Three brilliant students. The world’s best supercomputer. What could go wrong?
Mathilde, a brilliant student at l’ENS, Paris’ best research university, wants to simulate a new Big Bang. She goes to Szymon, her Polish roommate, for help.
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Chapter Two: Les Quais
Szymon burst out laughing.
“What?” she asked.
“It’s cute,” he said, “It’s a cute idea.”
“What?” she asked again angrily.
“Look,” he got up and opened the fridge, “It’s just, it’s clear that this is an idea from someone who only has a basic understanding of physics.” He grabbed a pack of grapefruit juice, opened it, and drank directly from the nozzle.
“Fuck off,” Mathilde crossed her arms and glowered at him, “And don’t drink from the bottle, it’s disgusting and unsanitary.”
He laughed again and sat back down in front of her.
“Come on, don’t be mad,” he said with a smile, “It’s just that it’s a lot more complicated than that. It’s impossible.”
“Why?” she pouted her lips.
“Because,” said Szymon, “We have no idea how the Big Bang actually happened.”
“What?” This was a surprise. “You mean we don’t know what caused it?”
Szymon raised an eyebrow. “No, I’m not even talking about that. That’s a whole other problem. Some say God, some say it’s an old collapsing universe that rebooted… I don’t even want to go there. What I mean is that if you look at the actual moment where the Big Bang starts, we have no idea what’s happening.” He closed his eyes for a few seconds. “Actually, that’s not technically correct either, because time doesn’t exist when the Big Bang starts, so it’s not really starting anyways.”
Mathilde took in a deep breath. Szymon was taking forever to get to the point. This was something about him that tended to get on her nerves. He focused so completely on being perfectly accurate that it ended up making things more complicated to understand.
“Explain like I’m five,” she said.
“Wait,” said Szymon, and checked his watch. “It’s 4:30 p.m., which means it’s socially acceptable to drink. If I’m really going to explain to you how the universe started, can we at least do it with wine?”
“Sure,” she said, getting up, “But no bars. I want to smoke. Let’s just grab a bottle and go to Les Quais.
“As long as it’s a bottle of rosé, I’m fine with that,” said Szymon, “Let me get my keys.”
They bought a bottle of rosé and three cans of Sprite from a small shop, asked for two plastic cups, and walked down Rue Monge, the large boulevard cutting through the Latin Quarter. As usual, Szymon walked with uneven steps, jumping left and right.
“Come on,” moaned Mathilde, “Knock it off.”
“I have to step on all the lines. Not my fault Paris has such messed up sidewalks.”
Szymon had a self-admitted obsessive-compulsive disorder. He would knock on wood eight times every time he said something that he hoped would happen, create elaborate rules on how to walk across irregular surfaces, and had once gone into great detail explaining to Mathilde how he wanted to make sure he was always at his initial position, which involved turning a full clockwise circle if he happened to have previously turned counter-clockwise. They were harmless quirks, and being at l’ENS, Mathilde had seen much worse. He showered at regular intervals, and that was all that really mattered.
She did, however, enjoy messing with him. “You missed a line there,” she pointed.
“Stop it!” he doubled back and stepped on the line, “Now I have to do it all over again!”
“You missed that one too!”
They finally made it to the street bordering La Seine, the river that split Paris in half, and walked down the uneven stone steps to Les Quais – the docks. The docks were a cobbled pedestrian street, barely a meter over the water level, that lined the river on either side for kilometers. It was her favorite spot in all of Paris. Being from Brittany, right on the English Channel, she missed the sea, and being near the water provided a comfort that she couldn’t fully explain. She was pretty sure it was the same for Szymon – his hometown, Gdansk, was Poland’s biggest port city.
As Mathilde sat on the stone bench, shivering from the cold seeping in through her jeans, she looked out towards the opposite bank. The white Parisian buildings with tall windows and blue and black-shingled roofs stretched out on either side, all the way to the spires of Notre Dame looming up from the small island in the middle of the river.
A giddy rush of pleasure ran down her spine. I can’t believe I’m in Paris. It had been five months, but every once in a while, she would be struck again by the fact that she had achieved a life-long dream. Finally free.
Out of the corner of her eye, she caught Szymon pouring Sprite into his glass of wine.
“Szymon, seriously?” she asked, “Don’t do that!”
“I like the taste,” he said without looking up.
“You’re in France. That’s a crime.”
He shrugged it off and kept pouring. “Look, you want me to explain this to you or not?”
“Fine. But you’ll have to stop doing that eventually. Bad things will happen to you here,” she said, crossing her arms.
He handed her a glass filled with pinkish-orange wine. She tasted it, and nodded approvingly. At least he hadn’t put any Sprite in hers.
“Let’s start,” he said, “So, the way physicists have been observing and trying to prove or disprove the Big Bang is by working their way backwards. We’ve been slowly moving closer and closer to the moment it happened, but the nearer we get to the actual beginning, the less sense it makes.”
Mathilde silently sipped from the cup.
“We’re basically able to more or less go back to 10 to the power of minus 43 seconds after the Big Bang. Meaning, zero point zero zero zero – 42 zeroes – and 1 seconds after. Before that, our current physical laws make no sense.”
“What do you mean?”
“Well, if you extrapolate what’s going on before that moment, then you end up with infinite energy and infinite mass at the beginning of the Big Bang – which is impossible. We kind of hope that quantum gravity will help us figure it out, but we really haven’t made much progress there yet.”
“So that’s why you were laughing – there’s no way we can model infinite energy and mass in a system where physical rules don’t apply.”
“Exactly,” said Szymon.
“Ok, but if we’re trying to simulate a Big Bang, can’t we just start at ten to the power of minus 43 thing? When stuff does makes sense?”
“No, because we don’t really understand what’s happening then either. I mean, we understand what happened, we just can’t explain why it happened,” Szymon swirled his wine in his cup, “It only really starts to make a little sense at ten to the power of minus 36 seconds, where you enter the grand unification epoch and the three forces of the Standard Model are unified, but then you have the problem of baryogenesis and-”
“Szymon,” she said, “Explain as if I’m five.”
Szymon pursed his eyebrows in thought. Mathilde waited. She knew how difficult it was to dumb things down. She had been a math tutor for years to make some money on the side, but had always been terrible at it. Things that appeared so clear and simple to her were mysteries to her students, and try as she might, she couldn’t explain them. How does one explain 1+1=2? That was how most complex mathematical formulae appeared to her though: they intuitively made sense. Szymon however, had a talent for putting things simply, as long as he was given time and the proper guidance.
“Alright, let me put it this way. When the Big Bang happens, there’s nothing. I don’t mean empty space. I mean nothing exists. There are no dimensions, there is no time, there is no space.” He waited until she nodded and continued.
“Now this is why we call it a “Bang”. All this energy and matter suddenly start to expand exponentially. It’s actually creating space as it expands, something known as cosmic inflation. In just a tiny fraction of a fraction of a second, space is created in all directions at once.”
“There’s two main reasons why it’s difficult to understand what’s going on during this period though, and especially, why it’s impossible to simulate,” he said, emphasizing the last words in an effort to rid her of the idea, “The first is that something really weird is happening, and we still don’t know how to explain it. At the origin of the universe, there are two things: matter,” he raised his right hand, as if holding something, “And anti-matter.”
“Now when you put them together,” he joined his hands, “Poof, they disappear, cancelling each other out. And at the time of the Big Bang, there’s exactly as much matter as anti-matter.”
“OK, so did the matter just concentrate somewhere where there was no anti-matter?” she asked, “And that’s how we got planets and galaxies and stuff?”
“No… It’s weirder than that. There started to be an imbalance. We ended up with slightly more matter than anti-matter. And we still don’t know why. We have a few ideas, like the Sakharov conditions, but since we don’t really understand what’s going on in the meantime anyway, it’s really more of a hypothesis than anything else.”
“What don’t we understand?”
“Well, that’s the second thing, and that’s why I’m saying it’s impossible to model. There are basically four fundamental interactions, which I’m sure you’ve heard of,” he said, counting them off on his fingers, “Gravitation. Why stuff falls. Electromagnetism. Why magnets work. The strong force. Which basically keeps the nuclei of atoms from blowing apart and having nuclear explosions all over the place, and finally, the weak force. Which is complicated.”
“Those I know,” she said, “But we can just code them in right? They’re part of the rules.”
“You could, except that while this imbalance is going on, the four interactions are essentially blended into one superforce. And then, one by one, without us being able to explain why or when this happens, they separate.”
“So the rules are changing as the Big Bang advances?”
“You could say so, but that’s not necessarily true. It might be that quantum physics will be able to explain it. We just don’t know.”
“Ok, I get it,” she said. She kicked a small pebble with her foot, “So it’s impossible to model. Fuck.”
“And then,” continued Szymon, oblivious to Mathilde’s resignation and intent on finishing his physics class, “Starts the quark epoch. That’s where everything finally starts to make sense. We get quarks and all four forces are separated.”
Mathilde perked up. “When’s this?”
“A picosecond after the Big Bang. Ten to the power of minus twelve,” he answered, “We start to get matter. But everything is so condensed that it’s the tiniest pieces of matter. As soon as they try to team up and form hadrons or atoms, they’re blown apart by a different quark coming in at full speed.”
“Explain quarks,” said Mathilde, leaning in.
“Well there are six types, although we call them flavors: Up, Down, Charm, Strange, Top and Bottom.”
“You’re kidding. That’s what they’re called? Charm? Strange?”
“This is physics, not marketing,” he waved a hand dismissively, “We call stuff ‘Big Bang’ and ‘Strong Force’. You’re not exactly going to get cool names here.”
Mathilde poured both of them another glass. “So all you have are 6 quarks?”
“No, you also have six leptons – electron, electron neutrino, muon, muon neutrino, tau and tau neutrino. And all twelve of these have their anti-matter counterparts. And then you have a bunch of bosons, like the photon, W, Z and Higgs.”
“And we know all of the physical properties of these?”
“More or less,” said Szymon, “We’re still working on proving the existence of a few but we’re pretty much there.”
“And at this point in time all of the four fundamental forces are separate?”
“Fundamental interactions,” corrected Szymon, “And yes.”
Mathilde fell silent. She moved her legs onto the bench, sitting cross-legged and facing Szymon. She rolled a cigarette while he stared off across the river. A handful of heartbeats later, she finally spoke.
“I know what you’re about to ask,” he interrupted, “Wait. Let me think.”
“If we use the quarks and the leptons and the bosons as the cells…”
“Let me think.”
“…and the rules are the four fundamental interactions, and whatever specificities apply to each cell…”
“Mathilde,” he warned.
“…why don’t we just start the simulation there?”
Szymon didn’t say anything. She slowly inhaled smoke and blew it out, waiting for him to come up with an objection. She could almost hear him think, trying to explore every possible angle. He didn’t move.
Her phone buzzed in her pocket. She silently pulled it out, careful not to disturb Szymon, and saw that it was a SzymonChat message from Oliver.
O: Just got home. Where are you idiots?
She typed back a reply.
M: Quais de Seine. Usual place. Bring wine.
She knew she didn’t have to ask him to join. Oliver hated being left out. He was sure to show up. The three of them were an unlikely trio. Szymon was like the cat of the house, long-legged and independent but wary of other human beings. Mathilde prided herself in being a rough-cut diamond, rebellious and tomboyish. They worked well together. But Oliver, well, Oliver was the social prodigy – good-looking, friendly and with just the right touch of arrogance to fit in perfectly with Paris.
Szymon finally broke the silence.
“It’s still super complicated,” he said, “At that point it’s so hot that they’re basically in a hot quark-gluon plasma. And we don’t know how many there were of each – we have an idea but it’s just estimates. And we’re still missing huge gaps, like how many dimensions to operate in.”
Mathilde read between the lines. If he was offering weak objections, it meant that it was possible.
“That’s not a problem. I’m not trying to reproduce our universe exactly – I just want to create a universe, any universe. We can plug in approximations or our best guess for each and see if it works. If it doesn’t, we slightly change the values, and try again.”
She handed him the glass of Sprite rosé that he hadn’t touched since he had fallen silent. He took it and drank.
“And for the dimensions, well that’s easy. We might not be able to fathom dimensions, but coding them in is child’s play. It’s all math. So we just try out all the theorized dimensions until something sticks.”
“It’s doable…” Szymon said hesitantly, “But how do we know if it sticks?”
“We set up a parallel machine that monitors the result. If we get anything up to a Class 3, we call it a failure and move on. It means it’s stable, and there are regular patterns, and that’s exactly what we don’t want. If it’s completely unpredictable however, interacting in complex and interesting ways, then it’s a Class 4. We just analyze for patterns, and whenever it’s stuck, we rule it a failure and change the variables a bit.”
Now that the conversation had finally moved to computing, she was in her element. The golden idea was finally shining again.
“Better yet, I’ll put in some reinforcement learning. We let the machine analyze the results, and begin to predict which variables are most likely to give us a complex system. If it fails fast, it means the variables were totally wrong. With every iteration and randomization of the variables, we’ll be making progress.”
“We can do one better,” said Szymon excitedly, “We can look if the quarks form up into hadrons. If they do, it’s one step closer to a universe.”
“Yeah!” Mathilde jumped off the bench, picking up on Szymon’s enthusiasm, “All we have to do is come up with which variables need to be changed and which are fixed. And then we run as many iterations as are needed until we have our very own universe to play in!”
Szymon looked up at her with bright eyes. “It might actually work.”
“Right?” Mathilde blurted out, “Imagine. A universe. With the full complexity of our own! That’s how you get to diversity!”
“But wait,” said Szymon, holding up a hand, “How do we even run something like this?”
“What do you mean? I can code it!”
“No, I mean, how do we get the processing power for an entire universe?”
Mathilde bit her lower lip and smiled.
“Well, about that. Ollie is on his way. And we’re going to need his help.”
~ End of Chapter 2 ~
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