scholarly journals Spin-wave study of entanglement and Rényi entropy for coplanar and collinear magnetic orders in two-dimensional quantum Heisenberg antiferromagnets

2020 ◽  
Vol 101 (19) ◽  
Author(s):  
Dag-Vidar Bauer ◽  
J. O. Fjærestad
Keyword(s):  
Spin Wave ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Two Dimensional ◽  
Magnetic Orders ◽  
Heisenberg Antiferromagnets

scholarly journals Excited state Rényi entropy and subsystem distance in two-dimensional non-compact bosonic theory. Part I. Single-particle states

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Jiaju Zhang ◽  
M.A. Rajabpour
Keyword(s):  
Excited States ◽  
Single Particle ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Large Momentum ◽  
Particle State ◽  
Two Dimensional ◽  
Universal Form ◽  
Conformal Field ◽  
Harmonic Chain

Abstract We investigate the Rényi entropy of the excited states produced by the current and its derivatives in the two-dimensional free massless non-compact bosonic theory, which is a two-dimensional conformal field theory. We also study the subsystem Schatten distance between these states. The two-dimensional free massless non-compact bosonic theory is the continuum limit of the finite periodic gapless harmonic chains with the local interactions. We identify the excited states produced by current and its derivatives in the massless bosonic theory as the single-particle excited states in the gapless harmonic chain. We calculate analytically the second Rényi entropy and the second Schatten distance in the massless bosonic theory. We then use the wave functions of the excited states and calculate the second Rényi entropy and the second Schatten distance in the gapless limit of the harmonic chain, which match perfectly with the analytical results in the massless bosonic theory. We verify that in the large momentum limit the single-particle state Rényi entropy takes a universal form. We also show that in the limit of large momenta and large momentum difference the subsystem Schatten distance takes a universal form but it is replaced by a new corrected form when the momentum difference is small. Finally we also comment on the mutual Rényi entropy of two disjoint intervals in the excited states of the two-dimensional free non-compact bosonic theory.

scholarly journals Infrared Electric Image Thresholding Using Two-Dimensional Fuzzy Renyi Entropy

2011 ◽  
Vol 12 ◽  
pp. 411-419 ◽  
Author(s):  
Songhai Fan ◽  
Shuhong Yang ◽  
Pu He ◽  
Hongyu Nie
Keyword(s):  
Renyi Entropy ◽  
Rényi Entropy ◽  
Two Dimensional ◽  
Image Thresholding ◽  
Electric Image

scholarly journals Correlation functions and quantum measures of descendant states

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Enrico M. Brehm ◽  
Matteo Broccoli
Keyword(s):  
Differential Operator ◽  
Correlation Functions ◽  
Recursive Formula ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Two Dimensional ◽  
Computer Implementation ◽  
Point Function ◽  
Rényi Divergence ◽  
Holographic Description

Abstract We discuss a computer implementation of a recursive formula to calculate correlation functions of descendant states in two-dimensional CFT. This allows us to obtain any N-point function of vacuum descendants, or to express the correlator as a differential operator acting on the respective primary correlator in case of non-vacuum descendants. With this tool at hand, we then study some entanglement and distinguishability measures between descendant states, namely the Rényi entropy, trace square distance and sandwiched Rényi divergence. Our results provide a test of the conjectured Rényi QNEC and new tools to analyse the holographic description of descendant states at large c.

LOCAL MODES AROUND THE FERROMAGNETIC IMPURITIES IN THE TWO-DIMENSIONAL HEISENBERG ANTIFERROMAGNETS

2001 ◽  
Vol 15 (08) ◽  
pp. 243-251
Author(s):  
YUN SONG
Keyword(s):  
Spin Wave ◽  
Green's Function ◽  
Nearest Neighbor ◽  
Numerical Procedure ◽  
Two Dimensional ◽  
Local Modes ◽  
Spin Wave Excitations ◽  
Ferromagnetic Domains ◽  
Double Time ◽  
Heisenberg Antiferromagnets

The behaviors of the spin-wave excitations around the ferromagnetic impurities in the two-dimensional spin-1/2 Heisenberg antiferromagnets are investigated for the cases with one, two and four impurities respectively. By means of the double-time Green's function numerical procedure, it is found that, in the two impurity case, two ferromagnetic impurities prefer to form an effective singlet. While in the four impurity case we obtained that, two nearest-neighbor ferromagnetic domains with contrary spin directions are formed in the antiferromagnetic background, and thus the whole system has the lowest energy.

scholarly journals Entanglement entropy from TFD entropy operator

2021 ◽  
Vol 36 (13) ◽  
pp. 2150092
Author(s):  
M. Dias ◽  
Daniel L. Nedel ◽  
C. R. Senise
Keyword(s):  
Analytic Continuation ◽  
Moduli Space ◽  
Degrees Of Freedom ◽  
Entanglement Entropy ◽  
Expected Value ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Two Dimensional ◽  
Von Neumann

In this work, a canonical method to compute entanglement entropy is proposed. We show that for two-dimensional conformal theories defined in a torus, a choice of moduli space allows the typical entropy operator of the TFD to provide the entanglement entropy of the degrees of freedom defined in a segment and their complement. In this procedure, it is not necessary to make an analytic continuation from the Rényi entropy and the von Neumann entanglement entropy is calculated directly from the expected value of an entanglement entropy operator. We also propose a model for the evolution of the entanglement entropy and show that it grows linearly with time.

scholarly journals Rényi entropy of a line in two-dimensional Ising models

2010 ◽  
Vol 82 (12) ◽  
Author(s):  
J.-M. Stéphan ◽  
G. Misguich ◽  
V. Pasquier
Keyword(s):  
Ising Models ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Two Dimensional

SPIN WAVE ANALYSIS OF THE TWO-DIMENSIONAL HEISENBERG ANTIFERROMAGNETS Rb2MnCl4 AND (CH3NH3)2MnCl4

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-753-C6-754
Author(s):  
B. Schröder ◽  
V. Wagner ◽  
N. Lehner ◽  
R. Geick
Keyword(s):  
Spin Wave ◽  
Two Dimensional ◽  
Wave Analysis ◽  
Heisenberg Antiferromagnets
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