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Recently it was shown that the calculation of quasiparticle energies using the $G_0W_0$ approximation can be performed without computing explicitly any virtual electronic states, by expanding the Green function and screened Coulomb…

Materials Science · Physics 2020-01-08 Han Yang , Marco Govoni , Giulia Galli

We apply the quasiparticle self-consistent GW method (QSGW) to slab models of ionic materials, LiF, KF, NaCl, MgO, and CaO, under electric field. Then we obtain the optical dielectric constants E(Slab) from the differences of the slopes of…

Strongly Correlated Electrons · Physics 2020-05-20 Hirofumi Sakakibara , Takao Kotani , Masao Obata , Tatsuki Oda

The GW approximation represents the state-of-the-art ab-initio method for computing excited-state properties. Its execution requires control over a larger number of (often interdependent) parameters, and therefore its application in…

The $GW$ approximation is a widely used framework for studying correlated materials, but it struggles with certain limitations, such as its inability to explain pseudogap phenomena. To overcome these problems, we propose a systematic…

Strongly Correlated Electrons · Physics 2024-09-26 Hui Li , Yingze Su , Junnian Xiong , Haiqing Lin , Huaqing Huang , Dingping Li

We present and benchmark a self-energy approach for quasiparticle energy calculations that goes beyond Hedin's $GW$ approximation by adding the full second-order self-energy (FSOS-$W$) contribution. The FSOS-$W$ diagram involves two…

Materials Science · Physics 2021-05-18 Yanyong Wang , Patrick Rinke , Xinguo Ren

We present an extension of the quasiparticle self-consistent $GW$ approximation (QS$GW$) [Phys. Rev. B, 76 165106 (2007)] to include vertex corrections in the screened Coulomb interaction $W$. This is achieved by solving the Bethe-Salpeter…

Materials Science · Physics 2023-10-11 Brian Cunningham , Myrta Grüning , Dimitar Pashov , Mark van Schilfgaarde

Using quasiparticle self-consistent $GW$ calculations, we re-examined the electronic structure of Sr$_2$RuO$_4$ and SrRuO$_3$. Our calculations show that the correlation effects beyond the conventional LDA (local density approximation) and…

Strongly Correlated Electrons · Physics 2016-02-16 Hyeonsang Ryee , Seung Woo Jang , Hiori Kino , Takao Kotani , Myung Joon Han

GW calculations with fully self-consistent G and W -- based on the iterative solution of the Dyson equation -- provide an approach for consistently describing ground and excited states on the same quantum mechanical level. We show that for…

Materials Science · Physics 2012-09-27 Fabio Caruso , Patrick Rinke , Xinguo Ren , Matthias Scheffler , Angel Rubio

On the basis of first-principles GW calculations, we study the quasiparticle properties of the guanine, adenine, cytosine, thymine, and uracil DNA and RNA nucleobases. Beyond standard G0W0 calculations, starting from Kohn-Sham eigenstates…

Chemical Physics · Physics 2015-05-27 Carina Faber , Claudio Attaccalite , Valerio Olevano , Erich Runge , Xavier Blase

The use of Green's function in quantum many-body theory often leads to nonlinear eigenvalue problems, as Green's function needs to be defined in energy domain. The $GW$ approximation method is one of the typical examples. In this article,…

Computational Physics · Physics 2024-09-11 Dongming Li , Eric Polizzi

We have developed a multi-GPU version of the quasiparticle self-consistent $GW$ (QSGW), a cutting-edge method for describing electronic excitations in a first-principles approach. While the QSGW calculation algorithm is inherently…

Computational Physics · Physics 2025-06-05 Masao Obata , Takao Kotani , Tatsuki Oda

We present algorithmic and implementation details for the fully self-consistent finite-temperature $GW$ method in Gaussian Bloch orbitals for solids. Our implementation is based on the finite-temperature Green's function formalism in which…

Materials Science · Physics 2022-12-14 Chia-Nan Yeh , Sergei Iskakov , Dominika Zgid , Emanuel Gull

Similar to other electron correlation methods, many-body perturbation theory methods based on Green functions, such as the so-called $GW$ approximation, suffer from the usual slow convergence of energetic properties with respect to the size…

Calculations of excited states in Green's function formalism often invoke the diagonal approximation, in which the quasiparticle states are taken from a mean-field calculation. Here, we extend the stochastic approaches applied in the…

Computational Physics · Physics 2023-09-28 Annabelle Canestraight , Xiaohe Lei , Khaled Ibrahim , Vojtech Vlcek

The decay rate of quasiparticles in quantum dots is studied through the real time calculation of the single-particle Green function in the self-consistent approximation. The method avoids exact diagonalization, transforming the problem into…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Alejandro M. F. Rivas , Eduardo R. Mucciolo , Alex Kamenev

Hedin's $GW$ approximation to the electronic self-energy has been impressively successful to calculate quasiparticle energies, such as ionization potentials, electron affinities, or electronic band structures. The success of this fairly…

Chemical Physics · Physics 2024-10-31 Arno Förster , Fabien Bruneval

Several widely used methods for the calculation of band structures and photo emission spectra, such as the GW approximation, rely on Many-Body Perturbation Theory. They can be obtained by iterating a set of functional differential equations…

Strongly Correlated Electrons · Physics 2012-01-31 Giovanna Lani , Pina Romaniello , Lucia Reining

We have recently implemented a new version of the quasiparticle self-consistent GW (QSGW) method in the ecalj package released at http://github.com/tkotani/ecalj. Since the new version of the ecalj is numerically stable and accurate…

Materials Science · Physics 2016-04-20 Daiki Deguchi , Kazunori Sato , Hiori Kino , Takao Kotani

The GW approximation within many-body perturbation theory is the state of the art for computing quasiparticle energies in solids. Typically, Kohn-Sham (KS) eigenvalues and eigenfunctions, obtained from a Density Functional Theory (DFT)…

We show that quasiparticle (QP) energies as calculated in the $GW$ approximation converge to the wrong value using the projector augmented wave (PAW) method, since the overlap integrals between occupied orbitals and high energy, plane wave…

Materials Science · Physics 2014-08-20 Jiří Klimeš , Merzuk Kaltak , Georg Kresse