Algebraic Representation of Correlation Functions in Integrable Spin Chains (original) (raw)
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We present a review of the method we have elaborated to compute the correlation functions of the XXZ spin-1/2 Heisenberg chain. This method is based on the resolution of the quantum inverse scattering problem in the algebraic Bethe Ansatz framework, and leads to a multiple integral representation of the dynamical correlation functions. We describe in particular some recent advances concerning the two-point functions: in the finite chain, they can be expressed in terms of a single multiple integral. Such a formula provides a direct analytic connection between the previously obtained multiple integral representations and the form factor expansions for the correlation functions.
Dynamical correlation functions of the spin- chain
Nuclear Physics B, 2005
We derive a master equation for the dynamical spin-spin correlation functions of the XXZ spin-1 2 Heisenberg finite chain in an external magnetic field. In the thermodynamic limit, we obtain their multiple integral representation.
Correlation functions of the XXZ Heisenberg spin- chain in a magnetic field
Nuclear Physics B, 2000
Using the algebraic Bethe ansatz method, and the solution of the quantum inverse scattering problem for local spins, we obtain multiple integral representations of the n-point correlation functions of the XXZ Heisenberg spin-1 2 chain in a constant magnetic field. For zero magnetic field, this result agrees, in both the massless and massive (anti-ferromagnetic) regimes, with the one obtained from the q-deformed KZ equations (massless regime) and the representation theory of the quantum affine algebra U q (ŝl 2) together with the corner transfer matrix approach (massive regime).
Spin–spin correlation functions of the XXZ- Heisenberg chain in a magnetic field
Nuclear Physics B, 2002
Using algebraic Bethe ansatz and the solution of the quantum inverse scattering problem, we compute compact representations of the spin-spin correlation functions of the XXZ-1 2 Heisenberg chain in a magnetic field. At lattice distance m, they are typically given as the sum of m terms. Each term n of this sum, n = 1,. .. m, is represented in the thermodynamic limit as a multiple integral of order 2n + 1; the integrand depends on the distance as the power m of some simple function. The root of these results is the derivation of a compact formula for the multiple action on a general quantum state of the chain of transfer matrix operators for arbitrary values of their spectral parameters.
On the spin–spin correlation functions of the XXZ spin- infinite chain
Journal of Physics A: Mathematical and General, 2005
We obtain a new multiple integral representation for the spin-spin correlation functions of the XXZ spin-1 2 infinite chain. We show that this representation is closely related with the partition function of the six-vertex model with domain wall boundary conditions.
Correlation Functions of the XXZ Spin-½ Heisenberg Chain: Recent Advances (Review)
International Journal of Modern Physics A, 2004
We review some recent advances in the computation of exact correlation functions of the XXZ-½ Heisenberg chain. We first give a general introduction to our method which is based on the algebraic Bethe ansatz and the resolution of the quantum inverse scattering problem, leading in particular to multiple integral representations for the correlation functions. Then we describe recently obtained compact formulas for the spin-spin correlation functions of the XXZ-½ Heisenberg chain. We outline how this leads to several explicit results including the known two point functions in the limit of free fermions, the so-called emptiness formation probability at anisotropy Δ=1/2 and its large distance asymptotic behaviour in the massless phase of the model.
Correlation functions of the XXZ Heisenberg spin chain: Bethe ansatz approach
We review recent progress in the computation of correlation functions of the XXZ spin-1/2 chain. We describe both finite and infinite chain results. Long distance asymptotic behavior is discussed. Our method is based on the resolution of the quantum inverse scattering problem in the framework of the algebraic Bethe ansatz.
Third-neighbor and other four-point correlation functions of spin-1/2 XXZ chain
2004
The correlation functions of the spin-1/2 XXZ chain in the ground state were expressed in the form of multiple integrals for -1<\Delta \leq 1 and 1<\Delta. In particular, adjacent four-point correlation functions were given as certain four-dimensional integrals. We show that these integrals can be reduced to polynomials with respect to specific one-dimensional integrals. The results give the polynomial representation of the third-neighbor correlation functions.
Master equation for spin–spin correlation functions of the chain
Nuclear Physics B, 2005
We derive a new representation for spin-spin correlation functions of the finite XXZ spin-1/2 Heisenberg chain in terms of a single multiple integral, that we call the master equation. Evaluation of this master equation gives rise on the one hand to the previously obtained multiple integral formulas for the spin-spin correlation functions and on the other hand to their expansion in terms of the form factors of the local spin operators. Hence, it provides a direct analytic link between these two representations of the correlation functions and a complete re-summation of the corresponding series. The master equation method also allows one to obtain multiple integral representations for dynamical correlation functions.
Correlation Functions in Spin Chains and Information Theory
2003
Antiferromagnetic spin chains play an important role in condensed matter physics and statistical mechanics. Recently XXX spin chain was discussed in relation to the information theory. We consider here localizable entanglement, introduced recently by F.Verstraete, M.Popp and J.I.Cirac. That is how much entanglement can be localized on two spins on average by performing local measurements on the other individual spins in a system of many interacting spins. We consider the ground state in antiferromagnetic spin chains and study localizable entanglement between two spins as a function of the distance. We start with isotropic spin chain. Then we study effect of anisotropy and magnetic field. We conclude that anisotropy increases localizable entanglement. We found an explicit dependence of critical exponents in XXZ spin chain on magnetic field. We discovered that the cases of high symmetry corresponds to high sensitivity of magnetic field. We also calculated the concurrence before the measurement to illustrate that the measurment raises the concurrence.