651 research outputs found
Water vapor at a translational temperature of one kelvin
We report the creation of a confined slow beam of heavy-water (D2O) molecules
with a translational temperature around 1 kelvin. This is achieved by filtering
slow D2O from a thermal ensemble with inhomogeneous static electric fields
exploiting the quadratic Stark shift of D2O. All previous demonstrations of
electric field manipulation of cold dipolar molecules rely on a predominantly
linear Stark shift. Further, on the basis of elementary molecular properties
and our filtering technique we argue that our D2O beam contains molecules in
only a few ro-vibrational states.Comment: 4 pages, 4 figures, 1 tabl
Accountability for social impact: A bricolage perspective on impact measurement in social enterprises
his is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record To fulfill external accountability expectations social impact measurement has become an important practice for social enterprises. Yet, the ambiguity around social impact and its measurement leads to a friction among stakeholders involved in a social enterprise. Based on interviews with small-to-medium-sized social enterprises, this paper investigates how social entrepreneurs handle the increasing pressure to measure social impact with formal methodologies through a bricolage lens. The findings show how social enterprises combine material and ideational bricolage as well as seek to delegitimize formal methodologies to increase the legitimacy of their bricolaged approaches for social impact measurement
Multinational enterprises and climate change strategies
Climate change is often perceived as the most pressing environmental problem of our time, as reflected in the large public, policy, and corporate attention it has received, and the concerns expressed about the (potential) consequences. Particularly due to temperature increases, climate change affects physical and biological systems by changing ecosystems and causing extinction of species, and is expected to have a negative social impact and adversely affect human health (IPCC, 2007). Moreover, as a result of the economic costs and risks of extreme weather, climate change could have a severe impact on economic growth and development as well, if no action is taken to reduce emissions (Stern, 2006). This means that it can affect multinational enterprises (MNEs) active in a wide variety of sectors and countries. Climate change is not a 'purely' environmental issue because it is closely linked to concerns about energy security due to dependence on fossil fuels and oil in particular, and to energy efficiency and management more generally. Controversy about the climate change issue has led to a broadening of the agenda in some cases, with policy-makers targeting energy to avoid commotion about the science and politics of climate change, and firms likewise, also because addressing climate change in practice usually boils down to an adjustment in the energy base of business models
Characterization of a Quantum Light Source Based on Spontaneous Parametric Down-Conversion
We have built a quantum light source capable of producing different types of
quantum states. The quantum light source is based on entangled state
preparation in the process of spontaneous parametric down-conversion. The
single-photon detection rate of eight-hundred thousand per second demonstrates
that we have created a bright state-of-the-art quantum light source. As a part
of the characterization we measured two-photon quantum interference in a
Hong-Ou-Mandel interferometer.Comment: 33 page
Nanophotonic hybridization of narrow atomic cesium resonances and photonic stop gaps of opaline nanostructures
We study a hybrid system consisting of a narrowband atomic optical resonance
and the long-range periodic order of an opaline photonic nanostructure. To this
end, we have infiltrated atomic cesium vapor in a thin silica opal photonic
crystal. With increasing temperature, the frequencies of the opal's
reflectivity peaks shift down by >20% due to chemical reduction of the silica.
Simultaneously, the photonic bands and gaps shift relative to the fixed
near-infrared cesium D1 transitions. As a result the narrow atomic resonances
with high finesse (f/df=8E5) dramatically change shape from a usual dispersive
shape at the blue edge of a stop gap, to an inverted dispersion lineshape at
the red edge of a stop gap. The lineshape, amplitude, and off-resonance
reflectivity are well modeled with a transfer-matrix model that includes the
dispersion and absorption of Cs hyperfine transitions and the
chemically-reduced opal. An ensemble of atoms in a photonic crystal is an
intriguing hybrid system that features narrow defect-like resonances with a
strong dispersion, with potential applications in slow light, sensing and
optical memory.Comment: 8 pages, 6 figure
Optical decay from a Fabry-Perot cavity faster than the decay time
The dynamical response of an optical Fabry-Perot cavity is investigated
experimentally. We observe oscillations in the transmitted and reflected light
intensity if the frequency of the incoupled light field is rapidly changed. In
addition, the decay of a cavity-stored light field is accelerated if the phase
and intensity of the incoupled light are switched in an appropriate way. The
theoretical model by M. J. Lawrence em et al, JOSA B 16, 523 (1999) agrees with
our observations.Comment: submitted to Josa
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