by Greg Egan
“The amazing thing is that you got together at all.” I scowled, and Will raised a hand placatingly. “I just meant, when you first moved in, you were pretty reserved. And down on yourself. When we interviewed you for the room, you practically begged us to give it to someone more deserving.”
“Now you’re taking the piss.”
He shook his head. “Ask any of the others.”
I fell silent. The truth was, if I took a step back and contemplated my situation, I was as astonished as he was. By the time I’d left my home town, it had become clear to me that good fortune had nothing much to do with luck. Some people were born with wealth, or talent, or charisma. They started with an edge, and the benefits snowballed. I’d always believed that I had, at best, just enough intelligence and persistence to stay afloat in my chosen field; I’d topped every class in high school, but in a town the size of Orange that meant nothing, and I’d had no illusions about my fate in Sydney.
I owed it to Francine that my visions of mediocrity had not been fulfilled; being with her had transformed my life. But where had I found the nerve to imagine that I had anything to offer her in return?
“Something happened,” I admitted. “Before I asked her out.”
“Yeah?”
I almost clammed up; I hadn’t told anyone about the events in the alley, not even Francine. The incident had come to seem too personal, as if to recount it at all would be to lay my conscience bare. But Will was off to Munich in less than a week, and it was easier to confide in someone I didn’t expect to see again.
When I finished, Will bore a satisfied grin, as if I’d explained everything. “Pure karma,” he announced. “I should have guessed.”
“Oh, very scientific.”
“I’m serious. Forget the Buddhist mystobabble; I’m talking about the real thing. If you stick to your principles, of course things go better for you – assuming you don’t get killed in the process. That’s elementary psychology. People have a highly developed sense of reciprocity, of the appropriateness of the treatment they receive from each other. If things work out too well for them, they can’t help asking, ‘What did I do to deserve this?’ If you don’t have a good answer, you’ll sabotage yourself. Not all the time, but often enough. So if you do something that improves your self-esteem—”
“Self-esteem is for the weak,” I quipped. Will rolled his eyes. “I don’t think like that,” I protested.
“No? Why did you even bring it up, then?”
I shrugged. “Maybe it just made me less pessimistic. I could have had the crap beaten out of me, but I didn’t. That makes asking someone to a concert seem a lot less dangerous.” I was beginning to cringe at all this unwanted analysis, and I had nothing to counter Will’s pop psychology except an equally folksy version of my own.
He could see I was embarrassed, so he let the matter drop. As I watched Francine moving through the crowd, though, I couldn’t shake off an unsettling sense of the tenuousness of the circumstances that had brought us together. There was no denying that if I’d walked away from the alley, and the kitchen hand had died, I would have felt like shit for a long time afterward. I would not have felt entitled to much out of my own life.
I hadn’t walked away, though. And even if the decision had come down to the wire, why shouldn’t I be proud that I’d made the right choice? That didn’t mean everything that followed was tainted, like a reward from some sleazy, palm-greasing deity. I hadn’t won Francine’s affection in a medieval test of bravery; we’d chosen each other, and persisted with that choice, for a thousand complicated reasons.
We were together now; that was what mattered. I wasn’t going to dwell on the path that had brought me to her, just to dredge up all the doubts and insecurities that had almost kept us apart.
2012
As we drove the last kilometer along the road south from Ar Rafidiyah, I could see the Wall of Foam glistening ahead of us in the morning sunlight. Insubstantial as a pile of soap bubbles, but still intact, after six weeks.
“I can’t believe it’s lasted this long,” I told Sadiq.
“You didn’t trust the models?”
“Fuck, no. Every week, I thought we’d come over the hill and there’d be nothing but a shriveled-up cobweb.”
Sadiq smiled. “So you had no faith in my calculations?”
“Don’t take it personally. There were a lot of things we could have both got wrong.”
Sadiq pulled off the road. His students, Hassan and Rashid, had climbed off the back of the truck and started toward the Wall before I’d even got my face mask on. Sadiq called them back, and made them put on plastic boots and paper suits over their clothes, while the two of us did the same. We didn’t usually bother with this much protection, but today was different.
Close up, the Wall almost vanished: all you noticed were isolated, rainbow-fringed reflections, drifting at a leisurely pace across the otherwise invisible film as water redistributed itself, following waves induced in the membrane by the interplay of air pressure, thermal gradients, and surface tension. These images might easily have been separate objects, scraps of translucent plastic blowing around above the desert, held aloft by a breeze too faint to detect at ground level.
The further away you looked, though, the more crowded the hints of light became, and the less plausible any alternative hypothesis that denied the Wall its integrity. It stretched for a kilometer along the edge of the desert, and rose an uneven fifteen to twenty meters into the air. But it was merely the first, and smallest, of its kind, and the time had come to put it on the back of the truck and drive it all the way back to Basra.
Sadiq took a spray can of reagent from the cabin, and shook it as he walked down the embankment. I followed him, my heart in my mouth. The Wall had not dried out; it had not been torn apart or blown away, but there was still plenty of room for failure.
Sadiq reached up and sprayed what appeared from my vantage to be thin air, but I could see the fine mist of droplets strike the membrane. A breathy susurration rose up, like the sound from a steam iron, and I felt a faint warm dampness before the first silken threads appeared, crisscrossing the region where the polymer from which the Wall was built had begun to shift conformations. In one state, the polymer was soluble, exposing hydrophilic groups of atoms that bound water into narrow sheets of feather-light gel. Now, triggered by the reagent and powered by sunlight, it was tucking these groups into slick, oily cages, and expelling every molecule of water, transforming the gel into a desiccated web.
I just hoped it wasn’t expelling anything else.
As the lacy net began to fall in folds at his feet, Hassan said something in Arabic, disgusted and amused. My grasp of the language remained patchy; Sadiq translated for me, his voice muffled by his face mask: “He says probably most of the weight of the thing will be dead insects.” He shooed the youths back toward the truck before following himself, as the wind blew a glistening curtain over our heads. It descended far too slowly to trap us, but I hastened up the slope.
We watched from the truck as the Wall came down, the wave of dehydration propagating along its length. If the gel had been an elusive sight close up, the residue was entirely invisible in the distance; there was less substance to it than a very long pantyhose – albeit, pantyhose clogged with gnats.
The smart polymer was the invention of Sonja Helvig, a Norwegian chemist; I’d tweaked her original design for this application. Sadiq and his students were civil engineers, responsible for scaling everything up to the point where it could have a practical benefit. On those terms, this experiment was still nothing but a minor field trial.
I turned to Sadiq. “You did some mine clearance once, didn’t you?”
“Years ago.” Before I could say anything more, he’d caught my drift. “You’re thinking that might have been more satisfying? Bang, and it’s gone, the proof is there in front of you?”
“One less mine, one less bomblet,” I said. “However many thousands there were to deal
with, at least you could tick each one off as a definite achievement.”
“That’s true. It was a good feeling.” He shrugged. “But what should we do? Give up on this, because it’s harder?”
He took the truck down the slope, then supervised the students as they attached the wisps of polymer to the specialized winch they’d built. Hassan and Rashid were in their twenties, but they could easily have passed for adolescents. After the war, the dictator and his former backers in the west had found it mutually expedient to have a generation of Iraqi children grow up malnourished and without medical care, if they grew up at all. More than a million people had died under the sanctions. My own sick joke of a nation had sent part of its navy to join the blockade, while the rest stayed home to fend off boatloads of refugees from this, and other, atrocities. General Mustache was long dead, but his comrades-in-genocide with more salubrious addresses were all still at large: doing lecture tours, running think tanks, lobbying for the Nobel peace prize.
As the strands of polymer wound around a core inside the winch’s protective barrel, the alpha count rose steadily. It was a good sign: the fine particles of uranium oxide trapped by the Wall had remained bound to the polymer during dehydration, and the reeling in of the net. The radiation from the few grams of U-238 we’d collected was far too low to be a hazard in itself; the thing to avoid was ingesting the dust, and even then the unpleasant effects were as much chemical as radiological. Hopefully, the polymer had also bound its other targets: the organic carcinogens that had been strewn across Kuwait and southern Iraq by the apocalyptic oil well fires. There was no way to determine that until we did a full chemical analysis.
We were all in high spirits on the ride back. What we’d plucked from the wind in the last six weeks wouldn’t spare a single person from leukemia, but it now seemed possible that over the years, over the decades, the technology would make a real difference.
#
I missed the connection in Singapore for a direct flight home to Sydney, so I had to go via Perth. There was a four-hour wait in Perth; I paced the transit lounge, restless and impatient. I hadn’t set eyes on Francine since she’d left Basra three months earlier; she didn’t approve of clogging up the limited bandwidth into Iraq with decadent video. When I’d called her from Singapore she’d been busy, and now I couldn’t decide whether or not to try again.
Just when I’d resolved to call her, an email came through on my notepad, saying that she’d received my message and would meet me at the airport.
In Sydney, I stood by the baggage carousel, searching the crowd. When I finally saw Francine approaching, she was looking straight at me, smiling. I left the carousel and walked toward her; she stopped and let me close the gap, keeping her eyes fixed on mine. There was a mischievousness to her expression, as if she’d arranged some kind of prank, but I couldn’t guess what it might be.
When I was almost in front of her, she turned slightly, and spread her arms. “Ta-da!”
I froze, speechless. Why hadn’t she told me?
I walked up to her and embraced her, but she’d read my expression. “Don’t be angry, Ben. I was afraid you’d come home early if you knew.”
“You’re right, I would have.” My thoughts were piling up on top of each other; I had three months’ worth of reactions to get through in fifteen seconds. We hadn’t planned this. We couldn’t afford it. I wasn’t ready.
Suddenly I started weeping, too shocked to be self-conscious in the crowd. The knot of panic and confusion inside me dissolved. I held her more tightly, and felt the swelling in her body against my hip.
“Are you happy?” Francine asked.
I laughed and nodded, choking out the words: “This is wonderful!”
I meant it. I was still afraid, but it was an exuberant fear. Another ocean had opened up before us. We would find our bearings. We would cross it together.
#
It took me several days to come down to Earth. We didn’t have a real chance to talk until the weekend; Francine had a teaching position at UNSW, and though she could have set her own research aside for a couple of days, marking could wait for no one. There were a thousand things to plan; the six-month UNESCO fellowship that had paid for me to take part in the project in Basra had expired, and I’d need to start earning money again soon, but the fact that I’d made no commitments yet gave me some welcome flexibility.
On Monday, alone in the flat again, I started catching up on all the journals I’d neglected. In Iraq I’d been obsessively single-minded, instructing my knowledge miner to keep me informed of work relevant to the Wall, to the exclusion of everything else.
Skimming through a summary of six months’ worth of papers, a report in Science caught my eye: An Experimental Model for Decoherence in the Many-Worlds Cosmology. A group at Delft University in the Netherlands had arranged for a simple quantum computer to carry out a sequence of arithmetic operations on a register which had been prepared to contain an equal superposition of binary representations of two different numbers. This in itself was nothing new; superpositions representing up to 128 numbers were now manipulated daily, albeit only under laboratory conditions, at close to absolute zero.
Unusually, though, at each stage of the calculation the qubits containing the numbers in question had been deliberately entangled with other, spare qubits in the computer. The effect of this was that the section performing the calculation had ceased to be in a pure quantum state: it behaved, not as if it contained two numbers simultaneously, but as if there were merely an equal chance of it containing either one. This had undermined the quantum nature of the calculation, just as surely as if the whole machine had been imperfectly shielded and become entangled with objects in the environment.
There was one crucial difference, though: in this case, the experimenters had still had access to the spare qubits that had made the calculation behave classically. When they performed an appropriate measurement on the state of the computer as a whole, it was shown to have remained in a superposition all along. A single observation couldn’t prove this, but the experiment had been repeated thousands of times, and within the margins of error, their prediction was confirmed: although the superposition had become undetectable when they ignored the spare qubits, it had never really gone away. Both classical calculations had always taken place simultaneously, even though they’d lost the ability to interact in a quantum-mechanical fashion.
I sat at my desk, pondering the result. On one level, it was just a scaling-up of the quantum eraser experiments of the ’90s, but the image of a tiny computer program running through its paces, appearing “to itself” to be unique and alone, while in fact a second, equally oblivious version had been executing beside it all along, carried a lot more resonance than an interference experiment with photons. I’d become used to the idea of quantum computers performing several calculations at once, but that conjuring trick had always seemed abstract and ethereal, precisely because the parts continued to act as a complicated whole right to the end. What struck home here was the stark demonstration of the way each calculation could come to appear as a distinct classical history, as solid and mundane as the shuffling of beads on an abacus.
When Francine arrived home I was cooking dinner, but I grabbed my notepad and showed her the paper.
“Yeah, I’ve seen it,” she said.
“What do you think?”
She raised her hands and recoiled in mock alarm.
“I’m serious.”
“What do you want me to say? Does this prove the Many Worlds interpretation? No. Does it make it easier to understand, to have a toy model like this? Yes.”
“But does it sway you at all?” I persisted. “Do you believe the results would still hold, if they could be scaled up indefinitely?” From a toy universe, a handful of qubits, to the real one.
She shrugged. “I don’t really need to be swayed. I always thought the MWI was the most plausible interpretation anyway.”
I left it at that, and went back
to the kitchen while she pulled out a stack of assignments.
That night, as we lay in bed together, I couldn’t get the Delft experiment out of my mind.
“Do you believe there are other versions of us?” I asked Francine.
“I suppose there must be.” She conceded the point as if it was something abstract and metaphysical, and I was being pedantic even to raise it. People who professed belief in the MWI never seemed to want to take it seriously, let alone personally.
“And that doesn’t bother you?”
“No,” she said blithely. “Since I’m powerless to change the situation, what’s the use in being upset about it?”
“That’s very pragmatic,” I said. Francine reached over and thumped me on the shoulder. “That was a compliment!” I protested. “I envy you for having come to terms with it so easily.”
“I haven’t, really,” she admitted. “I’ve just resolved not to let it worry me, which isn’t quite the same thing.”
I turned to face her, though in the near-darkness we could barely see each other. I said, “What gives you the most satisfaction in life?”
“I take it you’re not in the mood to be fobbed off with a soppy romantic answer?” She sighed. “I don’t know. Solving problems. Getting things right.”
“What if for every problem you solve, there’s someone just like you who fails, instead?”
“I cope with my failures,” she said. “Let them cope with theirs.”
“You know it doesn’t work like that. Some of them simply don’t cope. Whatever you find the strength to do, there’ll be someone else who won’t.”
Francine had no reply.
I said, “A couple of weeks ago, I asked Sadiq about the time he was doing mine clearance. He said it was more satisfying than mopping up DU; one little explosion, right before your eyes, and you know you’ve done something worthwhile. We all get moments in our lives like that, with that pure, unambiguous sense of achievement: whatever else we might screw up, at least there’s one thing that we’ve done right.” I laughed uneasily. “I think I’d go mad, if I couldn’t rely on that.”