Scientists at the Institute of Physics of the University of Tartu have found a way to develop optical quantum computers of a new type. Central to the discovery are rare earth ions that have certain characteristics and can act as quantum bits. These would give quantum computers ultrafast computation speed and better reliability compared to earlier solutions. The University of Tartu researchers Vladimir Hizhnyakov, Vadim Boltrushko, Helle Kaasik and Yurii Orlovskii published the results of their research in the scientific journal Optics Communications.

While in ordinary computers, the units of information are binary digits or bits, in quantum computers the units are quantum bits or qubits. In an ordinary computer, information is mostly carried by electricity in memory storage cells consisting of field-effect transistors, but in a quantum computer, depending on the type of computer, the information carriers are much smaller particles, for example ions, photons and electrons. The qubit information may be carried by a certain characteristic of this particle (for example, spin of electron or polarization of photon), which may have two states. While the values of an ordinary bit are 0 or 1, also intermediate variants of these values are possible in the quantum bit. The intermediate state is called the superposition. This property gives quantum computers the ability to solve tasks, which ordinary computers are unable to perform within reasonable time.