**(ScienceDaily)** Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and the University of Chicago (UChicago) have developed a method paving the way to using quantum computers to simulate realistic molecules and complex materials, whose description requires hundreds of atoms.

In the last three decades, quantum mechanical theoretical approaches have played an important role in predicting the properties of materials relevant to quantum information science and functional materials for energy applications, encompassing catalysts and energy storage systems. However, these approaches are computationally demanding, and it is still challenging to apply them to complex, heterogeneous materials.

“Our newly developed calculational method,” Galli said, “greatly improves on the accuracy attainable with existing quantum mechanical methods regarding calculations for specific defects in crystalline materials, and we have implemented it on a quantum computer.”

“In our research we developed a quantum embedding theory that permitted the simulation of ‘spin defects’ in solids by coupling quantum and classical computing hardware,” Govoni said.

The team then moved on to test the same calculations on a quantum simulator and finally on the IBM Q5 Yorktown quantum computer. The results confirmed the high accuracy and effectiveness of their quantum embedding method, establishing a stepping stone to solving many different kinds of materials science problems on a quantum computer.