The magnetoresistance tensor of La(0.8)Sr(0.2)MnO(3)

We measure the temperature dependence of the anisotropic magnetoresistance (AMR) and the planar Hall effect (PHE) in c-axis oriented epitaxial thin films of La(0.8)Sr(0.2)MnO(3), for different current directions relative to the crystal axes, and show that both AMR and PHE depend strongly on current orientation. We determine a magnetoresistance tensor, extracted to 4th order, which reflects the crystal symmetry and provides a comprehensive description of the data. We extend the applicability of the extracted tensor by determining the bi-axial magnetocrystalline anisotropy in our samples

Rydberg excitation of a Bose-Einstein condensate

We have performed two-photon excitation via the 6P3/2 state to n=50-80 S or D Rydberg state in Bose-Einstein condensates of rubidium atoms. The Rydberg excitation was performed in a quartz cell, where electric fields generated by plates external to the cell created electric charges on the cell walls. Avoiding accumulation of the charges and realizing good control over the applied electric field was obtained when the fields were applied only for a short time, typically a few microseconds. Rydberg excitations of the Bose-Einstein condensates loaded into quasi one-dimensional traps and in optical lattices have been investigated. The results for condensates expanded to different sizes in the one-dimensional trap agree well with the intuitive picture of a chain of Rydberg excitations controlled by the dipole-dipole interaction. The optical lattice applied along the one-dimensional geometry produces localized, collective Rydberg excitations controlled by the nearest-neighbour blockade.Comment: 7 pages, 7 figures, Laser Physics in press. arXiv admin note: text overlap with arXiv:1103.423

Planning to fail? Leveraging the Olympic bid

Purpose In recent years, there has been a decline in the number of cities seeking to host the Olympic Games, with several cities withdrawing from the bid process following referenda. The debate around bidding have hinged on the costs and benefits of hosting events, with little consideration as to the benefits of a bid itself. The purpose of this paper is to identify the ways in which Olympic bids be leveraged for positive outcomes, regardless of the outcomes of the bid. Design/methodology/approach This research employs a content analysis, examining the 16 bid responses to the question in the International Olympic Committee Candidate questionnaire: “What will be the benefits of bidding for the Olympic Games for your city/region, irrespective of the outcome of the bid?”. Findings This research found that bid cities do attempt to use the Olympic bid process as a leveraging resource, with four unique opportunities arising from this; national and city pride, Olympism, the formation of networks, and global focus. These provide the opportunities for Olympic bid cities to achieve the following strategic objectives: nation and community building, sport participation, business opportunities, enhancing image and profile, and to push through infrastructural projects. Originality/value There has been little consideration as to the ways an Olympic bid can be used to leverage positive outcomes for a city or a nation, and therefore this research contributes to the literature on leveraging mega-events. The research also has practical value, in providing potential bidders with information regarding positive outcomes whether the bid is successful or not

Giant planar Hall effect in colossal magnetoresistive La0.84Sr0.16MnO3 thin films

The transverse resistivity in thin films of La0.84Sr0.16MnO3 (LSMO) exhibits sharp field-symmetric jumps below TC . We show that a likely source of this behavior is the giant planar Hall effect combined with biaxial magnetic anisotropy. The effect is comparable in magnitude to that observed recently in the magnetic semiconductor Ga(Mn)As. It can be potentially used in applications such as magnetic sensors and nonvolatile memory devices

Rubidium Rydberg macrodimers

We explore long-range interactions between two atoms excited into high principal quantum number n Rydberg states, and present calculated potential energy surfaces (PES) for various symmetries of doubly excited ns and np rubidium atoms. We show that the PES for these symmetries exhibit deep (~GHz) potential wells, which can support very extended (~micrometers) bound vibrational states (macrodimers). We present n-scaling relations for both the depth De of the wells and the equilibrium separations Re of these macrodimers, and explore their response to small electric fields and stability with respect to predissociation. Finally, we present a scheme to form and study these macrodimers via photoassociation, and show how one can probe the various \ell-character of the potential wells

Ion detection in the photoionization of a Rb Bose-Einstein condensate

Two-photon ionization of Rubidium atoms in a magneto-optical trap and a Bose-Einstein condensate (BEC) is experimentally investigated. Using 100 ns laser pulses, we detect single ions photoionized from the condenstate with a 35(10)% efficiency. The measurements are performed using a quartz cell with external electrodes, allowing large optical access for BECs and optical lattices.Comment: 14 pages, 7 figure