The northeast monsoon swept into Beijing, carrying the bone-deep chill of the north as it scoured the somber gray-brick walls of the Institute of Theoretical Physics at the Chinese Academy of Sciences. Inside the senior researchers’ office, however, the atmosphere seemed frozen by another kind of silence. It was the silence of numbers, calculations, and mathematical models abstracted to the extreme.
Lu Chenjue stood before a tempered-glass blackboard that covered an entire wall. On its surface, complex partial differential equations and the notation of supersymmetry had been written in white chalk, interwoven like a gigantic spiderweb attempting to ensnare the universe’s truth. He had stood in that position for three hours. His thumb and forefinger loosely pinched a piece of chalk, but its tip had long since stopped touching the glass.
His research into eleven-dimensional string theory had hit a serious bottleneck. The exquisitely elegant Calabi–Yau manifolds of mathematical theory refused to remain self-consistent when placed within the boundary conditions of the early universe. Lu Chenjue himself felt that the world around him was unbearably noisy. The noise did not come from the car horns drifting in from the Fourth Ring Road, but from the chaos of meaningless information particles constantly battering the human eardrum in the digital age. He needed a moment of stillness, a stationary reference frame in which to reshape the variables in his mind.
The office door was suddenly pushed open without so much as a warning knock. Qin Zhao, an experimental physicist whose hair was perpetually disheveled from staying up late, walked in carrying a rush of cold air that filled the room.
“Chenjue, you’re still wrestling with that pile of invisible strings? I just finished the measurement series for the new particle accelerator, and the data was noisy enough to drive me insane.” As he spoke, Qin Zhao casually poured himself a cup of warm water from the purifier, his booming voice shattering the quiet. “Oh, and do you know about the new librarian at the Ancient Texts Library? That Wei Lan guy is a real iceberg. I went over to borrow some of the Institute’s early experimental notebooks, and he guarded them like they were the national treasury, giving me only half a glance. I called him Little Wei, and he icily corrected me: ‘Professor Qin, please show some self-respect.’ It was absolutely hilarious!”
Lu Chenjue frowned slightly and placed the chalk in its tray. He had no interest in this kind of disruptive small talk, much less any desire to let his brainpower be drained by the low-frequency oscillations of a colleague and friend. He put on his ash-gray overcoat and carefully adjusted the collar.
“I’m going out for a while,” Lu Chenjue said blandly, his low voice carrying the distinctive chill of someone who had spent years alone in a world of pure thought.
“Huh? Where are you going? The staff briefing is about to start!” Qin Zhao called after him, but Lu Chenjue’s tall, lean figure had already disappeared behind the half-closed door.
To escape Qin Zhao’s relentless noise and the unsorted experimental data, Lu Chenjue strode across the Institute’s grounds, shaded by gingko trees that had shed nearly all their leaves. He was headed for the old library building at the southwest corner of the campus. It was an architectural work blending classical Chinese design with the red brick of the nation’s early founding period, and it housed tens of thousands of handwritten manuscripts, ancient texts, and precious historical scientific documents. Unlike the modern electronic library, perpetually lit by fluorescent lights and filled with the clatter of keyboards, this place was immersed year-round in warm golden light and absolute silence.
As he passed through the heavy wooden door, a distinctive scent immediately enveloped Lu Chenjue’s senses. It was a blend of the naturally decomposing cellulose of centuries-old pages and the faint fragrance of incense—pure and delicate, never heavy. The air here seemed denser than outside, making every human movement slower and more cautious.
Lu Chenjue went deeper into the ancient-book stacks on the second floor. Tall mahogany shelves reached the ceiling, arranged in perfectly straight rows like fortress walls guarding the knowledge of the past. The late-afternoon sunlight streamed through small glass panes, illuminating dust motes suspended in the air and forming sparkling shafts of light like the trajectories of elementary particles moving through an invisible field.
It was at the secluded end of the twelfth row, beside a hexagonal window in the style of Jiangnan, that Lu Chenjue stopped.
An elegant figure sat with their back to him at a long wooden table. They wore a pale-blue sweater, and soft black hair fell slightly forward, veiling part of a refined profile. Their long, slender, pale fingers gently turned the pages of an ancient thread-bound book, their movements tender as though touching the most fragile thing in the world. The setting sun traced a soft halo around their shoulders and hair, giving the entire scene a lonely, distant beauty, like an ink-wash painting rendered in the finest brushstrokes.
Lu Chenjue was not easily swayed by his surroundings, but the moment he saw that back, his heartbeat skipped ever so slightly, like an electron leaping from one orbit to another under the excitation of an unfamiliar photon.
He approached quietly, careful not to make a sound on the wooden floor. As the distance narrowed, he could clearly see the title of the ancient book lying open. It was a collection of ci poetry by Su Shi, one of the great literary masters of the Song dynasty. On the yellowing xuan paper, lines of bold running-script calligraphy written in black ink stood out clearly.
The person seated there seemed to sense another presence. They tilted their head slightly, and clear eyes like the waters of an autumn lake lifted to meet Lu Chenjue’s gaze. It was a face steeped in the refinement of a scholarly family, possessing both the warmth of jade and a sharpness hidden beneath long lashes.
Shen Shuhe was slightly surprised to see a stranger appear in this remote corner of the old library, especially someone carrying a cold, keen aura as sharp as a scalpel from modern science. But he quickly regained his composure and gave a slight nod in minimal polite acknowledgment.
Lu Chenjue did not take his eyes off the ancient book. His voice was quiet yet clear in the stillness. “Are you studying the translation or the annotated edition of this work?”
Shen Shuhe closed the book halfway, keeping one finger between the pages as a marker. He looked up at the tall man before him and noticed the dark-blue staff badge from the Institute of Theoretical Physics pinned to the other man’s overcoat.
“I’m collating variant annotations for the ci section by Su Dongpo,” Shen Shuhe replied mildly, his voice as graceful as the sound of stone chimes striking one another. “I’m Shen Shuhe, a researcher at the Institute of Literature. Is Professor Lu interested in ancient poetry as well?”
Lu Chenjue pulled out the wooden chair opposite him and sat down politely, while still maintaining a clear social distance. His sharp gaze seemed intent on dissecting every layer of the other man’s structure.
“I don’t study poetry,” Lu Chenjue replied flatly. “I happened to see the page you had open. In this ‘Prelude to Water Melody,’ several lines describing natural phenomena look highly absurd from the perspective of modern physics.”
Shen Shuhe smiled faintly, his smile as gentle as a breeze passing over a lake, yet it did not yield before the intellectual provocation in the physicist’s coldness. He opened the book fully and pointed to the line: “People have sorrow and joy, they meet and part again; the moon is dim or bright, waxes or wanes—these things have long been hard to make perfect.”
“Are you referring to the moon’s waxing and waning, Professor Lu?” Shen Shuhe asked, a glimmer of interest shining directly into Lu Chenjue’s eyes.
“That’s right.” Lu Chenjue leaned forward slightly, tapping his finger against the wooden tabletop in a steady rhythm. “From the perspective of celestial mechanics, the moon is an almost perfect sphere. The ‘waxing and waning’ described by Su Shi, or by any ancient poet, is in reality merely an optical illusion created by the relative positions of Earth, the moon, and the sun. It is an entirely quantitative classical system whose state can be predicted precisely down to the millisecond using gravitational equations. Attributing qualitative emotions such as ‘sorrow and joy, meeting and parting’ to a purely mechanical, cyclical physical phenomenon is an unfounded romanticization.”
Shen Shuhe showed no irritation at the physicist’s dry, somewhat ruthless analysis. Instead, he gently shook his head, his slender fingers gliding over the edge of the ancient book in a gesture of utmost elegance.
“I see it differently, Professor Lu.” Shen Shuhe looked at him, his tone still gentle but filled with a literary scholar’s confidence. “Classical Chinese literature never intended to describe the objective world independently of human beings. When Su Shi wrote that the moon waxes and wanes, he was not trying to explain the orbit of a several-million-ton rock moving through the vacuum of space. He was describing the state of the observer. Without human consciousness to recognize the beauty of moonlight, to feel the emptiness of a waning moon and the fulfillment of a full one, that moon, no matter how geometrically perfect, would only be a dead entity. Its waxing and waning exist in the reciprocal relationship between subject and object, not as a simple physical property.”
Lu Chenjue paused for a beat. The words “the observer” that Shen Shuhe had just used suddenly activated a sensitive web of associations in the physicist’s brain.
“The observer...” Lu Chenjue repeated softly. His gaze darkened, then suddenly lit up like an electric spark discharged inside a vacuum chamber. “You’re using a concept very close to quantum mechanics to explain literature, Professor Shen.”
“Oh? I’d be honored to hear a specialist’s instruction.” Shen Shuhe tilted his head slightly, expressing a serious willingness to listen.
Lu Chenjue folded his arms across his chest. His voice began to carry a rare excitement as he discussed academic matters, though his tone remained cold and rational. “In early quantum theory, particularly under the Copenhagen interpretation, a physical system does not exist in a definite state before a measurement is performed. A particle’s wave function represents a superposition of all possible states. Only when an ‘observer’ or measuring device intervenes does the wave function collapse into a single actual state. In other words, observation creates reality. Applying this logic to your argument, Su Shi’s moon, before it was seen by the poet, was merely a cloud of probable meanings. It was the human gaze, filled with emotion, that collapsed that cloud into a moon of ‘parting’ or ‘reunion.’”
After hearing this, Shen Shuhe’s eyes lit up with astonished brilliance. He gently clapped his palms together, a natural and sincere gesture of appreciation.
“What a wonderful connection!” Shen Shuhe exclaimed, his voice carrying a warmth that softened the room’s chill. “I never expected a theoretical physicist like you to find such immediate resonance between quantum mechanics and Eastern philosophical thought. The ancient Chinese understood long ago that the world was not a cold mechanical clock existing independently of us. The doctrine of Heaven-Human Unity is precisely an acknowledgment that humanity and the universe are an indivisible whole. Our observation is itself part of what creates the universe.”
“But there is a fundamental difference.” Lu Chenjue immediately offered his rebuttal, refusing to be swept away by their momentary harmony. “In physics, wave-function collapse is a random process governed by strict mathematical probabilities. We can calculate precisely the likelihood of a particle appearing at a particular location. By contrast, the ‘collapse’ in your literature depends entirely on the poet’s subjective, volatile, and unpredictable mood. If he is sad today, the waning moon is tragic; if he is happy tomorrow, that same waning moon becomes a vision of serene beauty. It is a nonlinear system without rules, impossible to verify, and therefore lacking ultimate truth.”
Shen Shuhe looked directly into Lu Chenjue’s eyes. The smile on his lips deepened, carrying a hint of intellectual teasing. “Professor Lu, your definition of ‘truth’ is far too narrow. Your mathematics uses quantification to measure the outer world, while our literature uses qualitative understanding to see into the inner world. A partial differential equation can describe the trajectory of a raindrop falling to earth, but it cannot explain why the sound of rain would make a traveler shed tears. Both are accurate descriptions of reality; they simply operate on different planes of existence. The unpredictability of the human soul is not a defect, but a fundamental property of the most complex system in the universe.”
Lu Chenjue fell silent. For the first time in his life, he had encountered someone who could counter his logical arguments with such gentleness and yet such extraordinary force. His purely mathematical way of thinking, always proud of its sharpness and immovability, had now collided with Shen Shuhe’s equally rigorous system of romantic thought. This opposition did not create rejection. Instead, it generated an invisible force of attraction, like two opposite charges continuously drawing toward each other in empty space.
He looked down at the ancient book once more, his long finger gliding over the line: “I wonder what year it is tonight in the palace above the heavens.”
“This line is interesting too,” Lu Chenjue said. His voice had softened slightly, no longer as distant as it had been at first. “Su Shi wonders what year it is tonight in the palace above the heavens. From the perspective of Einstein’s general theory of relativity, time is not an absolute quantity. Gravity can curve spacetime. If the ‘palace above the heavens’ imagined by the poet lay in a region with an extremely strong gravitational field, near a black hole, for example, time there would indeed pass far more slowly than it does on Earth. One day in heaven equaling one year among mortals is no longer a mythological legend, but a proven physical reality.”
Shen Shuhe leaned back slightly in his chair, his eyes revealing deep admiration for this unique explanation. He tapped a finger lightly against the book, his tone carrying the spiritual resonance that was gradually taking shape between them.
“So poets and physicists arrive at the same stopping point on the boundary of imagination.” Shen Shuhe’s eyes reflected the sunset slowly fading beyond the window. “Su Shi used timeless emotional intuition to touch upon the dilation of time, while you use mathematical equations to prove it. But in the end, both of you are trying to free humanity from the limitations of this small, finite mortal existence.”
The atmosphere between them had completely changed. Lu Chenjue’s initial coldness had been partially melted by the warmth of the incense and Shen Shuhe’s erudition. They sat facing each other in a quiet corner of the ancient library, surrounded by tens of thousands of books bearing the breath of history, while their conversation built a bridge between humanity’s ancient past and its quantum future.
Lu Chenjue glanced at his wristwatch. Time seemed to have passed strangely faster than usual since he entered this place.