Fate and Quantum Entanglement—Physicists Say We Have Never Truly Been Apart
Translated by AI. Read the Chinese original ↗
Contents 7 sections
First Movement: Happening Now
[The physicist says]
Entanglement requires interaction.
Before two particles become entangled, they must first have made contact. A collision, a resonance, even simply passing through the same field at the same time. It can be brief—too brief for any instrument to record.
But from that moment on, they are no longer two independent systems.
They themselves do not know this.
[The year she was fourteen]
That summer in eighth grade, she went to the city library almost every weekend. In the third row by the window was a table of light-colored wood. At three in the afternoon, sunlight fell exactly on the back of her hand.
One day she did not read. With a ballpoint pen, she carved a line into the tabletop, lightly, as though afraid someone might hear.
After November she stopped going. More schoolwork, or simply no reason to go anymore.
That autumn, a boy began visiting the same library on weekends. He liked the seats by the window. The table in the third row was often empty, and he sat down.
He noticed someone had carved words into the tabletop; only a few blurred grooves remained. He touched them with his fingertip and thought nothing of it.
She did not know who sat in her seat. He did not know who had carved those words.
[The physicist says]
Entanglement does not require particles to “know” of each other’s existence. It depends neither on information nor consciousness.
It needs only one condition: they once belonged to the same system.
Even if only for an instant.
[Sixteen, first year of high school]
On the first day, she stood before the noticeboard outside the school gate, looking for her name. He approached from the side, looking too.
There were many people. She stepped aside and trod on his shoe.
“Sorry.”
“It’s okay.”
He noticed her finger resting on a class in the assignment list—the same class as his.
Later they sat in the same classroom. During roll call in the first lesson, he heard her name. She heard his.
Neither felt any sense of recognition.
How could they? He did not know she had carved words into the table where he used to sit. She did not know he had spent an entire year smoothing away her handwriting, inch by inch.
[The physicist says]
An entangled state has a characteristic: before measurement, particles are in superposition—all possible states exist simultaneously.
Not “we don’t know which state it is in.” It really is in every state at once.
Only when you measure it—force it to choose—does it collapse into a definite result.
Before that, everything is open.
[Three years of high school]
In the first year, he lent her a book. When she returned it, two characters had appeared on the title page: his name. A faint trace of sweet milk lingered among the pages, and did not fade for a long time.
He was unsure whether it was an unconscious act or a response. She could not explain what she had been thinking when she wrote those characters.
In the second year, at the New Year’s performance, she sang onstage. At the end, her gaze passed in his direction. Or perhaps not. The lights were too dim; neither was certain.
In the third year, everyone worked on practice questions. He looked into her eyes, wanting to say something, but whenever the words reached his lips, she turned and asked about a math problem. He lowered his head and helped solve it.
Three years. Neither spoke.
No confession, no rejection.
No collapse.
[The physicist says]
In 1964, physicist John Bell proved something: correlations between entangled particles exceed the limit any classical theory can explain.
This means their connection cannot be explained by “arranging it beforehand,” nor by “secretly passing signals.”
It is something deeper. So deep our language has no ready-made word for it.
[University, seventeen hundred kilometers]
She went south. He stayed north.
In the winter of her first year, she saw snow for the first time. She took a photograph outside her dormitory and posted it on WeChat Moments. Fourteen hundred kilometers away, he saw it, typed “It’s snowing here too,” then deleted it.
Late one night in her second year, she suddenly woke. No reason. The streetlights outside were orange-yellow, tinting the ceiling an indescribable color. She lay there, completely awake, completely quiet.
That same night, he sat on a rooftop in another city. After evening study, instead of returning to his dormitory, he climbed to the roof for no reason. The wind was strong.
They did not message each other that day.
In her third year, she almost began a relationship with someone else. The boy was kind. She tried: dinner, a film, a nighttime walk. At the end of the road, he asked whether she wanted to give it a chance.
She stood a long time. Then said sorry.
Not because she remembered anyone. It was something smaller—like a garment half a size off, like a note a quarter tone out of tune.
Wrong. Simply “wrong.”
That evening she messaged him on WeChat. Nothing in particular; she suddenly wanted to talk.
“The other person is typing…” appeared and disappeared on the screen. They chatted back and forth for forty minutes, all inconsequential little things.
After saying goodnight, she fell asleep holding her phone.
[The physicist says]
A common misconception is that entanglement weakens with distance.
It does not. One meter and one light-year make no difference to entanglement.
Only one thing can truly destroy it: decoherence. Particles interact too much with their external environment, and the information of entanglement is absorbed, diluted, and drowned out.
Not broken. Diluted. Like a drop of ink falling into the sea.
[Twenty-five]
Two years after graduation. Each working, each renting a place, each learning to go to hospital alone, assemble furniture alone, choose tomorrow’s breakfast alone in a late-night convenience store.
They still kept in touch. Less than at university.
Sometimes she opened their chat, saw the date of the last message, paused, and closed it. Not that she did not want to speak. She did not know which sentence to begin with.
Sometimes something reminded him of her—a kind of light, an intersection, a sudden trace of sweet milk drifting through cold air. But he said nothing. Saying it felt like explaining a problem that needed no explanation.
[This winter]
He traveled to her city for work.
They met in a café near her office. She arrived early and sat by the window. When he pushed the door open, she was unconsciously drawing something on the table with her finger.
“What are you drawing?”
“Nothing.” She withdrew her hand and smiled. “Habit.”
They sat there all afternoon, talking about many unimportant things.
Near the time to leave, they somehow began discussing school. He said, “In middle school I went to the city library every weekend. There was a table in the third row by the window. Someone had carved words into it, and eventually I rubbed them away. I never knew who wrote them.”
The hand holding her cup stopped briefly.
“Which library?”
He gave its name.
She put down the cup. The coffee was already cold.
“Let’s go,” she said. “I’ll walk you to the metro.”
They passed a ginkgo tree. Almost all its leaves had fallen.
She never told him.
At the metro entrance, he descended a few steps and looked back. She stood above, one corner of her scarf lifted by the wind.
Suddenly he desperately wanted to ask her something.
But the train arrived.
[The physicist says]
We have an equation that precisely describes the complete state of two entangled particles—every possible correlation, every possible result is written into it.
But the equation will not tell you:
Whether they will be measured.
When.
By whom.
When you measure a particle in superposition, it collapses to a definite result.
But one question has troubled physicists for decades: Where did the other result go?
In 1957, a young man named Hugh Everett offered an answer: nowhere. It is still there. With every measurement, the universe does not choose—the universe splits. All possible outcomes happen simultaneously, each continuing in its own branch.
No branch is more real than another. No path is more correct than another.
They are all happening. Now. At the same time.
Second Movement: Happening Simultaneously
The First World
[The physicist says]
Quantum teleportation uses entanglement to transmit information. You can transfer a particle’s complete quantum state to another distant particle. After the transfer, the receiver’s particle becomes a perfect reproduction of the sender’s—from the perspective of physics, it is that particle.
But there is a price: the original particle’s state is destroyed during transmission.
You achieve a perfect arrival. But the one that departed no longer exists.
The metro entrance. He descended three steps. Stopped.
Turned, climbed back, and stood before her. A corner of her scarf lifted in the wind. He held it down for her.
She said nothing. Neither did he. But that gesture was the sentence.
At twenty-eight, they married. A small wedding, only a few friends. When signing, she wrote her name beside his. He watched her fingers—the same hands that wrote on the title page in their first year of high school. But the handwriting had changed. Faster, more decisive, without that old hesitation.
He liked this version of her. But sometimes remembered the hesitant girl—not better, just different. Where had she gone?
At forty, he had become talkative. Friends said he was increasingly articulate and polished. Sometimes she watched him speaking fluently at dinners and found him unfamiliar. Not bad. She simply remembered that quiet high-school boy—the person who walked slowly at the back when the crowd dispersed from the sports field, stepping on his own shadow. Where had that person gone?
They loved each other deeply. But sometimes she woke late at night, looked at the face beside her—a face reshaped by time—and wondered: Is this the same person as then?
Yes.
But not entirely.
At fifty, she found the book among old belongings. The two characters remained on the title page—his name, her handwriting. But the writing looked like someone else’s. Slower, lighter, carrying a carefulness she no longer possessed.
She stared at those characters for a long time.
The girl who wrote them was gone. The woman she was now had inherited everything—memories, feelings, the book, the marriage. But the girl herself could not return.
She closed the book and put it back on the shelf.
She had reached the destination. But the person who set out no longer existed.
The Second World
[The physicist says]
Quantum mechanics has a theorem called the “no-cloning theorem”: an unknown quantum state cannot be perfectly copied.
This means that if two particles become entangled, you cannot “copy” that entanglement for a third particle. It is not a relationship that can be learned, imitated, or transferred.
It is unique. Once it happens, it occupies that place.
Forever.
The train arrived. The doors opened. He stepped inside.
As the doors closed, he looked at her through the window. She was still above. A corner of her scarf lifted in the wind. Nobody held it down for her.
At twenty-eight, she married. He received an invitation. Went. Sat in the last row. Before the ceremony ended, he left early. Outside, the sunlight was dazzling. He stood on the steps for a while, feeling that there ought to be an emotion, but there was nothing. Only brightness. Extreme brightness.
At thirty-five, he married too. His wife was kind. Truly kind. But sometimes she asked why he suddenly drifted away. He said he was thinking about an unfinished problem.
He was not lying.
One day at forty-five, he suddenly understood something. Not at a special moment, just an ordinary morning, brushing his teeth before the mirror.
He realized that since twenty-five, he had measured every person who approached him with the same ruler. Not a comparison of who was better. Something more hidden—a frequency. Everyone differed slightly from that frequency. Very slightly. But enough for him to notice.
He had not made that ruler. She had left it in him. He could neither dismantle it nor reproduce it for someone else.
At fifty, she divorced. Late one night, she thought of him very calmly. Not longing. Not regret. A confirmation—like reaching into darkness and touching a wall.
He was still there. Somewhere.
She did not need to know where. Only that he existed.
The Third World
[The physicist says]
Entanglement’s greatest enemy is not distance, but noise.
When an entangled particle interacts too much with its surroundings—struck by air molecules, disturbed by thermal radiation, pushed about by countless tiny forces—the entanglement information it carries gradually leaks into the environment.
Physicists call this “decoherence.”
The entanglement has not broken. It still exists in the total wave function of the whole system. But it has been diluted, until it is indistinguishable from background noise.
Like a drop of ink in the sea. The ink is still there. But you can never find it again.
That night in her third year of university. The boy asked whether she wanted to give it a try.
She stood a long time.
This time, she said yes.
Not because she no longer thought of him. The longing was simply too light—so light she could not tell whether it was longing or merely habit. The person before her was definite, warm, standing right there now.
At twenty-six, she and her husband lived in the south. Sometimes she messaged him and exchanged a few words. No different from any other high-school classmate gradually drifting away.
At thirty, contact shifted from monthly to holiday greetings. “Happy New Year.” “Happy New Year.” Like two mirrors facing each other, producing nothing.
At thirty-five, she took her child to the city library. Passing the table in the third row by the window, she paused. Her husband asked what was wrong. She said, “I used to sit here a lot.”
Nothing more.
At forty, she came across his WeChat Moments. Glanced at them. Did not like the post. Not deliberately. It felt natural, the kind of not-clicking that leaves nothing missing.
At forty-five, his name appeared in a group chat. Someone tagged him, discussing a class reunion. Seeing the name, she paused for one second.
One second.
Then scrolled away.
At fifty, sorting old possessions. A book. Two characters on the title page: a person’s name. She looked for a few seconds.
She could not remember who it was.
She put the book in the donation box.
The Fourth World
[The physicist says]
In 1978, physicist John Wheeler proposed a thought experiment: in a double-slit experiment, you can wait until a particle has already passed through the slits before deciding how to observe it.
The result: your decision now determines the particle’s “earlier” behavior. If you choose to observe which slit it took, it previously took only one. If you choose not to observe, it previously took both simultaneously.
A future choice changes a past fact.
Physicists call this “delayed choice.” It means the past is not fixed. The past awaits a decision from the future.
That afternoon in their final year of high school. He looked into her eyes.
This time, he did not wait for her to turn and ask a math question.
“There’s something I want to tell you.”
She turned.
He said it.
She lowered her head and smiled for a long time.
The summer they were seventeen, walking home from school, their shadows overlapped for the first time.
At nineteen, after the college entrance exam, different cities. They tried a long-distance relationship. Calls went from daily to weekly. Silences grew longer, not because they had nothing to say, but because nothing they said felt enough. Three months later, she said, “Let’s each walk our own way for a while.”
He said yes. That “yes” was very quiet.
Twenty-five to sixty. Separate lives. He married, divorced. She married, lost her husband. Each learned to spend every holiday alone. Occasionally he thought of her, but the way he remembered changed—not heartache, but a distant warmth. Like winter sunlight through glass. Warm. But untouchable.
At sixty-five, a high-school classmate’s funeral. They sat side by side, with one empty seat between them—for the person no longer there.
Afterward, everyone went their separate ways. They walked at the back.
At sixty-seven, they were together again. Quietly. No dramatic passion. Like a problem worked on for fifty years, finally receiving its written answer.
She found an old book in a box. On the title page was his name, written when she was sixteen. She put it beside his bed.
He opened it and saw the two characters. Looked for a long time.
“So you wrote it back then.”
“Yes. But you didn’t know then.”
He thought: she wrote those characters at sixteen, and he read them at sixty-seven. So when were they really written?
The day she put pen to paper? Or this day, when he opened the book?
Perhaps neither.
Perhaps those characters had always been waiting. Waiting for a decision from the future to give them meaning.
In the moment he opened the book, that afternoon fifty-one years earlier—when she bent over her school desk and wrote his name inside that book—truly happened.
Third Movement: Always Happening
[The physicist says]
The many-worlds interpretation has an unsettling implication: you cannot know which branch you occupy. In every branch, you believe your world is the only real one.
Your life now—your marriage, loneliness, regrets—is entirely different in another branch.
And that other you is equally certain that their version is the only one.
Fifty-five.
In one world, they sit side by side on a balcony, watching the lights in the opposite building go out one by one. She rests her head on his shoulder. He is unsure whether the person leaning on him is the same person who wrote his name on the title page all those years ago. But he does not ask.
In one world, he chooses oranges alone in a supermarket and suddenly stops. A smell nearby reminds him of a classroom. He stands for a few seconds, then continues choosing.
In one world, she no longer remembers that smell.
Sixty-five.
In one world, they meet again at a funeral. He says the sentence. She looks down at her hands.
In one world, she returns to the city library. The table is still there. Its top has been replaced. She sits down and carves nothing.
In one world, he no longer remembers which street the library was on.
[The physicist says]
No possibility is wasted.
The path you chose is real. The path you did not choose is also real. The regret you feel now is real. And in another branch, the you without that regret is also real.
You can simply never meet.
Seventy-five.
In one world, he falls asleep holding her hand. She looks at his face and thinks: this person is no longer the person from those days. But she loves this person.
In one world, he goes first. A winter morning. His heart stops. That same day, she sits beside a window and suddenly feels something gently release. Like a string held taut for a lifetime. She does not cry. She closes her eyes and remembers the table.
In one world, the book sits on a shelf in a secondhand bookshop. A name is written on its title page. Nobody has ever opened it.
In one world, sorting what she left behind, he finds the book. His own name on the title page. He sits on the floor, motionless for a long time. Suddenly he feels that opening this book now makes the act of her writing those two characters that afternoon more than fifty years ago real. Before, they were only ink. From this moment, they are a letter that has arrived.
Eighty.
A pair of hands carves words into a tabletop.
A pair of hands writes someone’s name on a title page.
A pair of hands holds another pair.
A pair of hands holds a cup of water gone cold.
A name is written, read, forgotten, and found again.
A table, by the window, where three o’clock sunlight falls exactly on the back of a hand.
[The physicist finally says]
In the many-worlds interpretation, there is no such phrase as “if only back then.”
Because every “if” is not a hypothesis. It is a fact. It is happening.
A table in the third row by the window.
Three o’clock sunlight falls on the tabletop. No hand is there to receive it.
The light does not care. It will return at the same time tomorrow.
[The physicist remains silent for a long time. Then says:]
I do not know.