2008/03/05 by Amit Tribedi, Indrani Bose · 1 citation
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum many-body systems #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1103/physreva.77.032307
published as PHYSICAL REVIEW A 77, 032307 (2008) · 18 pages, 7 figures
openalex publication_date 2008/03/05 · arxiv created 2008/03/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider a spin ladder model which is known to have matrix product states as exact ground states with spin liquid characteristics. The model has two critical-point transitions at the parameter values u=0 and \ensuremath∞. We study the variation of entanglement and fidelity measures in the ground states as a function of u and specially look for signatures of quantum phase transitions at u=0 and \ensuremath∞. The two different entanglement measures used are S(i) (the single-site von Neumann entropy) and S(i,j) (the two-body entanglement). At the quantum critical point (QCP) u=\ensuremath∞, the entanglement measure E [=S(i),S(i,j)] vanishes but remains nonzero at the other QCP u=0. The first and second derivatives of E with respect to the parameter u and the entanglement length associated with S(i,j) are further calculated to identify special features, if any, near the QCPs. We further determine the GS fidelity F and a quantity ln|D| related to the second derivative of F and show that these quantities calculated for finite-sized systems are good indicators of QPTs occurring in the infinite system.