Optimal energy storage and collective charging speedup in the central-spin quantum battery

Anno: 2025

Autori: Yang H.Y., Zhang K., Wang X.H., Shi H.L.

Affiliazione autori: Northwest Univ, Sch Phys, Xian 710127, Peoples R China; Shaanxi Key Lab Theoret Phys Frontiers, Xian 710127, Peoples R China; Peng Huanwu Ctr Fundamental Theory, Xian 710127, Peoples R China; CNR, INO, QSTAR, Largo Enrico Fermi 2, I-50125 Florence, Italy; LENS, Largo Enrico Fermi 2, I-50125 Florence, Italy.

Abstract: Quantum batteries (QBs) exploit principles of quantum mechanics to accelerate the charging process and aim to achieve optimal energy storage. However, analytical results for investigating these problems remain lacking due to the challenges associated with nonequilibrium dynamics. In this work, we analytically investigate a central-spin QB model in which N-b spin-(1)/(2) battery cells interact with N(c )spin-(1)/(2) charger units, using m initially excited charger units as a resource. By employing the invariant subspace method and the shifted Holstein-Primakoff transformation, we identify four scenarios in which optimal energy storage can be achieved: (i) N-b << m << N-c; (ii) m << N-b << N-c; (iii) m << N-c << N-b; and (iv) N-b << m=kN(c) [k is an element of(0,1)]. In these cases, optimal storage is ensured by the SU(2) symmetry emerging from the charging dynamics. The first three cases map the central-spin QB to different Tavis-Cummings (TC) QBs, while the fourth corresponds to the non-TC limit. We analytically determine the charging time and demonstrate that in the fully charging cases (i) and (iv), the collective charging exhibits an N-b-fold enhancement in speedup compared to the parallel charging scheme. Additionally, we numerically observe a unified charging behavior when m=N-c, showing that asymptotically optimal energy storage is possible when N-b=m=N-c. In this case, we find a collective charging enhancement scaling as N-b(0.8264). The origin of the collective charging advantage in central-spin quantum batteries is also analyzed through the quantum speed limit and a multipartite entanglement witness. Our results highlight the crucial role of dynamically emergent SU(2) symmetry in providing an analytical understanding of non-equilibrium charging dynamics in QBs. Giornale/Rivista: PHYSICAL REVIEW B

Volume: 111 (8)      Da Pagina: 85410-1  A: 85410-9

Maggiori informazioni: H.-L.S. thanks Xu Zhou for providing valuable experimental comments. This work was supported by the NSFC (Grants No. 12275215, No. 12305028, and No. 12247103) , Shaanxi Fundamental Science Research Project for Mathematics and Physics (Grant No. 22JSZ005) , and the Youth Innovation Team of Shaanxi Universities. H.-L.S. was supported by the European Commission through the H2 020 QuantERA ERA-NET Cofund in Quantum Technologies project MENTA.
Parole chiavi: Dynamics
DOI: 10.1103/PhysRevB.111.085410