Abstract: This disclosure relates to preserving a quantum state in a quantum memory. A controller of the quantum memory determines based on a characteristic of noise that causes deterioration of the quantum state a dynamical decoupling base sequence. The duration of the base sequence is shorter than or equal to an access latency time of the quantum memory to allow access to the quantum state within the access latency time. Further, the deterioration of the quantum state is bounded to an upper deterioration limit when the base sequence is repeatedly applied to the quantum system. This provides acceptable access times while simultaneously allowing long term storage of data in the quantum state with low error rates. Repeatedly applying the base sequence to the quantum system will first yield an increasing deterioration but that deterioration will eventually reach the upper limit. As a result, over time the error rates will not exceed that upper limit and the quantum state is stable.

Abstract: This disclosure relates to controlling an oscillator based on a measurement of a frequency reference. A controller determines a control value to control the oscillator based on multiple error values. Each error value is indicative of a measurement of a frequency difference between the oscillator and a frequency reference over a period of time. The determination of the error value is further based on an application time value indicative of a time of application of the control value to the oscillator. Since the control value is based on the application time the controller can compensate for inaccuracies arising from both evolution of the oscillator between measurements and applying the correction at a later time after the measurement. Further, since the multiple error values represent a frequency difference over different periods of time, the controller can compensate for wide range of statistical effects.

Abstract: This disclosure relates to controlling an oscillator based on a measurement of a frequency reference. A controller determines a control value to control the oscillator based on multiple error values. Each error value is indicative of a measurement of a frequency difference between the oscillator and a frequency reference over a period of time. The determination of the error value is further based on an application time value indicative of a time of application of the control value to the oscillator. Since the control value is based on the application time the controller can compensate for inaccuracies arising from both evolution of the oscillator between measurements and applying the correction at a later time after the measurement. Further, since the multiple error values represent a frequency difference over different periods of time, the controller can compensate for wide range of statistical effects.

Abstract: This disclosure relates to preserving a quantum state in a quantum memory. A controller of the quantum memory determines based on a characteristic of noise that causes deterioration of the quantum state a dynamical decoupling base sequence. The duration of the base sequence is shorter than or equal to an access latency time of the quantum memory to allow access to the quantum state within the access latency time. Further, the deterioration of the quantum state is bounded to an upper deterioration limit when the base sequence is repeatedly applied to the quantum system. This provides acceptable access times while simultaneously allowing long term storage of data in the quantum state with low error rates. Repeatedly applying the base sequence to the quantum system will first yield an increasing deterioration but that deterioration will eventually reach the upper limit. As a result, over time the error rates will not exceed that upper limit and the quantum state is stable.