Physicists have performed a groundbreaking simulation they say sheds new light on an elusive phenomenon that could determine the ultimate fate of the Universe.
Pioneering research in quantum field theory around 50 years ago proposed that the universe may be trapped in a false vacuum – meaning it appears stable but in fact could be on the verge of transitioning to an even more stable, true vacuum state. While this process could trigger a catastrophic change in the Universe's structure, experts agree that predicting the timeline is challenging, but it is likely to occur over an astronomically long period, potentially spanning millions of years.
In an international collaboration between three research institutions, the team report gaining valuable insights into false vacuum decay – a process linked to the origins of the cosmos and the behaviour of particles at the smallest scales. The collaboration was led by Professor Zlatko Papic, from the University of Leeds, and Dr Jaka Vodeb, from Forschungszentrum Jülich, Germany.
The paper's lead author Professor Papic , Professor of Theoretical Physics in the School of Physics and Astronomy at Leeds, said: "We're talking about a process by which the universe would completely change its structure. The fundamental constants could instantaneously change and the world as we know it would collapse like a house of cards. What we really need are controlled experiments to observe this process and determine its time scales."
The researchers say this work marks a significant step forward in understanding quantum dynamics, offering exciting possibilities for the future of quantum computing and its potential for studying some of the most challenging problems around the fundamental physics of the Universe.
Simulating a Cosmic Puzzle
The research, by the University of Leeds , Forschungszentrum Jülich , and the Institute of Science and Technology Austria (ISTA) , set out to understand the key puzzle of false vacuum decay – the underlying mechanism behind it. They used a 5564-qubit quantum annealer, a type of quantum machine designed by D-Wave Quantum Inc. to solve complex optimisation problems – which involve finding the best solution from a set of possible solutions – by harnessing the unique properties of quantum-mechanical systems.
In the paper , published today (04/02/2025) in Nature Physics , the team explain how they used the machine to mimic the behaviour of bubbles in a false vacuum. These bubbles are similar to liquid bubbles forming in water vapour, cooled below its dew point. It is understood that the formation, interaction and spreading of these bubbles would be the trigger for false vacuum decay.
Co-author Dr Jean-Yves Desaules, a postdoctoral fellow at ISTA, who completed his PhD at the University of Leeds, said: "This phenomenon is comparable to a rollercoaster that has several valleys along its trajectory but only one 'true' lowest state, at ground level.
"If that is indeed the case, quantum mechanics would allow the Universe to eventually tunnel to the lowest energy state or the 'true' vacuum and that process would result in a cataclysmic global event."
The quantum annealer enabled scientists to observe the intricate "dance" of the bubbles, which involves how they form, grow, and interact in real time. These observations revealed that the dynamics are not isolated events – they involve complex interactions, including how smaller bubbles can influence larger ones. The team say their findings provide new insights into how such transitions might have occurred shortly after the Big Bang.
The paper's first author Dr Vodeb, postdoctoral researcher at Jülich, said: "By leveraging the capabilities of a large quantum annealer, our team has opened the door to studying non-equilibrium quantum systems and phase transitions that are otherwise difficult to explore with traditional computing methods."
New Era of Quantum Simulation
Physicists have long questioned whether the false vacuum decay process could happen and if so, how long it would take. However, they have made little progress in finding answers due to the unwieldy mathematical nature of quantum field theory.
Instead of trying to crack these complex problems, the team set out to answer more simple ones that can be studied using newly available devices and hardware. This is thought to be one of the first times scientists have been able to directly simulate and observe the dynamics of false vacuum decay at such a large scale.
The experiment involved placing 5564 qubits — the elementary building blocks of quantum computing— into specific configurations that represent the false vacuum. By carefully controlling the system, the researchers could trigger the transition from false to true vacuum, mirroring the bubbles' formation as described by false vacuum decay theory. The study used a one-dimensional model, but it is thought 3D versions will be possible on the same annealer. The D-Wave machine is integrated into JUNIQ, the Jülich UNified Infrastructure for Quantum computing at the Jülich Supercomputing Centre. JUNIQ provides science and industry access to state-of-the-art quantum computing devices.
Professor Papic said: "We are trying to develop systems where we can carry out simple experiments to study these sorts of things. The time scales for these processes happening in the universe are huge, but using the annealer allows us to observe them in real time, so we can actually see what's happening.
"This exciting work, which merges cutting-edge quantum simulation with deep theoretical physics, shows how close we are to solving some of the universe's biggest mysteries."
The research was funded by the UKRI Engineering and Physical Sciences Research Council (EPSRC) and the Leverhulme Trust . The findings show that insights into the origin and the fate of the Universe need not always require multi-million-pound experiments in dedicated high-energy facilities, such as the Large Hadron Collider at CERN.
Professor Papic added: "It's exciting to have these new tools that could effectively serve as a table-top 'laboratory' to understand the fundamental dynamical processes in the Universe."
Real-World Impact
Researchers say their findings highlight the quantum annealers' potential in solving practical problems far beyond theoretical physics.
Beyond its importance for cosmology, the study has practical implications for advancing quantum computing, according to the researchers. They believe that understanding bubble interactions in the false vacuum could lead to improvements in how quantum systems manage errors and perform complex calculations, helping to make quantum computing more efficient.
Dr Vodeb concluded: "These breakthroughs not only push the boundaries of scientific knowledge but also pave the way for future technologies that could revolutionise fields such as cryptography, materials science, and energy-efficient computing."
Dr Kedar Pandya, EPSRC Executive Director for Strategy said: "Curiosity-driven research is a critical part of the work EPSRC supports. This project is a great demonstration of that work, with ideas from fundamental quantum physics coming together with technological advances in quantum computing to help answer deep questions about the nature of the Universe."
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