Coherent entangled light generated by quantum dots in the presence of   nuclear magnetic fields
  A practical source of high fidelity entangled photons is desirable for quantum information applications and exploring quantum physics. Semiconductor quantum dots have recently been shown to conveniently emit entangled light when driven electrically, however the fidelity was not optimal. Here we show that the fidelity is not limited by decoherence, but by coherent interaction with nuclei. Furthermore we predict that on 100\mu s timescales, strongly enhanced fidelities could be achieved. This insight could allow tailoring of quantum logic to operate using quantum dots in the fault tolerant regime. 
R. M. Stevenson, C. L. Salter, A. Boyer de la Giroday, I. A. Farrer,   C. A. Nicoll, D. A. Ritchie, and A. J. Shields
quant-ph