All-Optical Electron Spin Quantum Computers Using Quantum Dot Array Formed By AFM Oxidation

We have studied the physical implementation of quantum computer based on electron spin in semiconductor nanostructures. First, we have analyzed the basic characteristics of spin quantum gate. Next, we have proposed all-optical operation scheme using electron spins in coupled quantum dots. The formation of array of quantum dots whose sizes and positions are precisely controlled is a necessary technique for this scheme. We have succeeded in fabricating such an array of 20 to 30 nm sized quantum dots on the same surface using atomic force microscope lithography.