Quantum physics: the scientific revolution that reveals that reality is an illusion and the world around us works differently than we ever imagined
The mystique of science
Quantum physics is one of the most mysterious and revolutionary fields of modern science. While classical physics, formulated by Isaac Newton at the turn of the 17th and 18th centuries, describes the world as a predictable and fixed arrangement of objects in space, quantum mechanics brings a fundamental shake-up to this notion.
According to its laws, reality at the microscopic level behaves in ways that often contradict our intuitive ideas. Particles can be in two places at once, change their state depending on observation, and exist in a probabilistic range of almost infinite possibilities until they are measured. What does it all mean?
The birth of quantum physics
Quantum mechanics was born in the late 19th and early 20th centuries in response to problems that classical physics could not handle. In 1900, Max Planck came up with the theory of quanta when he discovered that energy is not transferred continuously, like water flowing from a tap, but in small doses - quanta.
This discovery helped explain the so-called black body - an ideal object that perfectly absorbs light and reflects none. While there is no such perfect object on Earth, the same principle underlies the behaviour of, for example, black holes or special materials used in laboratories, such as carbon aerogel.
Physicists have previously puzzled over why classical theories have failed to describe how a black body behaves. Until Planck came up with the theory of quanta. This idea was so fundamental that it laid the foundation for a new field of physics - quantum mechanics.
Thanks to quantum mechanics, we are now able to better understand the behaviour of atoms, electrons and other particles, which has led to huge advances in technology - from lasers to transistors to quantum computers. So quantum physics is not just affecting scientists, it's affecting everyone's everyday life.
Subsequently, it was none other than Albert Einstein who came up with the explanation of the photoelectric phenomenon in 1905, showing that light behaves not only as a wave but also as a particle - a photon. Scientists began to notice this phenomenon through experiments with metal surfaces, where they found that when illuminated with ultraviolet light, electrons were released from them. This defied classical physics, which could not explain why weak but high-energy light could release electrons while strong but less energetic light could not.
This can be seen, for example, in solar panels: when sunlight hits them, the photons contained in the light transfer their energy to electrons in the panel material, resulting in the generation of an electric current. This simply means that light transfers energy in small doses. Exactly as described above.
Another major breakthrough came in 1925 from Werner Heisenberg with his matrix mechanics (the first way that physicists found to express quantum physics in mathematical form) and Erwin Schrödinger with his famous wave equation. Schrödinger's equation showed that particles do not exist as solid objects until they are observed, but as spread-out probabilistic waves. This phenomenon is best illustrated by the thought experiment of Schrödinger's cat - a cat is enclosed in a box along with a vial of poison that can be released at any time. The animal in the box is thus simultaneously dead and alive until someone looks inside.
Zdroj: Giphy
The implications of quantum physics
One of the most surprising consequences of quantum mechanics is the uncertainty principle, formulated by the aforementioned Werner Heisenberg. This principle states that we can never accurately measure both the position and momentum of a particle at the same time. The more accurately we know one of these quantities, the less accurately we can determine the other. This essentially means that reality at the quantum level is uncertain at any instant. Even more simply, reality is exactly what we expect it to be.
Another fascinating phenomenon is quantum entanglement. If two particles become entangled, their states remain connected regardless of the distance that separates them. This means that a change in one object will immediately affect the other, even if they are light years apart. This phenomenon, which Einstein called "spooky action at a distance", was later confirmed experimentally.
Quantum physics today
Thanks to quantum mechanics, we now have a better understanding of the structure of atoms, chemical bonding and the behaviour of particles under extreme conditions. Quantum theories are used in semiconductor technology, leading to the development of transistors and computers. Quantum optics is behind the development of lasers, while quantum electrodynamics accurately describes the interactions between light and matter.
In recent years, quantum physics is moving towards the development of entirely new quantum computers that could revolutionise information processing. Quantum cryptography in turn promises unbreakable security for digital communications, an increasingly hot topic.
Fundamentally, quantum physics shows that reality as we perceive it is only an approximate interpretation of reality. At the subatomic level, our conventional logic and classical physics cease to apply. Although quantum physics remains mysterious in many ways, its conclusions have real and practical implications for our everyday lives and will shape future technologies in particular.
