Groundstate entanglement in interacting bosonic graphs
Abstract
We consider a collection of bosonic modes corresponding to the vertices of a graph Γ. Quantum tunneling can occur only along the edges of Γ and a local selfinteraction term is present. Quantum entanglement of one vertex with respect to the rest of the graph (mode entanglement) is analyzed in the ground state of the system as a function of the tunneling amplitude τ. The topology of Γ plays a major role in determining the tunneling amplitude τ_{max} that leads to the maximum value of the mode entanglement. Whereas in most of the cases one finds the intuitively expected result τ_{max} = ∞, we show that there exists a family of graphs for which the optimal value of τ is pushed down to a finite value. We also show that, for complete graphs, our bipartite entanglement provides useful insights in the analysis of the crossover between insulating and superfluid ground states.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 October 2004
 DOI:
 10.1209/epl/i2004101292
 arXiv:
 arXiv:quantph/0311058
 Bibcode:
 2004EL.....68..163G
 Keywords:

 Quantum Physics
 EPrint:
 5 pages (LaTeX) 5 eps figures included