IonQ Performs First Quantum Simulation of a Water Molecule

Today IonQ announced that its quantum computer has achieved a critical milestone: simulating the water molecule with accuracy approaching what is needed for practical applications in the promising field of computational chemistry.

These results demonstrate that IonQ’s technology has the precision and utility needed to achieve the potential of quantum computing,” said Christopher Monroe, IonQ’s Co-founder and Chief Executive Officer. “Make no mistake. This is a long journey, but we expect our devices to continually improve and eventually help answer some of the world’s most difficult problems.” Monroe also serves as the Bice Sechi-Zorn Professor of Physics at the University of Maryland.

Water is among the most complex molecules ever simulated on a quantum computer, and the IonQ system achieved a precision far higher than published simulations by other devices. A manuscript released today describes how IonQ scientists calculated the energy of the water molecule in its lowest or natural state. The results from IonQ’s machine approached the precision a computer model would need to make an accurate chemical prediction, known as chemical accuracy.

To achieve this, IonQ developed a new, efficient approach that can be applied to the simulation of any molecule. Scientists believe this approach can accelerate the development of quantum computer applications to solve important problems in chemistry and pharmaceutical development that have been out of reach for even the most powerful supercomputers.

Quantum computers harness the unusual physics of very small particles—quantum mechanics—to solve problems beyond the capability of conventional devices. IonQ’s systems, introduced in December, are the first in the market that store information on individual atoms. They are more accurate and can perform more complex calculations than any quantum computer built to date.

This is the first time someone has shown a quantum computer with the precision and stability to produce meaningful answers with the accuracy that chemists need,” said Jungsang Kim, Co- founder of IonQ and an engineering professor at Duke.

Apparatus and performance. a, Schematic representation of the trapped-ion QC. The qubit register is implemented in a linear chain of 171Yb+ ions residing inside an ultra-high vacuum chamber (not shown), and high-NA imaging optics enable individual addressing and readout of the ion qubits. The Raman beams (shown in red and purple) are generated from a pulsed laser at 355 nm and drive a two-photon transition between |0i and |1i. Full control of the amplitude, frequency, and phase of the individual addressing beams enables implementations of arbitrary single– and two–qubit operators.

Computational chemistry as a discipline seeks to create accurate computer simulations of chemical systems as an alternative to performing expensive experiments. It is seen as a promising way to develop new pharmaceuticals, chemicals, and materials. These simulations require a precise figure for the energy of each molecule participating in a reaction, a value calculable in theory by considering all possible quantum interactions among the particles that constitute the molecule. For all but the most simple substances, the necessary calculations are difficult or impossible on even the largest conventional computers.

The preprint released today describes how IonQ developed new methods that can get closer to the ground state energy of a molecule while using significantly fewer computing resources than the previous state of the art. These gains come from a new codesign process that exploited unique efficiencies in IonQ’s hardware.

This same type of optimization could someday be translated to other types of problems, from logistics to financial modeling,” Monroe said. “Anyone who wants to be at the leading edge of computational chemistry or other hard optimization problems should see our results as a wakeup call, to start co-designing applications today to take advantage of the next generation of quantum computers.”

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