Tunable Dynamics of a Dipolar Quantum Battery: Role of Spin-Spin Interactions and Coherence

TL;DR

This work addresses tunable energy storage in a dipolar two-qubit quantum battery that includes Dzyaloshinskii–Moriya interaction. By solving cyclic unitary charging dynamics and quantifying ergotropy $W(t)$, instantaneous power $\mathcal{P}(t)$, capacity $K$, and coherence $C_{l_1}$, the authors show that quantum coherence and DM coupling significantly boost extractable work and charging power, with magnetic-field tuning offering additional control. The study also incorporates a common dephasing environment, revealing that decoherence suppresses long-term work extraction, though DM can provide transient enhancements. Overall, the results highlight coherence-driven energy storage and spin-engineering as viable routes toward high-performance quantum batteries, while also outlining limitations imposed by realistic environments.

Abstract

This study explores the energy storage dynamics of a quantum battery (QB) modeled using a dipolar spin system with Dzyaloshinskii-Moriya (DM) interaction. We examine the performance of this system in terms of ergotropy, instantaneous power, capacity, and quantum coherence using a two-qubit model. By solving the system's time evolution under cyclic unitary processes, we analyze how external parameters such as temperature, magnetic field, and DM interaction influence the charging behavior and quantum resources of the battery. The findings demonstrate that quantum coherence and DM interaction significantly enhance the energy storage efficiency and power output of the quantum battery, offering promising strategies for designing high-performance quantum energy storage devices. Furthermore, we investigate the performance of quantum battery under the influence of a common dephasing environment, which limits the long-term work-extraction capability of dipolar quantum batteries.

Figures (8)

• Figure 1: Schematic representation of dipolar quantum battery (QB)
• Figure 2: Time evolution of (a) ergotropy $W(t)$, (b) power $\mathcal{P}(t)$, (c) capacity $\mathit{K}$ and (d) $l_{1}$-norm of coherence $C_{l_1}(t)$ at different temperatures $T=0.5$, $1$, $1.5$, and $2$. Here, $\epsilon=\Delta=2$ are the dipolar coupling strengths, $D=1$ is the DM coupling, $B=1$ and $\Omega=1$ are the strengths of the external magnetic fields.
• Figure 3: (a) Ergotropy $W(t)$, (b) power $\mathcal{P}(t)$, (c) capacity $\mathit{K}$ and (d) $l_{1}$-norm of coherence $C_{l_1}(t)$ evolve with time $t$ for varying DM interaction strengths, $D=0$, $1$, $2$, and $3$. Other parametric values are $\epsilon=\Delta=2$, $B=1$, $T=0.5$, and $\Omega=1$.
• Figure 4: The temporal evolution of (a) ergotropy $W(t)$, (b) power $\mathcal{P}(t)$, (c) capacity $\mathit{K}$ and (d) $l_{1}$-norm of coherence $C_{l_1}(t)$ as a function of time for different dipolar coupling constants $\epsilon=\Delta=2$, $3$, $4$, and $5$. Herein, $T=0.5$ is the temperature, $D=1$ is the DM interaction, $B=1$, and $\Omega=1$ are the applied fields.
• Figure 5: Evolution of (a) ergotropy $W$, (b) power $\mathcal{P}$, (c) capacity $\mathit{K}$, and (d) $l_{1}$-norm of coherence $C_{l_1}$ in the dipolar quantum battery for different magnetic field $B$ and time $t$. Other parametric values are fixed as $\epsilon=\Delta=2$, $D=1$, $T=0.5$, and $\Omega=1$.