Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1201.3305 · Physical Review B

Critical properties and Rényi entropies of the spin- 32 XXZ chain

Marcello Dalmonte, Elisa Ercolessi, Luca Taddia

Published Apr 6, 2012• 30 citations
arXivHTMLPDF

Abstract

We discuss entanglement and critical properties of the spin-$3/2$ $XXZ$ chain in its entire gapless region. Employing density-matrix renormalization-group calculations combined with different methods based on level spectroscopy, correlation functions, and entanglement entropies, we determine the sound velocity and the Luttinger parameter of the model as a function of the anisotropy parameter. Then, we focus on entanglement properties by systematically studying the behavior of R\'enyi entropies under both open and periodic boundary conditions, providing further evidence of recent findings about entanglement entropies of excited states in conformal field theory.

DOI
10.1103/physrevb.85.165112

Related papers

Renyi entanglement entropies of descendant states in critical systems with boundaries: conformal field theory and spin chains

Luca Taddia, Fabio Ortolani, Tamás Pálmai

Abstract We discuss the Renyi entanglement entropies of descendant states in critical one-dimensional systems with boundaries, that map to boundary conformal field theories in the scaling limit. We unify the previous conformal-field-theory approaches to describe primary and descendant states in systems with both open and closed boundaries. We provide universal expressions for the first two descendants in the identity family. We apply our technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and find excellent agreement with numerical results obtained for finite spin chains. We also demonstrate that entanglement entropies are a powerful tool to resolve degeneracy of higher excited states in critical lattice models.

arXiv:1606.02667•Journal of Statistical Mechanics Theory and Experiment•Sep 1, 2016•30 citations

Entanglement entropy, conformal invariance, and the critical behavior of the anisotropic spin- s Heisenberg chains: DMRG study

J. C. Xavier

Using the density-matrix renormalization group, we investigate the critical behavior of the anisotropic Heisenberg chains with spins up to $s=9/2$. We show that through the relations arising from the conformal invariance and the DMRG technique it is possible to obtain accurate finite-size estimates of the conformal anomaly $c$, the sound velocity ${v}_{s}$, the anomalous dimension ${x}_{bulk}$, and the surface exponent ${x}_{s}$ of the anisotropic spin-$s$ Heisenberg chains with relatively good accuracy without fitting parameters. Our results indicate that the entanglement entropy $S(L,{l}_{A},s)$ of the spin-$s$ Heisenberg chains satisfies the relation $S(L,{l}_{A},s)\ensuremath{-}S(L,{l}_{A},s\ensuremath{-}1)=1/(2s+1)$ for $s>3/2$ in the thermodynamic limit.

arXiv:1002.0531•Physical Review B•Jun 1, 2010•30 citations

Renyi entanglement entropies of descendant states in critical systems with boundaries: conformal field theory and spin chains

Taddia, L., Ortolani, F., Tamás Pálmai

We discuss the R´enyi entanglement entropies of descendant states in critical one- dimensional systems with boundaries, that map to boundary conformal field theories in the scaling limit. We unify the previous conformal-field-theory approaches to describe primary and descendant states in systems with both open and closed boundaries. We provide universal expressions for the first two descendants in the identity family. We apply our technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and find excellent agreement with numerical results obtained for finite spin chains. We also demonstrate that entanglement entropies are a powerful tool to resolve degeneracy of higher excited states in critical lattice models.

•Jan 1, 2016•23 citations

Finite-size corrections of the entanglement entropy of critical quantum chains

J. C. Xavier, Francisco Castilho Alcaraz

Using the density matrix renormalization group, we calculated the finite-size corrections of the entanglement $\ensuremath{\alpha}$-R\'enyi entropy of a single interval for several critical quantum chains. We considered models with $U(1)$ symmetry such as the spin-1/2 $XXZ$ and spin-1 Fateev-Zamolodchikov models, as well as models with discrete symmetries such as the Ising, the Blume-Capel, and the three-state Potts models. These corrections contain physically relevant information. Their amplitudes, which depend on the value of $\ensuremath{\alpha}$, are related to the dimensions of operators in the conformal field theory governing the long-distance correlations of the critical quantum chains. The obtained results together with earlier exact and numerical ones allow us to formulate some general conjectures about the operator responsible for the leading finite-size correction of the $\ensuremath{\alpha}$-R\'enyi entropies. We conjecture that the exponent of the leading finite-size correction of the $\ensuremath{\alpha}$-R\'enyi entropies is ${p}_{\ensuremath{\alpha}}=2{X}_{\ensuremath{\epsilon}}/\ensuremath{\alpha}$ for $\ensuremath{\alpha}>1$ and ${p}_{1}=\ensuremath{\nu}$, where ${X}_{\ensuremath{\epsilon}}$ denotes the dimensions of the energy operator of the model and $\ensuremath{\nu}=2$ for all the models.

arXiv:1111.6577•Physical Review B•Jan 24, 2012•43 citations

Rényi entropy and parity oscillations of anisotropic spin- s Heisenberg chains in a magnetic field

J. C. Xavier, Francisco Castilho Alcaraz

Using the density matrix renormalization group, we investigate the R\'enyi entropy of the anisotropic spin-$s$ Heisenberg chains in a $z$-magnetic field. We considered the half-odd-integer spin-$s$ chains, with $s=1/2$, 3/2, and $5/2$, and periodic and open boundary conditions. In the case of the spin-1/2 chain we were able to obtain accurate estimates of the new parity exponents ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ that gives the power-law decay of the oscillations of the $\ensuremath{\alpha}$-R\'enyi entropy for periodic and open boundary conditions, respectively. We confirm the relations of these exponents with the Luttinger parameter $K$, as proposed by Calabrese et al. [Phys. Rev. Lett. 104, 095701 (2010)]. Moreover, the predicted periodicity of the oscillating term was also observed for some nonzero values of the magnetization $m$. We show that for $s>1/2$ the amplitudes of the oscillations are quite small and get accurate estimates of ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ become a challenge. Although our estimates of the new universal exponents ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ for the spin-3/2 chain are not so accurate, they are consistent with the theoretical predictions.

arXiv:1103.2103•Physical Review B•Jun 29, 2011•39 citations

Entanglement properties of correlated random spin chains and similarities with conformally invariant systems

João C. Getelina, Francisco Castilho Alcaraz, José A. Hoyos

We study the R\'enyi entanglement entropy and the Shannon mutual information for a class of spin-1/2 quantum critical XXZ chains with random coupling constants which are partially correlated. In the XX case, distinctly from the usual uncorrelated random case where the system is governed by an infinite-disorder fixed point, the correlated-disorder chain is governed by finite-disorder fixed points. Surprisingly, we verify that, although the system is not conformally invariant, the leading behavior of the R\'enyi entanglement entropies are similar to those of the clean (no randomness) conformally invariant system. In addition, we compute the Shannon mutual information among subsystems of our correlated-disorder quantum chain and verify the same leading behavior as the $n=2$ R\'enyi entanglement entropy. This result extends a recent conjecture concerning the same universal behavior of these quantities for conformally invariant quantum chains. For the generic spin-1/2 quantum critical XXZ case, the true asymptotic regime is identical to that in the uncorrelated disorder case. However, these finite-disorder fixed points govern the low-energy physics up to a very long crossover length scale, and the same results as in the XX case apply. Our results are based on exact numerical calculations and on a numerical strong-disorder renormalization group.

arXiv:1511.00618•Physical review. B./Physical review. B•Jan 27, 2016•36 citations
We discuss entanglement and critical properties of the spin-3/23/23/2 XXZXXZXXZ chain in its entire gapless region. Employing density-matrix renormalization-group calculations combined with different methods based on level spectroscopy, correlation functions, and entanglement entropies, we determine the sound velocity and the Luttinger parameter of the model as a function of the anisotropy parameter. Then, we focus on entanglement properties by systematically studying the behavior of R'enyi entropies under both open and periodic boundary conditions, providing further evidence of recent findings about entanglement entropies of excited states in conformal field theory.
Abstract We discuss the Renyi entanglement entropies of descendant states in critical one-dimensional systems with boundaries, that map to boundary conformal field theories in the scaling limit. We unify the previous conformal-field-theory approaches to describe primary and descendant states in systems with both open and closed boundaries. We provide universal expressions for the first two descendants in the identity family. We apply our technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and find excellent agreement with numerical results obtained for finite spin chains. We also demonstrate that entanglement entropies are a powerful tool to resolve degeneracy of higher excited states in critical lattice models.
Using the density-matrix renormalization group, we investigate the critical behavior of the anisotropic Heisenberg chains with spins up to s=9/2s=9/2s=9/2. We show that through the relations arising from the conformal invariance and the DMRG technique it is possible to obtain accurate finite-size estimates of the conformal anomaly ccc, the sound velocity vs{v}_{s}vs​, the anomalous dimension xbulk{x}_{bulk}xbulk​, and the surface exponent xs{x}_{s}xs​ of the anisotropic spin-sss Heisenberg chains with relatively good accuracy without fitting parameters. Our results indicate that the entanglement entropy S(L,lA,s)S(L,{l}_{A},s)S(L,lA​,s) of the spin-sss Heisenberg chains satisfies the relation $S(L,{l}_{A},s)\ensuremath{-}S(L,{l}_{A},s\ensuremath{-}1)=1/(2s+1)$ for s>3/2s>3/2s>3/2 in the thermodynamic limit.
We discuss the R´enyi entanglement entropies of descendant states in critical one- dimensional systems with boundaries, that map to boundary conformal field theories in the scaling limit. We unify the previous conformal-field-theory approaches to describe primary and descendant states in systems with both open and closed boundaries. We provide universal expressions for the first two descendants in the identity family. We apply our technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and find excellent agreement with numerical results obtained for finite spin chains. We also demonstrate that entanglement entropies are a powerful tool to resolve degeneracy of higher excited states in critical lattice models.
Using the density matrix renormalization group, we calculated the finite-size corrections of the entanglement $\ensuremath{\alpha}$-R\'enyi entropy of a single interval for several critical quantum chains. We considered models with U(1)U(1)U(1) symmetry such as the spin-1/2 XXZXXZXXZ and spin-1 Fateev-Zamolodchikov models, as well as models with discrete symmetries such as the Ising, the Blume-Capel, and the three-state Potts models. These corrections contain physically relevant information. Their amplitudes, which depend on the value of $\ensuremath{\alpha}$, are related to the dimensions of operators in the conformal field theory governing the long-distance correlations of the critical quantum chains. The obtained results together with earlier exact and numerical ones allow us to formulate some general conjectures about the operator responsible for the leading finite-size correction of the $\ensuremath{\alpha}$-R\'enyi entropies. We conjecture that the exponent of the leading finite-size correction of the $\ensuremath{\alpha}$-R\'enyi entropies is ${p}_{\ensuremath{\alpha}}=2{X}_{\ensuremath{\epsilon}}/\ensuremath{\alpha}$ for $\ensuremath{\alpha}>1$ and ${p}_{1}=\ensuremath{\nu}$, where ${X}_{\ensuremath{\epsilon}}$ denotes the dimensions of the energy operator of the model and $\ensuremath{\nu}=2$ for all the models.
Using the density matrix renormalization group, we investigate the R\'enyi entropy of the anisotropic spin-sss Heisenberg chains in a zzz-magnetic field. We considered the half-odd-integer spin-sss chains, with s=1/2s=1/2s=1/2, 3/2, and 5/25/25/2, and periodic and open boundary conditions. In the case of the spin-1/2 chain we were able to obtain accurate estimates of the new parity exponents ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ that gives the power-law decay of the oscillations of the $\ensuremath{\alpha}$-R\'enyi entropy for periodic and open boundary conditions, respectively. We confirm the relations of these exponents with the Luttinger parameter KKK, as proposed by Calabrese et al. [Phys. Rev. Lett. 104, 095701 (2010)]. Moreover, the predicted periodicity of the oscillating term was also observed for some nonzero values of the magnetization mmm. We show that for s>1/2s>1/2s>1/2 the amplitudes of the oscillations are quite small and get accurate estimates of ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ become a challenge. Although our estimates of the new universal exponents ${p}_{\ensuremath{\alpha}}^{(p)}$ and ${p}_{\ensuremath{\alpha}}^{(o)}$ for the spin-3/2 chain are not so accurate, they are consistent with the theoretical predictions.
We study the R\'enyi entanglement entropy and the Shannon mutual information for a class of spin-1/2 quantum critical XXZ chains with random coupling constants which are partially correlated. In the XX case, distinctly from the usual uncorrelated random case where the system is governed by an infinite-disorder fixed point, the correlated-disorder chain is governed by finite-disorder fixed points. Surprisingly, we verify that, although the system is not conformally invariant, the leading behavior of the R\'enyi entanglement entropies are similar to those of the clean (no randomness) conformally invariant system. In addition, we compute the Shannon mutual information among subsystems of our correlated-disorder quantum chain and verify the same leading behavior as the n=2n=2n=2 R\'enyi entanglement entropy. This result extends a recent conjecture concerning the same universal behavior of these quantities for conformally invariant quantum chains. For the generic spin-1/2 quantum critical XXZ case, the true asymptotic regime is identical to that in the uncorrelated disorder case. However, these finite-disorder fixed points govern the low-energy physics up to a very long crossover length scale, and the same results as in the XX case apply. Our results are based on exact numerical calculations and on a numerical strong-disorder renormalization group.