Physicists confirm quantum mechanics in 73-qubit system
An international team of physicists has developed a quantum lie detector using Bell's test to verify genuine quantum behavior in large systems. By testing up to 73 qubits, they demonstrated correlations impossible in classical physics. This breakthrough affirms that quantum computers exhibit authentic quantum effects at scale.
Physicists from Leiden University in the Netherlands, Tsinghua University in Beijing, and Zhejiang University in Hangzhou have created a rigorous test to determine if large quantum systems truly follow quantum mechanics or merely simulate it. Dubbed a 'quantum lie detector,' the experiment relies on Bell's test, originally designed by physicist John Bell, to detect quantum nonlocality—where particles influence each other instantly across distances, a phenomenon recognized with the 2022 Nobel Prize in Physics.
The team, including theoretical physicists Jordi Tura, Patrick Emonts, and PhD candidate Mengyao Hu from Leiden, along with colleagues from the other institutions, pushed the boundaries by examining Bell correlations in systems of up to 73 qubits, the fundamental units of quantum computers. Rather than directly measuring these complex correlations, they optimized for energy minimization, a task quantum devices handle efficiently.
Using a superconducting quantum processor, the researchers generated a special quantum state across 73 qubits and recorded energy levels far below those achievable classically, with a difference of 48 standard deviations—indicating results unlikely due to chance. They further certified genuine multipartite Bell correlations, requiring all qubits to participate, succeeding up to 24 qubits in a series of low-energy states.
Quantum mechanics governs the behavior of tiny particles like atoms and electrons, featuring counterintuitive effects such as nonlocality. This study marks the first certification of such deep quantum behavior in systems of this scale, proving quantum computers are not only larger but more authentically quantum. The findings pave the way for enhanced quantum communication, more secure cryptography, and advanced quantum algorithms.