Quantum information processing in a silicon-based system

For the first time, long coherence times (T2) up to tens of microseconds were observed in a silicon-based charge quantum bit (qubit) device at 4.2 K. The coherence times demonstrated in this paper are two orders of magnitude longer, and the operating temperature is two orders of magnitude higher than the reported semiconductor charge qubit systems (see Table 1). In contrast to other approaches, in this work the qubits are formed by trench isolation instead of surface gate-defined. The qubits were fabricated on P-doped silicon-on-insulator (SOI) wafers through current industrial semiconductor manufacturing technology. We have demonstrated the accurate readout of the qubits' electronic states by using a single electron transistor (SET) as an electrometer. The first observation of the interaction between two sets of capacitively coupled charge movements was achieved by using our charge detection technique.