Spending Time in the Classical World
Alice and Bob were sitting in a quiet park, the sun casting long shadows across the grass. Alice kicked a soccer ball back and forth between her feet, reflecting on their most recent adventure in Quantum Land.
“Bob,” she said, pausing for a moment as the ball rolled to a stop, “I still can’t get over that clock, with its hands ticking both ways and hanging in a sky between dusk and dawn! We totally disrupted time in Quantum Land, and it felt like everything went haywire. I’m just glad we didn’t make it worse. Quantum Land is so fragile!”
Bob smiled kindly, “Don’t worry too much about it, Alice. Learning from our mistakes is the most important thing! Had we not forced the clock to move only forward, like time does in our everyday world, we wouldn’t have understood the profound effect it has. By doing that, we saw how forcing time to move forward actually ‘froze’ the quantum particles. They lost their ability to exist in multiple states at once, which is what make quantum systems such powerful platforms for things like quantum computing.”
Alice grinned sheepishly. “Yeah… do you mind reminding me exactly how that happened? I remember it was chaotic, but I am not sure I fully understand why. We fixed it, right? We brought everything back to normal?”
Bob nodded. “Okay, here’s the thing: normally in Quantum Land, time doesn’t have to move in one direction. Quantum systems, like the particles we saw, can be in many different states at the same time, that’s called superposition. But when we forced time to move in one direction, like we see in our world, we interrupted that balance. These particles lost their ability to be in multiple states at once and became ‘locked’ into one state. That transition — where things went from flexible and dynamic to rigid and frozen — was what caused the chaos.”
Alice tilted her head. “Ah, right. And I remember you said that time ‘emerges’ as a forward direction when quantum systems interact with each other. They just spontaneously choose a direction because nature prefers more disorder, and the direction with the most disorder is the one time naturally takes.”
Bob smiled. “Exactly. It’s all about balance and probabilities in Quantum Land. Just like how we fixed the clock by restoring balance, quantum systems need the right conditions to stay stable. When that balance is disturbed, uncertainty grows.”
Alice paused and caught the ball, holding it for a moment as she thought. “So, it’s like a soccer match, right? When the players are in sync, the game flows smoothly. But if one player is out of sync, the whole play falls apart. The key is balance. When that balance is disrupted, everything becomes uncertain.”
“Exactly,” Bob said. “But what if I told you that uncertainty isn’t just something that happens when things are out of balance in Quantum Land? It’s actually built into the very nature of quantum systems.”
Alice raised an eyebrow, confused. “How does that work?”
Before Bob could explain further, they both heard the familiar sharp whistle of the quantum train, signaling that it was time to shrink down and travel once again to the quantum world.
An Uncertain Place
Alice and Bob stepped off the quantum train, and the landscape around them felt different. The colors flickered, and the shapes around them kept shifting, constantly changing before their eyes.
“Bob, do you see that?” Alice asked, scanning the strange scene. “It’s like everything keeps changing. One moment, that rock is solid, and the next, it’s a tree. Then it disappears, only to reappear again.”
Bob looked around, eyes wide with curiosity. “Wow, today everything seems to be constantly shifting! It’s almost like the entire landscape is in a state of superposition, just like quantum particles. But this time, it’s not just the particles. The whole environment is involved.”
Alice stopped, thinking. “You mean it’s like when I kicked my soccer ball in Quantum Land, and it kept changing paths, all at once, until I looked at it and decided where it would go?”
Bob nodded, smiling at Alice’s understanding. “Exactly. It’s like this whole place is in multiple states at once, unsure of what it wants to be. But perhaps there’s something else going on here. I think we might be seeing the uncertainty principle in action.”
Alice furrowed her brow. “Uncertainty? What’s that got to do with everything changing?”
Bob adjusted his glasses. “In quantum mechanics, the uncertainty principle says that some things, like a particle’s position and its velocity, can’t both be known exactly at the same time. The more accurately we know one, the less we can know about the other. It’s not just about what we don’t know, it’s built into how quantum systems work.”
Alice looked around, trying to grasp the idea. “So, you are saying that because I know where that rock is, I can’t know what form it’s in? That’s why it keeps changing between a rock and a tree?”
“Yes, exactly,” Bob said. “Until we observe something, it’s not settled. It exists in a range of possibilities.”
Alice paused for a moment, considering this. “So, everything here is in a constant state of uncertainty, like the different paths my soccer ball took once I kicked it, before I decide where it should land? So it’s not there for sure, until we look at it or touch it?”
Bob nodded, his voice becoming more animated. “Exactly. The entire environment is in a state of uncertainty. It’s not that things are random. It’s just that they exist in various possibilities, and only once we measure or observe them does one outcome become definite.”
Alice thought for a moment, then pointed to the shape ahead. “Okay, then. I am going to say that it’s a tree!” She took a few steps forward, her focus now on the object that seemed to flicker between a rock and a tree.
The moment she decided it was a tree, it seemed to freeze into the shape of the tree. But then it shifted and changed distance! At one moment, it appeared closer, then farther, as if it couldn’t decide how far it should be from her. The tree’s position seemed uncertain.
Bob looked closely, his eyes widening in realization. “Ah, this is exactly what I meant! Because we have now decided by looking that it’s a tree, we can’t know exactly where it is! The more certain we are about the tree’s position, the less certain we are about its momentum or state of existence. Its position and momentum can’t both be fully known at the same time.”
Alice stepped back, looking at the tree again. “So, the tree keeps changing distance because it’s uncertain about where it’s supposed to be until I measure it? And earlier, because we knew how far it was, so it kept changing its form between a tree, rock, and air? At a time, we can either know its form or its position?”
“Yes,” Bob replied. “Exactly! The uncertainty principle is a built-in feature of quantum systems. It’s not random, but a fundamental property of how the world works at the quantum level.”
Alice gave the ball another gentle kick, watching as it left a trail of glowing possibilities behind. “This is so strange, Bob. It’s like everything is in a constant state of ‘maybe’ until we make it ‘definitely.’”
Bob grinned. “That’s exactly how quantum systems behave.”
Alice paused, looking around. “Then how come these uncertain things create our certain world?”
From Maybe to Definitely: How Measurement Shapes Quantum Reality
Bob smiled thoughtfully. “That’s the fascinating part. You are right to wonder about that. The uncertainty in quantum systems doesn’t last forever. When we interact with them, like we did with the tree, we force them to choose a specific state. That’s when the uncertainty collapses into a definite outcome.”
Alice squinted, considering. “So, when I decided that the shifting shape was a tree, I was basically forcing it to be a tree and nothing else? By observing it, I made it definite?”
Bob nodded. “Exactly. When you observed the tree, you collapsed its wave function. You took all those possibilities and chose one. But it’s more than just about deciding; it’s about what happens when we measure anything in quantum mechanics.”
Alice, kicking the ball again, paused mid-kick. “So, when I focus on anything, whether it’s the tree or the path of my ball, I measure it.. and thus make it real! It’s literally a ‘I think, therefore I am’ situation?!””
Bob was impressed and tried not to grin too widely. “That’s close! But here’s where it gets even more interesting. The uncertainty principle is universal, Alice. It applies to everything, not just the strange world of Quantum Land. When you observe something, you make it definite, but here’s the twist: the more a quantum system interacts with other systems, the more definite it becomes. The uncertainty gets averaged out.”
Alice tossed the ball into the air, giving it a thoughtful kick. As it floated, she watched its erratic motion. The ball hovered unpredictably in the air before it finally dropped into place. “Like the ball here,” Alice remarked, “it’s uncertain where it’s going until it finally lands. So, in a way, it’s like I am kicking the uncertainty out of it!”
Bob chuckled, enjoying the analogy. “Exactly! The more the ball interacts with the ground, the more predictable its path becomes. The uncertainty collapses as it interacts with more things around it. And just like that, quantum systems behave the same way . As they keep interacting with their environment, and their uncertainty keeps diminishing and things start seeming certain!”
Alice grinned. “So, the more I mess with the ball, the more ‘definite’ it becomes. I am like a quantum detective, forcing it to reveal its secrets!”
Bob smiled. “I like that! Yes, each time you interact with the ball — do anything to it at all, you help it decide where it’s going.”
Alice paused, thinking. “So, just like I help the ball choose its path, when we observe or measure quantum systems, we help them pick a specific state of being? Like soccer players, as a team, have to spontaneously decide which direction to take the ball, even though they all want to try different kicks?”
“Yes, indeed,” Bob replied. “By measuring or interacting with all of the soccer players, the ball or the quantum systems settle into one state, the state which somehow is a bit more preferred, out of different possibilities. After enough interactions, that state comes out as the certain state in our classical world.”
Alice smiled, clearly seeing the connection now. “So, it’s a bit like FC Barcelona’s tiki-taka .. each move builds on the last, and by watching the flow, you can kind of predict where the ball will go next!”
Bob grinned, impressed with her analogy. “Exactly! That’s the beauty of quantum mechanics. We understand how uncertainty works, and just like with a soccer team’s strategy, we can track the probabilities, anticipating the outcome even if it’s not fully determined yet.”
Alice gave the ball another push, watching it roll across the landscape. “It’s like playing the long game, huh? Where every move matters, and the more we pay attention, the more we can predict the outcome. Like a team’s fluid passing. Every decision builds up toward the goal.”
Bob nodded, a smile creeping up his face. “You got it, Alice. Just like a football match where every pass counts, quantum systems are all about understanding how small actions affect the bigger picture.”
Alice added, “With each interaction with everything around, a pattern starts to emerge… the more the interactions, and gradually we start going from ‘maybe’ to ‘definitely.’ If I remember correctly, you said each drop of water has trillions of atoms! No wonder that many interactions would remove all uncertainty, and we end up with the definite, predictable world that we experience.”
Bob started clapping excitedly. “At this rate Alice, I fear for my job… you are becoming the scientist now, while I am yet to improve my football kick!”
With a laugh, Alice kicked the ball towards Bob, “Let’s mend that, catch!”
Expectation and Reality: Collapsing the Possibilities
Bob proceeded towards the ball nervously and tried to kick it back to Alice. The ball hovered and momentarily showed various superposition paths, each a possibility, before Alice decided it was near her leg and kicked it back to him.
They continued playing for a while, laughing and observing the ball’s unpredictable path each time. Eventually, Bob insisted on a break. He pointed at the ball and said, “Do you see, Alice? I’m getting better! But in truth, each time, we don’t know exactly where the ball will land. But after many kicks, we can kind of predict the average spot where it will land, right? That’s exactly how it work in quantum mechanics as well.”
Alice’s eyes brightened as the analogy clicked. “So, even if I can’t predict where the ball will land each time, I can figure out where it’s most likely to land after a lot of kicks.”
“Exactly,” Bob confirmed. “It’s the statistics of landing which counts in the end. In quantum mechanics, these expectation values are the predicted average position or momentum of quantum systems, even if we can’t pin down exactly where the system will be at any given time. It’s like predicting the average number of goals per match for a player like Cristiano Ronaldo or Lionel Messi.”
Alice thought for a moment, her expression curious. “Wait, so are you saying that just like we know Messi scores on average about 0.8 goals per match, we can predict how a quantum system behaves over time?”
Bob nodded, clearly enjoying the analogy. “Yes, exactly! When we track the performance of a soccer player over many games, we can’t say for sure how many goals they’ll score in each individual match. But by looking at their average goals per match, we can get a good sense of their overall performance. Similarly, in quantum mechanics, the expectation value gives us a sense of the ‘average’ outcome of many measurements, even though each individual measurement might be unpredictable.”
Alice smiled. “So, just like how David Beckham’s free kick accuracy is more predictable over time, quantum systems, over many observations, settle into predictable averages, even though each individual event is uncertain?”
“True!” Bob said enthusiastically. “When you observe something in quantum mechanics, the uncertainty collapses, and you get a definite result. But in the quantum world, we can’t predict the result of one single measurement with certainty. Instead, we focus on the average behavior of many measurements, just like predicting the average number of goals or assists a player might have over a season.”
Alice looked around at the shifting landscape of Quantum Land, deep in thought. “So, it’s like the whole world of quantum systems is full of possibilities. But by observing them repeatedly, we can predict a general pattern, even if we can’t pin down each individual outcome.”
Bob smiled. “That’s the gist of it Alice. In Quantum Land, we collapse possibilities into reality by measuring repeatedly or the everything just interacting with everything else, and over time.. what we actually see is the ‘average’ outcome of all those possibilities. And what we think are certain in our everyday world, are in fact these expectation values that are actually average of the most likely possibility”.
Alice finished the thought for Bob, “So, the uncertainty isn’t just about not knowing; it’s about being able to predict the ‘big picture,’ even though individual results remain uncertain by noticing the emerging patterns. So, time, and patience is the key, and paying attention to observations!”
Bob’s eyes lit up in appreciation. “That’s the beauty of it, Alice. In both soccer and quantum mechanics, the more we observe and understand the system, the better we can predict the outcome, even if we can’t be certain about each individual moment. It’s the team, and not the individual players action that determines the outcome.”
Just as Bob was getting hit with the realization that he should exercise more to keep up with Alice on these adventure, they saw something peculiar happening at the horizon..
References
“Quantum Reality: Beyond the New Physics” by Nick Herbert — Explores the uncertainty principle and the collapse of the wave function, offering accessible explanations of the foundational concepts in quantum theory.
“The Quantum Mechanics of Minds and Worlds” by Jeffrey A. Barrett — Addresses the measurement problem in quantum mechanics, discussing how observation and the role of the observer influence the collapse of quantum states, directly engaging with the uncertainty principle.
“The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos” by Brian Greene — Explores parallel universes while explaining key quantum concepts like uncertainty and superposition, and how observation and measurement affect our understanding of the quantum world.
“Physics & Philosophy” by Werner Heisenberg — Written by the scientist who formulated the principle, the book covers the development of the uncertainty principle, its profound impact on science, and its philosophical implications. It reflects on how quantum mechanics challenges traditional notions of reality, blending scientific insights with deep philosophical questions
“The Quantum Universe: Everything That Can Happen Does Happen” by Brian Cox and Jeff Forshaw — Provides accessible explanation for the uncertainty principle and how quantum mechanics governs the behavior of the universe, highlighting the unpredictable yet predictable nature of quantum systems.
“The Structure of Scientific Revolutions” by Thomas S. Kuhn — While not specific to quantum mechanics, Kuhn’s book explores how paradigm shifts, like those caused by quantum mechanics, challenge traditional views of reality, including the radical implications of the uncertainty principle.
“Speakable and Unspeakable in Quantum Mechanics” by John S. Bell — Mathematically rigorous; discusses philosophical and scientific implications of quantum mechanics, with a focus on measurement and the uncertainty principle, offering a detailed discussion of its foundational importance.
I hope you enjoyed exploring Quantum Land with Alice and Bob! What adventures should they embark on next? If you really liked it, please comment. I would love to hear your thoughts, questions, or suggestions. Connect with me on LinkedIn or follow me here on Medium for more stories and reflections on science, fiction, life, and everything in between.
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