Ajeet Kumar
- Jan 13
- 6 min read

Quantum Physics

The most fundamental level in the study of matter and energy is quantum physics. It tries to learn more about the characteristics and actions of the very elements that make up nature.

The fundamental knowledge of materials, chemistry, biology, and astronomy now includes quantum insights. These findings have been a great source of innovation, leading to the development of gadgets like transistors and lasers as well as significant advancements in fields like quantum computing that were previously seen as entirely theoretical. The potential of quantum research to alter our understanding of gravity and its relationship to space and time is being investigated by physicists.

Quantum Mechanics

Quantum mechanics is a branch of physics that defines the behavior of particles, including atoms, electrons, photons, and nearly all molecules and sub-molecules. It serves as the theoretical cornerstone for all branches of quantum physics: quantum information science, quantum technology, quantum field theory, and quantum chemistry. The behavior of matter and radiation on an atomic scale is frequently strange, and the implications of quantum theory are so complex that require a deep understanding.

Fundamentally, radiation and matter are both made up of particles and waves. The progressive discovery by scientists of the particle-like characteristics of radiation and the wave-like characteristics of matter served as the catalyst for the creation of quantum mechanics.

History of Quantum Mechanics

According to the University of St. Andrews in Scotland, quantum mechanics has first proposed as a collection of contentious mathematical explanations for phenomena that the mathematics of classical mechanics were unable to explain. It began at the beginning of the 20th century, at the time Albert Einstein published his theory of relativity, a different revolution in physics that explains the motion of objects moving quickly. Quantum mechanics cannot be traced back to a single researcher. Instead, numerous scientists contributed to a foundation that, between the late 1800s and 1930, gradually acquired recognition and experimental proof.

Planck and Quanta

German theoretical physicist, Max Planck. He is commonly referred to as the father of quantum theory. In order to calculate the frequencies of light energy radiated from a heated object, Planck developed a new mathematical formula. It demonstrated how hot things would emit reddish frequencies. The frequencies of all visible colors would be emitted by hotter objects, giving them the appearance of glowing white. The most crucial prediction of Planck’s formula was that no ultraviolet frequencies would be released.

Planck’s original theory was that hot objects could only emit energy in discrete “packets” or tiny units at the subatomic scale (a single quantum is called a quantum). A quantum’s energy content increased with frequency, according to Planck. Lower frequencies, like red light, have less energy than higher frequencies, such as those in white light.

Bohr Model and Electron Orbitals

The popularity of quantum theory was rising. However, it remained merely a mathematical justification for some odd observations. Niels Bohr (Danish physicist) was the first to explain why energy exists in distinct packets. He presented a brand-new theory concerning the atom’s structure.

Bohr Model and Electron Orbitals- Abhiexo

Prior to Bohr, scientists believed that an atom was composed of a positively charged nucleus with negatively charged electrons revolving around it. However, Bohr completely altered this theory. According to him, those electrons had to follow one of a number of predetermined pathways. These paths resembled the orbits of planets around the Sun, and they were known as electron orbitals to him. There is a specific energy level for each orbital.

An electron “jumps” from one orbital to the next largest orbital when it takes in enough energy. Energy is released when an electron “falls” into the next lowest orbital. The energy differential between the two orbitals is exactly reflected in the amount of energy released. This is why energy doesn’t exist on a continuous scale; instead, it exists in discrete values known as “quanta.”

Einstein and Photons

Even before Bohr, the photoelectric effect problem was resolved with the aid of quantum theory. This is the finding that illuminating a metal surface can cause electrons to fly off the metal.

A larger amplitude led to more electrons ejecting when metal was exposed to light. Moreover, electrons are ejected with greater energy in response to higher-frequency light. The renowned German physicist, Albert Einstein, had a theory. He used the quantum theory of Planck to explain light. He proposed the idea that light can occasionally act as discrete electromagnetic energy packets. He gave these bundles the name photons.

In summary, Planck saw electromagnetic radiation coming from the heated objects’ electrons as the quantized energy. In contrast, the electrons in the metal received energy from Einstein’s photons. The electron would exit its orbital and completely leave the metal if the photon energy was high enough. In this way, Bohr’s electron orbitals gave quantum mechanics a theoretical justification.

The following fundamental Ideas also contributed to laying the groundwork for quantum physics:

Wave-particle Duality

This idea has been around since the early days of quantum research. According to how they were measured, light and matter had the characteristics of either particles or waves, as evidenced by the results of the tests that led to this conclusion. The double-slit experiment is the most famous example of this, in which particles like electrons are fired at a board with two slits cut into it; behind the board, a screen is placed that illuminates when an electron strikes it.

Entanglement

Quantum physics and upcoming quantum technologies are based on entanglement. Entanglement is a phenomenon that manifests at extremely small, subatomic scales, just like other parts of quantum science. When two or more items are connected in a way that allows them to be thought of as a unified system, even when they are extremely far apart, this phenomenon takes place.

Uncertainty Principle

This mathematical idea illustrates the trade-off between opposing viewpoints. This indicates that two attributes of an object, such as its position, and velocity, cannot be accurately understood at the same time in terms of physics. We will only be able to determine an electron’s speed to a certain degree if we properly measure its position.

Superposition

This refers to characterizing an object as a composite of several potential states existing simultaneously. In mathematical terms, superposition can be thought of as an equation that has several solutions.

The Probabilistic Nature of Quantum Objects and Mathematics

As quantum phenomena are probabilistic, maths is also required to represent them. For instance, it might not be possible to precisely pinpoint an electron’s position. Instead, it may be said to be in a variety of potential positions, each of which has a chance of containing an electron, such as within an orbital.

Mathematics is crucial to the study of quantum physics because many of its ideas are difficult, if not impossible, for us to visualize. Equations are utilized to describe or predict quantum objects and occurrences that human imaginations are capable of.

Where to start quantum mechanics? Start with Quantum Basics:

The classical intuition that serves us well in the macroscopic world but is utterly useless in the quantum realm must be ignored and unplugged in order to comprehend it. Let’s start by removing the outer layers of our traditional intuition.

Schrödinger’s Cat in a Box

In this fictitious experiment, a cat is placed in a box containing equipment that, when it detects beta particles released by a radioactive source, discharges a toxic gas.

It serves as one example of the way that quantum mechanics compels us to think. A particle exists simultaneously in every position up until it is measured, exactly like a cat that is both dead and alive.

De Broglie Wave

De Broglie waves, often known as matter waves, are any aspects of a material object’s behavior or attributes that change over time or space in accordance with the mathematical equations used to explain waves.

The concept of matter waves with wavelengths inversely proportional to particle momentum was proposed by French scientist Louis de Broglie in 1924. He claimed that each particle has its own set of matter waves, each of which has a certain wavelength.

In quantum mechanics, any particle’s wave function is a matter wave, whose shape can be calculated using the Schrödinger equation. As a result, the most significant aspect of quantum mechanics is matter waves.

Wave function Encoded Particle Information

Since the particle is a wave, its position in space is dispersed. The wavefunction, which is calculated in quantum mechanics using the Schrodinger equation, contains all of the information about particles. The probability distribution for position, momentum, spin or any other observable quantity can be described using particle wavefunctions.

Heisenberg's Uncertainty Principle

The uncertainty principle, which was developed by German physicist and Nobel laureate Werner Heisenberg in 1927, states that we cannot know a particle’s position and speed with perfect accuracy. The more precisely we can determine a particle’s position, the less we know about that particle’s speed, and vice versa.

In general, the uncertainty principle can be applied to any complementary pair of dual physical values that cannot be determined with arbitrary precision.

When first trying to understand the fundamentals of quantum mechanics, you may notice that your brain will explode at any moment. However, when you go more into the complexity and nuances of equations and observe how they apply in real life, the interest grows and reveals beauty at its most basic levels.