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Restriction data tranferred 2014-07-01T11:12:17-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 3478342 http://hdl.handle.net/2142/18907 en 1992 Aleksandar Belic deep inelastic scattering quantum liquids neutron scattering impulse approximation Pandharipande, V.R. Belic, Aleksandar 2011-05-04T18:27:47Z 2011-05-04T18:27:47Z 10000-01-01 1992 The impulse approximation and the related concept of the scaling of the dynamic structure function S(k, w) at large k and w have played a dominant role in the analysis of the deep inelastic neutron scattering by quantum liquids. These concepts are reviewed along with the prevalent approximations to treat final state interactions neglected in the impulse approximation. At large momentum transfers it is convenient to express the dynamic structure function S(k, w) as the sum of a part symmetric about w = k2 /2m and an antisymmetric part. The latter is zero in the impulse approximation, and its leading contribution is given by (mjk)2J1(y), where y = (mfk)(w- P /2m) is the usual scaling variable. The integrals of Jt(y), weighted withy, y3 and y5 in liquid 4He are calculated using sum-rules. Polynomial expansions are used to construct models of Jt(y) which appear to be in qualitative agreement with the observed antisymmetric part at large values of k. Next, we study the dynamic structure function S(k,w) of Bose liquids in the asymptotic limit k,w -+ oo at constant y, using the orthogonal correlated basis of Feynman phonon states. This approach has been traditionally and successfully used to study S(k,w) at small k,w, and it appears possible to develop it further to obtain a unified theory of S(k,w) at all k and w. In this thesis, we prove within this approach that S(k,w) scales exactly in the k,w-+ oo limit, as is well known. It is also shown that, within a very good approximation, the scaling function J(y) is determined solely by the static structure function S(q) of the liquid. In contrast, the traditional approach to determining S (k, w) at large k, w is based on the impulse approximation; hA(Y) is solely determined by the momentum distribution n(q) of the particles in the liquid. In weakly interacting systems, where the impulse approximation is exact, the J(y) calculated from the Feynman phonon basis is identical to hA(y). The J(y) of liquid 4He is calculated using this theory and the experimental S(q). It is quite similar to the hA(Y) obtained from the theoretical n(q) ofliquid 4He. A number oftechnical developments in orthogonal correlated basis theories are also reported. Finally, we develop the orthogonal correlated basis formalism that is suitable for studying the dynamic structure function S(k, w) of Fermi liquids in the asymptotic limit k, w --+ oo at constant y. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-04T18:27:47Z No. of bitstreams: 1 1992_belic.pdf: 3975652 bytes, checksum: cd43db561679047e8498ae154d352040 (MD5) Made available in DSpace on 2011-05-04T18:27:47Z (GMT). No. of bitstreams: 1 1992_belic.pdf: 3975652 bytes, checksum: cd43db561679047e8498ae154d352040 (MD5) Previous issue date: 1992 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-04T18:27:47Z Item is restricted indefinitely. dynamic structure function Deep inelastic scattering by quantum liquids Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.