Finite temperature phase diagram of a spin-1 Bose gas

We formulate a self-consistent Hartree-Fock theory for a spin-1 Bose gas at finite temperature and apply it to characterizing the phase diagram. We find that spin coherence between thermal atoms in different magnetic sub-levels develops via coherent collisions with the condensed atoms, and is a crucial factor in determining the phase diagram. We develop analytical expressions to characterize the interaction and temperature dependent shifts of the phase boundaries.Comment: 11 pages, 5 figure

Effects of thermal and quantum fluctuations on the phase diagram of a spin-1 87Rb Bose-Einstein condensate

We investigate effects of thermal and quantum fluctuations on the phase diagram of a spin-1 87Rb Bose-Einstein condensate (BEC) under a quadratic Zeeman effect. Due to the large ratio of spinindependent to spin-dependent interactions of 87Rb atoms, the effect of noncondensed atoms on the condensate is much more significant than that in scalar BECs. We find that the condensate and spontaneous magnetization emerge at different temperatures when the ground state is in the brokenaxisymmetry phase. In this phase, a magnetized condensate induces spin coherence of noncondensed atoms in different magnetic sublevels, resulting in temperature-dependent magnetization of the noncondensate. We also examine the effect of quantum fluctuations on the order parameter at absolute zero, and find that the ground-state phase diagram is significantly altered by quantum depletion.Comment: Comment: 21 pages, 7 figures Comment: 20 pages, 7 figures, paper reconstructed, nomenclature changed, references added, grammatical errors correcte

Accessibility of the resources of near Earth space using multi-impulse transfers

Most future concepts for exploration and exploitation of space require a large initial mass in low Earth orbit. Delivering this mass requires overcoming Earth's natural gravity well, which imposes a distinct obstacle to space-faring. An alternative for future space progress is to search for resources in-situ among the near Earth asteroid population. This paper examines the scenario of future utilization of asteroid resources. The near Earth asteroid resources that could be transferred to a bound Earth orbit are determined by integrating the probability of finding asteroids inside the Keplerian orbital element space of the set of transfers with an specific energy smaller than a given threshold. Transfers are defined by a series of impulsive maneuvers and computed using the patched-conic approximation. The results show that even moderately low energy transfers enable access to a large mass of resources

On the classical equivalence of monodromy matrices in squashed sigma model

We proceed to study the hybrid integrable structure in two-dimensional non-linear sigma models with target space three-dimensional squashed spheres. A quantum affine algebra and a pair of Yangian algebras are realized in the sigma models and, according to them, there are two descriptions to describe the classical dynamics 1) the trigonometric description and 2) the rational description, respectively. For every description, a Lax pair is constructed and the associated monodromy matrix is also constructed. In this paper we show the gauge-equivalence of the monodromy matrices in the trigonometric and rational description under a certain relation between spectral parameters and the rescalings of sl(2) generators.Comment: 32pages, 3figures, references added, introduction and discussion sections revise

Bistability patterns and nonlinear switching with very high contrast ratio in a 1550 nm quantum dash semiconductor laser

We report on the experimental observation of optical bistability (OB) and nonlinear switching (NS) in a nanostructure laser; specifically a 1550 nm quantum dash Fabry-Perot laser subject to external optical injection and operated in reflection. Different shapes of optical bistability and nonlinear switching, anticlockwise and clockwise, with very high on-off contrast ratio (up to 180:1) between output states were experimentally measured. These results added to the potential of nanostructure lasers for enhanced performance offer promise for use in fast all-optical signal processing applications in optical networks. © 2012 American Institute of Physics

The classical origin of quantum affine algebra in squashed sigma models

We consider a quantum affine algebra realized in two-dimensional non-linear sigma models with target space three-dimensional squashed sphere. Its affine generators are explicitly constructed and the Poisson brackets are computed. The defining relations of quantum affine algebra in the sense of the Drinfeld first realization are satisfied at classical level. The relation to the Drinfeld second realization is also discussed including higher conserved charges. Finally we comment on a semiclassical limit of quantum affine algebra at quantum level.Comment: 25 pages, 2 figure

Lunin-Maldacena backgrounds from the classical Yang-Baxter equation -- Towards the gravity/CYBE correspondence

We consider \gamma-deformations of the AdS_5xS^5 superstring as Yang-Baxter sigma models with classical r-matrices satisfying the classical Yang-Baxter equation (CYBE). An essential point is that the classical r-matrices are composed of Cartan generators only and then generate abelian twists. We present examples of the r-matrices that lead to real \gamma-deformations of the AdS_5xS^5 superstring. Finally we discuss a possible classification of integrable deformations and the corresponding gravity solution in terms of solutions of CYBE. This classification may be called the gravity/CYBE correspondence.Comment: 18 pages, no figure, LaTeX, v2:references and further clarifications adde

Classical integrability of Schrodinger sigma models and q-deformed Poincare symmetry

We discuss classical integrable structure of two-dimensional sigma models which have three-dimensional Schrodinger spacetimes as target spaces. The Schrodinger spacetimes are regarded as null-like deformations of AdS_3. The original AdS_3 isometry SL(2,R)_L x SL(2,R)_R is broken to SL(2,R)_L x U(1)_R due to the deformation. According to this symmetry, there are two descriptions to describe the classical dynamics of the system, 1) the SL(2,R)_L description and 2) the enhanced U(1)_R description. In the former 1), we show that the Yangian symmetry is realized by improving the SL(2,R)_L Noether current. Then a Lax pair is constructed with the improved current and the classical integrability is shown by deriving the r/s-matrix algebra. In the latter 2), we find a non-local current by using a scaling limit of warped AdS_3 and that it enhances U(1)_R to a q-deformed Poincare algebra. Then another Lax pair is presented and the corresponding r/s-matrices are also computed. The two descriptions are equivalent via a non-local map.Comment: 20 pages, no figure, further clarification and references adde

The Roles of ADAMs Family Proteinases in Skin Diseases

A disintegrin and metalloproteinases (ADAMs) are members of a new gene family of transmembrane and secreted proteins, which belong to the zinc proteinase superfamily. These molecules are involved in various biological events such as cell adhesion, cell fusion, cell migration, membrane protein shedding, and proteolysis. Growing evidence now attests to the potential involvement of ADAMs proteinases in diverse processes such as skin wound healing, inflammation, pigmentation, tumor development, cell proliferation, and metastasis. This paper focuses on the roles of ADAMs proteinases in a wide variety of skin diseases

Feasibility study of an Integrated Program for Aerospace vehicle Design (IPAD). Volume 1B: Concise review

Reports on the design process, support of the design process, IPAD System design catalog of IPAD technical program elements, IPAD System development and operation, and IPAD benefits and impact are concisely reviewed. The approach used to define the design is described. Major activities performed during the product development cycle are identified. The computer system requirements necessary to support the design process are given as computational requirements of the host system, technical program elements and system features. The IPAD computer system design is presented as concepts, a functional description and an organizational diagram of its major components. The cost and schedules and a three phase plan for IPAD implementation are presented. The benefits and impact of IPAD technology are discussed