We often find ourselves in quiet moments of reflection, contemplating our surroundings and the essence of reality. During these times, everyday objects lose their mundanity, prompting us to seek a deeper understanding. What constitutes the air we inhale, and what is the nature of the space we occupy?

The answer lies in molecules, atoms, and subatomic particles, of course.

While some may see this as a bleak portrayal of existence—viewing the beautiful rays of sunlight merely as photons with specific energy and frequency—I find it to be a profound aspect of reality. The realization that things are not as they seem, and that our perceptions can be radically different, adds layers of excitement and intrigue.

Yet, amidst this exploration, we confront a significant enigma: What constitutes the fundamental particles? What is the essence of quarks, the building blocks of protons and neutrons? How do they interact, and what is the origin of their mass?

What exactly is mass?

By examining the most comprehensive and successful theory of physics we possess, we may uncover many astonishing answers and unexpected consequences that speak to the very fabric of reality—a reality that, while seemingly detached, is the foundation of our existence.

This theory is Quantum Field Theory (QFT).

What exactly is QFT?

QFT is a foundational framework that merges concepts from quantum mechanics and special relativity to elucidate the behavior of subatomic particles. Its historical development is a complex narrative that spans the 20th century and remains a vibrant field of inquiry today.

The roots of QFT trace back to the dawn of quantum mechanics in the 1920s. This groundbreaking discipline adeptly described the behavior of single elementary particles with remarkable precision, setting the stage for QFT.

Its inception revolved around the realization that electrons are essentially vibrations within the electron field, and they possess a counterpart known as the positron. Envision a field that permeates the universe, encompassing all that exists. When this field vibrates, it brings particles into being. Thus, electrons emerge from the oscillations of the electron field, just as excitations in the electromagnetic field generate photons.

The connection between electrons and photons is crucial, as photons serve as the bosonic messengers that facilitate interactions between electrons and other charged particles.

In due course, through the contributions of James Clerk Maxwell, the electric and magnetic fields were unified into a singular framework: the electromagnetic force.

Describing the interactions of electrons and photons within the framework of QFT led to the development of Quantum Electrodynamics (QED), a field mastered by luminaries such as Dirac and Feynman.

There were challenges along the way, with the mathematics yielding infinities and nonsensical results—clear indicators of underlying issues. However, the renormalization process resolved these anomalies.

The elegance and precision with which QFT unified and described this fundamental force marked a pivotal moment in the field of physics.

Yet, this quest for unification was far from over.

The Electroweak Force

The next target for QFT was the Weak Force, which governs the radioactive decay of atoms. Researchers soon discovered that, akin to the electromagnetic force, the weak force also relied on bosonic messenger particles. However, unlike the massless photon, the weak bosons—W+, W-, and Z—are massive.

How could this be possible?

An intriguing aspect of QFT is its ability to manifest particles that seem to materialize from nowhere—known as virtual particles. This is particularly relevant to the W and Z bosons, which are generated as virtual particles, borrowing a vast amount of energy from their respective quantum fields to come into existence.

There is a trade-off, of course: the more energy a particle borrows, the shorter its lifespan as a tangible entity. Consequently, weak bosons have exceedingly brief lifetimes, limiting their influence to the minuscule realm of the atomic nucleus.

Through the lens of QFT, yet another fundamental force was elucidated as mere excitations within various interacting fields. But could this unification extend even further?

Revisiting the universe's early moments—a time when it was denser and hotter—reveals something extraordinary. The primordial conditions just prior to the quark epoch, characterized by unimaginably high temperatures, lead to a fusion of the electromagnetic and weak forces, revealing them to be two aspects of a single entity.

Thus, after merging electricity and magnetism, QFT now succeeds in unifying another pair of forces.

The Strong Force

Could the strong force achieve similar unification? Indeed, it did.

The identification of gluons and mesons unveiled the messenger particles of the strong force. Once again, excitations within their respective fields give rise to them (noting that mesons are not elementary) and reveal a wealth of new fundamental characteristics.

Examining the interactions among quarks, one immediately encounters a conundrum: they appeared to violate Pauli’s Exclusion Principle.

Such a foundational tenet of physics could not be disregarded, particularly not by fermions, indicating that something else was at play. In fact, something was hidden in plain sight: beyond positive and negative electric charges, quarks were found to possess color charge, with three distinct color charges and their corresponding anti-color counterparts. This revelation resolved the issue and upheld Pauli’s Principle.

Again, all interacting particles could be described as vibrations of a multitude of quantum fields.

Gluons—much like the W and Z bosons—borrow significant energy from their fields and burst into existence. Similar to their weak counterparts, the more energy they borrow, the sooner they must repay their energy debt. As a result, the range of the strong force is even shorter, yet its strength far surpasses that of the weak force.

Can the strong force be unified with the other forces?

Yes, it can. By looking back to the extreme conditions of pressure and temperature in the early universe, this unification occurs. The strong nuclear force merges with the electroweak force to form a singular, all-encompassing force.

Another triumph for QFT.

A Question of Mass

In 2012, the Large Hadron Collider (LHC) finally concluded a decades-long search. That year marked the confirmation of the elusive Higgs boson, which had remained purely theoretical until then.

This confirmation also affirmed the existence of the Higgs field, as predicted by QFT. The Higgs boson emerges as an excitation of the Higgs field. Like all phenomena predicted by this theory, it revolves around fields.

This discovery elucidated why particles possess the mass they do: it is their interaction with the Higgs field and Higgs bosons that manifests what we recognize as mass.

However, another aspect of mass presents a profound challenge to our understanding. One facet that twists our perception of reality and prompts us to reevaluate what is real.

The vast majority of an atom's mass resides within its nucleus. Protons and neutrons (and thus quarks) account for approximately 99% of an atom's mass. The strangeness arises when we realize that most of a quark's mass does not originate from the quark itself but from the messenger particles of the strong and weak nuclear forces.

Remember, these are virtual particles, emerging randomly by borrowing energy from their respective fields. Consequently, the majority of the mass in our universe derives from an elusive source—particles that flicker in and out of existence, following a pattern that remains elusive to us.

The fundamental aspects of our universe rest upon fleeting, phantom particles that seemingly appear out of nowhere.

A Sea of Fields

Quantum Field Theory represents an extraordinary and beautiful achievement of humanity. The capacity of the human mind to understand reality at such a profound level is truly astonishing.

The picture it paints of the universe is hauntingly elegant: everything we perceive is merely a vast expanse of fields interacting through excitations. Fields stretching as far as our eyes—composed of fields themselves—can see!

Currently, there are 17 known fields in our version of the Standard Model: 12 matter fields, 4 force fields, and 1 Higgs field.

The only aspect still unaccounted for is gravity.

Gravity presents a challenge. It manifests as the geometry of spacetime. Is it truly a force?

If we can quantize gravity and identify a particle responsible for its transmission (a unit of quantized spacetime), we will complete the integration of gravity with the standard model.

Until then, we will continue our pursuit. Loop Quantum Gravity and String Theory have produced remarkable results in their quest for a quantum theory of gravity, each with radically different interpretations of what gravity should entail. However, neither has yet proposed testable hypotheses, remaining in the theoretical realm.

This is our ultimate endeavor, the final step toward achieving a long-sought Theory of Everything (TOE).

Here, I present an 80-minute video filled with wonder from an incredible channel. It explores this journey with captivating visuals. I assure you, it will be time well spent!

Thank you for reading. I hope you found this exploration as enlightening as I did!

Keg

If you’re interested in exploring my other works, I would be grateful!