In this paper, we investigate the integrable boundary states in ABJM theory. We find an integrability condition for the two-site integrable matrix product state (MPS) similar to the KT-relation. We also construct a class of non-trivial MPSs from the projected K-matrices.
Abstract We develop a general framework for constructing 2n-site chiral integrable matrix product states in Aharony-Bergman-Jafferis-Maldacena spin chain, based on reflection equations and the fusion procedure. For four-site chiral integrable product states, we propose their exact overlap formulas with Bethe states. We also investigate the chiral integrable subspaces numerically.
Solving for the integrable boundary states of the ABJM spin chain from KT-relations
We study integrable boundary states of the alternating SU(4) spin chain arising in ABJM theory. Starting from the KT-relation, we directly solve the integrability constraints for states with n-site translational invariance. For odd and even n, these constraints are reduced respectively to state equations and operator equations for the elementary n-site block and the matrix K(u). We analyze chiral and achiral cases for n≤4. In the 1-site case we allow general operator-valued integrable pairs with an internal space, while in the remaining cases we focus on c-number solutions.
We introduce an efficient method to calculate the ground state of one-dimensional lattice models with periodic boundary conditions. The method works in the representation of matrix product states (MPS), related to the density matrix renormalization group (DMRG) method. It improves on a previous approach by Verstraete et al. We introduce a factorization procedure for long products of MPS matrices, which reduces the computational effort from m5 to m3, where m is the matrix dimension, and $m\ensuremath{\simeq}100--1000$ in typical cases. We test the method on the S=21 and S=1 Heisenberg chains. It is also applicable to nontranslationally invariant cases. The method makes ground-state calculations with periodic boundary conditions about as efficient as traditional DMRG calculations for systems with open boundaries.
We consider integrable Matrix Product States (MPS) in integrable spin chains and show that they correspond to “operator valued” solutions of the so-called twisted Boundary Yang-Baxter (or reflection) equation. We argue that the integrability condition is equivalent to a new linear intertwiner relation, which we call the “square root relation”, because it involves half of the steps of the reflection equation. It is then shown that the square root relation leads to the full Boundary Yang-Baxter equations. We provide explicit solutions in a number of cases characterized by special symmetries. These correspond to the “symmetric pairs” (SU(N),SO(N)) and (SO(N),SO(D) \otimes ⊗ SO(N-D)), where in each pair the first and second elements are the symmetry groups of the spin chain and the integrable state, respectively. These solutions can be considered as explicit representations of the corresponding twisted Yangians, that are new in a number of cases. Examples include certain concrete MPS relevant for the computation of one-point functions in defect AdS/CFT.