September 28, 2026 by University of Oulu edited by Sadie Harley, reviewed by Robert Egan Scientific Editor Senior Editor This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread Quantum batteries are an emerging area of research, with progress coming from theoretical studies and proof-of-principle experiments in small quantum systems. Unlike conventional chemical batteries used in everyday life, they use quantum systems to store and transfer energy. Researchers are exploring them as potential future energy sources for quantum processors and other quantum technologies. Previous research has focused mainly on how fast and powerfully quantum batteries can be charged. In new research, the researchers establish fundamental limits on fluctuations in both the energy delivered by a quantum battery and the rate at which it is delivered. The work, "Fundamental Limitations on the Reliabilities of Power and Work in Quantum Batteries," was published in PRX Quantum. "A quantum battery ideally should not only be fast and powerful but also needs to charge or deliver energy in a reliable and stable manner at the same time. Our work shows that quantum mechanics places fundamental limits on the reliabilities of quantum batteries," says Brij Mohan, a postdoctoral researcher at the University of Oulu and the study's first author. The researchers show that the well-known quantum-mechanical uncertainty relation prevents fluctuations in delivered energy and power from both being made arbitrarily small at the same time, meaning that reliable energy delivery and stable power cannot be achieved simultaneously. In this context, reliability and stability mean keeping these fluctuations small compared with their respective average values. This fundamental trade-off arises because work and power are represented by noncommuting operators in closed quantum batteries, much like position and momentum in quantum mechanics. The team then studied how this trade-off depends on the way many quantum battery cells are charged. In parallel charging, cells operate independently. In collective charging, all cells participate together. Hybrid charging lies between these two extremes, with groups of cells interacting during charging. The results show that stronger collective charging increases power but also increases power fluctuations, reducing power reliability. This indicates that maximum power alone is not sufficient for assessing quantum battery performance. "Our results show that there is a meaningful way to balance power enhancement and the reliability of work and power. A charging scheme based on intermediate-range interactions can provide a useful compromise between high power and stable operation," says Tanmoy Pandit of VTT in Espoo, Finland. The researchers also examined quantum batteries with transverse Ising-like many-body interactions and found the same qualitative power-reliability trade-off, indicating that the effect is not restricted to the simplest theoretical model. "The reliability limits connect quantum fluctuations with many-body quantum physics in a direct way. They provide useful charging strategies that are practically advantageous," says Manabendra Nath Bera of IISER Mohali in India. "Quantum batteries offer a fascinating link between quantum information, thermodynamics, and many-body physics. Understanding their fluctuations is essential if these systems are eventually to become useful technological resources," says Maciej Lewenstein of ICFO in Spain. The researchers next aim to investigate the reliability limits in more realistic settings, including noise, dissipation, open-system dynamics and experimentally relevant quantum platforms. Brij Mohan et al, Fundamental Limitations on the Reliabilities of Power and Work in Quantum Batteries, PRX Quantum (2026). DOI: 10.1103/fnv6-yqmk Journal information: PRX Quantum Provided by University of Oulu BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries.

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