Written by AZoQuantumNov 8 2017

**An international team including researchers from Russia, Germany, and Iran have developed a computational technique for making a theory that desribes how cold ions act as well as atoms in optical and electromagnetic traps. **

The demand for this type of study is high because of the probability of modeling with such entirely controlled quantum systems of complicated processes, including solid-state physics as well as high-energy physics. The research on developing elements of a high-precision atomic clock and a quantum computer based on trapped ultracold ions and atoms are being discussed. The outcomes of the recent work of the team were exhibited at the Grid, Cloud and High-Performance Computing in Science (Sinaia, Romania) conference. The study has been reported in the *Physical Review E* journal.

At ultralow temperatures, in the order of nano-Kelvins for those of alkali metal atoms, atoms travel at a lower speed, thereby allowing ultra-precise eperimentation results. Yet, interpretation and planning of the experiments needs theoretical computations. Vladimir Melezhik, Doctor of Physical and Mathematical Sciences from RUDN University, has been computing collision processes and resonant phenomena in ultracold quantum gases. Quantum gas is maintained at extremely low temperatures in an optical trap shaped by uniquely tuned laser beams. The experimental method that has been created renders it feasible to regulate and tune various parameters—such as the number of particles, temperature, spin composition of the particles, and the effective interaction between atoms—of these quantum systems. Yet, the challenge of quantitative representation of the processes that take place is made highly complex because the atoms in these systems interact with one another and with the trap.

The focus of Vladimir Melezhik and his colleagues is on atomic and ion traps shaped like largely elongated cigars and look like waveguides adopted for transmitting electromagnetic waves. For a long time, scientists have been investigating the transmission of electromagnetic radiation in waveguides and have proposed efficient techniques of calculation. Yet, a quantitative theory with the ability to elucidate ultracold processes in atomic and ion waveguides is still being developed.

*The trap adds a complexity to the problem. In free space, there are no preferred directions. This circumstance makes it possible to reduce the six-dimensional quantum two-body problem of two colliding atoms to a one-dimensional one. This is the key problem of quantum mechanics, described in textbooks. However, in the atomic trap, due to appearance of a preferred direction, the symmetry is violated which makes it impossible to reduce the problem to one-dimensional one. In certain cases the problem can be reduced to the two-dimensional Schrödinger equation. However, in most interesting cases it becomes necessary to integrate the Schrödinger equation in higher dimensions. To solve this class of problems, one needs to develop special computational methods and use powerful computers. We managed to make significant progress on this pass.*

Vladimir Melezhik, the author of the study,Doctor of Physical and Mathematical Sciences from RUDN University

The intensity of efficient interatomic interactions such as superstrong attraction and superstrong repulsion of atoms can be controlled by modifying the parameters of the trap. This fact renders it feasible to replicate different crucial quantum phenomena by using ultracold trapped atoms.

“*One of the areas of our work is a numerical study of ultracold quantum systems using hybrid atomic-ion traps, offering new possibilities for modeling some actual processes of solid state physics, elements of quantum computing and precision physics research*,” inferred Vladimir Melezhik.