The Sun’s Impossible Light

Before we start we must know the difference between the siblings that are quantum physics and quantum mechanics. As the organization QED‑C stated, “Quantum physics is the science of how the universe behaves at the smallest scales—think atoms, electrons, and photons (particles of light) and the coldest temperatures.” (QED‑C)

Caltech has also given a definition to quantum physics saying,“Quantum physics is the study of matter and energy at the most fundamental level. It aims to uncover the properties and behaviors of the very building blocks of nature.” (Caltech)

Quantum mechanics shares many similarities with quantum physics, however quantum mechanics is known to be more mathematical. Quantum mechanics is the field of physics that explains how extremely small objects simultaneously have the characteristics of both particles such as electrons and waves (a disturbance or variation that transfers energy). ( U.S. Department of Energy)

Quantum mechanics is the fundamental theory that sets a base for all of quantum physics, including quantum chemistry and emerging quantum technologies. ( Quantum Physics Lady )

In conclusion, Quantum mechanics, in essence, provides the mathematical framework and rules that govern the evolution and measurement of microscopic systems, while quantum physics refers more broadly to the phenomena, experiments, and applications that arise from those rules. (Britannica/New Scientist style descriptions)

The measurement problem asks why the smooth wave behavior of tiny particles seems to turn into a definite (exact) result only when we measure them, and scientists are still debating the answer, some have made theories but no idea is widely agreed upon. (Norton)

Standard quantum mechanics says that when you measure a quantum system, its multiple possible states instantly "collapse" into one definite state — but it doesn't define what constitutes a "measurement."

This leads to a bizarre possibility: one observer might see a quantum coin toss come up heads, while another might find it came up tails.(Horgan)

Attempts to avoid the measurement problem, like foreseeing a reality where quantum states never collapse have led physicists into strange terrain where measurement outcomes can be subjective.

Researchers at Oxford and ETH Zurich proved a theorem showing why certain theories have a measurement problem and how one might build alternatives that preserve "absoluteness of observed events.”

Theories have been made that try to “solve” the measurement problem. These consist of:

There is one key result through any BIL theory: The predictions of any BIL theory for measurement outcomes contradict the absoluteness of observed events — meaning all BIL theories themselves have a measurement problem. No one yet knows how to construct a theory that rejects dynamical separability while preserving the other BIL properties. (Horgan)

"Irrespective of one's personal view on which theory is better, all of them have to be explored." — Venkatesh

In quantum physics a particle can change in two ways. First, it spreads out like a wave that follows (Schrödinger’s smooth “wave‑evolution” rule), which works when the particle is left alone or only bumps into a few other particles, as seen in the two‑slit experiment. (Norton)

The double‑slit (two-slit) experiment demonstrates that particles such as photons and electrons behave both as waves and as particles. When a stream of particles passes through two closely spaced slits, patterns of bright and dark spots form bands rather than two simple clusters, showing that each particle traverses both slits simultaneously and interferes with itself. (Double-slit Experiment. Brilliant.org).

Light acts as a wave by bending around obstacles and creating interference patterns, such as the bright spot in the center of a shadow (Las Cumbres Observatory). Light behaves primarily as a wave but also as tiny packets of energy called photons, each carrying a specific amount of energy that increases as wavelength shortens (red photons have less energy than blue ones). (“Las Cumbres Observatory”).

Early experiments on the photoelectric effect showed that metals emit electrons when illuminated, but the number of emitted electrons depends on the light’s wavelength (color) rather than its brightness. (“Las Cumbres Observatory”). Short‑wavelength (blue or ultraviolet) light emits more electrons than long‑wavelength (red or infrared) light, and increasing intensity only raises the number of electrons emited, not the speed of emission. (“Las Cumbres Observatory”).

Quantum superposition is the idea that particles—like electrons and protons—don't just exist in one state, but in all possible states at once, until we measure them. An example of an observable display of this wouldbe a spinning coin: while it's spinning, it’s both heads and tails simultaneously. It only "chooses" a side when it stops. (Caltech: “What Is Superposition and Why Is It Important?”)

In mathematical terms, superposition can be thought of as an equation that has more than one solution. When we solve x²=4, x can either be 2 or –2. Both answers are correct. While this is a display of the concept of superposition, math example ( x²=4) implies a 50/50 split. However, in reality, superposition can be "weighted", a particle might be 70% likely to be in one state and 30% in another. Other Quantum equations are more difficult to solve, but they can be approached with the same type of mindset. (Caltech: “What Is Superposition and Why Is It Important?”)

“Many experiments have been conducted that definitively prove the existence of superposition. One example recruits the help of light filters: screens that selectively block light, such as those found in polarized sunglasses or camera lenses.Most of the light we see around us is a combination of many different waves coming from the sun and other sources. The peaks and valleys of these waves are rotated in different directions at once. In other words, the light is in a superposition of these different polarized states.” (Caltech: “What Is Superposition and Why Is It Important?”)

Superpsotion is what allows for the creation of quantum computers. Quantum computers process extreme amounts of data simultaneously, solving complex problems far beyond the reach of traditional computers.

Quantum mechanics explains that systems are described by a wavefunction. A wave fuctions is simply a catolof of all possible states that a system could be in, in addition it describes how these systems can interfere with each other. The wavefunction is a precise equation with no shifts or sudan jumps. It has no randomness in the math. In textbook quantum mechanics, a primary rule is: when you measure the wavefunction itself, it suddenly collapses from superposition (many possibilities at once) into one real outcome. (Norton)

The concept of many worlds is that we don’t add that collapse rule at all; we need to trust the original equation, even if measurements and observers are involved. “Everett believed that there was no reason to restrict the domain of quantum mechanics to only small, unobserved systems. Instead, Everett proposed that any system, even the system of the entire universe, could be encompassed in a single, albeit often intractable, ‘universal wave function.’” (Hubinger).

Imagine an electron that can be spin‑up or spin‑down. Before you measure, its wavefunction might be a superposition: “up + down” (with certain weights). When you measure, you (the measuring device, your brain, etc.) become entangled with the electron: One part of the total wavefunction describes: electron up + you seeing “up”. Another part describes: electron down + you seeing “down”. The key point in many‑worlds is: both parts remain in the total wavefunction. There is no single “collapse” that destroys one and keeps the other; the full quantum state just branches into non‑interacting sections. In essence, the many worlds theory suggests that with every decision you make, a new universe springs into existence containing a new version of you. (Carroll).

In quantum mechanics, A “world” is not a separate universe floating in a distant place; it is one branch of the universal wavefunction. As previously proposed, in one branch, the electron is up, the detector reads “up,” your memory records “I saw up,” and all records are consistent with that. In another branch, all of the above are “down.” These branches very quickly become effectively independent because of decoherence. “Decoherence is the process through which quantum superpositions of different states in a macroscopic system are effectively lost because the different states become entangled with the environment. In the many-worlds interpretation, this is what makes the different branches effectively independent of one another.(Bacciagaluppi).

So you can think of a “world” as a stable, decohered branch of the universal state that looks like a classical world with definite outcomes. From the “outside” (in the math), both branches exist. From the “inside” (your subjective experience), you are only aware of the version of you in one branch: the one that saw “up,” or the one that saw “down.” You don’t feel yourself splitting or notice other copies, because: Once branches decohere, they cannot communicate or interfere in any practically observable way, each version of you has a single, perfectly consistent memory and environment that tells just one story.