7,595 research outputs found
SPsimSeq : semi-parametric simulation of bulk and single-cell RNA-sequencing data
SPsimSeq is a semi-parametric simulation method to generate bulk and single-cell RNA-sequencing data. It is designed to simulate gene expression data with maximal retention of the characteristics of real data. It is reasonably flexible to accommodate a wide range of experimental scenarios, including different sample sizes, biological signals (differential expression) and confounding batch effects
Quantifying the unknown: issues in simulation validation and their experimental impact
The assessment of the reliability of Monte Carlo simulations is discussed,
with emphasis on uncertainty quantification and the related impact on
experimental results. Methods and techniques to account for epistemic
uncertainties, i.e. for intrinsic knowledge gaps in physics modeling, are
discussed with the support of applications to concrete experimental scenarios.
Ongoing projects regarding the investigation of epistemic uncertainties in the
Geant4 simulation toolkit are reported.Comment: To be published in the Proceedings of the 13th ICATPP Conference on
Astroparticle, Particle, Space Physics and Detectors for Physics
Applications, Villa Olmo, Como, 3-7 October 201
Graph-theoretic strengths of contextuality
Cabello-Severini-Winter and Abramsky-Hardy (building on the framework of
Abramsky-Brandenburger) both provide classes of Bell and contextuality
inequalities for very general experimental scenarios using vastly different
mathematical techniques. We review both approaches, carefully detail the links
between them, and give simple, graph-theoretic methods for finding
inequality-free proofs of nonlocality and contextuality and for finding states
exhibiting strong nonlocality and/or contextuality. Finally, we apply these
methods to concrete examples in stabilizer quantum mechanics relevant to
understanding contextuality as a resource in quantum computation.Comment: 13 pages; significantly rewritte
Implementing a neutral-atom controlled-phase gate with a single Rydberg pulse
One can implement fast two-qubit entangling gates by exploiting the Rydberg
blockade. Although various theoretical schemes have been proposed,
experimenters have not yet been able to demonstrate two-atom gates of high
fidelity due to experimental constraints. We propose a novel scheme, which only
uses a single Rydberg pulse illuminating both atoms, for the construction of
neutral-atom controlled-phase gates. In contrast to the existing schemes, our
approach is simpler to implement and requires neither individual addressing of
atoms nor adiabatic procedures. With parameters estimated based on actual
experimental scenarios, a gate fidelity higher than 0.99 is achievable.Comment: 6 pages, 5 figure
Advantages of gated silicon single photon detectors
We present a gated silicon single photon detector based on a commercially
available avalanche photodiode. Our detector achieves a photon detection
efficiency of 45\pm5% at 808 nm with 2x 10^-6 dark count per ns at -30V of
excess bias and -30{\deg}C. We compare gated and free-running detectors and
show that this mode of operation has significant advantages in two
representative experimental scenarios: detecting a single photon either hidden
in faint continuous light or after a strong pulse. We also explore, at
different temperatures and incident light intensities, the "charge persistence"
effect, whereby a detector clicks some time after having been illuminated
Effect of pedestrian movement on MIMO-OFDM channel capacity in an indoor environment
Effects of pedestrian movement on multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) channel capacity have been investigated using experiment and simulation. The experiment was conducted at 5.2 GHz by a MIMO-OFDM packet transmission demonstrator using four transmitters and four receivers built in-house. Geometric optics based ray tracing technique was used to simulate the experimental scenarios. Changes in the channel capacity dynamic range have been analysed for different number of pedestrian (0-3) and antennas (2-4). Measurement and simulation results show that the dynamic range increases with the number of pedestrian and the number of antennas on the transmitter and receiver array
Theory of Electron Spin Relaxation in n-Doped Quantum Wells
Recent experiments have demonstrated long spin lifetimes in uniformly n-doped
quantum wells. The spin dynamics of exciton, localized, and conduction spins
are important for understanding these systems. We explain experimental behavior
by invoking spin exchange between all spin species. By doing so we explain
quantitatively and qualitatively the striking and unusual temperature
dependence in (110)-GaAs quantum wells. We discuss possible future experiments
to resolve the pertinent localized spin relaxation mechanisms. In addition, our
analysis allows us to propose possible experimental scenarios that will
optimize spin relaxation times in GaAs and CdTe quantum wells.Comment: Small corrections made. Accepted to Phys. Rev. B. 8 pages, 5 figure
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