In this blog post, we will explore the nature of the universe, focusing on the Copenhagen interpretation and the many-worlds interpretation, which are representative interpretations of quantum mechanics.
Along with the theory of relativity, quantum mechanics is an important theory that has greatly changed the paradigm of modern science. It shattered our firm belief in Newton’s classical mechanics, which seemed to be unshakable at any time or place, and has been widely used not only in theory but also in applications, having a significant impact on technological development in our daily lives. For example, the theories of quantum mechanics form the core of modern electronic devices and semiconductor technology, which has enabled the development of devices such as smartphones, computers, and GPS. However, despite these everyday applications, quantum mechanics is still subject to various interpretations due to its elusiveness, which is contrary to human intuition, and there are still areas that cannot be fully explained, so new theories are constantly emerging.
To understand the reason for the difficulty of quantum mechanics and the various interpretations that have emerged, it is first necessary to understand the meaning of “interpretation of formulas” in physics. In physics, mathematics is used as a language to describe phenomena or problems because the formulas are logically consistent and coherent. The mathematical process of developing equations and functions seems perfect in itself, but the question of how to interpret them in the real world we live in causes another level of debate. Take the Schrödinger equation, a representative equation of quantum mechanics, as an example. The results obtained through this equation are expressed as “wave functions” that represent the state and energy of a substance, and very different interpretations are derived depending on what meaning is given to the results of this function.
The Copenhagen interpretation is a representative interpretation of quantum mechanics. This interpretation, which was advocated by Bohr, Heisenberg, Born, and Dirac, includes the Schrödinger equation, wave function, and uncertainty, and is based on probabilistic thinking. In other words, the position and state of the quantum are not specified, and are described as being distributed over a wide range of possibilities. This is why quantum mechanics uses a “probabilistic model” that can predict the outcome of an event, unlike the certainty that we commonly experience in everyday life. In other words, quantum mechanics can only suggest the possibility of a quantum being in a certain position, and the position is only clearly determined when the process of observation is involved. This explanation has brought about a major turning point in the interpretation of physical phenomena and has provided a very useful framework for predicting various experimental results.
Next, the Many Worlds Interpretation is another interesting interpretation of quantum mechanics. While the Copenhagen Interpretation explains the occurrence of a probabilistic event within a single world, the Many Worlds Interpretation explains that all possible events actually occur in each world. For example, if I play rock-paper-scissors with a friend, there is a world where I lose, and there is also a world where I win at the same time. The Many Worlds Interpretation has become well known to the public through the concept of parallel universes, and it is a theory that often appears in science fiction novels and films. The idea that the world diverges into multiple branches through the concept of quantum decoherence is a theory that is difficult to verify experimentally, but it has explained the properties of quantum mechanics that are counterintuitive in its own way.
Finally, the hidden variable theory claims that the uncertainty in quantum mechanics is actually due to a “hidden variable” that we do not know. In other words, the uncertainty in quantum mechanics is simply due to the fact that we do not fully understand all the variables of the phenomenon, and that all phenomena are in fact perfectly predictable. Albert Einstein supported this theory with his famous quote, “God does not throw dice.” However, in the 1960s, Bell’s inequality experiment showed that the results predicted by the hidden variable theory were not verified, and the credibility of this theory has dropped significantly. Nevertheless, this interpretation is considered to be a meaningful attempt to challenge the perfect explanation of quantum mechanics.
Although there are various interpretations of quantum mechanics, research based on the possibility of verification from a physical perspective is still needed. Since the development of science comes from verification through experiments and observations, verifiable interpretations are becoming more important. In fact, the experimental success of quantum mechanics has explained various phenomena that could not be explained by conventional physics and has laid the foundation for its application to various industrial fields. The Copenhagen interpretation is relatively highly regarded for these empirical achievements. For example, it explained why electrons maintain a specific orbital through the problem of the hydrogen atom’s orbit, and it proved the existence of particles that overcome energy barriers that cannot be explained by classical physics through the tunnel effect.
The influence of quantum mechanics on philosophy and other disciplines cannot be ignored. The multiverse interpretation has triggered philosophical discourse on topics such as parallel universes, and has influenced various theoretical studies, including string theory, providing an opportunity for the convergence of mathematics and science. Philosophers have also come to deeply ponder the meaning and nature of quantum mechanics, which has further enriched discussions on epistemology and ontology. The interpretation of quantum mechanics has crossed the boundaries between philosophy and science and has played a role in promoting the development of both.
Quantum mechanics still has many unsolved problems and various interpretations. While the Copenhagen interpretation, the mainstream theory, has strengths in terms of empirical aspects, many scientists and philosophers are still studying the many-worlds interpretation and the hidden variable theory. We hope that more experiments and theoretical reviews will shed more light on the mysteries of quantum mechanics. Ultimately, these studies will contribute to a deeper understanding of the fundamental laws of the universe, the truth that humanity seeks.
