Carsten Henkel

Learn More
The accurate measurement of extragalactic distances is a central challenge of modern astronomy, being required for any realistic description of the age, geometry and fate of the Universe. The measurement of relative extragalactic distances has become fairly routine, but estimates of absolute distances are rare. In the vicinity of the Sun, direct geometric(More)
A transport theory for atomic matter waves in low-dimensional waveguides is outlined. The thermal fluctuation spectrum of magnetic near fields leaking out of metallic microstructures is estimated. The corresponding scattering rate for paramagnetic atoms turns out to be quite large in micrometer-sized waveguides (approx. 100/s). Analytical estimates for the(More)
The limitations for the coherent manipulation of neutral atoms with fabricated solid state devices, so-called ‘atom chips’, are addressed. Specifically, we examine the dominant decoherence mechanism, which is due to the magnetic noise originating from the surface of the atom chip. It is shown that the contribution of fluctuations in the chip wires at the(More)
Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830–211, which is by far the best known target to study dense cool gas in absorption at intermediate redshift. Determining average radial velocities and performing Large Velocity Gradient radiative(More)
We observed the upper fine structure line of neutral carbon, C I(3P2 → 3P1) (νrest = 809GHz), the CO(J=3→2) line (νrest = 345GHz) and the 1.2mm continuum emission from H1413+117 (Cloverleaf quasar, z = 2.5) using the IRAM interferometer. Together with the detection of the lower fine structure line (Barvainis et al. 1997), the Cloverleaf quasar is now only(More)
The aim of this paper is to revisit the calculation of atom-surface quantum friction in the quantum field theory formulation put forward by Barton (2010 New J. Phys. 12 113045). We show that the power dissipated into field excitations and the associated friction force depend on how the atom is boosted from being initially at rest to a configuration in which(More)
We describe a simple mechanism of quantum friction for a particle moving parallel to a dielectric, based on a fully relativistic framework and the assumption of local equilibrium. The Cherenkov effect explains how the bare ground state becomes globally unstable and how fluctuations of the electromagnetic field and the particle's dipole are converted into(More)
Aims. Molecules that trace the high-density regions of the interstellar medium have been observed in (ultra-)luminous (far-)infrared galaxies, in order to initiate multiple-molecule multiple-transition studies to evaluate the physical and chemical environment of the nuclear medium and its response to the ongoing nuclear activity. Methods. The HCN(1−0),(More)
We report Karl G. Jansky Very Large Array (VLA) absorption spectroscopy in four methanol (CH3OH) lines in the z = 0.885 82 gravitational lens towards PKS1830−211. Three of the four lines have very different sensitivity coefficientsKμ to changes in the proton–electron mass ratio μ; a comparison between the line redshifts thus allows us to test for temporal(More)
We report the detection of the CO 4–3, 6–5, 9–8, 10–9, and 11–10 lines in the Broad Absorption Line quasar APM08279+5255 at z = 3.9 using the IRAM 30m telescope. We also present IRAM PdBI high spatial resolution observations of the CO 4–3 and 9–8 lines, and of the 1.4mm dust radiation as well as an improved spectrum of the HCN(5–4) line. Unlike CO in other(More)