Post on 2024/6/9

By Emily Xu

The “Three-Body Problem” is a groundbreaking novel composed by Liu Cixin, notably known as the recipient of the Hugo Award. The three novels in the series revolve around the frontiers of science’s contacts with an alien civilization, the Trisolarans. The trilogy explores profound questions regarding the human race as it delves into thought-provoking questions about the fate of our universe. Adding on to the wealth of philosophical questions, the science fiction series also includes a cornucopia of physics concepts; in fact, the base of the novel sets ground within the laws of physics. In addition to classical physics, the novel also explores concepts including quantum mechanics and general relativity.

Quantum-related topics are mentioned many times in the "Three Body" trilogy: Sophon directly involves quantum communication, and the first reference to quantum mechanics in "Three Body I" is Sophon's voyage:

The Science Archon said: "Führer, Sophons 1 and 2 will fly to the earth. Relying on the huge knowledge base stored in microscopic circuits, Sophons have a good understanding of the nature of space. They can draw energy from the vacuum and travel in extremely short periods of time. It turns into a high-energy particle within a short period of time, traveling at a speed close to the speed of light. This seems to violate the law of conservation of energy. The sophon 'borrows' energy from the vacuum structure, but the return is far away, and it will have to wait until the proton decays, and at that time. The end of the universe is not far away.”

Is it scientifically possible for sophons to borrow energy from a vacuum to accelerate?

From classical mechanics, the law of conservation of energy states the total energy of an isolated system remains constant over time. However, this law is accompanied by prerequisites in the lens of quantum mechanics. One of them requires time of measurement to approach infinity. In other words, as two particles collide, the energy will only be conserved if we measure the energy of both particles for a prolonged length of time before and after the collision, and the time is approximately infinite. Though the energy of each individual particle may not be conserved, the system as a whole ( two particles) does not change.

In high-energy particle collisions, new situations arise: particles after the collision may be entirely distinct from particles before the collision. To illustrate, a collision between a positron and an electron can result in two photons. Yet, even in these situations, energy will still be conserved.

Heisenberg’s uncertainty principle of quantum mechanics informs us that the shorter our measurement time is, the greater the disparity between energies before and after the collision. Thus, Liu Cixin’s sophon in the “Three Body Problem” most likely used this uncertainty principle as a means of borrowing energy from the vacuum.

Sophons in the “Three Body Problem” are used by the Trisolarans as a means of hindering the development of theoretical physics in the human civilization. This is done as sophons can travel through physical sensors to trigger and generate false data from particle accelerators. This halts the human’s abilities of improving their level of understanding of theoretical physics; and ultimately, this obstructs the human civilization from the very construction Sophons themselves. The Sophon contain the ability of traveling at relavistic speeds close to light while keeping a self-sustained energy manner where they can travel across from the alien civilizations and back to Earth.

Sophons are just one instance where quantum mechanics are involved in the science fiction series. The novels also delve into a plethora of physics concepts including relativity, black holes, wave-particle duality, quarks, and quantum entanglement.