(POPL 2022) Twist: Sound Reasoning for Purity and Entanglement in Quantum Programs
Quantum programming languages enable developers to implement algorithms for quantum computers that promise computational breakthroughs in classically intractable tasks. Programming quantum computers requires awareness of entanglement, the phenomenon in which measurement outcomes of qubits are correlated. Entanglement can determine the correctness of algorithms and suitability of programming patterns.
In this work, we formalize purity as a central tool for automating reasoning about entanglement in quantum programs. A pure expression is one whose evaluation is unaffected by the measurement outcomes of qubits that it does not own, implying freedom from entanglement with any other expression in the computation.
We present Twist, the first language that features a type system for sound reasoning about purity. The type system enables the developer to identify pure expressions using type annotations. Twist also features purity assertion operators that state the absence of entanglement in the output of quantum gates. To soundly check these assertions, Twist uses a combination of static analysis and runtime verification.
We evaluate Twist’s type system and analyses on a benchmark suite of quantum programs in simulation, demonstrating that Twist can express quantum algorithms, catch programming errors in them, and support programs that existing languages disallow, while incurring runtime verification overhead of less than 3.5%. DOI
Fri 17 JunDisplayed time zone: Pacific Time (US & Canada) change
13:30 - 14:50
|(POPL 2022) Twist: Sound Reasoning for Purity and Entanglement in Quantum Programs
Charles Yuan Massachusetts Institute of Technology, Christopher McNally Massachusetts Institute of Technology, Michael Carbin Massachusetts Institute of TechnologyLink to publication DOI Authorizer link Pre-print
|(ICFP 2020) Compiling effect handlers in capability-passing style
Philipp Schuster University of Tübingen, Jonathan Immanuel Brachthäuser University of Tübingen, Klaus Ostermann University of TuebingenLink to publication DOI Authorizer link Pre-print
|(POPL 2021) Intensional Datatype Refinement
|(POPL 2021) A Verified Optimizer for Quantum Circuits
Kesha Hietala University of Maryland, Robert Rand University of Chicago, Shih-Han Hung University of Maryland, USA, Xiaodi Wu Department of Computer Science, Institute for Advanced Computer Studies, and Joint Center for Quantum Information and Computer Science, University of Maryland, MD, Michael Hicks University of Maryland at College Park