Superconducting transmon qubit-resonator quantum baterry

Quantum battery (QB) is the miniature energy storage and release device and plays a crucial role in future quantum technology. Here, an implementation scheme of a QB is proposed on a superconducting circuit which is composed by $N$ coupled transmon qubits and a one-dimensional transmission line resonator. We derive the Hamiltonian of the QB system and investigate its charging performance by considering three decay channels. We find that the presence of the decay channels suppresses the high oscillation of the energy storage process, thereby realizing a stable and powerful QB. In particular, compared with the resonator decay and the qubit relaxation, the qubit dephasing shows a counterintuitive advantage in our QB. We show that the nearest neighbor interaction always have a positive impact on the stable energy and the coupling only significantly influences the maximum charging power in the fully nondegenerate ground state region. We also demonstrate the feasibility of our approach by evaluating the QB performance under experimental parameters.Comment: 8 pages, 6 figure

Cavity-Heisenberg spin chain quantum battery

We propose a cavity-Heisenberg spin chain (CHS) quantum battery (QB) with the long-range interactions and investigate its charging process. The performance of the CHS QB is substantially improved compared to the Heisenberg spin chain (HS) QB. When the number of spins $N \gg 1$, the quantum advantage $\alpha$ of the QB's maximum charging power can be obtained, which approximately satisfies a superlinear scaling relation $P_{max} \propto N^{\alpha}$. For the CHS QB, $\alpha$ can reach and even exceed $1.5$, while the HS QB can only reach about $\alpha=0.75$. We find that the maximum stored energy of the CHS QB has a critical phenomenon. By analyzing the Wigner function, von Neumann entropy, and logarithmic negativity, we demonstrate that entanglement can be a necessary ingredient for QB to store more energy, but not sufficient

Three-level Dicke quantum battery

Quantum battery (QB) is the energy storage and extraction device that is governed by the principles of quantum mechanics. Here we propose a three-level Dicke QB and investigate its charging process by considering three quantum optical states: a Fock state, a coherent state, and a squeezed state. The performance of the QB in a coherent state is substantially improved compared to a Fock and squeezed states. We find that the locked energy is positively related to the entanglement between the charger and the battery, and diminishing the entanglement leads to the enhancement of the ergotropy. We demonstrate the QB system is asymptotically free as $N \rightarrow \infty$. The stored energy becomes fully extractable when $N=10$, and the charging power follows the consistent behavior as the stored energy, independent of the initial state of the charger.Comment: 9 Pages, 9 Figure

Closed-loop three-level charged quantum battery

Quantum batteries are energy storage or extract devices in a quantum system. Here, we present a closed-loop quantum battery by utilizing a closed-loop three-state quantum system in which the population dynamics depends on the three control fields and associated phases. We investigate the charging process of the closed-loop three-level quantum battery. The charging performance is greatly improved due to existence of the third field in the system to form a closed-contour interaction. Through selecting an appropriate the third control field, the maximum average power can be increased, even far beyond the most ideal maximum power value of non-closed-loop three-level quantum battery (corresponding to the most powerful charging obtainable with minimum quantum speed limit time and the maximum charging energy). We study the effect of global driving-field phase on the charging process and find the maximum extractable work (`ergotropy') and charging power vary periodically under different control field, with a period of $2\pi$. Possible experimental implementation in nitrogen-vacancy spin is discussed

Adiabatic light propagation in nonlinear waveguide couplers with longitudinally varying detunings via resonance-locked inverse engineering

We investigate the adiabatic evolution of light in nonlinear waveguide couplers via resonance-locked inverse engineering based on stimulated Raman adiabatic passage (STIRAP). The longitudinal varying detunings of the propagation coefficients are designed to eliminate dynamically the nonlinear effect, which induce the non-adiabatic oscillations. We show that different light evolutions such as complete light transfer, light split and light return can be realized adiabatically with appropriate choices of the detunings even in the nonlinear regime. The features open new opportunities for the realization of all-optical nonlinear devices with high fidelity in integrated optics.Comment: 8 pages,6 figure

Analytically solvable many-body Rosen-Zener quantum battery

Quantum batteries are energy storage devices that satisfy quantum mechanical principles. How to obtain analytical solutions for quantum battery systems and achieve a full charging is a crucial element of the quantum battery. Here, we investigate the Rosen-Zener quantum battery with $N$ two-level systems, which includes atomic interactions and external driving field. The analytical solutions of the stored energy, changing power, energy quantum fluctuations, and von Neumann entropy are derived by employing the gauge transformation. We demonstrate that full charging process can be achieved when the external driving field strength and scanning period conforms to a quantitative relationship. The local maximum value of the final stored energy corresponds to the local minimum values of the final energy fluctuations and von Neumann entropy. Moreover, we find that the atomic interaction induces the quantum phase transition and the maximum stored energy of the quantum battery reaches the maximum value near the quantum phase transition point. Our result provides an insightful theoretical scheme to realize the efficient quantum battery.Comment: 9 pages,7 figure

(Methanolato)(pyridine)[N 2,N 2′-(pyridine-2,6-diyldicarbon­yl)diacetohydra­zide(2–)]iron(III) methanol solvate

In the title complex, [Fe(C11H10N5O4)(CH3O)(C5H5N)]·CH4O, the FeIII ion has a distorted penta­gonal-bipyramidal geometry. In the crystal structure, mol­ecules are linked into one-dimensional chains along [1 ] via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds

High-fidelity superadiabatic population transfer of a two-level system with a linearly chirped Gaussian pulse

We investigate high-fidelity superadiabatic quantum driving in a chirped Gaussian two-level model with a Gaussian temporal envelope and a linear detuning. We show that the nonadiabatic losses can be canceled to any desired order by constructing and adjusting an auxiliary Hamiltonian (counter-diabatic field) and a symmetry in the fidelity arises on the counter-diabatic field ratio. A high-fidelity, robust, and accelerated (in a shorter time) transitionless superadiabatic population transfer is achieved that ensures a perfect following of the instantaneous adiabatic ground state even in the nonadiabatic regime. The features make the superadiabatic protocol a potentially important tool for quantum information