The quantum control limit to a single electron transistor and operation frequency improvements

The Single Electron Transistor (SET) is regarded as one of the most promising quantum devices for advanced high capacitive information systems in the future. To analyze time dependent characteristics of SET and depict factors determining the device speed, three states probability equations, which are useful and effective for practical evaluations, are suggested and solved. The quantum control limit to the maximum operation frequency of SET is evaluated from the viewpoint of the uncertainty principle between an electric charge and a magnetic flux.