Perhaps not everyone knows what quantum physics is . A highly debated, fascinating subject capable of revolutionizing the idea we have of the universe that surrounds us. In fact, some people have adopted quantum discoveries as a way of looking at existence . So what is behind this relatively new discipline? We explain in detail, what is quantum physics, properties, what it is for and examples.
What is quantum physics, properties, what it is for and examples
Quantum physics is also known as quantum or mechanical theory. since it is based on a theory of mechanics that focuses on the phenomena of the length scale and atomic and subatomic energy, giving new life to previous theories, which are now considered obsolete.
What is the difference between classical physics and quantum physics? The latter describes radiation and matter as a dual phenomenon: wave and particle. Therefore, wave-particle dualism can be considered one of the characteristic features of this mechanics. The relationship between waves and particles is studied and confirmed by two principles:
- Principle of complementarity
- Heisenberg’s uncertainty principle (the latter formalizes the former).
We can certainly affirm that after the discovery of relativity and the birth of classical physics, these insights gave rise to a new era, that of modern physics. To study quantum mechanics in an integral way, an integration between different sectors of physics is required:
- Atomic physics
- Physics of matter
- Nuclear physics
- Physical particles
But how was quantum physics born?
How did quantum physics or modern physics originate?
Classical physics, at the end of the 19th century, was unable to study matter at the microscopic level, beyond the measurement of the atom so to speak. Therefore, experimental reality could not be investigated, especially the phenomena related to light and the electron. But man has always wanted to go further and his innate curiosity has led him to investigate further.
In the early years of the 20th century , discoveries that emerged from the atomic scales challenged old assumptions. Thus was born quantum theory, thanks to a term coined by the scholar Max Planck at the beginning of the 20th century. The basic concept is that the microscopic magnitudes and quantities of some physical systems can vary even in a non-continuous but discrete way.
But, thanks to what previous discoveries was it possible to reach these conclusions?
- 1803: recognition of atoms as a constituent element of molecules
- 1860: the periodic table groups atoms by chemical properties
- 1874: discovery of the electron and the nucleus
- 1887: studies on ultraviolet radiation
This last date is the one that perhaps marks the main dividing line. The phenomenon of interaction between electromagnetic radiation and matter (photoelectric effect) disappeared for radiation frequencies below a threshold value. With the photoelectric effect, the energy of the electrons was proportional to the frequency of the electromagnetic radiation. Maxwell’s wave theory was no longer sufficient to explain certain phenomena.
Origin of quantum theory
To provide a summary of what has contributed to the birth of quantum physics, we can list more important dates , linked to discoveries and knowledge that serve to trace the history of quantum mechanics:
- 1900 : Planck introduces the idea that energy is quantified, absorbed and emitted.
- 1905 : Einstein demonstrates the photoelectric effect (the energy of the electromagnetic field is transported by quanta of light (photons)
- 1913 : Bohr quantifies the orbital motion of the electron.
- 1915 : Sommerfeld introduces new rules , generalizing quantification methods.
But it was from 1924 on that the foundations of what we now know as quantum theory were laid . On this date Louise de Brogie develops a theory of material waves . The following year the name of Heinsenberg takes over, who formulates the mechanics of matrices, which was followed by Dirac in 1927 with the special theory of relativity . Until 1982, the year in which the Optical Institute of Orsay finished its investigation on the violation of Bell’s inequality, the discoveries followed one after another.
What are the basics of quantum physics?
Among the most fascinating discoveries we find:
- wave-particle duality
- complementarity principle
- Begining of uncertainty
Let’s go through them one by one to dig even deeper into this science.
Wave-particle dualism
Before, only classical physics existed. This was divided into two groups of laws:
- Newton’s Laws
- Maxwell’s Laws
The first group of laws describes the movement and dynamics of mechanical bodies, while the second group describes the tendency and the links between the subjects that are part of an electromagnetic field: light and radio waves, for example.
Some experiments suggested that light could be considered a wave. But they were not confirmed. Instead, the idea that light had a corpuscular nature (of Einstein and Planck) and that it was therefore made up of photons , gained more and more legitimacy. Thanks to Bohr it was understood that the nature of matter and radiation were:
- Make it a wave
- Make it a body
It was no longer possible to think in terms of one or the other, but in a complementary perspective. Bohr’s principle of complementarity emphasizes exactly this, that phenomena that occur at the atomic scales have dual properties, both of waves and of particles.
Heinsenberg uncertainty principle
As we noted earlier in 1927, Heinsenberg showed that some pairs of physical quantities, such as velocity and position, are impossible to record simultaneously without making mistakes. Accuracy can affect one of the two measurements, but not both, because a phenomenon such as speed causes consequences in the other and invalidates the measurement.
To locate the position of the electron, it will be necessary to illuminate a photon. The shorter the wavelength of the photon, the more accurate the measurement of the electron position.
In quantum physics, the photon’s low wave frequencies carry more and more energy and speed than the electron absorbs. At the same time, it will be impossible to establish the value of these measurements.
What are the applications of quantum physics?
We have quantum theory to thank if we now have access to cutting edge technologies. From electronics to information technology, there are many devices based on modern quantum intuitions. Some clear examples can be:
- To be
- Electronic microscope
- Computational chemistry
- Nuclear magnetic resonance
Consider also the CPUs of our computers , capable of containing billions of semiconductors within a few millimeters, amplifying signals, and which have proven to be indispensable. Without this, we could not move towards a future of research and evolution.
The issue of cybersecurity is also broadening horizons to understand whether it will be possible to exploit quantum cryptography to obtain and transmit information that is more secure and difficult to intercept.
It is very likely that we will see quantum computers in a few decades , with significantly better performance than current models.
