Quantum annealer has simulated the fundamental process of false vacuum decay, opening the window to the understanding of interactions between true vacuum bubbles. (Credit: Professor Zlatko Papic, University of Leeds, (Image created using Povray))

False vacuum decay model shows why our universe may be living on borrowed time

LEEDS, England — Scientists have achieved a breakthrough in quantum physics by creating and observing “false vacuum decay.” It’s a phenomenon that may have shaped our universe moments after the Big Bang and could potentially determine its ultimate fate.

The team of European researchers used a massive quantum computer with over 5,500 superconducting quantum bits (qubits) to study a phenomenon called “false vacuum decay.” This process suggests our universe currently exists in a temporary stable state that could transition to a more permanent one.

Researchers managed to simulate and study how bubbles of “true vacuum” form and interact within a false vacuum state, offering new insights into fundamental physics and the early moments of our cosmos.

“We’re talking about a process by which the universe would completely change its structure,” explains Professor Zlatko Papić, Professor of Theoretical Physics at the University of Leeds and the paper’s lead author. “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.”

Nearly 50 years ago, physicist Sidney Coleman proposed an intriguing idea: our universe might have cooled down into a temporarily stable “false vacuum” state after the Big Bang, rather than immediately settling into its lowest-energy “true vacuum” state. This metastable false vacuum would eventually decay into the true vacuum through a process involving the formation of expanding bubbles – much like how water vapor condenses into liquid droplets.

“This phenomenon is comparable to a roller coaster that has several valleys along its trajectory but only one ‘true’ lowest state, at ground level,” explains Dr. Jean-Yves Desaules, a postdoctoral fellow at ISTA. “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.”

While the idea of a universe-wide transformation might sound alarming, scientists believe this process would take millions of years to unfold. The real significance of this research lies in its ability to study these cosmic processes in a laboratory setting.

Until now, studying this process has proven extremely challenging due to its quantum mechanical nature and the difficulty of creating suitable experimental conditions. But researchers from Germany, Austria, the UK, and Slovenia developed an ingenious way to simulate and observe false vacuum decay using D-Wave’s quantum annealing device housed at the Jülich Supercomputing Centre in Germany.

The quantum annealer acts as a specialized quantum computer, using 5,564 superconducting elements called flux qubits arranged in a ring-like configuration. By carefully controlling magnetic fields applied to these qubits, they created small regions — similar to bubbles — that could form, grow, and interact with each other. These bubble-like structures mirror what scientists think happened in the early universe and what might occur during a future transition.

“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,” says Dr. Jaka Vodeb, the paper’s first author and postdoctoral researcher at Jülich.

What makes this work particularly significant is that researchers could watch the bubble formation process in real-time and study how these bubbles interact with each other — something that had never been achieved before. The team discovered that larger bubbles cannot spread in isolation but must interact with neighboring bubbles to grow or shrink, leading to a process of quantum bubbles exchanging energy.

The researchers likened the dynamics to a heterogeneous gas, where small “light” bubbles bounce around among larger “heavy” bubbles that interact directly with each other. This behavior emerged from the fundamental quantum mechanical rules governing the system and persisted for over 1,000 qubit time units — a remarkably long period for quantum coherence to maintain in such a large system.

Perhaps most remarkably, the research team managed to create and observe bubbles containing up to 306 qubits, a massive quantum object by current technological standards. This achievement, described in Nature Physics, showcases the rapid advancement of quantum computing technology and its potential for simulating complex quantum phenomena that are otherwise impossible to study directly.

“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,” Papić notes. “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.”