Dynamic control for a quantum computer
Methods and apparatus for dynamically controlling a quantum computer are described wherein the method includes selecting a first and second digital pulse signal stored in a memory, the first digital pulse signal having a first pulse shape and a first sample rate and the second digital pulse signal having a second pulse shape and a second sample rate, at least the first or the second sample rate being lower than an output sampling rate of a digital-to-analog converter (DAC); forming a digital pulse sequence signal, the forming including applying a first interpolation algorithm to determine a first upsampled digital pulse signal based on the first digital signal and a second interpolation algorithm to determine a second upsampled digital pulse signal based on the second digital signal, the sample rates of the first and second upsampled digital signals matching the sample rate of the DAC; and, providing the digital pulse sequence signal comprising the first and second upsampled digital pulse signals to an input of the DAC to transform the first and second upsampled digital signals into an analog pulse sequence signal for controlling the quantum device.
1. A method of controlling a quantum device comprising:
executing, by a first digital circuit-based sequence processor and a second digital circuit-based sequence processor, operations of a control program, the first and second sequence processors being associated with one or more memory modules comprising stored data representing a plurality of digital pulse signals, the executing of the operations of the control program comprising:
selecting by the first and second sequence processors a first and a second digital pulse signal, respectively, from the plurality of digital pulse signals, the first digital pulse signal being associated with a first upsampling rate and the second digital pulse signal being associated with a second upsampling rate, which is different from the first upsampling rate;
retrieving by a first pulse sequence generator controlled by the first sequence processor, first data representing the first digital pulse signal at a first sample rate from the one or more memory modules, upsampling, by a first upsampling module of the first pulse sequence generator, the first digital pulse signal based on the first upsampling rate, modulating the first digital pulse signal using a first modulation signal having a first modulation frequency, the first modulation signal being generated by a first oscillator controlled by the first sequence processor, and providing data representing a first modulated upsampled digital pulse signal at a sampling rate of a digital to analog convertor to a summer;
retrieving, by a second pulse sequence generator controlled by the second sequence processor, second data representing the second digital pulse signal at a second sample rate from the one or more memory modules, upsampling by a second upsampling module of the second pulse sequence generator the second digital pulse signal based on the second upsampling rate, modulating the second digital pulse signal using a second modulation signal having a second modulation frequency, which is different from the first modulation frequency, the second modulation signal being generated by a second oscillator controlled by the second sequence processor, and providing data representing a second upsampled digital pulse signal at the sampling rate of the digital to analog converter to the summer;
generating, by the summer, a digital pulse sequence signal based on the first and second modulated upsampled digital pulse signals; and,
converting the digital pulse sequence signal, by the digital to analog converter, into an analog pulse sequence signal, a sequence of pulses of the analog pulse sequence signal representing one or more operations on quantum elements of the quantum device.
2. The method according to claim 1 , wherein the executing of the operations of the control program further comprises:
applying a first interpolation filter to the first modulated upsampled digital pulse signal; and/or, applying a second interpolation filter to the second modulated upsampled digital pulse signal.
3. The method according to claim 1 , wherein the executing of the operations of the control program further comprises:
providing upsampling information for upsampling the first and second digital pulse signals.
4. The method according to claim 1 , wherein upsampling information for upsampling the first and second digital pulse signals is stored in the one or more memory modules and wherein the generating of the digital pulse sequence signals further comprises:
retrieving the upsampling information from the one or more memory modules.
5. The method according to claim 4 , wherein the first sequence processor is configured to provide a first upsampling module of the first pulse sequence generator with upsampling information for upsampling the first digital pulse signal; and/or, the second sequence processor is configured to provide a second upsampling module of the first pulse sequence generator with upsampling information for upsampling the second digital pulse signal.
6. The method according to claim 1 , wherein the one or more memory modules is one or more block random access memory modules.
7. The method according to claim 3 , wherein the upsampling information includes information about the first upsampling rate for upsampling the first digital pulse signal and the second upsampling rate for upsampling the second digital pulse signal.
8. The method according to claim 1 , wherein the first and second modulation frequency is generated by one or more numerically controlled oscillators.
9. A system for controlling a quantum device comprising:
at least a first electronic circuit-based sequence processor and a second electronic circuit-based sequence processor, the first and second sequence processors being associated with one or more memory modules comprising stored data representing a plurality of digital pulse signals, the first and second sequence processors being configured to execute operations of a program for controlling the quantum device;
at least a first pulse sequence generator and a second pulse sequence generator controlled by the first sequence processor and second sequence processor, respectively;
a summer configured to generate a digital pulse sequence signal based on digital pulse signals generated by the first pulse sequence generator and the second pulse sequence generator; and,
a digital-to-analog converter associated with a digital-to-analog converter sampling rate for converting the digital pulse sequence signal into an analog pulse sequence signal, a sequence of pulses of the analog pulse sequence signal representing one or more operations on quantum elements of the quantum device;
the first sequence processor being adapted to select a first digital pulse signal associated with a first upsampling rate from the plurality of digital pulse signals stored in the one or more memory modules;
the second sequence processor being adapted to select a second digital pulse signal associated with a second upsampling rate from the plurality of digital pulse signals stored in the one or more memory modules;
the first pulse sequence generator comprising a first upsampling module configured to retrieve first data representing the first digital pulse signal from the one or more memory modules, and to upsample the first digital pulse signal based on the first upsampling rate, a first signal modulator configured to modulate the first digital pulse signal using a first modulation signal having a first modulation frequency, the first modulation signal being generated by a first oscillator controlled by the first sequence processor, and configured to provide data representing a first modulated upsampled digital pulse signal at the digital-to-analog converter sampling rate to the summer;
the second pulse sequence generator comprising a second upsampling module configured to retrieve second data representing the second digital pulse signal from the one or more memory modules, and to upsample the second digital pulse signal based on the second upsampliing rate which is different from the first upsampling rate, a second signal modulator configured to modulate the second digital pulse signal using a second modulation signal having a second modulation frequency, which is different from the first modulation frequency, the second modulation signal being generated by a second oscillator controlled by the second sequence processor, and configured to provide data representing a second modulated upsampled digital pulse signal at the digital-to-analog converter sampling rate to the summer.
10. The system according to claim 9 , wherein the first upsampling module is further configured to apply a first interpolation filter to the first modulated upsampled digital pulse signal; and/or, the second upsampling module is further configured apply a second interpolation filter to the second modulated upsampled digital pulse signal.
11. The system according to claim 9 , wherein
the first sequence processor is further configured to provide upsampling information to the first upsampling module for upsampling the first digital pulse signal; and/or,
the second sequence processor is further configured to provide upsampling information to the second upsampling module for upsampling the second digital pulse signal.
12. The system according to claim 9 , wherein upsampling information for upsampling the first and second digital pulse signals is stored in the one or more memory modules and the first and second sequence processors are further configured to retrieve at least part of the upsampling information from the one or more memory modules.
13. The system according to claim 9 , wherein the first and second sequence processors, the one or more memory modules, the first and second pulse sequence generators, the summer, and, optionally, the digital-to-analog converter, are implemented as one or more digital circuits.
14. The system according to claim 9 , wherein the one or more memory modules is one or more block random access memory modules.
15. The system according to claim 9 , wherein the first and second modulation frequency is generated by one or more numerically controlled oscillators.
16. A non-transient computer-readable storage medium having stored thereon a computer program product comprising software code portions configured for, when run in the memory of a computer, executing the method steps according to claim 1 .