Quantum computing has emerged as a powerful tool with the potential to revolutionize various scientific domains. Researchers from the Department of Energy’s Oak Ridge National Laboratory recently conducted a study utilizing the capabilities of the Quantinuum H1-1 quantum computer. Their research not only provided insights into the best practices for scientific computing on quantum systems but also yielded intriguing results related to singlet fission. Singlet fission is a phenomenon in which a molecule absorbs a single photon of light and produces two excited states. This article will delve into the study conducted by the Oak Ridge National Laboratory team and explore the implications of their findings.
Singlet fission holds immense potential for the development of more efficient solar panels. Conventional solar cells have a theoretical maximum efficiency of approximately 33%. However, materials exhibiting singlet fission possess the ability to surpass this limit and achieve higher efficiency. The challenge lies in identifying materials that fulfill the specific energetic requirements of singlet fission. This aspect poses significant difficulties, and traditional methods often rely on approximations and lack accuracy. The prime objective of the study conducted by the Oak Ridge National Laboratory team was to investigate whether the linear H4 molecule’s energetic levels align with the requirements for singlet fission.
In their pursuit of accurate and efficient simulations for singlet fission, the researchers employed the capabilities of the Quantinuum H1-1 quantum computer. This approach provided a more effective method for identifying molecules demonstrating singlet fission properties, bypassing the limitations associated with classical computing techniques. The study utilized the PDS (Peeters-Devreese-Soldatov) quantum solver, developed at the Pacific Northwest National Laboratory. PDS offers several advantages over classical strategies for determining energetic properties, including higher accuracy than density functional theory and fewer computational demands than coupled cluster theory. Additionally, PDS aligns well with the potential advantages of quantum computers, making it an ideal choice for this research.
Singlet fission involves multiple quantum states, necessitating a computational method capable of accurately describing all aspects of the process. The researchers’ utilization of the PDS quantum solver enabled them to calculate precise energetic numbers for singlet fission. The unique characteristic of singlet fission revolves around double electronic excitations, wherein two electrons move up two higher energy levels simultaneously. Traditional algorithms struggle to address this phenomenon adequately, but quantum computers possess the inherent ability to handle the quantum correlations involved in singlet fission. The Oak Ridge National Laboratory team recognized the potential of quantum computers to tackle this unique problem and became pioneers in leveraging quantum computing for singlet fission research.
Access to the Quantinuum H1-1 quantum computer was made possible through the Quantum Computing User Program at the Oak Ridge Leadership Computing Facility. Quantum computing, although still in its formative stages, offers distinct advantages compared to classical supercomputers. Quantum bits, or qubits, used in quantum computers can represent both 1 and 0 simultaneously in a mixed superposition, exponentially increasing computational power for certain equations, particularly those based on quantum mechanics. However, quantum computer systems are susceptible to high error rates, which the researchers had to overcome to obtain reliable results.
The researchers implemented three independent strategies to decrease the computational workload of the problem, resulting in a significantly reduced time to reach a solution. Firstly, they employed a technique known as qubit tapering to decrease the number of qubits required to express the problem, effectively reducing its size. Secondly, they reduced the number of measurements by aggregating groups of terms rather than measuring each individual term. This optimization approach allowed them to solve the problem more efficiently. Lastly, the team found a way to run four circuits in parallel, utilizing all 20 qubits of the H1-1 quantum computer. This novel approach allowed them to tap into the quantum computer’s potential while maximizing the resources available.
The researchers’ project successfully demonstrated the practicality of current quantum computers in addressing scientific problems that can have significant real-world impact. Although singlet fission may not be an immediate focus for future research, the techniques and approaches employed in this study can pave the way for further advancements in utilizing quantum computing. Researchers must be mindful of the potential advantages offered by such approaches and ensure they leverage quantum resources effectively.
The study conducted by the Oak Ridge National Laboratory team showcased the power of quantum computing in the domain of singlet fission research. By employing the Quantinuum H1-1 quantum computer and the PDS quantum solver, the researchers identified the viability of current quantum systems to tackle complex scientific problems. The findings of their research hold promise for the development of more efficient solar panels and open doors to explore other domains where quantum computing may prove indispensable. As quantum computing continues to evolve, researchers must embrace innovative approaches and techniques, leveraging the full potential offered by this groundbreaking technology.