Summary of Key Points
A new paper by two MIT scholars proposes that quantum behavior can be precisely calculated using only the “principle of minimum action” from classical physics, without the need for Feynman path integrals. This does not overthrow existing quantum theories but offers an equivalent mathematical description, establishing a new bridge between classical and quantum mechanics. However, the media has widely misunderstood the findings (for example, claiming that “quantum phenomena are no longer mysterious”), when in fact the paper still relies on the principles of uncertainty and wave-particle duality. The paper has sparked discussions and academic skepticism regarding the interpretation of quantum mechanics.
1. What’s wrong with the media’s “AI-like” coverage?
Many media outlets have sensationalized the paper as suggesting that quantum phenomena are no longer mysterious or that physicists were overthinking the issue, which is completely misleading. The paper clearly states at the beginning that the position and momentum of a particle cannot be determined simultaneously (Heisenberg’s uncertainty principle), and wave-particle duality is a fundamental premise of the discussion—indeed, the title itself (“Quantum Waves”) emphasizes this concept. The authors repeatedly emphasize that they are not rejecting quantum theory but merely providing it with a different mathematical formulation, similar to expressing the same idea in Chinese and English. The media’s exaggeration has left professionals baffled and confused the general public about the true significance of the research.
2. A “new bridge” between classical and quantum mechanics: The multi-valued “action mountain”
In classical physics, the principle of minimum action dictates that particles follow the path that requires the least effort (e.g., the parabolic trajectory of a projectile). The corresponding Hamiltonian function can be thought of as a “mountain,” where the elevation at each point represents the total amount of energy the particle has traveled from its starting point. The slope of the mountain corresponds to the particle’s momentum.
In quantum mechanics, the phase of the wave function is directly related to the particle’s energy. While there were always differences between classical and quantum equations, the MIT scholars discovered that if the Hamiltonian function is allowed to have multiple values (i.e., it represents multiple possible paths with different energies), and the coefficients of the wave function are only valid for these extreme paths, those discrepancies disappear! This suggests that the principles of classical and quantum mechanics are actually consistent; it’s just that the possibility of multiple energy levels was not previously considered.
3. The impact on existing quantum tools: Feynman path integrals and Bohmian mechanics
- Feynman path integrals: Feynman proposed that particles have countless “avatars” that travel all possible paths, with the final outcome being determined by interference. The paper argues that these are redundant theoretical elements; particles actually only follow extreme paths, and Feynman’s approach is still a useful tool for solving complex problems (such as particle scattering) and will not be phased out in the near future.
- Bohmian mechanics: This theory relies on a “quantum potential” to explain quantum phenomena, but the paper shows that this concept is based on a misunderstanding of the multi-valued nature of energy. This further undermines the already marginalized status of Bohmian mechanics, although the paper itself contains elements suggestive of hidden variables (although the authors avoid explicitly acknowledging this).
4. Academic skepticism: The controversy over circular reasoning
Scholars from the University of Budapest have criticized the paper for assuming that coefficients are only valid for extreme paths and then concluding that particles always follow these paths—a form of circular reasoning. While the authors have not responded, this criticism undermines the general validity of the findings, as the results only hold true for specific quantum states and cannot be generalized.
5. The mystery of quantum interpretation: Copenhagen or hidden variables?
The authors claim to support the Copenhagen interpretation (where measurements are random because the outcome depends on the probability distribution of the wave function). However, those who truly understand quantum mechanics either lack a clear stance or are reluctant to express their true opinions. The paper’s use of multi-valued energy and deterministic paths actually aligns with hidden-variable theories, though the authors deliberately avoid discussing this topic.
The value of this paper lies in offering a new perspective on the relationship between classical and quantum mechanics. It encourages us to reconsider how these two fields are connected and reminds us that scientific advances often require time for verification. Excessive media interpretation can lead to confusion rather than clarity.