scholarly journals INTEGRABILITY OF OPEN SPIN CHAINS WITH QUANTUM ALGEBRA SYMMETRY

1991 ◽  
Vol 06 (29) ◽  
pp. 5231-5248 ◽  
Author(s):  
LUCA MEZINCESCU ◽  
RAFAEL I. NEPOMECHIE
Keyword(s):  
Spin Chain ◽  
Quantum Algebra ◽  
Quantum Spin ◽  
Spin Chains ◽  
Invariant Chain ◽  
Quantum Spin Chain ◽  
Fundamental Representation ◽  
R Matrix ◽  
Boundary Terms ◽  
Xxz Chain

We construct an open quantum spin chain from the “twisted” [Formula: see text]R matrix in the fundamental representation which has the quantum algebra symmetry Uq[ su (2)]. This anisotropic spin-1 chain is different from the Uq[ su (2)]-invariant chain constructed from the “untwisted” [Formula: see text] spin-1 R matrix (namely, the spin-1 XXZ chain of Fateev-Zamolodchikov with boundary terms) but, nevertheless, is also completely integrable. We discuss the general case of an R matrix of the type g(k), where k∈{1, 2, 3}, and g is any simple Lie algebra.

Bethe ansatz solution of the Fateev-Zamolodchikov quantum spin chain with boundary terms

1990 ◽  
Vol 147 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Luca Mezincescu ◽  
Rafael I. Nepomechie ◽  
V. Rittenberg
Keyword(s):  
Bethe Ansatz ◽  
Spin Chain ◽  
Quantum Spin ◽  
Quantum Spin Chain ◽  
Boundary Terms ◽  
Bethe Ansatz Solution

scholarly journals Spin chains with boundary inhomogeneities

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Rafael I. Nepomechie ◽  
Ana L. Retore
Keyword(s):  
Quantum Group ◽  
Bethe Ansatz ◽  
Transfer Matrix ◽  
Spin Chain ◽  
Quantum Spin ◽  
Spin Chains ◽  
Group Symmetry ◽  
Quantum Spin Chain ◽  
Open Quantum ◽  
Bethe Ansatz Solution

Abstract We investigate the effect of introducing a boundary inhomogeneity in the transfer matrix of an integrable open quantum spin chain. We find that it is possible to construct a local Hamiltonian, and to have quantum group symmetry. The boundary inhomogeneity has a profound effect on the Bethe ansatz solution.

A TEMPLATE FOR QUANTUM SPIN CHAIN SPECTRA

1992 ◽  
Vol 07 (supp01b) ◽  
pp. 707-730 ◽  
Author(s):  
PAUL MARTIN ◽  
VLADIMIR RITTENBERG
Keyword(s):  
Spin Chain ◽  
Hecke Algebra ◽  
Quantum Spin ◽  
Spin Chains ◽  
Irreducible Representations ◽  
Quantum Spin Chains ◽  
Young Diagrams ◽  
Quantum Spin Chain ◽  
Fixed Length

We consider a series of N-state L(≥N) site quantum spin chains, characterised by the ordered partition of N into 2 parts, N=P+M. These (P/M) chains are invariant under an action of UqSU(P/M), and are built from a representation of the Hecke algebra HL-1(q). We establish that the intersection of the spectra of a (P/M) and (P'/M') chain of fixed length L is the spectrum of the (min(P,P')/min(M,M')) chain of that length. We establish that the spectrum of the (P/M) chain breaks into blocks corresponding to irreducible representations of HL-1(q) (or equivalently irreducible representations of UqSU(P/M)) characterised by Young diagrams with no rectangular subdiagrams of dimension (P+1)×(M+1) (height × width resp.). We give the corresponding quotient relations for the Hecke algebra. We discuss several implications of these results.

SPECTRUM OF THE TRANSFER MATRIX FOR THE Uq(Bn)-INVARIANT $A_{2n}^{(2)}$ OPEN SPIN CHAIN

1995 ◽  
Vol 10 (13) ◽  
pp. 1937-1952 ◽  
Author(s):  
SIMONE ARTZ ◽  
LUCA MEZINCESCU ◽  
RAFAEL I. NEPOMECHIE
Keyword(s):  
Asymptotic Behavior ◽  
Transfer Matrix ◽  
Spin Chain ◽  
Periodic Boundary ◽  
Periodic Boundary Conditions ◽  
Quantum Spin ◽  
Quantum Spin Chain ◽  
Fundamental Representation ◽  
Closed Chain ◽  
Matrix Eigenvalues

We propose an expression for the eigenvalues of the transfer matrix for the Uq(Bn)-invariant open quantum spin chain associated with the fundamental representation of [Formula: see text] By assumption, the Bethe ansatz equations are “doubled” with respect to those of the corresponding closed chain with periodic boundary conditions. We verify that the transfer matrix eigenvalues have the correct analyticity properties and asymptotic behavior. We also briefly discuss the structure of the eigenstates of the transfer matrix.

scholarly journals T − W relation and free energy of the Heisenberg chain at a finite temperature

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Pengcheng Lu ◽  
Yi Qiao ◽  
Junpeng Cao ◽  
Wen-Li Yang ◽  
Kang jie Shi ◽  
...  
Keyword(s):  
Free Energy ◽  
Spin Chain ◽  
Quantum Spin ◽  
Heisenberg Chain ◽  
Quantum Spin Chain ◽  
Heisenberg Spin ◽  
Heisenberg Spin Chain ◽  
Lattice Quantum ◽  
Quantum Integrable Models ◽  
Invariant Quantum

Abstract A new nonlinear integral equation (NLIE) describing the thermodynamics of the Heisenberg spin chain is derived based on the t − W relation of the quantum transfer matrices. The free energy of the system in a magnetic field is thus obtained by solving the NLIE. This method can be generalized to other lattice quantum integrable models. Taking the SU(3)-invariant quantum spin chain as an example, we construct the corre- sponding NLIEs and compute the free energy. The present results coincide exactly with those obtained via other methods previously.

scholarly journals Quantum spin chain dissipative mean-field dynamics

2018 ◽  
Vol 51 (32) ◽  
pp. 325001 ◽  
Author(s):  
F Benatti ◽  
F Carollo ◽  
R Floreanini ◽  
H Narnhofer
Keyword(s):  
Spin Chain ◽  
Mean Field ◽  
Quantum Spin ◽  
Quantum Spin Chain
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