Welcome to the Rydbergator - Rydberg Atom Simulator.
A game and a simulator with atoms which interact with each other at a large distance.

Niels Bohr’s model of the atom explains how atoms absorb and emit light, and while doing so, the electrons inside the atoms are jumping between different states. The model accounts for spectroscopic investigations by the Swedish scientist Johannes Rydberg, and in particular, it reveals that electrons can orbit the atomic nucleus at a large distance, much like the outer planets in the solar system. Such orbits are referred to as Rydberg states, with the atomic electron placed on an orbit that is far from the ionic core.

Due to weak binding of the electron to the ion, the atoms in the Rydberg states are easily polarisable, resulting in strongly enhanced, long-range interatomic interactions. 

In a European research network, RySQ, a number of universities across Europe study the use of lasers to excite electrons into the Rydberg states. The aim is to induce interactions between different atoms and to make the state of some atoms control whether other atoms get excited or not. Ultimately, these studies can teach us about dynamics in complex systems, and they may lead to the construction of a quantum computer.

In the Rydbergator you can play with a system of atoms confined to a plane. You can excite them in spatial patterns, and you can see how such patterns evolve with each laser excitation pulse. If you like, you can choose among different physical parameter settings, and see how that influences the dynamics. You can define games and challenges so that you can compete with your friends on who gets the largest number of Rydberg atoms, whose atoms get to dominate a specific domain, or who conquers the atomic flag.

At this moment, we have not determined what are the best games – it is up to you to explore!

The Rydbergator - Rydberg Atom Simulator is not gathering data from your play apart from general statistics on how much the simulator is utilized (number of plays for the different levels). The game serves as a tool for exploring dynamics of these type of systems allowing the user to choose the evolution rules. The primary users are scientists working with Rydberg Atoms and students that are interested in this field. A secondary goal is popularization of Physics by means of people having fun with a physics-inspired game.

Watch the playthrough with Professor Klaus Mølmer and find out more about the Rydbergator.

The science behind

Rydberg atoms are atoms with highly excited electrons (usually just one of them). The electron in a Rydberg state with high principal quantum number n orbits the nucleus at a large distance, where the Bohr model of an atom becomes a good approximation.

The electronic states of an atom are generally quantized and require a very specific amount of energy to be excited. The quantum of energy carried by light particles (photons) is determined by the color or more specifically, the wavelength of the light. Therefore only photons with the right wavelength (resonant photons) can be efficiently absorbed by the atoms making their electrons excited.

The excitation energy of an atom depends on the forces inside the atom and on externally applied electromagnetic fields.

Since the electron of a Rydberg atom is far away from its ionic core, it creates a strong dipolar field around it and can thereby influence the resonant energy of the surrounding atoms. Depending on the strength and sign of the interaction, this can either block or facilitate excitation of these atoms when the next laser light pulse is applied. In the case of facilitation, only atoms at a specific distance from an already excited Rydberg atom (where the resonance condition is satisfied) can get excited. This resonant excitation radius can be precisely controlled by the choice of the laser light wavelength.

Rydberg states

Rydbergator simulates excitation of atoms into Rydberg states in a 2-dimensional plane. The atoms are placed on a hexagonal grid. Only atoms at the right distance from the already excited atoms can get excited (shown as raised blue hexagons in the figure). Too close or too far, the electron energy level is either too high (light blue) or too low (grey color hexagons) for the laser frequency. The excitation occurs in turns, in analogy with a sequential application of laser pulses in a real experiment.

The excitation mechanics in the real experiment occurs with a finite probability, depending on the power of the laser and the excited atoms may decay back to the ground state. In the game, the player is allowed to vary all laser and atomic parameters, and explore both physical and unphysical regimes, e..g, simplified excitation rules that allow excitation of all particles with certainty if their frequency is right.

The scientific purpose of the game is to provide a graphical tool for simulation of different excitation scenarios and to visualize the possible interesting dynamics in the field of Rydberg atoms.

To turn the physical simulator into a game, two species of Rydberg excitations (blue and yellow) can be excited by different laser frequencies. This allows the players to control and compare the excitation patterns formed and to compete, e.g., to conquer the largest group of excited atoms of a specific color.