Quantum mechanics is the branch of contemporary physics dedicated to the study of objects and forces of a very small spatial scale, that is, of matter at the size of the atom and the particles that compose it, and also the movements that characterize them. Surprisingly, quantum theory normally only allows probabilistic or statistical calculations of the observed characteristics of elementary particles, understood in terms of wave functions. The Schrödinger equation plays a role in quantum mechanics that Newton’s laws and conservation of energy do in classical mechanics. That is, the prediction of the future behavior of a dynamic system, and it is a wave equation in terms of a wave function that analytically predicts the precise probability of the events or results.
History of Quantum Mechanics

The starting point of quantum mechanics is constituted by the studies of the Frenchman Louis de Broglie, who formulated the law that dictates both the corpuscular (body) and undulatory (wave) motion of subatomic particles. This discipline was initially known as wave mechanics. However, this would have been impossible without the previous developments of Max Planck, who postulated the hypothesis that light (electromagnetic radiation) was absorbed and emitted by matter as quanta of light according to Planck’s constant. This was the first quantum development in history, demonstrating the possibility of wave-particle duality.
The properties of Quantum Physics are very different from those of Classical Physics, which describes nature on our scale. It is mainly characterized by not being deterministic but probabilistic. Furthermore, Energy inbound systems (i.e., atoms) are not exchanged continuously but rather discreetly, which implies the existence of minimal energy packages, called quanta
Quantum Mechanical Phenomena

Quantum mechanics is the science that studies phenomena from the point of view of the totality of possibilities. Contemplate what is not seen and explain the phenomena from the invisible. Contemplate the non-measurable trends, such as non-locality and indeterminism of particles.
- The phenomenon of superposition: It tells us that an electron can be present at the same time in your house, on the highest peak of Everest, or on the surface of Jupiter. That is, a particle is present in many places at the same time with different probabilities, as long as it is not observed.
- The phenomenon of entanglement: It tells us that an electron found in our computer may be entangled with another electron located on a distant planet 400 light-years away. When we modify the state of one of the electrons, the other changes instantly.
- The tunnel effect: It tells us that an electron can sometimes pass through walls or thin walls of energy as if it were a ghost. This is due to the wave-particle duality, which quantum mechanics confirms.
Applications of Quantum Mechanics

Quantum technologies are characterized by using and taking advantage of properties and phenomena of the microscopic world that do not occur in the macroscopic world and that have great potential. This has excellent applications in computing, allowing us to perform several calculations or simulations simultaneously instead of sequentially. While at least seven emerging quantum technologies can be distinguished, there are three that are especially relevant to the future of medicine, biology, and genetics. These are quantum optics, quantum simulation, and quantum computing. The last two consist of devices capable of performing certain calculations and simulations exponentially faster than current computers, being able to execute computations in minutes or hours that today would take thousands of years to process. The third consists of the study of all kinds of optical processes, such as the emission and absorption of radiation by matter. The control of these processes is important for the improvement of techniques that make possible the detection of damaged organs or tumors and to manipulate them at the molecular level with high precision.
Bottom Line
The development applications of this field revolutionized not only physics but also chemistry and other closely related areas. This set of scientific experiences has allowed the study of the atom, of the particles that compose it (electrons, quarks, and gluons), and of all elementary particles in general. Likewise, quantum mechanics made broad technological development possible.