rquant

A quantum computing library written entirely in rust.

It allows for qubit measurement and basic quantum logic in complex vector space. Gates can be applied to qubits in complex vector space, then those qubits can be measured to observe the outcome.

Getting Started

1. Download the repo
2. Open a terminal and navigate to the repo root
3. Run cargo run to see the output of the (very simple) main function
4. Run cargo test to run all the tests
5. Run cargo doc --no-deps to generate the docs

Examples

Creating a qubit

You can create a qubit by using one of the premade qubits, or using a premade quantum position:

use rquant::{
    log_info,
    quantum::types::{quantum_position::QuantumPosition, qubit::Qubit},
};

fn main() {
    // create a zero qubit: |0>
    let zero_qubit = Qubit::zero();
    log_info!("Zero qubit: {zero_qubit}");

    // create an identity qubit: |1>
    let identity_qubit = Qubit::one();
    log_info!("Zero qubit: {identity_qubit}");

    // create a custom qubit using a quantum position:
    // 0+1i|0>
    let custom_qubit = Qubit::new(QuantumPosition::QUARTER_TURN);
    log_info!("Custom qubit: {custom_qubit}");
}

This example will produce the following output:

Applying gates to qubits

You can apply a gate to a single qubit:

use rquant::{
    log_info,
    quantum::types::{quantum_gate::QuantumGate, qubit::Qubit},
};

fn main() {
    // use the '!' operator to apply the FLIP gate
    let flipped_zero_qubit = !Qubit::zero();
    log_info!("Flipped zero qubit: {flipped_zero_qubit}");

    // use premade quantum gates to modify a qubit
    let rotated_qubit = Qubit::one()
        .apply_gate(&QuantumGate::PHASE)
        .apply_gate(&QuantumGate::ROTATE);
    log_info!("Rotated identity qubit: {rotated_qubit}");
}

This example will produce the following output:

Create multiple associated qubits

You can create a collection of many qubits using a qubit register:

use rquant::{
    log_info,
    quantum::types::{quantum_gate::QuantumGate, qubit_register::QubitRegister},
};

fn main() {
    // create a register of 100 qubits with the |0> state
    let qubit_register = QubitRegister::new(10);
    log_info!("Qubit register:\n{qubit_register}");

    // get the amount of qubits in the qubit register
    let qubit_count = qubit_register.len();
    log_info!("There are {qubit_count} qubits in the register.");

    // get a (zero-indexed) qubit from the register
    let fifth_qubit = qubit_register
        .get(4)
        .expect("There was no fifth qubit in the register.");
    log_info!("The fifth qubit in the register: {fifth_qubit}");

    // modify the fifth qubit by applying the PHASE gate
    let phased_fifth_qubit = fifth_qubit.apply_gate(&QuantumGate::ROTATE);
    log_info!("Phased fifth qubit: {phased_fifth_qubit}\n");
}

This example will produce the following output:

Run simulations on qubits

You can simulate and report on behavior on any amount of qubits:

use rquant::{
    quantum::types::qubit::Qubit,
    simulation::types::{simulation::Simulation, simulation_report::SimulationReport},
};

fn main() {
    // create 1,000,000 superpositioned qubits, and observe
    // their measurements using the report function.
    Qubit::one()
        .simulate_superposition(1000000)
        .report(Qubit::one());
}

This example will produce the following output:

Dependencies

Crate	Purpose
rand v0.9.1	Used to measure qubit position
num-complex v0.4	Used as the basis of quantum positions for qubits