00mjk / feynman

Quantum circuit analysis toolkit

Feynman

Feynman is a toolkit for quantum circuit analysis in the path integral model of quantum mechnics. The toolkit comprises synthesis, optimization and verification methods based around representations of circuit actions as sums-over-paths.

Two ways of interfacing with the Feynman project are possible. Standalone tools built on Feynman, found in tools, provide command-line interfaces for optimizing and/or verifying quantum circuits, or the Feynman library can be imported and used directly in other Haskell projects.

Prerequisites

The Feynman project requires GHC >=8.0.2 and Cabal >=1.24.0. Older versions of GHC may work but have not been tested.

Installation

The Feynman library and binary executables for optimization (feynopt) and verification (feynver) can be installed globally with

cabal install

or via the slightly more fine-grain series of commands

cabal configure
cabal build
cabal install

Sandboxes

Dependency hell is a common problem in Haskell, so earlier versions of Cabal had the option to explicitly create a local sandbox where package dependencies would be installed without causes problems for other packages. To install Feynman's dependencies in a sandbox, before building or installing Feynman first run

# Cabal 1 & 2
cabal sandbox init
cabal install --only-dependencies

# Cabal 3
cabal v1-sandbox init
cabal install --only-dependencies

Install directory

By default, Cabal installs the binaries in ~/cabal/bin/ for unix builds. To specify another folder, install with

cabal install --installdir=DIR

Using feynopt

Feynman currently has frontends for openQASM and .qc. Examples of both can be found in the benchmarks folder.

To run the Feynman optimizer feynopt on a .qc or openQASM file, execute the command

feynopt <filename>.(qc | qasm)

feynopt automatically recognizes the extensions .qc and .qasm as .qc and openQASM files, respectively.

For a list of all available optimizations and transformations, use the command

feynopt -h

Using feynver

The feynver binary tool allows for equivalence checking of separate circuit files. Standard usage is

feynver <filename1>.qc <filename2>.qc

The input circuits must agree on the names of the primary inputs (i.e. non-initialized qubits), but they may use different ancillas.

Note: feynver currently only supports the .qc frontend

Benchmarks

The Feynman repository comes with a suite of quantum circuit benchmarks, found in the benchmarks folder. For more information on the benchmarks the user is directed to Formal Methods in Quantum Circuit Design.

The benchmark suite also includes example openQASM circuits, taken from the openQASM github repository.

Citing

Feynman is a collection of algorithms and techniques spanning a number of papers. If you wish to cite in an academic paper, the relevant papers are listed below.

• M. Amy, Formal methods in Quantum Circuit Design. PhD thesis, 2019. (General)
• M. Amy, Towards Large-scale Functional Verification of Universal Quantum Circuits. In Proc. Quantum Physics & Logic (QPL), 2018. (Verification)
• M. Amy, P. Azimzadeh, M. Mosca, On the CNOT complexity of CNOT–phase circuits. Quantum Science & Technology 4(1). 2018. (CNOT-minimization)
• M. Amy, D. Maslov, M. Mosca, Polynomial-Time T-Depth Optimization of Clifford+T Circuits Via Matroid Partitioning. IEEE Trans. Computer-Aided Design of Integrated Circuits and systems 33(10). 2014. (T-par and phase-folding)

Authors

Matthew Amy