オオサカダイガク ニ オケル サイシュウ コウギ ヲ モト ニ ダイイチブ サイエンスロコミュニケーション ノ ジッセン ダイニブ ダイガク ノ キョウイク コクサイカ ノ ホウコウ

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Ab-initio study of SrTiO3 surfaces

We present first-principles total-energy calculations of (001) surfaces of SrTiO3. Both SrO-terminated and TiO2-terminated surfaces are considered, and the results are compared with previous calculations for BaTiO3 surfaces. The major differences are in the details of the relaxed surface structures. Our calculations argue against the existence of a large ferroelectric relaxation in the surface layer, as had been previously proposed. We do find some indications of a weak surface ferroelectric instability, but so weak as to be easily destroyed by thermal fluctuations except perhaps at quite low temperatures. We also compute surface relaxation energies and surface electronic band structures, obtaining results that are generally similar to those for BaTiO3.Comment: 11 pages with 2 postscript figures embedded. Uses Elsevier (elsart) macros (provided) as well as epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#pad_st

Jordan Decomposition of Non-Hermitian Fermionic Quadratic Forms

We give a rigorous proof of Conjecture 3.1 by Prosen [Prosen T 2010 J. Stat. Mech. $\textbf{2010}$ P07020] on the nilpotent part of the Jordan decomposition of a quadratic fermionic Liouvillian. We also show that the number of the Jordan blocks of each size can be expressed in terms of the coefficients of a polynomial called the $q$-binomial coefficient and describe the procedure to obtain the Jordan canonical form of the nilpotent part.Comment: 11 pages, no figure