Volume 77, Number 5, March 2007
Article Number 50009
Number of page(s) 5
Section General
Published online 26 February 2007
EPL, 77 (2007) 50009
DOI: 10.1209/0295-5075/77/50009

A non-Markovian optical signature for detecting entanglement in coupled excitonic qubits

F. J. Rodríguez1, L. Quiroga1 and N. F. Johnson2

1  Departamento de Física, Universidad de Los Andes - A.A, 4976, Bogotá, Colombia
2  Physics Department, Clarendon Laboratory, Oxford University - Oxford, OX1 3PU, UK

received 4 August 2006; accepted in final form 23 January 2007; published March 2007
published online 26 February 2007

We identify an optical signature for detecting entanglement in experimental nanostructure systems comprising coupled excitonic qubits. This signature owes its strength to non-Markovian dynamical effects in the second-order temporal coherence function of the emitted radiation. We calculate autocorrelation and cross-correlation functions for both selective and collective light excitation, and prove that the coherence properties of the emitted light do indeed carry information about the entanglement of the initial multi-qubit state. We also show that this signature can survive in the presence of a noisy environment.

03.65.Yz - Decoherence; open systems; quantum statistical methods.
03.65.Ud - Entanglement and quantum nonlocality.
78.67.Hc - Quantum dots.

© Europhysics Letters Association 2007