Teleportation on a Quantum Dot Array

We present a model of quantum teleportation protocol based on a double quantum dot array. The unknown qubit is encoded using a pair of quantum dots, with one excess electron, coupled by tunneling. It is shown how to create a maximally entangled state using an adiabatically increasing Coulomb repulsion between different dot pairs. This entangled state is exploited to perform teleportation again using an adiabatic coupling between itself and the incoming unknown state. Finally, a sudden separation of Bob's qubit allows a time evolution of Alice's, which amounts to a modified version of standard Bell measurement. A transmission over a long distance could be obtained by considering the entangled state of a chain of $N$ coupled double quantum dots. The system is shown to be increasingly robust with $N$ against decoherence due to phonons.

Figure 1

QDs 1 and 2 represent the unknown qubit to teleport. QDs from 3 to 6 are in the entangled state $\frac{1}{\sqrt{2}}[|0_3,1_4,0_5,1_6\rangle +|1_3,0_4,1_5,0_6\rangle ]$. Initially the systems are separated. Solid lines represent tunneling, while dashed lines represent Coulomb repulsion.

Figure 2

Final step of quantum teleportation: Bob's qubit is separated by other QDs which evolve providing a Bell measurement process.