Ion Trapping is one of the suggested methods among several methods suggested for building a practical quantum computer. In this article we’re going to attempt to clarify what ion trapping is and how this method can be used to build a quantum computer.
What are Ions?
Everything in this universe is created up of atoms and molecules, whether living or non-living. The smallest unit is Atom. An atom comprises of proton charged positively, electron charged negatively, and neutrons. The atom center is formed by a nucleus surrounded by moving electrons. Nucleus is made up of neutrons and protons.
A Schematic diagram of an Atom
image source : wikipedia
The electrons, protons and neutrons are arranged so that the overall impact is that the atom remains charged neutrally. The amount of protons is therefore equal to the amount of electrons. For instance, if an atom has 20 electrons, it will contain the same number of protons as well. Now if one of the electrons is removed from the arrangement then the atom becomes positively charged ion. Similarly, if one of the proton gets displaced from the arrangement then the atom becomes negatively charged ion. These charged ions become the carrier of information in the form of qubits for the quantum computers.
What is Ion Trapping?
A string of charged ions are isolated and trapped in a vacuum and confined between electromagnetic fields. This process of trapping ions inside a vacuum tube is called Ion Trapping. The information is shared due to the motion of the ions in the shared trap.
The concept of Ion Trapping which is being used in research and in effort to build practical quantum computers was invented by Wolfgang Paul in 1950s.
Once Ions are trapped they need to be cooled and in this regard inter-galactic temperatures(-273 degree celsius) are used. The vibrational energy of the ions is quantized into photon in cooled environment.
How Information is transferred in shared trap?
A laser beam is used to induce coupling amongst qubits state and ions exchange information through oscillatory motions. Any external interference can easily disrupt the oscillatory motion of the ions and thus impact the exchange of information. This phenomena is known as decoherence.
As of December 2018 IonQ had revealed two new quantum computers of 160 stored and 79 processing qubits based on ion trap. These two quantum computers were the high qubits capacity system known based on ion trap method at the time of writing this article. Ion Trap approach has been the forerunner in the number of methods suggested to build a practical quantum computer. Google has been for a while trying to use another approach known as superconducting circuits. Building a practically operational quantum computer faces number of challenges and only time will tell which approach is the best way to build a practical quantum computer.