University of Manchester Validates Exotic Molecular Behavior Using Quantum Computing

An international team of scientists from IBM, The University of Manchester, Oxford University, ETH Zurich, EPFL and the University of Regensburg have successfully created and validated a molecule exhibiting a previously unobserved form of electronic behavior, confirmed through high-fidelity quantum computing simulation. Published in Science, the molecule, with the formula C₁₃Cl₂, displays a half-Möbius electronic topology, causing electrons to move in a corkscrew-like pattern and fundamentally altering its chemical properties. This marks the first experimental observation of this topology in a single molecule, a feat scientists previously hadn’t even predicted. “First, we designed a molecule we thought could be created, then we built it, and then we validated it and its exotic properties with a quantum computer,” said Alessandro Curioni, IBM Fellow, Vice President, Europe and Africa, and Director of IBM Research Zurich. The research demonstrates a new level of control over material properties and showcases quantum computing’s potential to model complex quantum mechanical behavior beyond the reach of classical computers.

Dr Igor Rončević, paper co-author and Lecturer in Computational and Theoretical Chemistry at The University of Manchester, added: “Chemistry and solid-state physics advance by finding new ways to control matter. In the second half of the 20th century, substituent effects were very popular. For example, researchers explored how the potency of a drug or the elasticity of a material changes if, for example, a methyl is replaced with chlorine. The turn of the century brought us spintronics, introducing electron spin as a new degree of freedom to play with, and transforming data storage. Today, our work shows that topology can also serve as a switchable degree of freedom, opening a new powerful route for controlling material properties.” The non-trivial topology of this molecule, and the exotic behavior of many other systems, arises from interactions between their electrons. Simulating electrons with classical computers is very hard; a decade ago we could exactly model 16 electrons, and today we can go up to 18. Quantum computers are naturally well-suited for this problem because their building blocks, qubits, are quantum objects, which mirror electrons. Using IBM’s quantum computer, we were able to explore 32 electrons. Half-Möbius Topology Achieved in Novel C₁₃Cl₂ Molecule A newly synthesized molecule, designated C₁₃Cl₂, exhibits a unique half-Möbius topology, fundamentally altering how electrons move through its structure and opening new avenues for materials control. Researchers assembled the molecule atom-by-atom, employing calibrated voltage pulses under ultra-high vacuum and near-absolute-zero temperatures at IBM Research facilities, starting from a precursor created at Oxford University. This meticulous construction yielded a structure where the electronic configuration undergoes a 90-degree twist with each circuit, necessitating four complete loops to return to its original phase, a characteristic unlike any previously documented in chemistry. Confirmation of this unusual topology wasn’t achieved through conventional means; it demanded the power of quantum computing. Classical computers struggle with the exponentially increasing computational demands of modeling entangled electrons, but quantum computers, leveraging qubits that mirror electron behavior, proved capable of simulating the interactions within the C₁₃Cl₂ molecule, exploring 32 electrons.

Dr Igor Rončević, paper co-author and Lecturer in Computational and Theoretical Chemistry at The University of Manchester, added: “Chemistry and solid-state physics advance by finding new ways to control matter. In the second half of the 20th century, substituent effects were very popular. For example, researchers explored how the potency of a drug or the elasticity of a material changes if, for example, a methyl is replaced with chlorine. The turn of the century brought us spintronics, introducing electron spin as a new degree of freedom to play with, and transforming data storage. Today, our work shows that topology can also serve as a switchable degree of freedom, opening a new powerful route for controlling material properties.” The team discovered helical molecular orbitals for electron attachment, a clear indicator of the half-Möbius topology, and identified a helical pseudo-Jahn-Teller effect as the mechanism driving its formation, demonstrating that electronic topology can be deliberately engineered.

Quantum Computing Validates Exotic Electronic Structure The convergence of advanced molecular design and quantum computation is reshaping our understanding of electronic behavior at the smallest scales. While chemists have long sought to manipulate molecular properties through substituent effects and, more recently, spintronics, a new paradigm is emerging: the deliberate engineering of electronic topology. An international team of scientists from IBM, The University of Manchester, Oxford University, ETH Zurich, EPFL and the University of Regensburg has not only synthesized a molecule exhibiting a previously unseen half-Möbius topology, but crucially, validated its unusual characteristics using a quantum computer, demonstrating a significant step forward in the field. The non-trivial topology of this molecule, and the exotic behavior of many other systems, arises from interactions between their electrons. Simulating electrons with classical computers is very hard; a decade ago we could exactly model 16 electrons, and today we can go up to 18. Quantum computers are naturally well-suited for this problem because their building blocks, qubits, are quantum objects, which mirror electrons. Using IBM’s quantum computer, we were able to explore 32 electrons. The success of this experiment extends beyond chemistry, showcasing the potential of quantum-centric supercomputing, integrating quantum processing units with classical CPUs and GPUs, to tackle previously intractable scientific problems. As Curioni noted, this work represents “a leap towards the dream laid out by renowned physicist Richard Feynman decades ago to build a computer that can best simulate quantum physics and a demonstration where, as he said, ‘There’s plenty of room at the bottom.’” First, we designed a molecule we thought could be created, then we built it, and then we validated it and its exotic properties with a quantum computer. Alessandro Curioni, IBM Fellow, Vice President, Europe and Africa, and Director of IBM Research Zurich Source: https://www.manchester.ac.uk/about/news/researchers-create-a-never-before-seen-molecule-and-prove-its-exotic-nature-with-quantum-computing/ Tags: