A quasi-pure Bose-Einstein condensate immersed in a Fermi sea

We report the observation of co-existing Bose-Einstein condensate and Fermi gas in a magnetic trap. With a very small fraction of thermal atoms, the 7Li condensate is quasi-pure and in thermal contact with a 6Li Fermi gas. The lowest common temperature is 0.28 muK = 0.2(1) T_C = 0.2(1) T_F where T_C is the BEC critical temperature and T_F the Fermi temperature. Behaving as an ideal gas in the radial trap dimension, the condensate is one-dimensional.Comment: 4 pages, 5 figure

Measurements and Simulation Studies of Piezoceramics for Acoustic Particle Detection

Calibration sources are an indispensable tool for all detectors. In acoustic particle detection the goal of a calibration source is to mimic neutrino signatures as expected from hadronic cascades. A simple and promising method for the emulation of neutrino signals are piezo ceramics. We will present results of measruements and simulations on these piezo ceramics.Comment: 5 pages, 5 figure

Collective Oscillations of an Imbalanced Fermi Gas: Axial Compression Modes and Polaron Effective Mass

We investigate the low-lying compression modes of a unitary Fermi gas with imbalanced spin populations. For low polarization, the strong coupling between the two spin components leads to a hydrodynamic behavior of the cloud. For large population imbalance we observe a decoupling of the oscillations of the two spin components, giving access to the effective mass of the Fermi polaron, a quasi-particle composed of an impurity dressed by particle-hole pair excitations in a surrounding Fermi sea. We find $m^*/m=1.17(10)$, in agreement with the most recent theoretical predictions.Comment: 4 pages, 4 figures, submitted to PR

Multi-component gap solitons in spinor Bose-Einstein condensates

We model the nonlinear behaviour of spin-1 Bose-Einstein condensates (BECs) with repulsive spin-independent interactions and either ferromagnetic or anti-ferromagnetic (polar) spin-dependent interactions, loaded into a one-dimensional optical lattice potential. We show that both types of BECs exhibit dynamical instabilities and may form spatially localized multi-component structures. The localized states of the spinor matter waves take the form of vector gap solitons and self-trapped waves that exist only within gaps of the linear Bloch-wave band-gap spectrum. Of special interest are the nonlinear localized states that do not exhibit a common spatial density profile shared by all condensate components, and consequently cannot be described by the single mode approximation (SMA), frequently employed within the framework of the mean-field treatment. We show that the non-SMA states can exhibits Josephson-like internal oscillations and self-magnetisation, i.e. intrinsic precession of the local spin. Finally, we demonstrate that non-stationary states of a spinor BEC in a lattice exhibit coherent undamped spin-mixing dynamics, and that their controlled conversion into a stationary state can be achieved by the application of an external magnetic field.Comment: 12 pages, 13 figure

Konfliktmanagement durch ECOWAS und SADC – die Rolle Nigerias und Südafrikas in subregionalen Interventionen:ein Beitrag zum Frieden?

Die Arbeit widmet sich der Fragestellung, inwieweit die Southern African Development Community (SADC) und Südafrika sowie die Economic Community of West African States (ECOWAS) und Nigeria einen Beitrag zum Frieden in regionalen Konflikten leisten. Die Analyse zeigt, dass subregionale Organisationen auf dem Kontinent an Bedeutung gewonnen haben. Insbesondere ECOWAS fungiert für Afrika inzwischen als ein Modell einer eigenständig praktizierten Konfliktregulierung. Trotz dieser positiven Erfahrungen tragen die subregionalen Akteure allerdings nicht ausreichend zum Frieden bei. Zum einen fehlt der politische Wille, auch in der Sicherheitspolitik Kompetenzen an überstaatliche Instanzen abzugeben. Zum anderen fehlen Ressourcen. Daher definiert sich Kooperation in strukturschwachen Regionen stark über Schlüsselstaaten wie Nigeria und Südafrika, die meist größere Truppenkontingente zur Verfügung stellen. Zugleich löst ihre Dominanz intra-regionale Spannungen aus und behindert Kooperation. This book examines to what degree the Southern African Development Community (SADC) and South Africa as well as the Economic Community of West African States (ECOWAS) and Nigeria contribute to peace in regional conflicts. The analysis shows that sub-regional organisations play an important role on the continent. Particularly, ECOWAS seems to be a model for an Africa-based conflict-resolution. Nevertheless, neither organisation restores or keeps peace successfully. On the one hand, their members lack political will to hand over competences to supra-national bodies. On the other hand, resource constraints hinder the implementation of an effective peacekeeping. This is the reason why cooperation between states in economically and politically weak regions depends on key states like Nigeria or South Africa. They provide the interventions with significant contingents of troops. However, these states often act in a dominant way that causes intra-regional tensions and weakens cooperation

A smoothing monotonic convergent optimal control algorithm for NMR pulse sequence design

The past decade has demonstrated increasing interests in using optimal control based methods within coherent quantum controllable systems. The versatility of such methods has been demonstrated with particular elegance within nuclear magnetic resonance (NMR) where natural separation between coherent and dissipative spin dynamics processes has enabled coherent quantum control over long periods of time to shape the experiment to almost ideal adoption to the spin system and external manipulations. This has led to new design principles as well as powerful new experimental methods within magnetic resonance imaging, liquid-state and solid-state NMR spectroscopy. For this development to continue and expand, it is crucially important to constantly improve the underlying numerical algorithms to provide numerical solutions which are optimally compatible with implementation on current instrumentation and at same time are numerically stable and offer fast monotonic convergence towards the target. Addressing such aims, we here present a smoothing monotonically convergent algorithm for pulse sequence design in magnetic resonance which with improved optimization stability lead to smooth pulse sequence easier to implement experimentally and potentially understand within the analytical framework of modern NMR spectroscopy

Expansion of a lithium gas in the BEC-BCS crossover

We report on experiments in $^6$Li Fermi gases near Feshbach resonances. A broad s-wave resonance is used to form a Bose-Einstein condensate of weakly bound $^6$Li$_2$ molecules in a crossed optical trap. The measured molecule-molecule scattering length of $170^{+100}_{-60}$ nm at 770 G is found in good agreement with theory. The expansion energy of the cloud in the BEC-BCS crossover region is measured. Finally we discuss the properties of p-wave Feshbach resonances observed near 200 Gauss and new s-wave resonances in the heteronuclear $^6$Li- $^7$Li mixture.Comment: 10 pages, 3 figures, Proceedings of ICAP 200

Perancangan Tugas Akhir Video Musik Slank Bobrokisasi Borokisme

Skripsi : Prancangan Video Musik Slank Bobrokisasi BorokismePerancangan video berjudul “ PRANCANGAN VIDEO MUSIK SLANK BOBRKISASI BOROKISME ” menjawab banyaknya dan maraknya praktek korupsi di Indonesia. Video berdurasi 3: 13 dan menggunakan media sosial seperti youtube dan facebook sehingga mudah diakses. Konsep perancangan video ini menggunakan pendekatan simbolis agar tidak menyudutkan satu pihak dan menjunjung prinsip azas praduga tak bersalah. Materi pembuatan video ini didapatkan dengan menggunakan metode wawancara dengan penggemar slank yang biasa disebut slankers dan masyarakat umum kususnya generasi muda di tambah dengan mengumpulkan artikel dan literatur yang ada tentang korupsi