Quantum theory and its ultimate applications in today’s life.
It is needless to say that light is a form of energy. Scientists have propagated /propounded many theories to solve many queries and mysteries of light for years together. In 1860 physicist James Clerk Maxwell of Scotland propounded the electromagnetic theory of light, which changed the perception and understanding of light.
What is quantum theory?
What is a quantum theory of light? Scientists have propagated /propounded many theories to solve many queries and mysteries of light for years together. In 1860 physicist James Clerk Maxwell of Scotland propounded the electromagnetic theory of light, which changed the perception and understanding of light.
Michel Faraday’s conception of electric and magnetic effects laid the foundation for Maxwell’s theory. He formulated that light energy travels in the form of electromagnetic waves. These waves are made up of electrical and magnetic vectors, which are perpendicular to each other and to the direction of propagation. But it has no solution for the frequencies of the ultra violate light.

The quantum theory of German physicist Max Karl Planck solved the above issues of light in 1900. He suggested that light is emitted in bundles or packets instead of a steady stream. This packet of light is referred to as quantum and this theory specifies that the energy of each quantum is proportional to its frequency. For the above propagation, he is considered the founder or originator of the quantum theory of light. He got Nobel Prize in Physics for his quantum theory in 1918.
Further, the quantum theory was carried forward by another German Physicist Albert Einstein to a new height. He proposed that light is a composition of small packets of energy, which he termed as “light quantum”(photon), and has wave-like properties.
He further explained the process of emission of electrons from metals when exposed to light which is called the photo-electric effect. In a broader sense, the light may be infrared, visible, or ultraviolet light, X- rays, or gamma rays, and the material may be a solid, liquid, or gas and the released particles may be ions (electrically charged particle atoms or molecules) as well as electrons.
Einstein suggested that minimum energy is required to liberate an electron from metal or surface-only photons with greater energies than this minimum can emit an electron. His photon model was experimentally proved by American physicist Robert Andrews Millikan in 1916.

Einstein’s “light quantum” was later termed/coined as photon by an American chemist Gilbert N. Lewis to describe the unit of light in a letter to Nature. Photon is now invariably applied to the energy quantum of light.
The quantum theory of light; the photo-electric effect became an important discovery that revolutionized many branches of science and human understanding of atomic & subatomic processes. Einstein got the Nobel Award for his monumental works on quantum theory in physics in 1921.
Applications of quantum theory;
Modern-day lives utilize quantum theory in many fields including quantum chemistry, quantum optics/cryptography, quantum tunneling, quantum computing, optical atomic clocks, superconducting magnets, light emitting diodes, laser, transistors and semiconductors, medical and research imaging, and so on.
Modern electronic devices are being designed using quantum mechanics. Laser, microchips, electronic microscopes, magnetic resonance imaging (MRI), and global positioning system (GPS) are a few examples of this field. In quantum tunneling, the quantum mechanical phenomenon plays a very critical role in physical phenomena like nuclear fusion and alpha-radioactive decay of atomic nuclei.
Even a simple electric switch works on quantum tunneling principles. Flash memory chips found in USB drives use quantum tunneling to erase their memory data. Quantum computing relies on keeping things very cold. Quantum computers perform certain tasks reasonably faster than classical computers.
Because quantum computers use qubits instead of classical bits. Recently it is reported that IBM has built the world’s largest fridge for quantum computers, which is a hundred thousand times colder than outer space and may house quantum computers with 4000 qubits.
Further research says a micro-fridge can keep cooling cell size objects to be used in research of quantum entanglement. Quantum computing can perform a wild variety of tasks very efficiently in error free manner including financial services, medicines, logistics, cloud security, artificial intelligence(AI), etc.

Quantum optics has practical application in quantum cryptography, which allows the secure transmission of information on a guaranteed theoretical approach. Quantum cryptography allows the completion of various cryptographic tasks that are proven or conjectured to be impossible using classical/traditional (nonquantum) communication.
Optical atomic clocks use light energy to provide the movements of atoms to keep time. In quantum chemistry better understanding of electronic structures and molecular dynamics is made. Quantum theory has also given many solutions towards working on so many diverse biological systems including protein structure and smell receptors.

Bottom line;
For the observation of quantum effects on very tiny particles like atoms and molecules extremely low temperature is needed. Quantum theory has solved many mysteries in the universe for the last century including previous unexplained phenomena such as blackbody radiation, tiny particles, atoms, and molecules.
Further, it provided many solutions to human needs, comfort, and ambitions, It also taught us that universe is very strange, and may not be completely understood by humans at any point in time. The Quantum entanglement of everyday objects is still a puzzle.
6 Comments
Very well written Sir
Thank you for following and review
I hadn’t learned this much of physics in any of my advanced classes by IITians teachers …….
You explained it in a much better and easy way…..✨✨🔆🔆✨✨✨✨✨🔆🔆
Nicely explained👌👌👌👌.
For me blackbody radiation is a new concept which is mentioned at the last portion of this article. Great👏👏👏
Sir vividly described. Easy to understand.
Thank you