High-power collective charging of a solid-state quantum battery (1707.04930v2)

Abstract: Quantum information theorems state that it is possible to exploit collective quantum resources to greatly enhance the charging power of quantum batteries (QBs) made of many identical elementary units. We here present and solve a model of a QB that can be engineered in solid-state architectures. It consists of $N$ two-level systems coupled to a single photonic mode in a cavity. We contrast this collective model ("Dicke QB"), whereby entanglement is genuinely created by the common photonic mode, to the one in which each two-level system is coupled to its own separate cavity mode ("Rabi QB"). By employing exact diagonalization, we demonstrate the emergence of a quantum advantage in the charging power of Dicke QBs, which scales like $\sqrt{N}$ for $N\gg 1$.

• The paper introduces a collective charging method that leverages quantum entanglement to enhance battery charging power.
• It compares Dicke and Rabi quantum battery models, highlighting a sqrt(N) scaling advantage for the Dicke approach.
• The study bridges theoretical analysis with practical solid-state implementations, suggesting feasible pathways for advanced energy storage systems.

High-Power Collective Charging of a Solid-State Quantum Battery

The paper "High-power collective charging of a solid-state quantum battery" presents a theoretical framework for enhancing the charging power of quantum batteries (QBs) through quantum entanglement. The approach leverages collective quantum effects in solid-state architectures to significantly boost performance compared to conventional methods.

Quantum Battery Models

Two models are discussed: the Dicke quantum battery (Dicke QB) and the Rabi quantum battery (Rabi QB). Both models utilize two-level systems (TLS) exhibited within solid-state systems, such as superconducting qubits or semiconductor quantum dots. However, they differ in their interaction with the photonic environment:

1. Rabi QB: Each TLS is independently coupled to a distinct photonic mode within a separate cavity. This model addresses charging via local interactions and serves as the standard approach.
2. Dicke QB: TLSs are collectively coupled to a single photonic mode shared within the same cavity. The introduction of a common resonant interaction gives rise to collective quantum correlations (entanglements), which the paper argues are capable of yielding an operational quantum advantage. The Dicke QB exploits the Dicke model principles to effectively enhance charging dynamics.

Charging Dynamics and Quantum Advantage

One of the central themes of this research is quantifying the enhancement in charging power that results from collective operations. Through exact diagonalization of the Hamiltonian models, it was demonstrated that the charging power of the Dicke QB scales as $\sqrt{N}$ for $N \gg 1$, where $N$ denots the number of TLSs. Such scaling indicates a quantum collective enhancement over the parallel charged Rabi QB, which scales linearly with $N$.

Implications and Theoretical Considerations

The implications are twofold. First, this mechanism capitalizes on the inherent quantum mechanical advantage of TLS entanglement to realize more efficient energy storage systems. Second, the work bridges foundational theoretical concepts with practical considerations—albeit under idealized conditions—suggesting experimental architectures rooted in established solid-state technologies, such as circuit-QED and cavity-QED systems.

Potential for Experimental Realization

Practical realization viability is discussed with computational modeling suggesting the feasibility of solid-state QBs utilizing superconducting qubits and semiconductor quantum dots within current technological capabilities. Implementations could achieve efficient operation despite the complexity posed by decoherence and relaxation dynamics in real-world scenarios. Current research shows promise in overcoming technical hurdles, especially considering the success of experimental setups such as embedded qubits within resonant cavities, and recent strides in controlling photonic modes in microcavity structures.

Future Prospects

The paper lays groundwork for further inquiries into scalability, examining limits and transitions such as superradiant quantum phase transitions which remain a crucial consideration in maximizing quantum battery efficiency. Future work could focus on integrating these concepts into large-scale practical applications, with potential exploration into hybrid systems that could capitalize on quantum phenomena under various real-world constraints.

In conclusion, the paper represents a comprehensive analysis of collective effects in quantum battery systems, demonstrating both theoretical novelties and potential pathways to energize solid-state quantum technology, punctuated by its robust $\sqrt{N}$ advantage in charging power dynamics.