From Block Diagrams to Bloch Spheres: Graphical Quantum Circuit Simulation in LabVIEW

TL;DR

QuVI (Quantum Virtual Instrument), an open-source quantum circuit toolkit developed natively within the NI LabVIEW environment, is introduced, offering educators and researchers a powerful platform for prototyping quantum logic without leaving the graphical engineering workspace.

Abstract

As quantum computing transitions from theoretical physics to engineering applications, there is a growing need for accessible simulation tools that bridge the gap between abstract linear algebra and practical implementation. While text-based frameworks (like Qiskit or Cirq) are standard, they often present a steep learning curve for students and engineers accustomed to graphical system design. This paper introduces QuVI (Quantum Virtual Instrument), an open-source quantum circuit toolkit developed natively within the NI LabVIEW environment. Moving beyond initial proof-of-concept models, QuVI establishes a robust framework that leverages LabVIEW's "dataflow" paradigm-where wires represent data and nodes represent operations-to provide an intuitive, visual analog to standard quantum circuit notation while enabling the seamless integration of classical control structures like loops and conditionals. The toolkit's capabilities are demonstrated through the construction and visualization of fundamental quantum algorithms, verifying results against theoretical predictions. By translating "Block Diagrams" directly into quantum state evolutions ("Bloch Spheres"), QuVI offers educators and researchers a powerful platform for prototyping quantum logic without leaving the graphical engineering workspace.

Figures (4)

• Figure 1: QuVI architecture demonstrating execution flow. Top wires: Independent operations execute in parallel via native dataflow. Bottom wires: Entangling gates (e.g., CNOT) enforce synchronization using Notifiers to handle state dependencies between control and target qubits.
• Figure 2: Butterfly crossovers illustrating the stride logic for qubit $k$ (adapted from mcguffin). The figure details the transformation formula of $|b\rangle$ from $|a\rangle$ for each case of a three-qubit system ($k=0, 1, 2$), where $I_2$ denotes the $2 \times 2$ Identity matrix. The arrow of the partner amplitude $a_{\text{partner}}$ is colored blue for $i_k=0$ and red for $i_k=1$ (dashed arrows mark $i_k$ indices for each case).
• Figure 3: Quantum Teleportation implemented in QuVI. The green dashed wires represent the classical channel, carrying measurement results from Alice's qubits to control Case Structures that apply corrections ($X$ and $Z$ gates) to Bob's qubit.
• Figure 4: 4-Qubit Grover Search in QuVI. (a) LabVIEW Block Diagram utilizing a For Loop for algorithm iterations and a Case Structure for dynamic Oracle selection. The tagged state is set to $|0101\rangle$. (b) Simulation result showing the probability distribution of the final state, with a dominant peak ($>96\%$) at the index 0101 (decimal 5).