Quantum physics is a branch of physics that studies the behaviour and interactions of matter and energy at the quantum scale. Quantum physics is primarily concerned with the behaviour of atoms, electrons, photons and other subatomic particles.

Quantum physics deals with the study of how light and other things move around in space. It also studies how particles move around in space or how they are positioned in space. Quantum physics is characterised by wave-particle duality, uncertainty, and nonlocality. Let us understand in detail quantum tunnelling and the concept which describes the quantum state of a system known as the wave function.

## Behaviour of Particle

A wave function is a mathematical expression that describes the probability amplitude of a particle. This function has two components, one describing the spatial distribution of the particle and another describing its momentum. The wave function can be considered as a kind of map that tells us where we are most likely to find a particle and how fast it is moving. The probability of finding a particle if it exists is 1. The probability distribution in three dimensions is established using the wave function. The Schrödinger Equation is the most fundamental equation in quantum mechanics, and it describes the time evolution of a quantum system’s wavefunction. It is named after Erwin Schrodinger. Schrödinger Equation is the linear partial differential equation describing the wave function, 𝚿. Using this equation, energy calculations become easy. In the year 1925, the concept of wave function was introduced with the help of the Schrodinger equation.

A wave function can be visualised as a surface in space, which varies with time and other parameters in space. Wave functions are used to compute the probability of finding an electron in any given region around the nucleus when it is not bound to an atomic nucleus. The electron wave function is a continuously differentiable complex-valued function of position in space and time, with the value of the function equal to being either inside or outside the atom.

### Know about a quantum mechanical phenomenon

Quantum tunnelling is a quantum mechanical phenomenon that allows particles to pass through a barrier they could not normally pass. Quantum tunnelling is an effect that takes place when an atomic-sized particle passes through a potential barrier, also known as a potential well, without any energy cost. Such particles are said to be “tunnelling”. When an atom or subatomic particle can exist on the other side of a physical barrier that is typically impossible for the particle to pass through, this phenomenon takes place.

Quantum tunnelling is used in many applications, including the development of semiconductors, transistors, and diodes. Quantum tunnelling is forecasted to create physical limits to the dimensions of the transistors employed in microelectronics. It is used in the scanning tunnelling microscope as well as quantum biology. It is also one of the key parts of the nuclear fusion reaction. It is a frequent source of current leakage in VLSI electronics.