libquantum is a C library for the simulation of quantum mechanics, with a special focus laid to quantum computing. It started as a pure quantum computer simulator, but support for general quantum simulation has been recently added.

Quantum computing

Based on the principles of quantum mechanics, libquantum provides an implementation of a quantum register. Basic operations for register manipulation such as the Hadamard gate or the Controlled-NOT gate are available through an easy-to-use interface. Measurements can be performed on either single qubits or the whole quantum register.

General quantum simulation

Besides quantum computing, libquantum is able to compute the time-evolution of arbitrary Hamiltonians, including time-dependent ones. This is done via numerical integration of the Schrödinger equation. Computing the time-evolution for time-independent Hamiltonians via exact diagonalization is also possible.

Features

• Simulation of arbitrary quantum algorithms is possible
• High performance and low memory consumption
• Optional time-evolution using fourth-order Runge-Kutta or exact diagonalization, including optimizations for sparse Hamiltonians
• Decoherence support for realistic quantum computation
• Interface for quantum error correction (QEC)
• Supports the density operator formalism
• Implementations of Shor's factoring algorithm and Grover's search algorithm are included
• libquantum is available as Free Software under the terms of the GNU General Public License (GPL), version 3. See the file COPYING for further details.

Requirements

libquantum requires a C compiler with complex number support. The simulator has been reported to work on the following platforms:

• GNU/Linux (This is the main development platform)
• FreeBSD
• OpenBSD
• NetBSD
• Mac OS X
• HP Tru64 UNIX
• AIX

Awards

• Official SPEC CPU2006 benchmark
• Jugend forscht Baden-Württemberg 2003 runner-up

Authors

libquantum has been written by Björn Butscher and Hendrik Weimer. The authors can be contacted at libquantum@libquantum.de.