Designing better catalysts with quantum computers  

Riverlane develops a tool to unlock simulations using a quantum computer

At this year’s UK National Quantum Technologies Showcase, held on 5th November in London, the Riverlane and Rigetti teams presented a suite of software tools that should help pave the way for a breakthrough in scientists’ ability to develop sustainable materials and catalysts using quantum computers. Catalysts, chemicals that make impractically slow chemical reactions go fast, are crucially important to all areas of modern life: from manufacturing new drugs and plastics to cleaning our air and tackling the climate crisis.  

The core software tool, developed by Riverlane in partnership with global sustainable technologies company Johnson Matthey, generates a set of instructions that a quantum computer can use to calculate the properties of a specific material or catalyst. For most applications, these calculations are impossible to do accurately on regular ‘classical’ computers, which cannot simulate the complex and dynamic web of sub-atomic interactions in a chemical reaction. Quantum computers, by contrast, can encode and analyse many individual interactions simultaneously, significantly speeding up the full calculation. With the improvements in quantum hardware widely anticipated in the coming years, our tool could play a part in one day allowing scientists to design the sustainable catalysts of the future: a vital component of the development of alternative fuel technologies which will transform our society.  

One promising sustainable fuel technology is hydrogen fuel cells, which produce energy from hydrogen gas with only water as the by-product. Fuel cells work by carrying out a simple chemical reaction: reacting hydrogen with oxygen to form water, and generating an electrical current in the process. One important step in this reaction, splitting hydrogen into positively charged hydrogen ions and negatively charged electrons, would occur incredibly slowly if the hydrogen and oxygen were simply mixed together. Fuel cells therefore contain an additional component, a catalyst, which significantly speeds up the reaction. Fuel cell catalysts are often made from precious metals like platinum – very efficient but highly expensive and environmentally damaging to mine. 

A large error-corrected quantum computer would give us the opportunity to design much more efficient catalysts based on sustainable and affordable materials. By contrast, even today’s fastest supercomputers must use approximate methods to do calculations, meaning their predictions must be verified by extensive experiments in the lab. Quantum computers have the potential to do much more accurate calculations, reducing the need for time-consuming lab work. 

Riverlane has been working for the past year on some important first steps that will enable such quantum simulations down the road. On 5th November, we shared the first results of this work via a live demo on a Rigetti quantum computer.  

To perform a calculation quantum computers are programmed with a quantum circuit, a series of instructions which tells them what operations and measurements they should perform to output a result. Writing the correct quantum circuit for a specific application is highly complex, however, requiring substantial expertise and time to achieve. 

This is where Riverlane comes in. 

Using an algorithm called quantum phase estimation, our tool generates quantum circuits which can be read directly by a quantum computer. The user only needs to enter a chemical description of a molecule or material they are interested in, meaning chemists can use the tool to rewrite their simulations in the language of a quantum computer without needing to get lost in the details of how the circuits are designed. 

We demonstrated our tool by calculating the energy of a hydrogen molecule on a platinum surface, running the final circuit on Rigetti’s Aspen-10 quantum processor. Understanding the stability and reactivity of hydrogen-platinum systems can give us insight into the inner workings of existing fuel cells, the first step towards designing better alternatives.  

“It was great to run quantum chemistry calculations on a Rigetti QPU with Riverlane’s tools. It shows the potential of quantum computing technology and is an important step to designing the catalysts of the future,” said Marco Paini, Rigetti Technology Partnerships Director, Europe 

The demo also shows the potential of our tool to translate a chemical problem into something which can be run on a quantum computer. This allows companies like Johnson Matthey to access quantum computation more easily, and companies like Rigetti to apply their hardware technology to a wider range of problems.  

How can we make quantum computers more useful sooner? 

Realising quantum computing’s full potential to simulate complex materials and chemical reactions will require significant developments in quantum computing technology, from hardware to error correction methods. But we can get to useful quantum computers sooner if we can predict which developments the industry should prioritise to unlock different applications of quantum computing as early as possible.  

An additional tool we presented on 5th November takes a key step towards addressing this challenge. Using the tool, a hardware manufacturer can understand what size quantum computer would be needed to simulate different molecules or materials in the future. They can also virtually test different proposed hardware improvements and get feedback from the tool on how much closer these changes would get a quantum computer to being ready to for different applications.   

We demonstrated this tool by estimating the computing resources required to calculate the energy of paraquinone, a molecule which is thought could be a component of future sustainable non-metal batteries, on a quantum computer. This calculation is not yet possible to do with high accuracy on a quantum computer, as paraquinone is a larger and more complex molecule, but our tool allows a user to understand exactly how hard the problem is and to explore how best to improve their hardware to tackle simulations of battery materials of this type. 

By identifying the key bottlenecks in hardware development for specific applications, we hope that this second tool will also help to bridge the communications gap between quantum computer manufacturers and the companies that want to apply the technology.  

Overall our tools represent an important step towards useful quantum computers, accelerating the development of sustainable materials and getting us to net-zero faster. 

With thanks to our partners Johnson Matthey and Rigetti, and Innovate UK and SBRI for funding for this project  – we can’t wait to see what transformative experiments will be modelled next! 

Want to know more about our software or join our Early Access Programme? Contact us at team@riverlane.com.