Correlation between non-invasive optimal vessel volume flow rate and time-of-flight signal intensity ratio: value in unilateral internal carotid artery occlusion

Non-invasive optimal vessel analysis quantitative magnetic resonance angiography (NOVA-QMRA) is increasingly recognized as an effective method for measuring cerebral blood flow in individuals suffering from intracranial atherosclerotic disease (ICAD). This study aimed to investigate the potential relationship between volume flow rate (VFR) obtained through NOVA-QMRA and the signal intensity ratio (SIR) from time-of-flight (TOF) MRA in bilateral M1- and P2-segments of patients with unilateral internal carotid artery (ICA) occlusion

A scheme for quantum-logic based transfer of accuracy in polarizability measurement for trapped ions using a moving optical lattice

Optical atomic clocks based on trapped ions suffer from systematic frequency shifts of the clock transition due to interaction with blackbody radiation from the environment. These shifts can be compensated if the blackbody radiation spectrum and the differential dynamic polarizability is known to a sufficient precision. Here, we present a new measurement scheme, based on quantum logic that allows a direct transfer of precision for polarizability measurements from one species to the other. This measurement circumvents the necessity of calibrating laser power below the percent level, which is the limitation for state-of-the-art polarizability measurements in trapped ions. Furthermore, the presented technique allows to reference the polarizability transfer to hydrogen-like ions for which the polarizability can be calculated with high precision

The panopticon of Germany’s foreign trade, 1880–1913: New facts on the first globalization

We present and analyze the panopticon of Germany’s foreign trade, with new data on all products, all trade partners, quantities, and values, at annual frequency, 1880–1913. Historical product categories are reclassified according to the Standard International Trade Classification (SITC) to ensure comparability over time and across countries. Germany became increasingly specialized in manufacturing, in line with theories of comparative advantage. However, most trade growth occurred along the extensive margin, and 20–25 percent of trade was intra-industry trade, at five-digit SITC. Both facts suggest substantial within-sector heterogeneity. We discuss why this matters for our understanding of the first globalization.Peer Reviewe

Efficient sympathetic motional ground-state cooling of a molecular ion

Cold molecular ions are promising candidates in various fields ranging from precision spectroscopy and test of fundamental physics to ultra-cold chemistry. Control of internal and external degrees of freedom is a prerequisite for many of these applications. Motional ground state cooling represents the starting point for quantum logic-assisted internal state preparation, detection, and spectroscopy protocols. Robust and fast cooling is crucial to maximize the fraction of time available for the actual experiment. We optimize the cooling rate of ground state cooling schemes for single $^{25}\mathrm{Mg}^{+}$ ions and sympathetic ground state cooling of $^{24}\mathrm{MgH}^{+}$. In particular, we show that robust cooling is achieved by combining pulsed Raman sideband cooling with continuous quench cooling. Furthermore, we experimentally demonstrate an efficient strategy for ground state cooling outside the Lamb-Dicke regime.Comment: 11 pages, 11 figure

Welche Bedeutung haben Unternehmenscharakteristika und regionales Umfeld für die Beschäftigungsdynamik? Eine mikroökonometrische Analyse für das ostdeutsche Verarbeitende Gewerbe

In this paper, we analyse the influence of firm characteristics and the regional environment on employment growth of East German manufacturing firms between 1992 and 1996. Our results confirm the negative impact of firm size and age on employment growth found in various studies for several developed economies. An additional negative effect far firms which have emerged from former state-owned establishments can only be observed for firms with more than nine employees. Our analysis also shows some evidence that there exists a positive influence of localization economies on the firm specific growth rate of employment. Furthermore. the regional wage rate influences the growth rate in the expected way. --

Detection of motional ground state population of a trapped ion using delayed pulses

Efficient preparation and detection of the motional state of trapped ions is important in many experiments ranging from quantum computation to precision spectroscopy. We investigate the stimulated Raman adiabatic passage (STIRAP) technique for the manipulation of motional states in a trapped ion system. The presented technique uses a Raman coupling between two hyperfine ground states in $^{25}$Mg$^+$, implemented with delayed pulses, which removes a single phonon independent of the initial motional state. We show that for a thermal state the STIRAP population transfer is more efficient than a stimulated Raman Rabi pulse on a motional sideband. In contrast to previous implementations, a large detuning of more than 200 times the natural linewidth of the transition is used. This approach renders STIRAP suitable for atoms in which resonant laser fields would populate fluorescing excited states and thus impede the STIRAP process. We use the technique to measure the wavefunction overlap of excited motional states with the motional ground state. This is an important application for photon recoil spectroscopy and other force sensing applications that utilize the high sensitivity of the motional state of trapped ions to external fields. Furthermore, a determination of the ground state population enables a simple measurement of the ion's temperature.Comment: 17 pages, 7 figure

Quantum sensing of oscillating electric fields with trapped ions

Quantum noise is a fundamental limitation for quantum sensors and results in the so-called shot-noise limit. Nowadays, several systems such as optical clocks or gravitational wave detectors approach measurement sensitivities where this limitation poses a major contribution to the total statistical uncertainty. It is known that this limit can be overcome by preparing the probe in a non-classical state. We will give an overview over the different non-classical states that have been implemented in the motion of single trapped ions and discuss their individual advantages and limitations in metrology. Possible applications for the presented experiments are the measurement of small oscillating electric fields and trapping frequencies. The Focus will be on our experimental work on Fock states, where quantum-enhanced sensing in both scenarios is possible with the same quantum state