Rewriting quantum circuits

The module pbo (for Pattern Based Opimization) provides an interface to efficiently manipulate quantum circuits via rule-based rewriting.

For instance, this module could automatically rewrite

into:

using only few lines of code. This example could be implemented by using defining the rule H-H pattern is equivalent to the identity. Such rewriting can optimize a quantum circuit, by reducing the number of gates composing the circuit, or transpile a circuit by changing the gate set.

This module provides 3 main tools:

• A low level rewriter named GraphCircuit, taking two patterns (left pattern and right pattern) and replacing the first occurence of left pattern by right pattern

• An high-level rewriter named PatternManager, taking a set of patterns and applying them automatically to minimize a cost function

• A KAK compression plugin, named KAKCompression, merging the consecutive one qubit gates into a temporary unitary matrix, and decomposing this temporary matrix using a pattern

These tools are parametrized by patterns. This module provides collections of pattern (to be used with PatternManager) but user defined patterns are also available

Low-level optimization

High-level optimization

Compressing single qubit gates

Writing patterns

Pattern collections (to be used with PatternManager)