The centenary of quantum mechanics：from microscopic quantum structures to macroscopic quantum effects

The critical theme of development in theoretical physics in the 20th century was quantization. It also serves as the intersection hub of“vertical hierarchical leap”and “horizontal paradigm evolution”in physics. In the vertical dimension, quantization is a basic tool for crossing the components of material levels and deconstructing physical laws. The quantization of many-body systems breaks the singular paradigm of reductionism, and focuses on the macroscopic behavior resulting from the accumulation of quantum effects. In the horizontal dimension, it promotes the paradigm revolution of physics from classical determinism to quantum probability theory, establishing the microscopic origin of randomness in nature. From the perspective of the logic of scientific development, quantum mechanics has passed through three quantization stages over the past century since its birth. The first stage (1925 to the late 1920s) quantized the degrees of freedom of single particles into non-commuting operators, laying the basic framework of quantum mechanics. The second stage (1930s to 1970s) extended quantization to many-body systems and light fields, establishing quantum field theory combined with relativity. It explained macroscopic quantum phenomena such as superconductivity and superfluidity, and introduced the concepts of order parameter and spontaneous symmetry breaking. The third stage (after the 1980s) realized the re-quantization of macroscopic order parameters, demonstrating quantum coherence effects at the macroscopic scale and spawning new fields such as superconducting quantum computing. It can be said that quantization has not only expanded human understanding of the world but also reshaped the foundation of modern technological civilization. Currently, it is supporting the accelerated evolution of numerous hightech systems.