Testing quantum foundations with quantum computers

We present two complementary viewpoints for combining quantum computers and the foundations of quantum mechanics. On the one hand, ideal devices can be used as test beds for experimental tests of the foundations of quantum mechanics: We provide algorithms for the Peres test for complex numbers in quantum superpositions and the Sorkin test of Born's rule. On the other hand, noisy intermediate-scale quantum devices can be benchmarked using these same tests. These are deep quantum benchmarks based on the foundations of quantum theory itself. We present test data from Rigetti hardware

Nanocrystal-based Ohmic contacts on n and p-type germanium

We report a simple method of forming Ohmic contacts to n and p-type germanium (Ge) simultaneously using Au nanocrystals embedded in Ti contact metal. The electric field due to the work-function difference of Ti and Au reduces the tunneling resistance at the Ti-Au/Ge interface for n and p-type contacts. The nanocrystal-based contacts on n-Ge exhibit quasi-Ohmic current-voltage characteristics with >1000x increase in current density and an apparent reduction of 0.18 eV in the barrier height over Ti/n-Ge and Au/n-Ge contacts that show rectifying characteristics due to Fermi level pinning. On n(+)Ge, the nanocrystal-based contacts exhibit Ohmic characteristics with >35x reduction in zero-bias resistance over Ti/n(+)Ge contacts. Similar to Ti and Au contacts on p-Ge, Au nanocrystals embedded in Ti continue to exhibit Ohmic characteristics. This is in contrast to methods that convert p-type contacts from Ohmic to rectifying in the process of forming an Ohmic contact on n-Ge by inserting a thin dielectric layer between the metal and Ge. Device simulations reinforce the observed decrease in tunneling resistance due to the enhanced electric field at the Ti-Au/Ge interface. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3700965

A Highly Reliable and Unbiased PUF Based on Differential OTP Memory

Physically unclonable functions (PUF) are essential for hardware identity and security for IoT devices. The PUF consists of amulti-bit string that requires unbiased randomness. A one-time programmable memory (OTPM) uses insulator breakdown inmetal-insulator-metaldevice to switch between insulating ("0") and conducting ("1") state. An OTPM based PUF produces an unbiased bit-string if exactly median breakdown voltage (V-BD) and time are used. The exact application of median V-BD is challenging in an integrated circuit as a conventional voltage supply tolerance specification is 10%. In this letter, we propose a differential OTPM-based PUF with a parallel circuit of two OTPM in series with a resistance. A high voltage stochastically produces a breakdown in one of the two OTPM first, which then reduces the voltage drop across the parallel OTPM circuit to prevent further breakdown events. The experimental results of differential OTPM PUF binary string generation show essentially unbiased randomness to demonstrate excellent resistance to supply voltage variation. Ideal uniqueness and reproducibility are observed. Thus, our approach enables PUF implementation with standard voltage supply tolerance and negligible post-processing

Changing scenario of micronutrient deficiencies in India during four decades and its impact on crop responses and nutritional health of human and animals

Changing scenario of micronutrient deficiencies phase wise during four decades (1968-2008) was studied in soils of India, their impact of crop production and changes in micronutrient concentration in seeds and fodders, thereby influences on animal and human health. Results of 269,000 soil sample analysis revealed that mean deficiency of zinc, iron, copper, manganese, boron, molybdenum was found in 49, 12, 3, 5, 33 and 13% samples, respectively. Throughout country, zinc deficiency is increasing except Punjab, Haryana and Uttar Pradesh.where zinc deficiency is declining from initial 70-90 percent in Punjab and Haryana to the level of 13-20 percent due to regular application of zinc sulphate. On the other hand, deficiency of zinc has increased in southern states due to extensive use of multi micronutrient mixtures containing less zinc. Periodic assessment of soil data also suggests that zinc deficiency in soils of India is likely to increase from 49% to 63% by the year 2025 as most of the marginal soils brought under cultivation are showing zinc deficiency. In states like Gujarat, Bihar and Madhya Pradesh zinc deficiency is found almost stagnant during four decades despite much efforts have gone to popularize zinc application in various crops. Zinc deficiency is increasing in soils, so zinc content in seed and in blood plasma of animal and humans is decreasing. In Haryana and Punjab, zinc concentration in grains of wheat is improving from 23 to 72 mg kg-1. Farming family consuming their crop produce from zinc deficient farms had low zinc in their blood plasma compared to those which were fed on produce received from farms fertilized with zinc regularly. Similarly improvement in zinc fertility in Dahima village in Haryana resulted in adequate level of zinc in staple grains, fodder, blood plasma of humans and animals. Fodders in Haryana showed copper deficiency instead of zinc. Manganese concentration in grains and fodders was found low in Bihar and Punjab. Zinc supplementation is therefore essential for maintaining high zinc content in soil, seed and blood plasma of human and animals