Italian physicists have proposed a new concept of a quantum battery entangled qubits that can be implemented on the basis of existing technologies. They hope to create an experimental model with five qubits for three years. An article with the results published in the journal Physical Review Letters.
A few years ago, theoretical physicists have proposed the idea of quantum battery that will store energy in the form of chemical compounds, and due to the excited States of quantum objects. Most of these works were written by scientists involved in research on quantum information theory, interested in the fundamental theorems about limits of energy storage and transfer. In the new work, physicists have proposed a scheme that can be implemented in practice.
Italian physicists have proposed to use as qubits superconducting circuits or semiconductor quantum dots. In the authors considered the simplest case, they must have two energy levels — the basic and excited. All qubits are placed in a common optical cavity, where they can simultaneously transfer in the excited state and to confuse one effect, for example, by a laser pulse of a certain energy. As a result, according to scientists, the power with which to charge the battery, increases proportionally to the square root of the qubits. At the same time for the battery of the array of qubits in separate resonators this value does not change when adding new elements.
The authors note that the proposed system does not violate any thermodynamic laws, since it uses a more intense energy flow from the source to the battery, than say for other devices. Also physicists say that such devices will not replace contemporary batteries. Despite the proximity to the theoretical charging rate, they will also be discharged extremely quickly — on the scale of nanoseconds. In addition, compared with the chemical elements they have tiny capacity: typical difference of energy between levels of the qubit is 0.001 electronvolts, while modern laptop batteries store about 1024 eV. Therefore, the main field of application of such batteries may be the field of quantum computing. In this case the battery located inside a quantum computer will work in a loop: each qubit will charge while the computer takes energy from the following for calculations.