second provides a translation of circuit-to measurement-based schemes. Both schemes offer problem-specific advantages in terms of the required resources and coherence times.

Can readers exert control (albeit unconsciously) over activation at particular loci in the reading system? The authors addressed this issue in 4 experiments in which participants read target words aloud and the factors of prime-target relation (semantic, repetition), context (related, unrelated), stimulus quality (bright, dim), and relatedness proportion (RP; high, low) were manipulated. In the high RP condition (RP = .5), an interaction between semantic context and stimulus quality was observed in which low stimulus quality slowed unrelated targets more than related ones, replicating previous work. In contrast, the low RP condition (RP = .25) yielded additive effects of semantic context and stimulus quality. However, when low RP was examined within the context of repetition priming, context and stimulus quality once again interacted. These results are discussed in the context of a widely endorsed framework with the addition of the central assumption that there is control over feedback between various levels.

We have studied the growth by gas-source molecular beam epitaxy (GS-MBE) of SiGe virtual substrates. We have first determined the relationship existing between the Ge concentration in SiGe thick films and the gas phase ratio of disilane and germane, and its behaviour versus growth temperature. We find that Si atoms are 4.6 times more likely to be incorporated than Ge atoms at 550 • C. This incorporation probability decreases as the growth temperature increases, following a thermally activated law with a 0.082-0.126 eV characteristic energy. The dependence of SiGe growth rate on substrate temperatures has a cross-over point at approximately 8% of Ge, above which the growth rate decreases significantly as the temperature increases. Otherwise, we show what p-type or n-type doping levels are typically achievable in SiGe virtual substrates, and the influence diluted diborane and arsine have on the growth kinetics of SiGe. Additionally, we demonstrate that the 'pre-build-up/flash-off' technique originally proposed by Iyer et al for solid-source MBE (1981 J. Appl. Phys. 52 5608) yields abrupt arsenic doping profiles in GS-MBE.

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