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We develop a formulation of the coherent potential approximation (CPA) on the basis of the Wannier representation to develop a computationally efficient method for the treatment of homogeneous random alloys that is independent on the…

We present a real-space method for computing the random phase approximation (RPA) correlation energy within Kohn-Sham density functional theory, leveraging the low-rank nature of the frequency-dependent density response operator. In…

Computational Physics · Physics 2025-04-03 Boqin Zhang , Shikhar Shah , John E. Pask , Edmond Chow , Phanish Suryanarayana

Computationally-efficient semilocal approximations of density functional theory at the level of the local spin density approximation (LSDA) or generalized gradient approximation (GGA) poorly describe weak interactions. We show improved…

An effective medium approach similar to the coherent potential approximation (CPA) in the theory of disordered alloys and to the DMFT has been extended to the renormalization group equations in the local potential approximation (LPA).…

Statistical Mechanics · Physics 2019-10-14 V. I. Tokar

Collective nuclear excitations, like giant resonances, are sensitive to nuclear deformation, as evidenced by alterations in their excitation energies and transition strength distributions. A common theoretical framework to study these…

Nuclear Theory · Physics 2024-04-23 A. Ravlić , T. Nikšić , Y. F. Niu , P. Ring , N. Paar

The magnetic properties of solids are typically analyzed in terms of Heisenberg models where the electronic structure is approximated by interacting localized spins. However, even in such models the evaluation of thermodynamic properties…

Materials Science · Physics 2025-01-31 Varun Rajeev Pavizhakumari , Thorbjørn Skovhus , Thomas Olsen

The matrix equations of the relativistic random-phase approximation (RRPA) are derived for an effective Lagrangian characterized by density-dependent meson-nucleon vertex functions. The explicit density dependence of the meson-nucleon…

Nuclear Theory · Physics 2009-11-07 T. Niksic , D. Vretenar , P. Ring

The effect of interactions on a system of fermions that are in a non-equilibrium steady state due to a quantum quench is studied employing the random-phase-approximation (RPA). As a result of the quench, the distribution function of the…

Strongly Correlated Electrons · Physics 2015-05-28 Jarrett Lancaster , Thierry Giamarchi , Aditi Mitra

Random phase approximation ground state contains electronic configurations where two (and more) identical electrons can occupy the same molecular spin-orbital violating the Pauli exclusion principle. This overcounting of electronic…

Chemical Physics · Physics 2017-10-25 Daniel S. Kosov

We develop and implement a formalism which enables calculating the analytical gradients of particle-hole random-phase approximation (RPA) ground-state energy with respect to the atomic positions within the atomic orbital basis set…

Chemical Physics · Physics 2021-09-03 Muhammad N. Tahir , Tong Zhu , Honghui Shang , Jia Li , Volker Blum , Xinguo Ren

Semilocal density functionals for the exchange-correlation energy are needed for large electronic systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) meta-generalized gradient approximation (meta-GGA) is semilocal and usefully accurate, but…

Materials Science · Physics 2009-06-30 John P. Perdew , Adrienn Ruzsinszky , Gabor I. Csonka , Lucian A. Constantin , Jianwei Sun

A characteristic feature of collective and particle-hole excitations in neutron-rich nuclei is that many of them couple to unbound neutron in continuum single-particle orbits. The continuum random phase approximation (cRPA) is a powerful…

Nuclear Theory · Physics 2021-09-15 Teruyuki Saito , Masayuki Matsuo

Reconstructing a density of states or similar distribution from moments or continued fractions is an important problem in calculating the electronic and vibrational structure of defective or non-crystalline solids. For single bands a…

Strongly Correlated Electrons · Physics 2015-05-20 Roger Haydock , C. M. M. Nex

The optimized random phase approximation (ORPA) for classical liquids is re-examined in the framework of the generating functional approach to the integral equations. We show that the two main variants of the approximation correspond to the…

Chemical Physics · Physics 2009-10-30 G. Pastore , O. Akinlade , F. Matthews , Z. Badirkhan

A general method is proposed for calculating a fully k-dependent, continuous, and causal spectral function A(k,E) within the recently introduced nonlocal version of the coherent-potential approximation (NLCPA). The method involves the…

Materials Science · Physics 2009-11-11 G. M. Batt , D. A. Rowlands

Second RPA (SRPA) calculations of nuclear response are performed and analyzed. Unlike in most other SRPA applications, the ground state, approximated by the Hartree-Fock (HF) ground state, and the residual couplings are described by the…

Nuclear Theory · Physics 2010-04-06 P. Papakonstantinou , R. Roth

We explore different variants of the random phase approximation (RPA) to the correlation energy derived from closed-shell ring-diagram approximations to coupled cluster doubles theory. We implement these variants in range-separated…

Chemical Physics · Physics 2011-09-01 Julien Toulouse , Wuming Zhu , Andreas Savin , Georg Jansen , János G. Angyán

We investigate the existence of several (anti-)ferromagnetic phases in the diluted ferromagnetic Kondo-lattice model, i.e. ferromagnetic coupling of local moment and electron spin. To do this we use a coherent potential approximation (CPA)…

Disordered Systems and Neural Networks · Physics 2011-06-24 M. Stier , S. Henning , W. Nolting

The General Spectral Modeling (GSM) code employs the quasi-static approximation, a standard, low-density methodology that assumes the ionization balance is separable from a determination of the excited-state populations that give rise to…

Atomic Physics · Physics 2008-11-26 Justin Oelgoetz , Christopher J. Fontes , Hong Lin Zhang , Anil K. Pradhan

The nonequilibrium steady states of quantum materials have many challenges. Here, we highlight issues with the relaxation time approximation (RTA) for the DC conductivity in insulating systems. The RTA to the quantum master equation (QME)…

Mesoscale and Nanoscale Physics · Physics 2024-05-27 Ibuki Terada , Sota Kitamura , Hiroshi Watanabe , Hiroaki Ikeda