Qiskit Cold Atom

Qiskit is an open-source SDK for working with quantum computers at the level of circuits, algorithms, and application modules.

This project builds on this functionality to describe programmable quantum simulators of trapped cold atoms in a gate- and circuit-based framework. This includes a provider that allows access to cold atomic quantum devices located at Heidelberg University.

Traditionally, each wire in a quantum circuit represents one qubit as the fundamental unit of information processing. Here, we extend this concept and allow wires to represent individual internal states of trapped cold atoms. This currently covers two settings, one for fermionic modes and one for spin modes, demonstrating that a broad range of hardware can be accommodated in Qiskit.

We encourage new users to familiarize themselves with the basic functionalities through the tutorial-style python notebooks in /docs/tutorials. These require an environment to execute .ipynb notebooks such as jupyter lab.

Installation

To install Qiskit Cold Atom from source and further develop the package, clone this repository and install from the project root using pip:

pip install -e .

To use the repository you can also install using either

pip install git+https://github.com/Qiskit-Extensions/qiskit-cold-atom.git

or Pypi

pip install qiskit-cold-atom

Setting up the Cold Atom Provider

Qiskit Cold Atom includes local simulator backends to explore the cold atomic hardware. In order to access remote device backends, you will need valid user credentials. To this end, the user has to specify the url of the desired backend and a valid username and token as a password, which can be saved as an account:

from qiskit_cold_atom.providers import ColdAtomProvider

# save an account to disk
ColdAtomProvider.save_account(urls = ["url_backend_1", "url_backend_2"], username="my_name", token="my_password")

Loading the account instantiates the provider from which the included backends can be accessed.

# load the stored account
provider = ColdAtomProvider.load_account()

# get available backends
print(provider.backends())

# Example: Get a simulator backend
spin_simulator_backend = provider.get_backend("collective_spin_simulator")

Cold atomic circuits

The circuits that can be run on the cold atomic hardware explored in this project use different gates from the qubit circuits typically employed in Qiskit, because their systems are described by different Hilbert spaces. To see how to define and run gates through quantum circuits in this setting, please refer to the tutorials (in /docs/tutorials).

Documentation

The documentation can be found as Github pages here https://qiskit-extensions.github.io/qiskit-cold-atom/. To build the API reference locally, run:

pip install -r requirements-dev.txt
make -C docs html
open docs/_build/html/index.html

Tests

Test are located in the test folder. All contributions should come with test files that are named test_*.py which test the new functionalities. To execute the test suite locally, run