Limits on partition noise from the heating rate of vibrational phonons in radio-frequency quadrupole traps

Limits on partition noise from the heating rate of vibrational phonons in radio-frequency (rf) quadrupole traps were discussed. The heating rate of trapped ions provided a sensitive measure of partition noise arising fron the flow of rf current in the trap electrodes. Results showed a partition noise power spectral density less than 10-8 of the Poisson value, showing a sensitivity >106 greater than the solid state measurements.