Quantum information processing with electron spins/ informatique quantique avec le spin des électrons

计算机处理信息的速度之快是由于它具有操纵电荷的能力。电荷的基本载体——电子，也能很好地改变信息技术。由于固有的角动量，就好像电子在自身旋转。这一特性从量子力学开始就为人所知，但直到最近才被利用起来。通过测量给定轴的旋转，观察者总是会得到以下两种结果中的一种：电子以一定的速度顺时针旋转，或者电子以相同的速度逆时针旋转。这两种状态可以用来在一个非常小的物理尺度上编码一个比特的信息：电子本身的大小。此外，利用磁场，可以将电子激发到同时向两个方向转动的状态，从而有效地实现量子逻辑运算。

The rapidity at which a computer processes information is due to the facility to manipulate electric charges. The elemental carrier of the electric charge, the electron, also performs an action that could very well revolutionize the information technologies. Because of an intrinsic angular momentum, it is as if the electron turns, or spins, on itself. This property, known since the beginning of quantum mechanics, has been harnessed only recently. By measuring the rotation around a given axis, an observer will always obtain one of the two following results: either the electron spins at a certain speed clockwise, or the electron spins at the same speed anti-clockwise. These two states can be used to encode one bit of information at a very small physical scale: the size of the electron itself. Furthermore, using magnetic fields, it is possible to excite the electron to a state where it turns in both directions simultaneously, effectively implementing a quantum logical operation.