19,652 research outputs found

    Complexity bounds on supermesh construction for quasi-uniform meshes

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    Projecting fields between different meshes commonly arises in computational physics. This operation requires a supermesh construction and its computational cost is proportional to the number of cells of the supermesh nn. Given any two quasi-uniform meshes of nAn_A and nBn_B cells respectively, we show under standard assumptions that n is proportional to nA+nBn_A + n_B. This result substantially improves on the best currently available upper bound on nn and is fundamental for the analysis of algorithms that use supermeshes

    The Zel'dovich effect in harmonically trapped, ultra-cold quantum gases

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    We investigate the Zel'dovich effect in the context of ultra-cold, harmonically trapped quantum gases. We suggest that currently available experimental techniques in cold-atoms research offer an exciting opportunity for a direct observation of the Zel'dovich effect without the difficulties imposed by conventional condensed matter and nuclear physics studies. We also demonstrate an interesting scaling symmetry in the level rearragements which has heretofore gone unnoticed

    Superorbital Period in the High Mass X-ray Binary 2S 0114+650

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    We report the detection of a superorbital period in the high-mass X-ray binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously reported neutron star spin period of 2.7 h and the binary orbital period of 11.6 d. It is unclear if the superorbital period can be ascribed to the precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript expanded to include discussion of evolution of periods, and hardness ratio variability. Number of figures increased from 5 to 9. Accepted for publication 19th December 200
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