Enhancing self-discharging process with disordered quantum batteries

One of the most important devices emerging from quantum technology are quantum batteries. However, self-discharging, the process of charge wasting of quantum batteries due to decoherence phenomenon, limits their performance, measured by the concept of ergotropy and half-life time of the quantum battery. The effects of local field fluctuation, introduced by the disorder term in the Hamiltonian of the system, on the performance of the quantum batteries is investigated in this paper. The results reveal that the disorder term could compensate disruptive effects of the decoherence, i.e., self-discharging, and hence improve the performance of the quantum battery via “incoherent gain of ergotropy” procedure. Adjusting the strength of the disorder parameter to a proper value and choosing a suitable initial state of the quantum battery, the amount of free ergotropy, defined with respect to the free Hamiltonian, could exceed the amount of initial stored ergotropy. In addition harnessing the degree of the disorder parameter could help to enhance the half-life time of the quantum battery. This study opens perspective to further investigation of the performance of quantum batteries that explore disorder and many-body effects.

Figure 1

The dynamics of averaged ergotropy of the two-cell QBs ($N=2$) with different initial state (a) in the absence of disorder and (b) in the presence of disorder. The results are averaged over ${10}^2$ realizations and $J_{k,k+1}=J=10\mathrm{\Gamma }$.

Figure 2

(a) The percentage of spontaneous deposited charge and (b) half-life time of the three batteries versus the degree of disorder. The other parameters are the same as Fig. 1.

Figure 3

The dynamics of averaged ergotropy of the multicell QBs ($N=7$) with different initial state (a) in the absence of disorder and (b) in the presence of disorder. The results are averaged over ${10}^2$ realizations and $J_{k,k+1}=J=10\mathrm{\Gamma }$.

Figure 4

(a) The first and (b) second term of Eq. (8), (c) time derivative of the internal energy, and (d) ${\dot{\mathcal{U}}}_0(\rho ,H_0)$ for $N=7$ and three degrees of disorder. The other parameters are the same as Fig. 1.

Figure 5

The percentage of maximal spontaneous deposited charge of the coherent battery for (a) fixed degree of disorder ($\delta =5$) and different numbers of quantum cells and (b) fixed number of quantum cells ($N=7$) and various degrees of disorder. The number of realizations for $N=3,4,5,6,7$ are 5000, 3000, 1000, 500, 100, respectively, and $J_{k,k+1}=J=10\mathrm{\Gamma }$.

Figure 6

(a) The percentage of spontaneous deposited charge and (b) half-life time of multicell batteries ($N=7$) versus the degree of disorder over 50 realizations. Here also $J_{k,k+1}=J=10\mathrm{\Gamma }$.

Figure 7

Dynamics of ergotropy of QBs in the absence (left) and presence (right) of disorder with various numbers of quantum cells. The results for $N=3,4,5,6$ are averaged over 5000, 3000, 1000, and 500 realizations, respectively. Here we consider $J_{k,k+1}=J=10\mathrm{\Gamma }$.

Figure 8

The time evolution of internal energy and the ratio defined by (B1) in the absence (a) and (c), and presence (b) and (d) of disorder with $N=7$. The results are averaged over 100 realizations. Here we consider $J_{k,k+1}=J=10\mathrm{\Gamma }$.