Direct correlation functions, quantum fluid

Closely related to the QHS fluid is the QHSY fluid. In this regard, one notes that while QHS state points can be characterized with two parameters, that is, (Ag, pI ), QHSY state points need two additional parameters, which are the de Boer quantumness /C=hl(me(T and the inverse range of the attraction k = kdifferent ranges of conditions within (0.2 < A < 0.6 0.27 pi 0.5). Use of direct correlation functions (BDH) was also made, and its reliability to identify the onset of critical behavior was clearly stated [108]. These QHSY studies covered the following issues mechanical and pair structural properties [108] the asymptotic behavior of the pair radial correlations, with a view to the existence of FW lines [159] and the features of triplet correlations in Fourier space [161]. 

The scheme proposed by the author consists in the direct application of the classical OZ2 Eq. (Ill) followed by the use of BDH+GC. In view of the patent differences between the classical and the PI quantum partition functions regarding functional calculus (e.g., ET2 problems, or problems related to the factor in Eq. (89)) [138], one might wonder about the general reliability of this classi-cal-like scheme. There is evidence, however, that supports its applicability. First, in the same sense as in the classical domain, this OZ2 scheme is exact for (a) CM2 correlations in PI, GFH, ISVP, and ASVP and (b) ET2 and TLR2 correlations in GFH. Second, this scheme provides an approximate framework to deal with the rest of ET2 and TLR2 correlations not included on the previous listing. Third, the PI-CM2 exact framework serves the purpose of computing accurate fluid EOS. 

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