Gravitational wave detection with single-laser atom interferometers

We present a new general design approach of a broad-band detector of gravitational radiation that relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser will be used for operating the two atom interferometers. We consider atoms in the atom interferometers not only as perfect inertial reference sensors, but also as highly stable clocks. Atomic coherence is intrinsically stable and can be many orders of magnitude more stable than a laser. The unique one-laser configuration allows us to then apply time-delay interferometry to the responses of the two atom interferometers, thereby canceling the laser phase fluctuations while preserving the gravitational wave signal in the resulting data set. Our approach appears very promising. We plan to investigate further its practicality and detailed sensitivity analysis.Comment: Paper submitted to General Relativity and Gravitation as part of the prceedings of the International Workshop on Gravitational Waves Detection with Atom Interferometry (Florence, February 2009)

Searching for stochastic background of ultra-light fields with atomic sensors

We propose a cross-correlation method for the searches of ultra-light fields, in particular, with a space network of atomic sensors. The main motivation of the approach is cancellation of uncorrelated noises in the observation data and unique pattern the fields leave on the cross-spectrum, depending on their nature (i.e., scalar, vector or tensor). In particular, we analytically derive a dependence of the cross-spectrum on the angle between two pairs of detectors. We then confirm obtained angular curves with a numerical simulation. We imply application of the method to the detection of dark matter and gravitational waves.Comment: 16 pages. Minor revision. Submitted to the Universe journa

Generation of optical combs in a whispering gallery mode resonator from a bichromatic pump

An optical comb is shown to arise from a whispering gallery mode resonator pumped by two optical frequencies. Two externally excited modes couple due to Kerr nonlinearity to initially empty modes and give rise to new frequency components. This thresholdles process is much more efficient than the previously reported single-pump four-wave mixing. As a result, a few milliwatt pump is sufficient to generate strong secondary fields, that efficiently generate higher-order frequency components and so on, in a cascade process leading to an optical comb.Comment: 4 pages, 6 figure

A taxonomy of asymmetric requirements aspects

The early aspects community has received increasing attention among researchers and practitioners, and has grown a set of meaningful terminology and concepts in recent years, including the notion of requirements aspects. Aspects at the requirements level present stakeholder concerns that crosscut the problem domain, with the potential for a broad impact on questions of scoping, prioritization, and architectural design. Although many existing requirements engineering approaches advocate and advertise an integral support of early aspects analysis, one challenge is that the notion of a requirements aspect is not yet well established to efficaciously serve the community. Instead of defining the term once and for all in a normally arduous and unproductive conceptual unification stage, we present a preliminary taxonomy based on the literature survey to show the different features of an asymmetric requirements aspect. Existing approaches that handle requirements aspects are compared and classified according to the proposed taxonomy. In addition,we study crosscutting security requirements to exemplify the taxonomy's use, substantiate its value, and explore its future directions