Passive Newtonian noise suppression for gravitational-wave observatories based on shaping of the local topography

In this article we propose a new method for reducing Newtonian noise in laser-interferometric gravitational-wave detectors located on the Earth's surface. We show that by excavating meter-scale recesses in the ground around the main test masses of a gravitational wave detector it is possible to reduce the coupling of Rayleigh wave driven seismic disturbances to test mass displacement. A discussion of the optimal recess shape is given and we use finite element simulations to derive the scaling of the Newtonian noise suppression with the parameters of the recess as well as the frequency of the seismic excitation. Considering an interferometer similar to an Advance LIGO configuration, our simulations indicate a frequency dependent Newtonian noise suppression factor of 2 to 4 in the relevant frequency range for a recesses of 4m depth and a width and length of 11m and 5m, respectively. Though a retrofit to existing interferometers seems not impossible, the application of our concept to future infrastructures seems to provide a better benefit/cost ratio and therefore a higher feasibility.Comment: 12 pages, 5 figure

Living conditions and subjective well-being of farmers - An ordered response analysis of regional differences and changes over time

The liberalisation of trade with building down of tariffs and quotas, and with subsequently lower output prices, has enforced considerable structural changes in the agricultural sector. In Norway, both naturally given factors such as climate and topography, and social conditions such as a tradition for small family farms and strong governmental regulations, contribute in making this process even harder on the individual farmer. So how do the farmers respond? National farm statistics show that the amount of cultivated land stays approximately the same even though the number of farm units and agricultural employment falls annually. This implies that both farm size and productivity have increased. In this paper we utilise sample survey data on living conditions in agricultural households to examine whether we can observe changes in farmers ’experienced utility. Have contentment dropped and are there any obvious regional differences in contentment? The data consists of non-overlapping cross-sections for the years 1995 and 2002 and we make use of a standard ordered probability model in the estimations.

Probabilistic Modelling of the Joint Labour Decisions of Husband and Wife in Farm Households

When working with micro data one sometimes encounters situations involving qualitative choices in addition to the continuous choices that are the traditional focus of empirical analysis. One such situation arises when we study the increase in multiple job-holdings among farm operators in western economies. In these analyses we are both interested in the qualitative choice of entering the off-farm labour market and the continuous choice of determining labour supply in all occupations. This paper presents a unified framework for formulating such a discrete/continuous choices that include randomness within the decision-making process. We consider the joint labour decisions of operator and spouse through an agricultural household model that combines the agricultural production, consumption, and labour supply decisions in a single framework. We develop a probabilistic decision rule for participating in off farm work and derive the demand functions in farm production and labour supply functions in off-farm sector.Consumer/Household Economics, Labor and Human Capital,

Phase Diagram of Bosons in Two-Color Superlattices from Experimental Parameters

We study the zero-temperature phase diagram of a gas of bosonic 87-Rb atoms in two-color superlattice potentials starting directly from the experimental parameters, such as wavelengths and intensities of the two lasers generating the superlattice. In a first step, we map the experimental setup to a Bose-Hubbard Hamiltonian with site-dependent parameters through explicit band-structure calculations. In the second step, we solve the many-body problem using the density-matrix renormalization group (DMRG) approach and compute observables such as energy gap, condensate fraction, maximum number fluctuations and visibility of interference fringes. We study the phase diagram as function of the laser intensities s_2 and s_1 as control parameters and show that all relevant quantum phases, i.e. superfluid, Mott-insulator, and quasi Bose-glass phase, and the transitions between them can be investigated through a variation of these intensities alone.Comment: 4 pages, 3 figure

Towards formative interpretation: a theological hermeneutical proposal

How can we read the Bible to be formed as readers? This question opens a number of possible avenues of academic inquiry, but the one taken in this paper is mainly concerned with hermeneutical questions of how we read the Bible and whether we can formulate a hermeneutical framework for formative interpretation. To that end we analyse interpretative approaches of the modern era and ask whether these are hospitable or hostile to Christian formation. Our findings show the negative effects of pluralism and secularisation that dominate in the field of hermeneutics. Our work then focuses on the development of a theological hermeneutics, within which formative interpretation receives stable goals and criteria. This we achieve in three steps; one, we propose three basic hermeneutical decisions that constitute theological hermeneutics; two, we define and describe formation from a Christian perspective and use those insights as guidelines for formative interpretation; three, we describe two formal characteristics of formative interpretation. In essence, this paper sees formative interpretation as an ecclesial task that focuses on discernment of God’s being and presence in the world, which Scripture witnesses of and explains. Formative interpretation is a holistic task of the reader to bring one’s whole self before God in the reading of Scripture, and in that posture and practice we expect God to speak through the entirety of Scripture to use today

Response of Bose gases in time-dependent optical superlattices

The dynamic response of ultracold Bose gases in one-dimensional optical lattices and superlattices is investigated based on exact numerical time evolutions in the framework of the Bose-Hubbard model. The system is excited by a temporal amplitude modulation of the lattice potential, as it was done in recent experiments. For regular lattice potentials, the dynamic signatures of the superfluid to Mott-insulator transition are studied and the position and the fine-structure of the resonances is explained by a linear response analysis. Using direct simulations and the perturbative analysis it is shown that in the presence of a two-colour superlattice the excitation spectrum changes significantly when going from the homogeneous Mott-insulator the quasi Bose-glass phase. A characteristic and experimentally accessible signature for the quasi Bose-glass is the appearance of low-lying resonances and a suppression of the dominant resonance of the Mott-insulator phase.Comment: 20 pages, 9 figures; added references and corrected typo