Work

Scaling of entanglement entropy and correlations in the variable-range extended Ising model

Year: 2026

Type: article

Abstract: We study the two-point correlation functions and the bipartite entanglement in the ground state of the exactly-solvable variable-range extended Ising model of qubits in the presence of a transverse field on a one-dimensional lattice. We introduce the variation in the range of interaction by varying the coordination number, $\mathcal{Z}$, of each qubit, where the interaction strength between a pair of qubits at a distance $r$ varies as $\sim r^{-α}$. We show that the algebraic nature of the correlation functions is present only up to $r=\mathcal{Z}$, above which it exhibits short-range exponential scaling. We also show that at the critical point, the bipartite entanglement exhibits a power-law decrease ($\sim\mathcal{Z}^{-γ}$) with increasing coordination number irrespective of the partition size and the value of $α$ for $α>1$. We further consider a sudden quench of the system starting from the ground state of the infinite-field limit of the system Hamiltonian via turning on the critical Hamiltonian, and demonstrate that the long-time averaged bipartite entanglement exhibits a qualitatively similar variation ($\sim\mathcal{Z}^{-γ}$) with $\mathcal{Z}$.

Source: Physical Review A

DOI: 10.1103/vgrd-dg8j

Authors: Harikrishnan K J, Debasis Sadhukhan, Amit Kumar Pal

Institutions: Indian Institute of Technology Palakkad, Banaras Hindu University, Indian Institute of Engineering Science and Technology, Shibpur

Language: English

Topic: Quantum many-body systems

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Arthritis National Research Foundation, National Research Foundation, Department of Science and Technology, Ministry of Science and Technology, India, Banaras Hindu University

Awards: G3040754589, G4589692837