quantum-signal-processing

Construct phase-optimized single-qubit QSP circuits and simulate polynomial transformations.

30|2|Updated Apr 16, 2026
One-click install
npx skills add https://github.com/unitarylab/quantum-skills --skill quantum-signal-processing
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Skill: quantum-signal-processing
Source: https://github.com/unitarylab/quantum-skills/tree/main/algorithms/linear-systems/quantum-signal-processing
Command: npx skills add https://github.com/unitarylab/quantum-skills --skill quantum-signal-processing

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires unitarylab, and includes scripts (resource) components.

What problem does it solve?

Enables construction and understanding of quantum signal processing (QSP) algorithms to transform eigenvalues and simulate Hamiltonians using phase sequences, with a focus on educational demonstration and practical experimentation.

Core Features & Use Cases

  • Phase-optimized single-qubit QSP circuit construction using W(x) = Rx(2 arccos(x)) interleaved with Rz gates.
  • Classical phase optimization via L-BFGS-B to approximate target functions like e^{-i τ x} for given τ.
  • End-to-end workflow: circuit construction, statevector simulation, error analysis, and SVG circuit export for visualization.
  • Educational demonstrations across quantum algorithms, including QSP for Hamiltonian simulation and polynomial transforms.

Quick Start

Run the QSP example by invoking QSPAlgorithm with your target_tau, degree, and x_value and inspect the resulting circuit diagram and error.

Frequently Asked Questions about quantum-signal-processing

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I simulate Hamiltonian evolution using quantum signal processing?

Quantum signal processing simulates Hamiltonian evolution by applying phase-optimized single-qubit circuits to approximate target functions like e^{-iτx}, allowing you to transform eigenvalues using computed phase sequences.

What is quantum signal processing and how does it implement polynomial transformations?

Quantum signal processing is a technique that implements polynomial transformations on a quantum signal by interleaving W(x) = Rx(2 arccos(x)) rotations with Rz phase gates to achieve targeted function approximations.

How do I optimize phase sequences for a target function in quantum signal processing?

You optimize phase sequences by using classical L-BFGS-B optimization to approximate your target function, such as e^{-iτx}, for a specified degree and evolution time parameter τ.

Can I export and visualize the quantum circuits generated by quantum signal processing?

Yes, the end-to-end workflow includes statevector simulation, error analysis, and SVG circuit export, enabling you to visualize the constructed gate sequences and evaluate approximation accuracy.

What are the limitations of using single-qubit quantum signal processing for Hamiltonian simulation?

The approach focuses on single-qubit circuits using W(x) = Rx(2 arccos(x)) interleaved with Rz gates, which is primarily suited for educational demonstration and analyzing polynomial approximations rather than large-scale multi-qubit systems.