Spin Readout Techniques of the Nitrogen-Vacancy Center in Diamond

The diamond nitrogen-vacancy (NV) center is a leading platform for quantum information science due to its optical addressability and room-temperature spin coherence. However, measurements of the NV center's spin state typically require averaging over many cycles to overcome noise. Here, we review several approaches to improve the readout performance and highlight future avenues of research that could enable single-shot electron-spin readout at room temperature.Comment: 21 pages, 7 figure

On the sum-of-squares degree of symmetric quadratic functions

We study how well functions over the boolean hypercube of the form $f_k(x)=(|x|-k)(|x|-k-1)$ can be approximated by sums of squares of low-degree polynomials, obtaining good bounds for the case of approximation in $\ell_{\infty}$-norm as well as in $\ell_1$-norm. We describe three complexity-theoretic applications: (1) a proof that the recent breakthrough lower bound of Lee, Raghavendra, and Steurer on the positive semidefinite extension complexity of the correlation and TSP polytopes cannot be improved further by showing better sum-of-squares degree lower bounds on $\ell_1$-approximation of $f_k$; (2) a proof that Grigoriev's lower bound on the degree of Positivstellensatz refutations for the knapsack problem is optimal, answering an open question from his work; (3) bounds on the query complexity of quantum algorithms whose expected output approximates such functions.Comment: 33 pages. Second version fixes some typos and adds reference

Effects of mechanically separated dairy cow slurry on grazing performance

No abstract available

Innovative activity in rural areas: the importance of local and regional characteristics

Innovation, supported by a developed and active entrepreneurial system, long has been recognized as critical to regional economic competitiveness. Innovation also plays an essential role for rural economic development as these regions respond to the challenges of competing in the global economy. Barkley and Henry identify assets that contribute to nonmetro innovation “hot spots.”Community development ; Research and development ; Patents

Innovative Activity in Rural Areas: The Role of Local and Regional Characteristics

Community/Rural/Urban Development,