Classical processor for quantum control
Methods and systems for classical processing in a quantum controller.
1. A system comprising:
a pulser comprising:
a pulse computation and signal processing circuit (CSP) comprising a plurality of building blocks; and
a pulse modification circuit, wherein:
the CSP is configured to execute a program in real-time independently from a control flow of a quantum algorithm,
the pulse modification circuit is configured dynamically according to the control flow of the quantum algorithm,
the CSP is configured to selectively dispatch, according to the control flow of the quantum algorithm, one or more dispatch results and an outbound pulse from the plurality of building blocks,
the one or more dispatch results comprise a matrix representation of a modification,
the matrix representation of the modification comprises a plurality of rows and a plurality of columns,
the pulse modification circuit is configured to generate the matrix representation in real-time according to one or more pulse operations specified by a digital control signal,
the outbound pulse is represented by a vector, and
the pulse modification circuit is configured to modify the outbound pulse according to the one or more dispatch results.
2. The system of claim 1 , wherein:
each building block of the plurality of building blocks of the CSP is configured to operate in parallel with one or more different building blocks of the plurality of building blocks according to a fixed timing, and
each building block of the plurality of building blocks of the CSP is configured to receive, as an input, a result from a different building block of the plurality of building blocks.
3. The system of claim 1 , wherein the pulser is configured to modify the control flow of the quantum algorithm according to the one or more dispatch results.
4. The system of claim 1 , wherein the pulser is configured to modify one or more of an amplitude, a phase, a time and a frequency of the outbound pulse according to the one or more dispatch results.
5. The system of claim 1 , wherein one or more of the building blocks are configured to determine a state of a quantum element according to a readout pulse.
6. The system of claim 1 , wherein:
the plurality of building blocks of the CSP comprises different types of building blocks,
each building block of the plurality of building blocks is configured to update at least one of a plurality of register vectors in a CSP bus, and
the plurality of register vectors in the CSP bus is visible to all building blocks of the plurality of building blocks.
7. The system of claim 6 , wherein the different types of building blocks comprise one or more of an arithmetic logic unit (ALU), a comparator logic units (CLU), a multiplier (Mult), a counter, a configurable delay and a programmable Boolean function.
8. The system of claim 6 , wherein each of the plurality of building blocks is:
operably coupled to the CSP bus,
configured to receive one or more selectors, as input, to select an input from the CSP bus,
configured to receive an opcode, as an input, to determine an operation type, associated with a deterministic latency,
configured to receive a new input every cycle, and
configured to update the CSP bus.
9. The system of claim 6 , wherein the plurality of building blocks comprises a storage block, and wherein the storage block is:
operably coupled to the CSP bus,
configured to receive a selector, as an input, to select a register vector from the CSP bus,
configured to receive an opcode, as an input, to determine an address and one of a read operation and a write operation,
associated with a deterministic latency,
configured to receive a new input every cycle, and
configured to update the CSP bus.
10. The system of claim 6 , wherein the plurality of building blocks comprises an immediate building block, and wherein the immediate building block is:
configured to receive data from a CSP memory,
configured to store the data to the CSP bus, and
associated with a deterministic latency.
11. The system of claim 6 , wherein the different types of building blocks comprise one or more signal processing building blocks.
12. The system of claim 6 , wherein the different types of building blocks comprise a demodulation circuit configured to demodulate a feedback pulse from the quantum processor.
13. The system of claim 6 , wherein the system comprises a plurality of pulsers and the pulser is a first pulser of the plurality of pulsers, and wherein the plurality of building blocks in the CSP of the first pulser comprises an intra-communication block, and wherein the intra-communication block is:
configured to receive a selector, as an input, to select information from the CSP bus,
associated with a deterministic latency,
configured to receive a new input every cycle, and
configured to update an intra-bus that is accessible by the plurality of pulsers.
14. The system of claim 13 , wherein the intra-bus allows the CSP of the first pulser to share a register vector with a different CSP of a different pulser within a quantum controller, and wherein data on the shared register vector is one of analog data and digital data.
15. The system of claim 13 , wherein a different pulser is configured to modify one or more of an amplitude, a phase, a time and a frequency of the outbound pulse according to the one or more dispatch results from the first pulser.
16. The system of claim 1 , wherein the CSP comprises a dispatch circuit, and wherein the dispatch circuit is configured to:
receive a CSP bus as input,
receive a set of selects and enables from a CSP program memory,
select a register vector from the CSP bus, and
dispatch at least a portion of the selected register vector to a destination in a quantum controller.
17. The system of claim 1 , wherein the CSP comprises a control flow circuit and a program memory, and wherein:
the control flow circuit is configured to fetch a block of commands stored in the program memory cycle-by-cycle,
the control flow circuit is configured to jump to a different command according to an IF statement, and
the CSP is configured to execute the commands received from the control flow circuit.
18. The system of claim 17 , wherein the control flow circuit is configured to:
jump to a sub-routine at a different address, and
return from the sub-routine to resume an operation of a main program.
19. The system of claim 17 , wherein the control flow circuit is configured to pause a CSP command while maintaining a CSP bus state.
20. The system of claim 17 , wherein the pulser is configured to modify a control flow of the CSP according to the one or more dispatch results.