[en] The investigation of dilute gases of ultracold atoms is currently a fast growing field, both in experimental and theoretical physics. Major research directions include the simulation of condensed matter systems, the investigation of superfluidity and the realization of controlled quantum chemistry. In this thesis we present our contributions in form of several experiments covering four different topics, sharing the usage of optical lattice potentials and the tunability of interatomic interactions. In a three-dimensional optical lattice, we investigate the properties of ultracold atoms for various interatomic interaction strengths. Such a system can be described by the Bose-Hubbard model, which originates from solid state physics. For large repulsive values of the interaction strength, we create a strongly interacting system and show the breakdown of the basic assumptions of the Bose Hubbard model by precisely measuring the excitation spectrum. When preparing a Mott insulating state and subsequently changing to attractive interactions, we observe a surprising stability and find indications that the system stabilizes itself via inhibited three-body loss, grounded on the quantum zeno effect. We examine the dynamics of matter waves along a lattice potential by analyzing Bloch oscillations, which occur when a force is applied along the lattice direction. The effect of interactions and of external force gradients is investigated in detail, and we can demonstrate the analog between this system and the Talbot effect known from classical optics. When modulating the applied force, we observe large oscillations in position space, so called super Bloch oscillations, which can be used to induce transport along the lattice direction without dissipation. In a set of experiments, we achieved the production of ultracold rovibronic groundstate molecules, a prerequisite for many fundamental studies in quantum chemistry. We associate ultracold atoms to weakly bound dimers employing a Feshbach resonance, and use an optical lattice to shield the molecules against inelastic collisions. Subsequently we transfer them into the rovibronic ground state using the STIRAP technique, removing a binding energy corresponding to a temperature of 5200K without additional heading. This allows full control over all internal and external degrees of freedom. Elongated tubes created by an optical lattice potential realize an effective one-dimensional geometry, which we use to study the physical models describing such systems. For strong repulsive interactions we enter deeply into the regime of the Tonks-Girardeau gas, a gas of impenetrable pointlike particles. Employing a confinement induced resonance, we can switch the interactions to strong attractive values and thereby prepare a novel, highly excited quantum phase, the Super-Tonks-Girardeau gas. By adding a weak lattice along the tubes, we observe the so-called pinning quantum phase transition from a Luttinger liquid to a Mott insulator. (author)

No abstract available

[en] We are addressing the need to measure nuclear wastes, residues, and spent fuel in order to process these for final disposition. For example, TRU wastes destined for the WIPP must satisfy extensive characterization criteria outlined in the Waste Acceptance Criteria, the Quality Assurance Program Plan, and the Performance Demonstration Plan. Similar requirements exist for spent fuel and residues. At present, no nondestructive assay (NDA) instrumentation is capable of satisfying all of the PDP test cycles (particularly for Remote-Handled TRU waste). One of the primary methods for waste assay is by active neutron interrogation. We plan to improve the capability of all active neutron systems by providing a higher intensity neutron source (by about a factor of 1,000) for essentially the same cost, power, and space requirements as existing systems. This high intensity neutron source will be an electrostatically confined (IEC) plasma device. The IEC is a symmetric sphere that was originally developed in the 1950s as a possible fusion reactor. It operates as D-T neutron generator. Although it was not believed to scale to fusion reactor levels, these experiments demonstrated a neutron yield of 2 x 1010 neutrons/second on table-top experiments that could be powered from ordinary laboratory circuits (10 kilowatts). Subsequently, the IEC physics has been extensively studied at the University of Illinois and other locations. We have established theoretically the basis for scaling the output up to 1x1011 neutrons / second. In addition, IEC devices have run for cumulative times approaching 10,000 hours, which is essential for practical application to NDA. They have been operated in pulsed and continuous mode. The essential features of the IEC plasma neutron source, compared to existing sources of the same cost, size and power consumption, are: Table 1: Present and Target Operating Parameters for Small Neutron Generators Parameter Present IEC Target or Already Proven Neutron Yield (n/s) 108 1011 Lifetime (hours) 500 10,000 Operation Pulsed Pulsed or steady state Nominal cost $k $100k Same Power 1kW 10kW

[en] We are addressing the need to measure nuclear wastes, residues, and spent fuel in order to process these for final disposition. For example, TRU wastes destined for the WIPP must satisfy extensive characterization criteria outlined in the Waste Acceptance Criteria, the Quality Assurance Program Plan, and the Performance Demonstration Plan. Similar requirements exist for spent fuel and residues. At present, no nondestructive assay (NDA) instrumentation is capable of satisfying all of the PDP test cycles (particularly for Remote-Handled TRU waste). One of the primary methods for waste assay is by active neutron interrogation. The objective of this project is to improve the capability of all active neutron systems by providing a higher intensity neutron source (by about a factor of 1,000) for essentially the same cost, power, and space requirements as existing systems. This high intensity neutron source is an electrostatically confined (IEC) plasma device. The IEC is a symmetric sphere that was originally developed in the 1960s as a possible fusion reactor. It operates as DT neutron generator. Although it is not likely that this device will scale to fusion reactor levels, previous experiments1 have demonstrated a neutron yield of 2 x 1010 neutrons/second on a table-top device that can be powered from ordinary laboratory circuits (9 kilowatts). Subsequently, the IEC physics has been extensively studied at the University of Illinois and other locations. We have established theoretically the basis for scaling the output up to 1 x 1011 neutrons/second. In addition, IEC devices have run for cumulative times approaching 10,000 hours, which is essential for practical application to NDA. They have been operated in pulsed and continuous mode. The essential features of the IEC plasma neutron source, compared to existing sources of the same cost, size and power consumption, are: Table 1: Present and Target Operating Parameters for Small Neutron Generators Parameter Present IEC Target or Already Proven Neutron Yield (n/s) 108 1011 Lifetime (hours) 500 10,000 Operation Pulsed Pulsed or steady state Nominal cost $k $100k Same Power 1kW 25kW 5. Methods and Results: The design of a conventional IEC source is deceptively simple. The basic system is a spherical vacuum chamber containing a spherical grid. The grid is raised to a high negative potential. A breakdown develops between the chamber wall and the grid, and this plasma becomes a source of positive deuterium and tritium ions. These ions are accelerated to the center of the vacuum chamber sphere where they may collide. The ion energy may achieve the full potential of the accelerating grid. If the grid is raised to a nominal 100 kV, the D-T fusion cross section becomes large and the neutron production proceeds. The IEC concept was initially developed in the 1950s and 1960s by R. L. Hirsch and collaborators. It was originally proposed as a possible plasma fusion energy device. The idea was initially presented to the DOE with a table-top experiment using ordinary office power. That system produced in excess of 106 neutrons per second. Although the IEC was not favored for a future electric energy generator, the application as a potential neutron source was clearly established. Using nominal laboratory power and a modest sized sphere, Hirsch was able to achieve a maximum neutron yield of 2xl010 neutrons per second (in D-T)in the mid 1960s

[en] Report over the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013

[en] The long-term limit motions of individual heavy-tailed (power-law) particle jumps that characterize anomalous diffusion may have different scaling rates in different directions. Operator stable motions {Y(t):t≥0} are limits of d-dimensional random jumps that are scale-invariant according to c^HY(t)=Y(ct), where H is a dxd matrix. The eigenvalues of the matrix have real parts 1/α_j, with each positive α_j≤2. In each of the j principle directions, the random motion has a different Fickian or super-Fickian diffusion (dispersion) rate proportional to t^1/α_j. These motions have a governing equation with a spatial dispersion operator that is a mixture of fractional derivatives of different order in different directions. Subsets of the generalized fractional operator include (i) a fractional Laplacian with a single order α and a general directional mixing measure m(θ); and (ii) a fractional Laplacian with uniform mixing measure (the Riesz potential). The motivation for the generalized dispersion is the observation that tracers in natural aquifers scale at different (super-Fickian) rates in the directions parallel and perpendicular to mean flow

[en] The Jefferson Lab program to measure the symmetry energy of neutron-rich nuclear matter, using precision electroweak methods, is progressing well. The initial measurement by the PREX experiment, leading to a 2-sigma determination of the 'neutron skin' in ²⁰⁸Pb, has been published. Design and preparation for a further, more-precise measurement on ²⁰⁸Pb is progressing well and there is general acceptance of the great advantage to a further measurement on ⁴⁸Ca. The surprising ancillary result that the beam-normal single-spin asymmetry for ²⁰⁸Pb is consistent with zero is also now in the literature. This paper will discuss the current experimental situation of the program

[en] Different cultivars of bush beans (Phaseolus vulgaris L.) originating from Central and Southern Europe were grown from July to August/September 1993 up to 7 and 8 weeks, respectively, in two greenhouses covered by different UV-B-absorbing (280-320nm) plastic foils. By using the ambient UV-B radiation of the southern location (Portugal, 38.7°N, 9.1°W) in one of the greenhouses as intense UV-B radiation compared to the reduced radiation in the second greenhouse at the same place, a difference in UV-B of about 8–10% was simulated. All cultivars examined showed significant reductions in height of up to 31,8% in most growth phases under intense UV-B. Also fresh and dry weight as well as leaf area were reduced under intense UV-B in the cultivars Purple Teepee, Cropper Teepee and Goldstrahl, and in early growth phases also in Coco bianco, but with ongoing development this cultivar caught up. Cultivars Hilds Maja, Primel, Manata and Cannellino exhibited no UV-B effects on weight and leaf area. A flowering delay of up to 1 day was observed under intense UV-B in several cultivars. Probably due to this delay the yield (fresh weight of fruits) decreased in all cultivars up to 55% under intense UV-B at harvest time, while the potential yield (sum of buds, opened flowers and fruits) was reduced only in the cultivars Cropper Teepee, Purple Teepee, Cannellino and Goldstrahl. The UV-sensitivity index (UVSI) calculated according to the UV induced changes in growth, dry weight and yield at the second harvest date has shown that all cultivars are UV-sensitive, however the index was numerically higher for Southern European cultivars (average = 2.5) than for Central European ones (average = 2.3) which means that the first group was slightly less UV-sensitive than the second. (author)

[en] Hall A at Jefferson Lab has recently completed three experiments done using the technique of parity-violating electron scattering. Taken together these experiments are a good demonstration of the versatility of this approach. Looking forward, there are two very large scale parity-violation experiments approved to run in Hall A in the 12 GeV era. These experiments represent a significant increase in precision and technical requirements.

[en] Hall A at Jefferson Lab has recently completed three experiments done using the technique of parity-violating electron scattering. Taken together these experiments are a good demonstration of the versatility of this approach. Looking forward, there are two very large scale parity-violation experiments approved to run in Hall A in the 12 GeV era. These experiments represent a significant increase in precision and technical requirements