Electronic and Optical Properties of PtSn₂

Abstract

The electronic energy bands of PtSn2 are calculated using composite wave variational version of the APW method. The results show a narrowing of d‐band which indicates a weaker d‐d overlap interaction between Pt atoms. A comparative study of this band structure result with that of PtAl2 and Pt provide interesting information about d‐d interaction as a function of primary interatomic distance. From the band structure results, density of states, joint density of states, ε2(ω) spectra and the Fermi surfaces are calculated and interpreted.

Chiral phase transition and instanton–anti-instanton molecules

“…We find that there is a substantial residual attraction in the scalar-pseudoscalar meson channels even above T c . This results is in agreement with lattice simulations, in which the presence of an attractive interaction in the scalar channel has been established from an analysis of spacelike screening masses [38] and direct measurements of the scalar susceptibility [41]. The considerably weaker interaction in the vector channel follows from the behavior of the quark number (vector) susceptibility [42,43].…”

“…The considerably weaker interaction in the vector channel follows from the behavior of the quark number (vector) susceptibility [42,43]. In agreement with our effective Lagrangian, lattice calculations result in a coupling constant that is four times larger in the scalar-pseudoscalar channel than in the axial-vector channel [41,44].…”

Spatial and temporal hadron correlators below and above the chiral phase transition

“…(This relation also holds below the transition, and gives a definition of the constituent quark mass.) As is already known [4], this simplification does not hold in the P S channel, and an effective interaction between quarks remains. The value of µ per P S is accordingly somewhat smaller than µ per V .…”

“…While bosonic modes (bound states in mesonic operators) will not be sensitive to changes of the usual antiperiodic boundary conditions to periodic ones, fermionic modes (freely propagating quarks) will be sensitive to these changes. We will also extend the studies of scalar and vector channel couplings [4] to the case of QCD with dynamical fermions.…”

Chiral symmetry and dileptons in heavy ion collisions

“…In this work we shall concentrate on thermal dilepton production, which is mainly affected by the temperature dependence of pion and p meson masses and their decay widths. The behaviour of hadron parameters at finite T has been studied recently within the framework of chiral perturbation theory [7], the virial expansion [8], a Nambu-Jona-Lasinio model [-9], QCD sum rules [10] as well as lattice gauge theory [11]. These investigations lead to similar conclusions about the behaviour of the low lying hadron masses for temperatures well below the chiral symmetry restoration phase transition temperature.…”