Design Philosophy and Architecture¶

Given the heterogeneous nature of the hardware we target, We have decided to use a compiler-based approach to our software stack, allowing us to target different hardware backends with the same high-level language. Below is a diagram of the software stack in Bloqade.

graph TD
    Builder["Builder Representation"]
    PythonAST["Bloqade AST Python"]
    JuliaAST["Bloqade AST Julia"]

    EmulatorPy["Emulator IR Python"]
    EmulatorJL["Emulator IR Julia"]

    QuEra["QuEra IR"]
    Braket["Braket IR"]
    JuliaEmulator["Bloqade.jl"]
    PythonEmulator["Python Emulator"]

    Aquila["Aquila"]

    Builder -->|parse| PythonAST
    PythonAST -->|lower| EmulatorPy
    PythonAST -->|lower| QuEra
    PythonAST -->|lower| Braket
    PythonAST -->|transpile| JuliaAST

    QuEra -->|execute| Aquila
    Braket -->|execute| Aquila

    JuliaAST -->|lower| EmulatorJL
    EmulatorPy -->|execute| PythonEmulator
    EmulatorJL -->|execute| JuliaEmulator

High-Level Builder Representation¶

When programming Bloqade using the Python API, the user constructs a representation of an analog quantum circuit. This representation is a flattened version of the actual analog circuit. Flattened means that the user input is a linear sequence of operations where the context of neighboring nodes in the sequence of instructions can determine the program tree structure. The Bloqade AST describes the actual analog circuit.

Bloqade AST¶

The Bloqade AST is a representation of a quantum analog circuit for neutral atom computing. It is a directed acyclic graph (DAG) with nodes for different hierarchical levels of the circuit. The base node is the AnalogCircuit which contains the geometry of the atoms stored as a AtomArragment or ParallelRegister objects. The other part of the circuit is the Sequence, which contains the waveforms that describe the drives for the Ryberg/Hyperfine transitions of each Rydberg atom. Each transition is represented by a Pulse including a Field for the drive's detuning, Rabi amplitude, and Rabi phase . A Field relates the spatial and temporal dependence of a drive. The spatial modulates the temporal dependence of the waveform. A DAG also describes the Waveform object. Finally, we have basic Scalar expressions as well for describing the syntax of real-valued continuous numbers.

Bloqade Compilers and Transpilers¶

Given a user program expressed as the Bloqade AST, we can target various backends by transforming from the Bloqade AST to other kinds of IR. For example, when submitting a task to QuEra's hardware, we transform the Bloqade AST to the IR that describes a valid program for the hardware.

This process is referred to as lowering, which in a general sense is a transformation that takes you from one IR to another where the target IR is specialized or has a smaller syntactical structure. Transpiling corresponds to a transformation that takes you from one language to equivalent expressions in another. For example, we can transpile from the Bloqade AST in Python to the Bloqade AST in Julia. The generic term for both of these types of transformation in Bloqade is Code Generation. You will find various code generation implementations in various codegen modules.