Quantum Algorithms Database
Variational Quantum Eigensolver (VQE)
A hybrid quantum-classical algorithm for finding the lowest energy state of a molecule or material, designed to work on noisy near-term hardware.
Year
2014
Inventor(s)
Peruzzo et al.
Speedup Type
Heuristic (No Proven Speedup)
Difficulty
★★★☆☆
The Problem
Finding the ground-state energy of a quantum system (like a molecule), which is exponentially hard to compute classically as system size grows.
How It Works
A quantum computer prepares trial states and measures their energy, while a classical optimizer iteratively adjusts parameters to minimize that energy — splitting the work between quantum and classical hardware.
Real-World Impact
One of the most promising NISQ-era applications, actively used in early quantum chemistry and materials science research, including drug discovery exploration.