Chapter 3-6 Quantum Tunneling
Understanding Quantum Entanglement and its "instantaneous arrival" characteristic makes it easier to grasp the occurrence of "Quantum Tunneling".
The "Quantum Tunneling Effect" was first discovered by the Curie couple while studying the radioactivity of polonium and radium. Quantum tunneling refers to the phenomenon where microscopic particles can pass through "walls" they would normally be unable to penetrate, also known as "Barrier Penetration".
The Tunneling Effect cannot be explained by classical mechanics. We can imagine the "barrier" as a mountain. A microscopic particle with energy less than the potential energy of the mountain peak is on the left side of the mountain. According to "classical world" experience, due to the influence of "negative kinetic energy", this particle would absolutely not be able to climb to the right side of the mountain. To use a more straightforward analogy, suppose someone is using a test pencil to measure current. One can consider that electrons are free within the metal of the screwdriver, but the insulation layer acts as a barrier. Because of its presence, electrons cannot conduct to the human body no matter what.
Similarly, in the real world, if you want to climb over a high wall, it is impossible without overcoming gravity and having enough kinetic energy; otherwise, either you or the wall must break first. However, the quantum world is peculiar and does not follow conventional rules (Figure 3.13). Even if the height of the "barrier" is far greater than the particle's total energy, there is a certain probability that the microscopic particle can "tunnel through" the mountain effortlessly and instantaneously, as if it traversed a virtual tunnel without actually overcoming the obstacle of the "wall".
Figure 3.13: Schematic of Quantum Tunneling Effect
The "Quantum Tunneling Effect" easily reminds us of the "ability to pass through walls" seen in "Harry Potter", "The Journey to the West", as well as the "vanishing acts" often seen in magic shows. It may seem like pure fantasy, but could such phenomena occur in the macroscopic world? If there really are negative matter or "spiritual entities", can these "souls", "immortals", or "ghosts" pass through wall?
One outlandish theory suggests that in the quantum world, objects do not need enough potential energy to traverse obstacles because obstacles themselves are made of quanta, and there are invisible gaps between quanta (as mentioned earlier, fundamental particles themselves are "empty"). As long as these gaps are navigated, one can pass through obstacles. Such speculative ideas, however, cannot be verified.
Quantum properties, however, can be utilized in cutting-edge science, such as in superconductivity and biomedical fields. As early as the mid-20th century, physicist Erwin Schrödinger proposed in his book "What is Life? The Physical Aspect of the Living Cell" that quantum mechanics could play a role in biological systems.
