Entanglement witnesses in spin models
Abstract
We construct entanglement witnesses using fundamental quantum operators of spin models which contain two-particle interactions and have a certain symmetry. By choosing the Hamiltonian as such an operator, our method can be used for detecting entanglement by energy measurement. We apply this method to the Heisenberg model in a cubic lattice with a magnetic field, the XY model, and other familiar spin systems. Our method provides a temperature bound for separable states for systems in thermal equilibrium. We also study the Bose-Hubbard model and relate its energy minimum for separable states to the minimum obtained from the Gutzwiller ansatz.
- Publication:
-
Physical Review A
- Pub Date:
- January 2005
- DOI:
- 10.1103/PhysRevA.71.010301
- arXiv:
- arXiv:quant-ph/0406061
- Bibcode:
- 2005PhRvA..71a0301T
- Keywords:
-
- 03.65.Ud;
- 03.67.-a;
- 05.50.+q;
- Entanglement and quantum nonlocality;
- Quantum information;
- Lattice theory and statistics;
- Quantum Physics;
- Condensed Matter - Statistical Mechanics
- E-Print:
- 5 pages including 3 figures, revtex4