The research team at the Duke Quantum Center used a quantum simulator to study the dynamics of string breaking, a process associated with the creation of particle-antiparticle pairs. This experiment became one of the first demonstrations of its kind in quantum physics.

The study, published on September 23 in the journal Nature Physics, showed that ion-based quantum computers can be used to investigate fundamental physical processes. During the experiment, the team simulated a scenario in which two connected elements of matter move apart until enough energy accumulates to form new particles as the bond breaks. Quantum simulations provide an effective platform for exploring complex phenomena, such as the formation of matter, which cannot be observed directly—for example, under conditions similar to those of the Big Bang. The results indicate significant progress in quantum science and open new opportunities for studying the dynamics of string breaking.

The research was conducted by an international team that included experts from the University of Maryland, Oxford University, the California Institute of Technology, Cornell University, and KU Leuven. The results were published alongside other recent studies where similar physical processes were reproduced using different types of quantum computing devices.

Quarks are among the fundamental building blocks of matter and are found inside protons and neutrons, with sizes about a billion times smaller than an atom. Currently, isolated quarks cannot be observed directly because they typically remain tightly bound to each other.

The connection between quarks can be imagined as two charged particles linked by a stretched string. As the distance between them increases, the energy in this connection grows. At a certain point, the accumulated energy becomes sufficient to create additional charged particles, as explained by Einstein’s equation E=mc². As a result, breaking the original bond leads to the formation of new particle pairs. Such processes require significant energy and occur only under extreme conditions, such as inside the Large Hadron Collider or in the first moments after the Big Bang.

In the new experiment, the Duke team recreated similar string-breaking behavior using a trapped-ion platform. Quantum simulators allow precise control over the system and can be programmed to mimic physical processes at the atomic and subatomic levels.

To conduct the simulation, the researchers encoded a model of string breaking in a chain of 13 trapped ions. Controlled laser beams were used to tune the interactions between the ions, enabling the team to manage the system’s energy and reproduce the stretching and subsequent breaking of the particle “string.”

The system was prepared in a non-equilibrium state, after which its evolution over time was tracked. This made it possible to observe the emergence of effective charges and reconstruct the dynamics associated with the string-breaking process in the simulation.

To verify the results, the team also simulated the same process on a classical computer. The classical calculations matched the experimental data obtained from the quantum simulator. At the current level of complexity, classical computers can handle such tasks, but it is expected that as experiments scale up, quantum computers will be able to solve problems that are inaccessible to classical machines.

Other research groups have recently achieved similar results using different types of quantum hardware. Teams from Google and QuEra Computing reproduced analogous string-breaking models using superconducting circuits and neutral atoms, respectively. Each approach has its own advantages and limitations.

The results with trapped ions represent another step toward quantum simulations that will be too complex even for the most powerful modern supercomputers. As quantum systems continue to scale, they could be used to study processes that are difficult or impossible to reproduce in laboratory conditions, including the behavior of matter shortly after the Big Bang.

Even small discoveries from models of non-equilibrium physics may, in the future, contribute to a deeper understanding of the conditions of the early Universe.