Strong experimental guarantees in ultrafast quantum random number generation

We describe a methodology and standard of proof for experimental claims of quantum random number generation (QRNG), analogous to well-established methods from precision measurement. For appropriately constructed physical implementations, lower bounds on the quantum contribution to the average min-entropy can be derived from measurements on the QRNG output. Given these bounds, randomness extractors allow generation of nearly perfect "{\epsilon}-random" bit streams. An analysis of experimental uncertainties then gives experimentally derived confidence levels on the {\epsilon} randomness of these sequences. We demonstrate the methodology by application to phase-diffusion QRNG, driven by spontaneous emission as a trusted randomness source. All other factors, including classical phase noise, amplitude fluctuations, digitization errors and correlations due to finite detection bandwidth, are treated with paranoid caution, i.e., assuming the worst possible behaviors consistent with observations. A data-constrained numerical optimization of the distribution of untrusted parameters is used to lower bound the average min-entropy. Under this paranoid analysis, the QRNG remains efficient, generating at least 2.3 quantum random bits per symbol with 8-bit digitization and at least 0.83 quantum random bits per symbol with binary digitization, at a confidence level of 0.99993. The result demonstrates ultrafast QRNG with strong experimental guarantees.Comment: 11 pages, 9 figure

Measurement of the solar neutrino capture rate with gallium metal

The solar neutrino capture rate measured by the Russian-American Gallium Experiment (SAGE) on metallic gallium during the period January 1990 through December 1997 is 67.2 (+7.2-7.0) (+3.5-3.0) SNU, where the uncertainties are statistical and systematic, respectively. This represents only about half of the predicted Standard Solar Model rate of 129 SNU. All the experimental procedures, including extraction of germanium from gallium, counting of 71Ge, and data analysis are discussed in detail.Comment: 34 pages including 14 figures, Revtex, slightly shortene

Engineering a Multi-Electrode Patch Clamp System:A novel tool to quantify retinal circuits

The human brain contains almost 100 billion neurons. They form distinct neural circuits that underlie the computational power of the brain. To understand how these neural networks function, high-detail physiological recordings from multiple identified neurons within a circuit are required. However, the technical possibilities to achieve this have been limited. Simultaneous patch clamp recordings from multiple well-defined neurons at the same time would give an excellent opportunity to obtain a deeper mechanistic understanding of neural circuit function. Thus, the goal of this master’s project was to build the first state-of-the-art multi-electrode patch clamp system, along with acquisition and analysis software for retinal studies. This multi-electrode patch clamp system makes it possible for the first time to study at high physiological resolution how identified neurons in the vertebrate retina contribute to processing in small networks. The system is flexible to study other areas of the brain and can be extended to eight electrodes with only a few changes. The custom written software ensures protocol standardization for rig calibration, data acquisition, and analysis. All toolboxes are freely available as open source code, which ensures seamless collaboration between researchers and laboratories