Folding lattice proteins confined on minimal grids using a quantum-inspired encoding

Abstract

Steric clashes pose a challenge when exploring dense protein systems using conventional explicit-chain methods. A minimal example is a single lattice protein confined on a minimal grid, with no free sites. Finding its minimum energy is a hard optimization problem, withsimilarities to scheduling problems. It can be recast as a quadratic unconstrained binary optimization (QUBO) problem amenable to classical and quantum approaches. We show that this problem in its QUBO form can be swiftly and consistently solved for chain length 48, using either classical simulated annealing or hybrid quantum-classical annealing on a D-Wave system. In fact, the latter computations required about 10 seconds. We also test linear and quadratic programming methods, which work well for a lattice gas but struggle with chain constraints. All methods are benchmarked against exact results obtained from exhaustive structure enumeration, at a high computational cost.

22 pages, 5 figures

References in corpus (7)

• Quantum Annealing in the Transverse Ising Model
• A Quantum Adiabatic Evolution Algorithm Applied to Random Instances of an NP-Complete Problem
• From the Quantum Approximate Optimization Algorithm to a Quantum Alternating Operator Ansatz
• Resource-Efficient Quantum Algorithm for Protein Folding
• Polymer Physics by Quantum Computing
• Using quantum annealing to design lattice proteins
• Resource analysis of quantum algorithms for coarse-grained protein folding models