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　特別プログラム留学生 MD. Atiqur Rahman Patoary君の修士論文発表会を下記のように開催しますので，御出席よろしくお願いします．

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CENTER:修士論文発表会


''発表者'':　　　Patoary MD. Atiqur Rahman

''発表題目'':　  A Momentum Dependent Variational Ansatz to Correlated Electrons in Solids
　　　　　　　　　（固体における電子相関の運動量依存変分理論）


''日時'':　　　　８月１２日(木)　１６：３０〜１７：００

''場所'':　　　　理学部本館　３１３教室


CENTER:Abstract

>We propose a new momentum dependent local-ansatz wavefunction approach 
(MLA) and develop the method to solve a self-consistent equation for 
variational parameters in order to describe the correlated electron 
system in solids. Within the first-order approximate solution 
interpolating between the weak and strong Coulomb interaction limits 
we performed the numerical calculations for the half-filled band 
as well as non-half-filled band in the Hubbard model on the hypercubic 
lattice in infinite dimensions. We verified that the self-consistent 
MLA much improves the correlation energy and the momentum distribution 
as compared with the non-self-consistent MLA.  The result indicates 
that the new approximate solution with use of the self-consistent 
variational parameters is significantly important.  We also demonstrate 
that the theory much improves the standard variational methods such as 
the Local-Ansatz approach (LA) and the Gutzwiller wavefunction approach 
(GA). In fact the ground-state energy in the MLA is lower than those of 
the LA and the GA in the weak and intermediate Coulomb interaction regimes. 
The double occupation number is suppressed as compared with the LA. 
Especially, we find that calculated momentum distribution functions show 
a distinct momentum dependence, which is qualitatively different from 
those of the LA and the GA
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