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We propose a hypergraph expansion which facilitates the direct treatment of quantum spin models with many-site interactions via perturbative linked cluster expansions. The main idea is to generate all relevant subclusters and sort them into…

Strongly Correlated Electrons · Physics 2022-06-22 M. Mühlhauser , K. P. Schmidt

The cold and dense regime of the QCD phase diagram is to this day inaccessible to first principle lattice calculations owing to the sign problem. Here we present progress of an ongoing effort to probe this particularly difficult regime…

High Energy Physics - Lattice · Physics 2015-11-04 Jonas Glesaaen , Mathias Neuman , Owe Philipsen

A cluster mean-field method is introduced and the applications to the Ising and Heisenberg models are demonstrated. We divide the lattice sites into clusters whose size and shape are selected so that the equivalence of all sites in a…

Strongly Correlated Electrons · Physics 2013-05-29 Daisuke Yamamoto

We show the existence of quasi-cluster $\mathcal{A}$-structures and cluster Poisson structures on moduli stacks of sheaves with singular support in the alternating strand diagram of grid plabic graphs by studying the microlocal parallel…

Symplectic Geometry · Mathematics 2024-01-01 Roger Casals , Daping Weng

A self-energy-functional approach is applied to construct cluster approximations for correlated lattice models. It turns out that the cluster-perturbation theory (Senechal et al, PRL 84, 522 (2000)) and the cellular dynamical mean-field…

Strongly Correlated Electrons · Physics 2007-05-23 M. Potthoff , M. Aichhorn , C. Dahnken

A cluster expansion is proposed, that applies to both continuous and discrete systems. The assumption for its convergence involves an extension of the neat Kotecky-Preiss criterion. Expressions and estimates for correlation functions are…

Mathematical Physics · Physics 2007-05-23 Daniel Ueltschi

It is often of interest to perform clustering on longitudinal data, yet it is difficult to formulate an intuitive model for which estimation is computationally feasible. We propose a model-based clustering method for clustering objects that…

Methodology · Statistics 2020-05-19 Daniel K. Sewell , Yuguo Chen , William Bernhard , Tracy Sulkin

In this work, we investigate the dynamics and attenuation properties of a one-dimensional inertial amplified lattice with opposite chirality. The unit cell of the structure consists of a hollow-square plate connected to a ring through…

We use the coupled cluster method (CCM) to study the ground-state properties and lowest-lying triplet excited state of the spin-half {\it XXZ} antiferromagnet on the square lattice. The CCM is applied to it to high orders of approximation…

Strong-coupling series expansions are calculated for the Hamiltonian version of compact lattice electrodynamics in (2+1) dimensions, with 4-component fermions. Series are calculated for the ground-state energy per site, the chiral…

High Energy Physics - Lattice · Physics 2009-10-30 C. J. Hamer , J. Oitmaa , Zheng Weihong

In this article, we propose two classes of semiparametric mixture regression models with single-index for model based clustering. Unlike many semiparametric/nonparametric mixture regression models that can only be applied to low dimensional…

Methodology · Statistics 2017-08-15 Sijia Xiang , Weixin Yao

We report progress in the computation and analysis of strong-coupling series of two- and three-dimensional ${\rm O}(N)$ $\sigma$ models. We show that, through a combination of long strong-coupling series and judicious choice of observables,…

High Energy Physics - Lattice · Physics 2009-10-28 Massimo Campostrini , Andrea Pelissetto , Paolo Rossi , Ettore Vicari

Mixture models extend the toolbox of clustering methods available to the data analyst. They allow for an explicit definition of the cluster shapes and structure within a probabilistic framework and exploit estimation and inference…

Methodology · Statistics 2025-09-15 Bettina Grün

We identify a fundamental challenge for non-perturbative linked cluster expansions (NLCEs) resulting from the reduced symmetry on graphs, most importantly the breaking of translational symmetry, when targeting the properties of excited…

Strongly Correlated Electrons · Physics 2015-05-13 K. Coester , S. Clever , F. Herbst , S. Capponi , K. P. Schmidt

We introduce in this paper two dimensional lattice models whose continuum limit belongs to the $N=2$ series. The first kind of model is integrable and obtained through a geometrical reformulation, generalizing results known in the $k=1$…

High Energy Physics - Theory · Physics 2009-10-22 Hubert Saleur

Using exact diagonalizations, Green's function Monte Carlo simulations and high-order perturbation theory, we study the low-energy properties of the two-dimensional spin-1/2 compass model on the square lattice defined by the Hamiltonian $H…

Strongly Correlated Electrons · Physics 2009-11-11 J. Dorier , F. Becca , F. Mila

It is shown that detailed and accurate information about the mass spectrum of the massive Schwinger model can be obtained using the technique of strong-coupling series expansions. Extended strong-coupling series for the energy eigenvalues…

High Energy Physics - Lattice · Physics 2009-10-30 C. J. Hamer , Zheng Weihong , J. Oitmaa

Dualities between quantum field theories have proven to be a powerful tool in various areas of physics. In this paper, we introduce a new perspective for obtaining strong coupling expansions based on a well-known technique -- the…

High Energy Physics - Lattice · Physics 2025-02-11 Nikita A. Ignatyuk , Daniel Skliannyi

A quantitative first-principles description of complex substitutional materials like alloys is challenging due to the vast number of configurations and the high computational cost of solving the quantum-mechanical problem. Therefore,…

Materials Science · Physics 2025-06-24 Adrian Stroth , Claudia Draxl , Santiago Rigamonti

We present cluster Monte Carlo algorithms for the $XYZ$ quantum spin models. In the special case of $S=1/2$, the new algorithm can be viewed as a cluster algorithm for the 8-vertex model. As an example, we study the $S=1/2$ $XY$ model in…

Condensed Matter · Physics 2009-10-28 N. Kawashima