Measurement-feedback capacity enhancement in quantum batteries

Fang-Yuan Zheng, Li-Hang Ren

Xie Chuanmei, Senbo Tian, Jianlan Chen +1 more

Abstract Quantum batteries, as an important energy storage system in the future, are of vital importance to practical applications. However, due to the interaction between the quantum battery system and the environment, the battery capacity will decline. Then how to increase the capacity of quantum batteries becomes crucial. In this paper, we propose a new scheme via a local bipartite projective measurement to enhance the quantum battery capacity (QBC). Initially, two Werner states are taken as the carriers of the quantum batteries. Performing a local bipartite projective measurement performed on the two initially Werner states, a final state as a new quantum battery carrier can be realized. It is found that the QBC in the final state can be larger than those in the two initial states. That is to say, the enhancement of QBC can be realized via the local bipartite projective measurement.

Oscar Bohórquez

Xian-Li Yin, Meixi Guo, Jian Huang +2 more

Quantum batteries (QBs), acting as energy storage devices, have potential applications in future quantum science and technology. However, the QBs inevitably losses energy due to their interaction with environment. How to enhance the performance of the QBs in the open-system case remains an important challenge. Here we propose a scheme to realize the driven-dissipative QBs in atom-waveguide-QED systems and demonstrate significant improvements in both the stored energy and extractable work (ergotropy) of the QBs via feedback control. For a single-atom QB, we show that combining the measurement and coherent feedback controls enables nearly perfect stable charging under the weak coherent driving. For the QB array, the measurement-based feedback allows us to control different dynamical phases in the thermodynamic limit: (i) a continuous boundary time-crystal phase, where persistent periodic energy charge-discharge oscillations emerge despite the presence of the dissipation into the waveguide, and (ii) two stationary phases -- one reaches full charge while the other maintains only small energy storage. This work broadens the scope of driven-dissipative QBs and provides practical strategies for enhancing their performance.

Tinggui Zhang, Hong Wei Yang, Shao-Ming Fei

Quantum batteries have significant potential applications for future industry and daily life. The capacity is an important indicator for a battery. Methods to improve the capacity of quantum batteries are important. We consider quantum batteries given by bipartite quantum systems and study the enhancement of the battery capacity under local projective measurements on a subsystem of the quantum state. By using two-qubit Bell-diagonal states and $X$-type states as examples, we show that quantum battery capacity with respect to the whole system or a subsystem can be improved by local projective measurements. Our theoretical analysis will provide ideas for the experimental development of quantum batteries.