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Quantum renormalization group for ground-state fidelity

Langari, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1088/1367-2630/14/5/053014
  3. Abstract:
  4. Ground-state fidelity (GSF) and quantum renormalization group (QRG) theory have proven to be useful tools in the study of quantum critical systems. Here we lay out a general, unified formalism of GSF and QRG; specifically, we propose a method for calculating GSF through QRG, obviating the need for calculating or approximating ground states. This method thus enhances the characterization of quantum criticality as well as scaling analysis of relevant properties with system size. We illustrate the formalism in the one-dimensional Ising model in a transverse field (ITF) and the anisotropic spin-1/2 Heisenberg (XXZ) model. Explicitly, we find the scaling behavior of the GSF for the ITF model in both small- and large-size limits, the corresponding critical exponents, the exact value of the GSF in the thermodynamic limit and a closed form for the GSF for arbitrary size and system parameters. In the case of the XXZ model, we also present an analytic expression for the GSF, which captures well the criticality of the model, hence excluding doubts that GSF might be an insufficient tool for signaling criticality in this model
  5. Keywords:
  6. Analytic expressions ; Closed form ; Critical exponent ; Heisenberg ; Large sizes ; Lay-out ; One-dimensional Ising model ; Quantum critical ; Quantum criticality ; Renormalization group ; Scaling analysis ; Scaling behavior ; System size ; Thermodynamic limits ; Transverse field ; Criticality (nuclear fission) ; Ising model ; Statistical mechanics ; Ground state
  7. Source: New Journal of Physics ; Volume 14 , 2012 ; 13672630 (ISSN)
  8. URL: http://iopscience.iop.org/article/10.1088/1367-2630/14/5/053014/meta;jsessionid=AB991197DA0AC109CBCE04175343BCBF.c1.iopscience.cld.iop.org