Quantum mechanics is undoubtedly one of the most important and successful theories in physics of all time. Unlike most other theories, it is the culmination of efforts of a number of great minds from the past century. The inception of quantum mechanics was when scientists could deduce the fact that everything in our universe was quantized. The theory of Max Planck is considered as one of the establishing pillars of quantum mechanics. To that end, he is attributed as the father of quantum mechanics.
Planck was born in 1858 at Kiel in Germany. He was the 6th child in the family. In 1867, his family moved to Munich, and Planck enrolled in the Maximilians gymnasium school, where he came under the tutelage of Hermann Müller, a mathematician who took an interest in him. While Planck was at the school, Müller taught him astronomy and mechanics as well as mathematics. It was from Müller that Planck first learned the principle of conservation of energy. Planck graduated early, at the age of 17. This is how Planck first came in contact with the field of physics. Planck was gifted when it came to music. He took several singing lessons and played piano, organ and cello, and composed songs and operas. But besides all those he took physics as his passion. Max Planck maintained an academic career in different institutions all throughout his life .
In 1894, Planck was mostly interested in solving the age-old problem: black body radiation. The problem had been first spotted by Kirchhoff in 1859 which asked how does the intensity of the electromagnetic radiation emitted by a black body, also known as the perfect absorber, depend on the frequency of the radiation and the temperature of the body. This situation had been inspected experimentally, but no theory agreed with the experimental data. Willhelm Wien proposed his own law also known as the Wien’s law, which precisely predicted the behavior at high frequencies, but failed at low frequencies. The Rayleigh–Jeans law, another approach to the problem, supported the experimental results at low frequencies, but generated a problem at high frequencies also known as the ‘Ultraviolet Catastrophe’.
Considering all other speculations about energy and how to solve the specific heat-related problems of black bodies, Max Planck gave his revolutionary theory about the quantization of not only heat energy but also any kind of energy. It is known that when he was formulating his famous equation:
where the left-hand side indicates the energy content and the right side denotes the product of the frequency of light and a new constant known as the Planck's constant, he he had used the constant as a stand-in under the assumption it would eventually be removed. But it seemed the final product of the equation contained the constant that he had introduced. This surprised Planck because the main reason he considered the new constant was because in his calculation he assumed the absorption and emission of energy to be in a definite chunk. This idea received an unduly response from the academic community as in that time it was considered that the amount of absorption and emission of energy was continuous. However, the retention of the Planck's constant in the final equation opposed contemporary scientists' assumption as energy transmission occurred in certain chunks i.e. energy is quantized.
This theory of Max Planck is mostly significant because the same Planck constant reduced by a factor of 2 (known as the reduced Planck constant) is used in calculating the Hamiltonian (or energy content) of a quantum system using the famous Schrödinger equation. This allows us to calculate the temporal evolution of energy of a quantum system which lies at the base of quantum mechanics. Also, using the famous E= mc² and the energy equation of Planck opened a new realm, a French physicist was able to show that all particles can act as waves and vice versa. Ultimately, quantum computing technology is dependent on this calculation of energy of different quantum states along with the explicit quantum phenomena: superposition, teleportation and interference. It can undoubtedly be stated that the Planck equation is one of the baseline equations that gave birth to quantum mechanics as well as quantum computing.
The idea of quantization of energy changed the course of physics for all time. Max Planck was awarded the Nobel Prize in physics in 1918 for introducing the world to such a revolutionary idea.
Later in his life, Max Planck was more interested and devoted to philosophical, religious and aesthetic writings. Some of his famous books include: The Theory of Heat Radiation, Quantum Theory, Where is science going? etc. Together with other prominent scientists like Einstein and Erwin, he opposed the indeterministic and statistical worldview introduced by Max Born, Bohr and Werner Heisenberg. There is a well-known opinion of Planck: a world dominated by indeterminism lacks harmony.
This revolutionary scientist, whose work forms the foundations for numerous the postulates of modern quantum mechanics, breathed his last on the 4 October 1947 (aged 89) in Göttingen, Lower Saxony, Bizone, Allied-occupied Germany. However, he will remain ever immortal in the scientific community for his extraordinary contribution in the field of physics.