Trapped electrons in vacuum for a scalable quantum processor

We describe in detail a theoretical scheme to trap and manipulate an arbitrary number of electrons in vacuum for universal quantum computation. The particles are confined in a linear array of Penning traps by means of a combination of static electric and magnetic fields. Two-electron operations are realized by controlling the Coulomb interaction between neighboring particles. The performances of such a device are evaluated in terms of clock speed, fidelity, and decoherence rates.

Figure 1

Schematic drawing of a cylindrical trap with the lateral surface consisting of nine ring electrodes at alternate potentials. This device reproduces along the axial direction four Penning traps where electrons can be confined.

Figure 2

Three-dimensional plot showing the electrostatic energy of the electron in the cylindrical trap sketched in Fig. 1. Electrons can be stored near the four minima along the $z$ axis.

Figure 3

Schemes (a) and (b) show the electrode arrangement giving, respectively, $V_C(r,z)$ and $V_D(r,z)$. Scheme (c) displays the complete trapping device with the lateral surface consisting of trapping, decompensating, detuning, and driving electrodes.

Figure 4

Schematic drawing of two electrons $e_1$ and $e_2$ confined in neighboring microtraps separated by a distance $d$.