Topological quantum chemistry (TQC) is a successful framework for identifying noninteracting topological materials, based on the symmetry analysis of Bloch Hamiltonian and reference states known as atomic limits. However, TQC grinds to halt once interactions are included. Here, authors put forward analogous TQC, but employing $n$-particle Green's function techniques indicate topology in interac...

It is shown that the Coulomb correlation problem for a system of two electrons (two charged particles) in an external oscillator potential possesses a hidden sl2-algebraic structure being one of recently-discovered quasi-exactly-solvable problems. The origin of existing exact solutions to this problem, recently discovered by several authors, is explained. A degeneracy of energies in electron-el...

Modern condensed-matter theory from first principles is highly successful when applied to materials of given structure-type or restricted unit-cell size. But this approach is limited where large cells or searches over millions of structure types become necessary. To treat these with first-principles accuracy, one 'coarse-grains' the many-particle Schrodinger equation into 'model hamiltonians' w...

2014 An effective Hamiltonian has been proposed for the study of the neutral states of boron clusters, i.e. for a 1/6th filled band. This generalization of Heisenberg Hamiltonians rests upon the definition of a model space spanned by products of ground state 2P(s2p) atomic wave-functions. The resulting effective Hamiltonian involves, besides Heisenberg-type effective spin exchange terms, angula...

Theories which have been used to describe the quantized electromagnetic field interacting with a nonlinear dielectric medium are either phenomenological or derived by quantizing the macroscopic Maxwell equations. Here we take a different approach and derive a Hamiltonian describing interacting fields from from one which contains both field and matter degrees of freedom. The medium is modelled a...

We discuss a bottom up approach for modeling photosynthetic light-harvesting. Methods are reviewed for a full structure-based parameterization of the Hamiltonian of pigment-protein complexes (PPCs). These parameters comprise (i) the local transition energies of the pigments in their binding sites in the protein, the site energies; (ii) the couplings between optical transitions of the pigments, ...

The marriage of density functional theory (DFT) and deep-learning methods has the potential to revolutionize modern computational materials science. Here we develop a deep neural network approach represent DFT Hamiltonian (DeepH) crystalline materials, aiming bypass computationally demanding self-consistent field iterations substantially improve efficiency ab initio electronic-structure calcula...

We have developed the finite size scaling method to treat the criticality of Shannon-information entropy for any given quantum Hamiltonian. This approach gives very accurate results for the critical parameters by using a systematic expansion in a finite basis set. To illustrate this approach we present a study to estimate the critical exponents of the Shannon-information entropy S approximately...

The one-dimensional Ising model with its connections to several physical concepts plays a vital role in comprehension of principles, phenomena and numerical methods. Hamiltonian coupled dissipative spin system the presence magnetic field can be obtained from model. We simulate above by designing quantum circuit precise gate measurement execute IBMQ experience platform through different [Formula...

Currently there is a great amount of scientific research directed at ratchet devices and mechanisms. Initially stimulated by a need to understand biological systems, the field has widened to encompass mesoscopic and atomic physics as well as quantum effects. The great majority of this effort has been directed at systems which include noise (Brownian ratchets). Comparatively little work has been...