In this study we investigate the properties of trapped atoms subjected to rapid rotations. The study is divided into two distinct parts, one for fermions, another for bosons. In the case of the degenerate Fermi gas we explore the density structure of non-interacting cold atoms when they are rotated rapidly. On the other hand, for rapidly rotating two component Bose condensate, we search for new lattice structures in the presence of contact and dipolar interactions. First, the density structure of Fermi gases in a rotating trap is investigated. We focus on the anisotropic trap case, in which two distinct regimes, two and one dimensional regimes, depending on rotation frequency and anisotropy are observed. Two regimes can be illustrated by a simple description of maximum number of states between two Landau levels, which is strongly related to the dimensionality of the system. The regimes are separated from each other by a minimum point in this description. For small anisotropy values the density profiles show a step structure where each step is demonstrated by an elliptical plateau. Each plateau represents a Landau level with a constant density. The local density approximation describes the two dimensional regime with a perfect similarity in the structure of fermion density. The case for one dimensional regime is a little different from the two dimensional case. For large anisotropy values the Friedel oscillation is the dominant aspect of the density profiles. The density profiles show gaussian structure along the direction of strong trapping, and a semicircular form with prominent oscillations along the weak confining direction. Again, the system is nicely described by local density approximation in this regime. A smooth crossover between two regimes is observed, with a switching from a step structure profile to a soft edge transition with Friedel oscillations. At finite temperatures, the step structures are smeared out in two dimension. In one dimensional regime the Friedel oscillations are cleaned as soon as the temperature is turned on. The second part of the study is devoted to the investigation of different lattice structures in two component Bose condensates subjected to very fast rotation, this time in the presence of interactions. We explore the existence of new vortex lattice structures for dipolar two component condensates scanning a wide range of interaction strengths. We introduce a phase diagram as a function of intra and inter-component interactions showing different type of vortex lattice structures. New types of lattice structures, overlapped square and overlapped rectangular, emerge as a result of dipolar interactions and s-wave interaction for a two component condensate. The region where the attractive inter-component interactions dominate the repulsive interactions, the overlapped lattices are formed. The intra-component interactions, which defines the behavior of each component inside, result in different type of lattices by changing the strength of interactions. Two different limits of phase diagram reproduce the results of ordinary two component and dipolar one component Bose condensates. The results of calculation are in agreement with the results of previous studies for two regimes.

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for the Observations of Stars (ESPaDOnS) spectropolarimeter at the Canada–France–Hawaii Telescope and the Narval spectropolarimeter at the Télescope Bernard Lyot. Using least-squares deconvolution we obtain definite detections of signal in Stokes V in three observations. No significant signal is detected in the diagnostic null (N) spectra. The Zeeman signatures are broad and track the radial velocity of the secondary component; we therefore conclude that the rapidly rotating secondary component is the magnetized star. Correcting the polarized spectra for the line and continuum of the (sharp-lined) primary, we measured the longitudinal magnetic field from each observation. The longitudinal field of the secondary is variable and exhibits extreme values of −810 ± 150 and +680 ± 190 G, implying a minimum surface dipole polar strength of 2850 ± 500 G. In contrast, we derive an upper limit (3σ) to the primary's surface magnetic field of 230 G. The combination of a strong magnetic field and rapid rotation leads us to conclude that the secondary hosts a centrifugal magnetosphere fed through a magnetically confined wind. We revisit the properties of the optical line profiles and X-ray emission – previously interpreted as a consequence of colliding stellar winds – in this context. We conclude that HD 47129 represents a heretofore unique stellar system – a close, massive binary with a rapidly rotating, magnetized component – that will be a rich target for further study.