Quantum memory

A component of a memory configured to store and manipulate a qubit state, said component comprising:

• a quantum dot molecule, said molecule comprising a first quantum dot provided in a first layer and a second quantum dot provided in a second layer, the first and second layers being separated by a barrier layer, the second layer being arranged above the first layer;
• an exciton comprising an electron and hole bound state in said quantum dot molecule, the spin state of said exciton forming said qubit;
• a first electrical contact being provided below the first quantum dot and a second electrical contact being provided above the second quantum dot to allow an electric field to be provided across said quantum dot molecule;
• a voltage source connected to the electrical contacts configured to apply an electric field across said quantum dot molecule,
• a voltage source controller configured to modulate the electric field across the quantum dot molecule such that an exciton in the quantum dot molecule is switched between a direct configuration where the electron and hole of the exciton are in the same quantum dot and an indirect configuration wherein the electron and hole are located in different quantum dots of the quantum dot molecule, the voltage source controller comprising an information acquiring circuit and a timing circuit, the information acquiring circuit being configured to acquire information concerning the relationship between the fine structure splitting of said exciton and the applied electric field, the timing circuit being configured to allow switching of the exciton from an indirect configuration to a direct configuration at predetermined times derived from the fine structure splitting.