Cracking chemistry with quantum simulations.

Atoms and molecules undergo changes in state as they interact with each other and the environment. The free-energy difference of a system transitioning from an initial to final state is crucial for understanding chemical reactions and other molecular processes because it informs the likelihood of a conversion to occur. Calculating the free-energy difference is often difficult because it fluctuates with temperature. Simulating properties of quantum systems (that exhibit behavior relevant at atomic and subatomic scales), such as the free-energy difference, is difficult because of the "curse of dimensionality" that arises from the number of particles involved and the many possibilities of their interaction. Quantum computers may accurately measure the free-energy differences by performing an exact simulation without introducing errors apart from those that arise from transforming continuous variables such as position and time into finite numbers. This enables precision that is not attainable with existing classical computers. [ABSTRACT FROM AUTHOR]