Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points

Details Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points

2008-12-22

arxiv.org/abs/0812.4106v1

Physics

Quantum Physics

13 pages, 8 figures, accepted for publication in Physical Review A

Scientific paper

10.1103/PhysRevA.79.012331

We consider a two-chain, spin-1/2 antiferromagnetic Heisenberg spin ladder in an external magnetic field H. The spin ladder is known to undergo second order quantum phase transitions (QPTs) at two critical values, Hc1 and Hc2, of the magnetic field. There are now known examples of strongly coupled (rung exchange interaction much stronger than nearest-neighbour intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investigate whether well-known bipartite entanglement meaures like one-site von Neumann entropy, two-site von Neumann entropy and concurrence develop special features close to the quantum critical points. As suggested by an earlier theorem, the first derivatives of the measures with respect to magnetic field are expected to diverge as H tends to Hc1 and Hc2. Based on numerical diagonalization data and a mapping of the strongly-coupled ladder Hamiltonian onto the XXZ chain Hamiltonian, for which several analytical results are known, we find that the derivatives of the entanglement measures diverge as H tends to Hc2 but remain finite as H tend to Hc1. The reason for this discrepancy is analysed. We further calculate two recently proposed quantum information theoretic measures, the reduced fidelity and reduced fidelity susceptibility, and show that these measures provide appropriate signatures of the QPTs occuring at the critical points H=Hc1 and H=Hc2.

Affiliated with

Also associated with

No associations

Rating

Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-538339