A fast "hybrid" silicon double quantum dot qubit
  We propose a quantum dot qubit architecture that has an attractive combination of speed and fabrication simplicity. It consists of a double quantum dot with one electron in one dot and two electrons in the other. The qubit itself is a set of two states with total spin quantum numbers $S^2=3/4$ ($S=\half$) and $S_z = -\half$, with the two different states being singlet and triplet in the doubly occupied dot. The architecture is relatively simple to fabricate, a universal set of fast operations can be implemented electrically, and the system has potentially long decoherence times. These are all extremely attractive properties for use in quantum information processing devices. 
Zhan Shi, C. B. Simmons, J. R. Prance, John King Gamble, Teck Seng   Koh, Yun-Pil Shim, Xuedong Hu, D. E. Savage, M. G. Laga...
quant-ph cond-mat.mes-hall