Page 1: 第1页 Welcome. Today, we embark on an intellectual journey into the heart of modern physics. We will explore a monumental achievement that brought the famously counter-intuitive principles of the quantum world into a realm we can see and manipulate. Let us begin. Page 2: 第2页 The Royal Swedish Academy of Sciences awarded the 2025 Nobel Prize in Physics to three scientists for a truly profound discovery. They demonstrated that two of the most bizarre quantum phenomena—tunneling and energy quantization—are not confined to the subatomic world. Their work proved these effects can occur in a macroscopic system, an object large enough to be held, fundamentally altering our understanding of the boundary between the quantum and classical realms. Page 3: 第3页 To appreciate the laureates' achievement, we must first grasp the concept of quantum tunneling. Imagine throwing a ball at a wall; it will invariably bounce back. This is the predictable world of classical physics. In the quantum world, however, a particle confronting a similar energy barrier behaves differently. It has a certain probability of simply appearing on the other side, as if it has tunneled through the wall. This phenomenon, though deeply counter-intuitive, is a cornerstone of quantum theory and explains processes like radioactive decay. The central question then became: can a large object, composed of many particles, perform this same feat? Page 4: 第4页 To observe a macroscopic quantum event, one must first construct an appropriate arena. The laureates did this by fabricating a device known as a Josephson junction. Its architecture is deceptively simple: two superconductors sandwiching a wafer-thin insulator. This insulating layer acts as the critical energy barrier. The entire system, though macroscopic by quantum standards, was engineered with exquisite precision to create the conditions under which a collective quantum phenomenon might be observed. Page 5: 第5页 Why use a superconductor? Because within it, electrons exhibit a remarkable collective behavior. They form what are known as Cooper pairs, which then move as a single, coherent entity without any electrical resistance. Think of it as a vast, perfectly synchronized orchestra where every musician plays the same note. This collective state allows the entire system of billions of electrons to be described by one wave function, effectively behaving as a single macroscopic quantum object. This "macro-particle" was the protagonist of their experiment. Page 6: 第6页 With the stage set, the experiment commenced. Initially, the circuit registered no voltage, as if a lever was stuck in the "off" position. According to classical physics, it should have remained there indefinitely. However, the researchers observed a startling phenomenon: a voltage would suddenly materialize from nothing. This was the definitive evidence they sought. The entire collective of Cooper pairs, acting as one, had performed the quantum tunneling feat. It was not a single particle, but a macroscopic system, that had passed through the wall. Page 7: 第7页 Beyond tunneling, the experiment revealed another fundamental quantum characteristic. The energy of this macroscopic system was not continuous. It could not be analogized to a ramp, but rather to a staircase. The system could only exist on specific energy steps, and nowhere in between. This is energy quantization. By exposing the circuit to microwaves, they found it would only absorb energy when the dose was just right to boost it from one step to the next. This proved that their circuit, a human-made object, possessed the quantized energy structure once thought to be the exclusive domain of atoms. Page 8: 第8页 For decades, the "Schrödinger's Cat" paradox has illustrated the conceptual chasm between the quantum and classical worlds. We do not observe cats that are simultaneously alive and dead. However, the theorist Anthony Leggett posited that under specific, isolated conditions, a macroscopic object *could* indeed sustain quantum behavior. The laureates' experiment was the physical embodiment of this very idea. They created a system that, while far simpler than a cat, was undeniably macroscopic and yet behaved according to the laws of quantum mechanics. They brought the cat out of the box and placed it onto a circuit board. Page 9: 第9页 The implications of this work extend far beyond fundamental physics. It is the bedrock of modern quantum computing. John Martinis, one of the laureates, recognized that the discrete energy levels they had discovered could serve as the '0' and '1' states of a new type of information unit—the qubit. Because the system is quantum, it can also exist in a superposition of these states. This progression, from a physical discovery to the conceptual framework of a qubit, is the genesis of the powerful quantum processors being developed today. Page 10: 第10页 In conclusion, the 2025 Nobel Prize in Physics honors an achievement that transformed our perspective. Clarke, Devoret, and Martinis used a centimeter-sized circuit to show that the strange and wonderful rules of quantum mechanics can govern a system large enough to see and hold. They took a concept as abstract as Schrödinger's cat and gave it a physical, measurable form. This journey, from a profound question of fundamental physics to the enabling technology of the future, marks a true turning point in our ability to harness the quantum world.