Breakthrough Quantum Method Cuts Simulation Complexity by 80%

Scientists at the Tata Institute of Fundamental Research have developed a new computational method for modelling energy and information transfer in complex quantum systems. The approach, named quantum-classical hierarchical equations of motion (QC-HEOM), offers a more efficient way to simulate realistic environments. The QC-HEOM method separates thermal fluctuations from residual quantum memory without relying on complex mathematical expansions. Its hierarchical structure builds a series of auxiliary quantum influence functionals, reducing the number of auxiliary objects needed by five times compared to traditional methods.

Using classical trajectories to represent environmental fluctuations, QC-HEOM can accurately model systems like the seven-site Fenna, Matthews, Olson (FMO) complex. This complex plays a key role in light harvesting for green bacteria and was successfully simulated with the new approach.

The method maintains accuracy across a broad range of environmental conditions and system parameters. However, it may introduce approximations in strongly anharmonic environments where quantum effects are more pronounced. The Institute plans to refine QC-HEOM further and extend its use to even more complex systems. The method’s efficiency and accuracy mark a significant advance in simulating open quantum systems. Its success with the FMO complex demonstrates its potential for broader applications.