stringebraic

Stringebraic is a library of methods for representing a Hamiltonian (i.e., a matrix) as a sum of Pauli strings and a quantum state (i.e., a vector) as a sum of bitstrings. This perspective allows for a variety of operations using these strings, such as matrix-vector multiplication, inner products, and other algebraic manipulations.
🐦: Why take this approach?
🐧: Because the computational complexity of these operations typically grows exponentially with the number of qubits—or, equivalently, with the size of the matrix.

In layman's terms, it automates Pauli algebra by:

1. removing the concept of matrix and vector size,
2. performing the matrix multiplication with string-based rules.

Input Files:

• input_string_list.pkl – A pickle file containing a list of bitstrings that compose the quantum state.
• input_string_coeff_list.pkl – A pickle file containing a list of coefficients that compose the quantum state.
• pauli_matrix_list.pkl – A pickle file containing a list of Pauli strings that compose the Hamiltonian.
• pauli_coeff_list.pkl – A pickle file containing a list of Pauli coefficients that compose the Hamiltonian.

Output:

• The inner product value – A scalar for what the inner product (e.g., expected energy) is.

Installation

It can be installed with pip, ideally by using a virtual environment. Open up a terminal and install the package and the dependencies with:

    pip install stringebraic

or

    python -m pip install stringebraic

🐍 This requires Python 3.8 or newer versions

Steps to fast compute the inner product energy using Pauli string algebra

1. Prepare the input files (i.e., converting the quantum Hamiltonian and quantum state into lists of strings and coefficients, as specified in the above section).

2. Run the command to generate a inner product (i.e., a scalar):

          stringebraic input_string_list.pkl input_string_coeff_list.pkl pauli_matrix_list.pkl pauli_coeff_list.pkl

Test

You may test the installation using the sample input files (input_string_list.pkl and input_string_coeff_list.pkl, pauli_matrix_list.pkl and pauli_coeff_list.pkl) located in the test folder.

♥ Lastly executed on Python 3.10 on 2025-06-05.