Quantum Leap: Researchers Achieve First Experimental Simulation of Spontaneous Symmetry Breaking at Absolute Zero on a Superconducting Quantum Processor
In a groundbreaking advance at the intersection of quantum computing and condensed matter physics, an international team of scientists has experimentally simulated spontaneous symmetry breaking (SSB) at zero temperature using a superconducting quantum processor. This pioneering achievement, realized with over 80% fidelity, opens new pathways for understanding fundamental quantum phenomena and designing future quantum technologies.
The study marks the first time researchers have captured the delicate process of spontaneous symmetry breaking in a quantum system precisely at zero temperature—an elusive regime where traditional experimental observations have long remained out of reach. By leveraging a state-of-the-art seven-qubit superconducting quantum processor, the team faithfully emulated the dynamics of a quantum many-body system undergoing a phase transition from a classical antiferromagnetic state to an entangled ferromagnetic quantum phase.
Initially, the system was arranged in a classical antiferromagnetic phase, where neighboring particles exhibit spin orientations that alternate sharply between two opposite directions, reflecting an ordered, staggered pattern with inherent symmetry. Through a carefully engineered digitized evolution, the quantum circuit guided the system to spontaneously reorganize itself into a ferromagnetic quantum phase, where all particle spins align uniformly while establishing intricate quantum correlations — a signature of entanglement.
According to Alan Santos, a physicist associated with the Institute of Fundamental Physics of the Spanish National Research Council and a key member of the theoretical team, the experiment reveals profound insights into quantum phase transitions driven by symmetry breaking. He elaborates, “The original spin configuration of alternating orientations evolved spontaneously into a uniformly aligned state—this transition is a direct consequence of the system breaking its initial symmetry as it reorganizes into a new phase.”
Spontaneous symmetry breaking lies at the heart of many critical phenomena in physics, from superconductivity to the Higgs mechanism, and serves as an essential mechanism enabling complex structures to emerge in nature. Yet, achieving a direct experimental handle on SSB at absolute zero—a state where thermal fluctuations vanish and quantum effects prevail exclusively—has remained one of the field’s most formidable challenges until now.
Absolute zero, defined as 0 Kelvin or -273.15 degrees Celsius, represents a theoretical limit where all classical motion ceases. While physically unattainable, simulating systems at this temperature theoretically strips away classical noise, isolating pure quantum mechanical behavior. The research team circumvented the impossibility of reaching absolute zero experimentally by instead digitally simulating the zero-temperature adiabatic evolution of their quantum spin lattice using a superconducting processor capable of exquisite control and measurement.
The quantum processor employed in the experiment featured seven superconducting qubits arranged in a linear lattice configuration that permitted only immediate neighbor interactions. This architecture closely mimicked the local interactions found in real quantum materials. By executing specialized algorithms that implement adiabatic evolution—a gradual ramping of system parameters to avoid excitations—the researchers ensured the system faithfully reproduced the zero-temperature ground state dynamics underlying symmetry breaking.
A critical aspect of detecting the phase transition involved analyzing quantum correlation functions and quantifying entanglement through Rényi entropy measures. Rényi entropy, a mathematical tool introduced by Hungarian mathematician Alfréd Rényi in the 1960s, provides a powerful metric to characterize the degree and distribution of quantum entanglement within a many-body system. The marked changes in these observables corroborated the onset of order and quantum coherence indicative of the ferromagnetic phase.
Entanglement, one of the most baffling yet fundamental features of quantum mechanics, describes correlations between particles so strong that the state of one instantaneously influences the state of another, regardless of spatial separation. “Superposition and entanglement are the dual pillars of quantum computation,” Santos explains. “While superposition allows a quantum system to explore multiple computational paths simultaneously, entanglement unlocks correlations that classical computers cannot replicate, vastly accelerating certain calculations.”
This quantum advantage was tangibly demonstrated through the simulation itself: what would be prohibitively complex for classical computers—tracking an evolving many-body quantum state with local interactions at zero temperature—became feasible within a manageable runtime on the superconducting quantum processor. The experiment thus validates the promise of quantum computing as a transformative tool to explore complex quantum phenomena that lie beyond classical reach.
The work was a collaborative triumph involving researchers from top institutions worldwide, including the Southern University of Science and Technology (SUSTech) in Shenzhen, China; Aarhus University in Denmark; and the Federal University of São Carlos (UFSCar) in Brazil. The actual physical implementation and execution of the quantum circuits took place at SUSTech, utilizing its cutting-edge superconducting quantum hardware cooled to near absolute zero temperatures—around one millikelvin—achieved through advanced dilution refrigerators.
Superconducting qubits, composed of aluminum and niobium alloys, offer strong advantages in scalability and coherence, a main reason why leading quantum computing efforts worldwide harness this technology. As Santos notes, “Building hundreds or even thousands of these qubits on a chip is technically feasible, providing a promising route toward practical, large-scale quantum processors essential for future quantum simulations and applications.”
Beyond the fundamental physics questions addressed, this experiment’s success underscores a broader paradigm shift ushered in by quantum computing: the capacity to simulate and understand quantum materials and phase transitions that have long eluded traditional approaches. Such capabilities could accelerate the discovery of novel quantum phases, materials, and technologies that harness quantum effects for computing, sensing, and communication.
Moreover, the research highlights how intertwining theoretical developments with state-of-the-art hardware implementations—in this case combining adiabatic algorithms with superconducting lattice processors—can yield unprecedented experimental insights into deep quantum phenomena. It eloquently embodies the symbiotic relationship between advancing quantum theory and enabling experimental quantum device engineering.
As physics continues to revolve around the profound interplay between symmetry and its breaking, this landmark study demonstrates that quantum computers are not merely abstract curiosities but potent new instruments to probe nature’s subtleties at the most fundamental level. The exploration of zero-temperature spontaneous symmetry breaking, once a purely theoretical concept, now takes a decisive step toward experimental reality—heralding a new age of quantum discovery.
Subject of Research: Quantum simulation of spontaneous symmetry breaking at zero temperature using superconducting qubits.
Article Title: Digital simulation of zero-temperature spontaneous symmetry breaking in a superconducting lattice processor
News Publication Date: 7-Apr-2025
Web References: https://doi.org/10.1038/s41467-025-57812-8
Image Credits: Alan Santos
