Breakthrough Algorithm Enables Imaginary-Time Evolution on Quantum Computers

A team of researchers from the University of Birmingham has developed an algorithm that enables imaginary-time evolution (ITE) on quantum computers using real-time data. This breakthrough addresses a long-standing challenge in quantum simulations, where ITE calculations are notoriously difficult to implement.

The new method links ITE to more easily implemented real-time simulations by performing analytic continuation of measured correlation functions. This approach was demonstrated using both classical diffusion processes and quantum mechanical scattering problems on IBM hardware, utilizing only two qubits. The researchers found that their technique successfully applied to one-dimensional Fokker-Planck equations, describing classical diffusion processes, and verified its ability to simulate particle movement governed by random forces.

The algorithm's versatility was showcased as it extended to imaginary-time evolution of integrated correlation functions in one dimension within quantum mechanical scattering. Although the present form remains limited to one-dimensional systems, this represents a significant step forward in making complex quantum simulations accessible. The connection between ITE and real-time simulations arises through analytic continuation, effectively extending functions beyond their initial boundaries.