Network analysis of 3D complex plasma clusters in a rotating electric field

Network analysis was used to study the structure and time evolution of driven three-dimensional complex plasma clusters. The clusters were created by suspending micron-size particles in a glass box placed on top of the rf electrode in a capacitively coupled discharge. The particles were highly charged and manipulated by an external electric field that had a constant magnitude and uniformly rotated in the horizontal plane. Depending on the frequency of the applied electric field, the clusters rotated in the direction of the electric field or remained stationary. The positions of all particles were measured using stereoscopic digital in-line holography. The network analysis revealed the interplay between two competing symmetries in the cluster. The rotating cluster was shown to be more cylindrical than the nonrotating cluster. The emergence of vertical strings of particles was also confirmed.Comment: 9 pages, 9 figures; corrected Fig.4 and typo

Quantum memories for fundamental science in space

Investigating and verifying the connections between the foundations of quantum mechanics and general relativity will require extremely sensitive quantum experiments. To provide ultimate insight into this fascinating area of physics, the realization of dedicated experiments in space will sooner or later become a necessity. Quantum technologies, and among them quantum memories in particular, are providing novel approaches to reach conclusive experimental results due to their advanced state of development backed by decades of progress. Storing quantum states for prolonged time will make it possible to study Bell tests on astronomical baselines, to increase measurement precision for investigations of gravitational effects on quantum systems, or enable distributed networks of quantum sensors and clocks. We here promote the case of exploiting quantum memories for fundamental physics in space, and discuss both distinct experiments as well as potential quantum memory platforms and their performance

BOOST -- A Satellite Mission to Test Lorentz Invariance Using High-Performance Optical Frequency References

BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for violations of Lorentz invariance by comparing two optical frequency references. One is based on a long-term stable optical resonator and the other on a hyperfine transition in molecular iodine. This mission will allow to determine several parameters of the standard model extension in the electron sector up to two orders of magnitude better than with the current best experiments. Here, we will give an overview of the mission, the science case and the payload.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.

Quantum Memories for Fundamental Physics in Space

Investigations into the foundations of quantum mechanics and their link to gravity and general relativity require sensitive quantum experiments. To provide ultimate insight, the realization of such experiments in space will sooner or later become a necessity. With their advanced state and backed by decades of development, quantum technologies and among them quantum memories are providing novel approaches to reach conclusive experimental results. We therefore want to highlight the use case of quantum memories for investigations of fundamental physics in space, and discuss both concrete experiments as well as platforms and performance of candidate quantum memorie

Das Forschungsdatenzentrum der Universität Hamburg

The more recent discussion of research data practices at relevant conferences, workshops and respective publications suggest substantially different foci of problems and solutions in managing data between scientific disciplines. There seems to be a particularly profound gap in natural science and humanities whereas social and life sciences are placed somewhere in between. Indeed data centers tailored to the specific needs of a single discipline (physics, chemistry, climate studies) are numerous in science and tend to be nearly absent for a specific humanities subject. While the former ask for and report solutions on scaling up (larger quantities of data can be run by the same application) and scaling out (larger quantities of data can use the same infrastructure), the latter are concerned with the heterogeneity of relatively small amounts of data (long-tail problem) and a divergence of agreed standards; something we may term as cross scaling. In either case, an efficiency problem has to be solved. On the one hand, huge amounts of data have to be handled within an acceptable time frame, on the other hand, many different applications with diverse functionalities have to be handled with an acceptable number of resources.  We would like to argue here that independent from the discipline either optimization problem should be addressed. Throughout the last decade, we have also observed that projects in science diversify and prefer individualized solutions which additionally hints at increasing data heterogeneity in natural science as well while, at the same time, some humanities projects produce petabytes of data. To show the necessity of a differentiated approach, the research data center of Universität Hamburg is offered as a case in point. The evolution of the center specialized in humanities projects to a research data center offering services for the whole university whereas other disciplinary data centers continue to exist side by side illustrates the entire range of tasks of data stewardship. It includes the continuous development of services while getting more and more involved in natural science projects as well as task sharing and communication with other data institutions. A core asset to understand the requirements of each discipline is a multidisciplinary team. Yet, the main organizing principle of the offered services centers around the stages of the data life cycle (1. data creation and deposit, 2. managing active data, 3. data repositories and archives, 4. data catalog and registries). The interdigitation of these stages is paramount in the long term strategy

Network analysis of 3D complex plasma clusters

Network analysis was used to study the structure and time evolution of driven three-dimensional complex plasma clusters. The clusters were created by suspending micron-size particles in a glass box placed on top of the rf electrode in a capacitively coupled discharge. The particles were highly charged and manipulated by an external electric �eld that had a constant magnitude and rotated uniformly in the horizontal plane. Depending on the frequency of the applied electric �eld, the clusters rotated in the direction of the electric �eld or remained stationary. The three-dimensional positions of all particles were measured using stereoscopic digital in-line holography. The network approach was used to elucidate the structural changes in the cluster consisting only of a very limited number of particles (64). The Analysis revealed an interplay between two competing symmetries in the cluster. Spherical and cylindrical ordering of the particles was examined by comparing network measures of the experimental data with null models. The null models were arti�cial data with a certain number of points in perfectly spherical order, and the rest in cylindrical order. The well established network measures local connectivity, clustering coe�cient and average path length were considered. Network analysis of the clusters showed that the rotating cluster was more cylindrical than the nonrotating cluster. These �ndings were in agreement with the estimate of the radial con�nement with the aid of a dynamical force balance. Neglecting friction and inertial forces due to the low particle velocities in the cluster, the pro�le of the electrical con�nement could be estimated by calculating the repulsing Yukawa-type interaction between the particles. The radial con�nement was shown to be stronger in the case of cluster rotation, increasing the cylindricity of the cluster. The emergence of vertical strings of particles was also con�rmed by using a network analysis. While the traditional method of a �xed threshold has limitations such as erroneously including passing by particles and a somewhat arbitrary threshold, community �nding algorithms yield a more elegant approach of �nding structures in complex systems. With the aid of multislice networks, it is possible to examine the whole time series at once and thus resolve the time evolution of the strings. As we demonstrated, network analysis is a powerful tool to analyze the structure of complex plasma clusters and may have numerous applications in other complex systems where the characertization of the spatial structure plays a vital role.

Microgravity facilities for cold atom experiments

Microgravity platforms enable cold atom research beyond experiments in typical laboratories by removing restrictions due to the gravitational acceleration or compensation techniques. While research in space allows for undisturbed experimentation, technological readiness, availability and accessibility present challenges for experimental operation. In this work we focus on the main capabilities and unique features of ground-based microgravity facilities for cold atom research. A selection of current and future scientific opportunities and their high demands on the microgravity environment are presented, and some relevant ground-based facilities are discussed and compared. Specifically, we point out the applicable free fall times, repetition rates, stability and payload capabilities, as well as programmatic and operational aspects of these facilities. These are contrasted with the requirements of various cold atom experiments. Besides being an accelerator for technology development, ground-based microgravity facilities allow fundamental and applied research with the additional benefit of enabling hands-on access to the experiment for modifications and adjustments

The deep space quantum link: prospective fundamental physics experiments using long-baseline quantum optics

The National Aeronautics and Space Administration's Deep Space Quantum Link mission concept enables a unique set of science experiments by establishing robust quantum optical links across extremely long baselines. Potential mission configurations include establishing a quantum link between the Lunar Gateway moon-orbiting space station and nodes on or near the Earth. This publication summarizes the principal experimental goals of the Deep Space Quantum Link. These goals, identified through a multi-year design study conducted by the authors, include long-range teleportation, tests of gravitational coupling to quantum states, and advanced tests of quantum nonlocality