Our world is made up by countless big and small objects. The big objects are planets, stars, mountains, stones and so many man-made objects. All these are made up by atoms and molecules. How small are the atoms? We often read that there are millions of microorganisms at the tip of a needle. It is such a small space. If millions of organisms are accommodated on it, we can imagine how small are the atoms, which are smaller than these organisms..
The methods of studying big objects and small objects are different. Big objects are studied by classical physics and small objects are studied by Quantum Physics. All these exceedingly small particles (atoms and sub-atomic particles) either absorb energy or emit energy and they do it in peculiar quantities — it is called quantization of energy. The energy absorbed by small particles or emitted by them in its minutest form is called quantum and the study is called Quantum Physics.
The behaviors of these exceedingly small particles is totally different. We are always surrounded by big objects and are familiar with their behaviour. As we are not familiar with exceedingly small particles, their behaviour, appears weird to us.
One such difference is that these particles can exist in more than one state at the same time — it is called superposition. These can pass through a hindrance. An exceedingly small particle moves straight through a barrier, using a process called tunneling. When large number of particles are involved, quantum mechanical effects become insignificant.
The year 2025 Nobel laureates proved that the quantum tunelling could be observed in macroscopic objects too Nobel laureates of physics, 2025 are Michel Devoret, University of California, a professor of physics; John Martinis, University of California, Santa Barbara, Emeritus, professor of Physics; and John Clarke, University of Berkeley, Emeritus Professor of Physics.
Their research is based on Josephson’s research on super conductors. In superconductors, there is no electrical resistance. If a circuit of superconductors is separated by a thin layer (less than 10000th times the thickness of hair) of non-conducting material, a set up called Josephiann junction comes into existence. A current was passed through such a circuit. The charged particles move through a superconductor. They form a system that behaves as if they were a single particle. Initially, the current flow does not show any voltage. Later it shows quantum character to escape zero voltage stage through tunelling and it appears as voltage. As superconductors are used, the electrons behave as if they are a wave of one entity and flow collectively. Josephian received Nobel in Physics for this research in 1973. The set-up of superconductors separated by a non-conductor is called Josephina junction. Anthony in 2003 predicted that quantum behaviour could be shown by macroscopic objects using a circuit such as Josephian junction. This was demonstrated by Nobel laureates trio of 2025. They used such a circut. They controlled the external environment. The temperature was kept a notch above the Kelvin temperature. Because of superconductors, the current penetrated the non-conducting material. Millions of particles penetrated the non-conducting material. This will lead to the information unit -qubit- in reality. The superposition and quantum entanglement improves the capacity and speed of quantum computer several times those of classical computers.
This is the discovery of macroscopic quantum mechanical tunelling and energy quantisation in an electric circuit.
A research essay on quantum physics was published by Heisenberg in 1925 some hundred years ago. This year is the International Year of Quantum Science and Technology. It is a coincidence that the trio received Nobel in physics in this centenary year.