Australian Researchers Use Quantum Computer to Simulate Molecular Behavior
A team of researchers in Australia has used a quantum computer to simulate how real molecules behave after absorbing light, demonstrating a new level of complexity in quantum chemistry experiments.
Published in the Journal of the American Chemical Society, the study showcases a method that models how molecules evolve over time after being excited by light something conventional quantum computers have struggled to do. Previous efforts were mostly limited to static properties like energy levels.
The researchers used a trapped-ion quantum computer, which manipulates individual atoms in a vacuum using electromagnetic fields. Instead of relying solely on traditional quantum bits, or qubits, they incorporated the vibrational states of atoms called bosonic modes into the simulation. This approach, known as mixed qudit-boson simulation, allowed them to perform highly complex calculations using significantly fewer quantum resources.
The team simulated three molecules: allene, butatriene, and pyrazine. These were chosen for their complex behavior after light absorption, including rapid electronic and vibrational changes that occur within femtoseconds. In the experiment, these ultrafast events were slowed down by a factor of 100 billion, allowing the researchers to observe the transformations in milliseconds.
Their method proved to be far more efficient than standard quantum techniques. A conventional quantum computer would require at least 11 qubits and hundreds of thousands of precise operations to replicate the same simulation. In contrast, the Australian team achieved it with a single laser pulse acting on one trapped ion, making the process roughly a million times more resource-efficient.
The researchers also tested how molecules interact with their environment, which is usually difficult to simulate. By introducing controlled noise, they mimicked the energy loss that real molecules experience, showing that even environmental effects can be captured.
According to the authors, the work represents meaningful progress for quantum chemistry. While today’s quantum computers remain limited in size and capability, the researchers believe that scaling their method to include 20 or 30 ions could allow scientists to simulate complex chemical systems beyond the reach of classical supercomputers.
This advance could eventually accelerate discoveries in medicine, energy, and materials science by providing new tools to understand how atoms and molecules behave in real-world conditions.