QuTiP: An open-source Python framework for the dynamics of open quantum systems

Abstract

We present an object-oriented open-source framework for solving the dynamics of open quantum systems written in Python. Arbitrary Hamiltonians, including time-dependent systems, may be built up from operators and states defined by a quantum object class, and then passed on to a choice of master equation or Monte Carlo solvers. We give an overview of the basic structure for the framework before detailing the numerical simulation of open system dynamics. Several examples are given to illustrate the build up to a complete calculation. Finally, we measure the performance of our library against that of current implementations. The framework described here is particularly well suited to the fields of quantum optics, superconducting circuit devices, nanomechanics, and trapped ions, while also being ideal for use in classroom instruction. Program summaryProgram title: QuTiP: The Quantum Toolbox in PythonCatalogue identifier: AEMB_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMB_v1_0.htmlProgram obtainable from: CPC Program Library, Queenʼs University, Belfast, N. IrelandLicensing provisions: GNU General Public License, version 3No. of lines in distributed program, including test data, etc.: 16 482No. of bytes in distributed program, including test data, etc.: 213 438Distribution format: tar.gzProgramming language: PythonComputer: i386, x86-64Operating system: Linux, Mac OSX, WindowsRAM: 2+ GigabytesClassification: 7External routines: NumPy (http://numpy.scipy.org/), SciPy (http://www.scipy.org/), Matplotlib (http://matplotlib.sourceforge.net/)Nature of problem: Dynamics of open quantum systems.Solution method: Numerical solutions to Lindblad master equation or Monte Carlo wave function method.Restrictions: Problems must meet the criteria for using the master equation in Lindblad form.Running time: A few seconds up to several tens of minutes, depending on size of underlying Hilbert space.