The heat in Calcutta is pulverising. Ed Hatt finds it almost impossible to think clearly about anything other than shade and cold water. His Bengali is good enough to direct a taxi driver to a place and count out the cash afterwards, but outside of vehicles, the only way to get anywhere in India is to traipse, or possibly to slog. Wandering, ambling and strolling simply aren't appropriate gaits for an Englishman in such a climate. The sky is unbroken blue, and standing in direct sunlight hurts.

It's 1974 and Hatt is a newly-minted adult, fresh out of Oxford and adrift eastward, looking for whatever, or whatever. Real life has been on hold all the way through his MEng, and is still on hold. He knows that, some months from now, it will reassert itself. At that point, he will be grudgingly forced to find a job. He hopes that he can find something worth becoming excited about by then. He hopes for some kind of epiphany. Or, failing all of that, he hopes to bore himself and tire himself out, sufficiently that going home and doing the same thing every weekday for a year sounds like a welcome break.

Hatt is learning that the world doesn't exist entirely for his benefit. A random city in the world may or may not contain birthplaces, memorials, teeming tat-filled markets and picturesque little bars stocked with cheap booze. A city may or may not be geared to speak English back to Ed Hatt, the tourist, but a city is always a functional machine, and his final impression of any given day, as he's traipsing back to the hotel, is of the machinery. It has operated for hundreds of years before he arrived and it'll continue to operate for hundreds of years after he's gone. Calcutta is flooded with people with crowded lives to lead, lives that have nothing whatsoever to do with him.

After four and a half days Hatt has left a crisscrossing trail over the city. He's seen the stunning white stone colonial relics, the stadiums, the museums, and the astonishing Hindu temples resembling fractal stone eggs - built according to Vastu shastra, the Hindu equivalent to feng shui. He's eaten and drunk, finished reading one book, bought another book, scribbled pages of experiences and sent a dozen postcards. The food is other-worldly. Twice every day (once on the way out from the hotel, once on the way back) he passes the same bunch of kids and joins in with their back-alley cricket game for half an hour. But he hasn't got it yet. His compass is still spinning.

This far east, Hatt realises, and he's really looking for a reason to go home again.

On his way home on the fifth day, Hatt cuts through a park to get to a main road to find a taxi. Or tries, but there are around a hundred people in the way. It's clearly a demonstration, although Hatt can't tell which sense of the word is more appropriate. Hatt is in no hurry so he allows himself to be delayed. He finds a low wall and stands on it to get a better view.

A circle roughly thirty metres wide has been cleared, and two men are marking out a pattern in the grass using pegs, string and surveyor's wheels. Hatt's first guess is that they are pitching a rangoli pattern of some kind. At calculated points, they plant thin poles in the ground. Most of the poles are metal - any of a million identical-looking shiny grey metals and alloys. Some are recognisably copper. Some are recognisably glass. The men are college- or Ph.D.-aged, within five years of Hatt himself. They wear white shirts and dark trousers and have pens in their breast pockets. A third, much older fellow with a tie and a large blue binder full of ragged-edged scraps of paper is directing the activity. He is sixty-something, and his glasses are small and circular.

As for the crowd, they are men and women of all ages. There's a healthy murmur in the crowd but they are mostly watching quietly. Some people carry flags or occasionally shout slogans. Hatt unexpectedly recognises some of the slogans. But the fragments he recognises aren't the elementary fragments of Bengali that he's gathered together from his phrasebook. They're mathematical terminology; obscure and cryptic keywords from a plasma dynamics course still very fresh in Hatt's memory.

There's a clear demarcation between the observers and the scientists. The crowd is treating it like a pre-show, waiting for something cool to start. The scientists are treating the crowd like a nuisance. They're trying to get something accomplished; they never formally invited any onlookers. There's nothing priestly about their movements. It's an experiment under construction.

The lead scientist uses a magnetometer-like device to examine the highly symmetrical arrangement of poles, sometimes closing one eye and sighting along a row of them in one direction, sometimes uprooting another pole and replanting it a few millimetres to the left. Once the poles are arranged to his satisfaction he carries out a similar series of measurements and adjustments using a theodolite. He stands behind the pole at the north end of the system. The crowd falls silent. He speaks, measuring out discrete syllables like sand grains:

" Aum. Asnaku pambetamba alasana rathaa ka'u kah kadhunda jarama ra alanashyi a aum. Alithua j'lu j'la aurot'e we iktha'u gee sub ai. Murihaa akurutaatwanhibhrandya aum. Traanhdha epil sub ai anah myu oshodapachaa. Nath bhoshu alef ad'yegh. Aum. "

The words are noise to Hatt, meaningless in English, French or Bengali, although the "sub ais" tickle something in Hatt's mind, brushing up against understanding without actually finding purchase. But he doesn't have the chance to think about it, because, after the last "aum", the hairs on his arms stand straight up and the seven glass light tubes light up in red and blue so bright at the core as to be white. It's like a camera flash, but much longer in duration, at least a second. It bathes the entire park and the surrounding buildings. Everybody winces and shields his or her eyes, scientists and crowd alike. A round of applause follows immediately.

Hatt joins in the applause although he still doesn't know what he just saw. The sciencey types are all congratulating one another, particularly the senior man, and the crowd is pressing in on them as well to add their congratulations. Hatt doesn't know if the demonstration qualifies as a magic trick. Powering up a fluorescent tube without touching it is far from impossible.

"Not bad," Hatt remarks aloud, to nobody, and then he sees it: his own breath, condensing out in a thin white cloud.

He shivered when the light flash began. For that first second he thought it was just nervous tension. Power for the lights could have come from anywhere. And he can feel the warm, cloyingly wet air stirring back in even as seconds pass. But for this one second, he's cold. He can feel himself thinking more clearly than he ever has since he first stepped off the plane. And he can feel thermodynamics as he knows it quietly swivelling upside-down.

He dives into the crowd, wading towards the man in the small circular glasses.

*

Half an hour later Vidyasagar has brought him to the machine room. The room is completely white and immaculately clean, populated with huge cuboidal blocks full of raw, humming computer. Along one wall are filing cabinets full of manuals and printouts and computer code. Vidyasagar invites Hatt to take a seat next to one of the terminals, an intimidatingly large panel of lights and switches as comprehensible as the dashboard of a 747. Hatt relaxes, actually feeling rather at home.

Rajesh Vidyasagar does not sit, or lean against anything. He carries himself carefully. He is tidy, and putting weight on. His English is hesitant and very dry, or in other words fully fifty thousand times better than Hatt's Bengali; they settle on English. For his part, Hatt tries to clamp down on the colloquialisms and florid metaphors. They have to speak loudly to overcome the noise of computer system fans and the air conditioning. At least it's cool here.

"One says the correct words," Vidyasagar explains, "and thinks the correct thoughts at the same time. Then, a physical effect occurs."

"That's it?"

"As far as we can tell, that's it."

Hatt rubs an eye, barely believing it despite the evidence of his own senses. "That's insane."

Vidyasagar nods sadly. "I know."

"And there's no religious element? There's no spiritual element?"

"No," says Vidyasagar. "It's pure physics. Despite what it looked like out there. We are surrounded by believers of things which are not actually true. We try to separate the science out from the 'ritual', but it's difficult. Unfortunately, that park is the nearest open space that we have access to."

"The University of Calcutta doesn't have a tennis court you can book, or something?"

"Of course," says Vidyasagar, mildly indignant. "On the other side of the city. This is the Science College."

"So it doesn't overlap with Hindu teachings? Or Buddhist or Sikh?"

"If it did, don't you think we would have discovered all of this a thousand years ago?"

"I..." Hatt's ancient Indian history is lamentable, despite all his visits to holy sites. "Maybe? I don't know."

"It doesn't overlap. Any overlap is just a coincidence," Vidyasagar says. "Or convenient terminology. To you, the language sounds similar to Bengali or Hindi. In reality it is a code for a sequence of quantum mechanical effects. We think that what we are seeing is a previously unknown function of the human brain. We also think a new form of potential energy must be involved; this is the only explanation for the apparent violation of the laws of thermodynamics. And that's... almost all we know so far. There is still a vast number of unanswered questions. We don't understand the mechanism at all yet. Or the language. We are still exploring the rules."

"The shastra," Hatt says.

"The rules," Vidyasagar says. He holds up his blue binder of notes. "We know a little so far. We are filling this in as we go. Today, we ran a new program on the mainframe. A problem of optimisation. We solved the equations numerically. For a specific area and sequence of words."

"The program told you where to place the metal rods?"

"And what kind of rods to use. We find that the noble gases are best. Also, steel is good. Everything must be arranged correctly in space."

Hatt thinks hard. He gets up and stalks around the room, circling one of the heavy mainframes. It resembles a monolith from 2001, both in form factor and computational power. It practically glows with radiant heat. "Okay," he says. "So. You haven't announced anything publicly yet. Or if you have, you've been ignored by other scientists, other than your two students. In either case, I can see why. Every unanswered question you have is a reason why. It feels like cargo cult physics. This whole thing is--"

"It's trash," Vidyasagar says. Hatt looks at him a little more carefully, and Vidyasagar's expression seems to be one of self-revulsion.

"Trash?"

"We haven't announced anything because people would laugh at us. We have found some kind of fault in the universe. We need to fix it before we can say anything. And we need to understand it before we can fix it."

On this point, Ed Hatt completely disagrees. "Agriculture was an industry thousands of years before humans understood photosynthesis. A thing doesn't have to be understood before it can be useful. And using a thing is the best way to understand it. And if nobody will take a scientific paper seriously, we can demonstrate result after result until they take us seriously. We can make the world better until they take us seriously. Do you have the slightest idea how big this is?"

Vidyasagar says, carefully, "I have a slight idea."

Hatt says, "There isn't a single field of engineering, which I can think of, for which this discovery isn't colossally important. There isn't a single machine in the world which can't be made more efficient. The commercial applications are limitless. Electricity generation, heat management in space, heat management in--" he points with a thumb "--computer microprocessors, refrigeration of every kind. When you're outside, you're surrounded with religious zealots who don't understand that what you've found isn't a new religion. Or some old religion in new clothes. The students you're leading are physicists, with an eye for the hard questions and no conception of financial reality. I'm here to tell you that I get it. I'm a man of business and machinery. I felt something during that demonstration. Like we just hit the tip of some colossal iceberg. I mean... like this is the beginning of a huge and incredibly important future. This is the new electricity."

"Don't talk about the future," Vidyasagar says.

"What? Why not?"

"Look at this computer," Vidyasagar says, gesturing at the mainframe. "Computers are getting more powerful, yes?"

"Sure."

"What is the most powerful computer that will be built? Ever. Not this year. Not this decade. What computer will be the most powerful? And how powerful will it be? And how big?"

Hatt thinks on this for ten long seconds. He opens his mouth, but never actually forms a word. The scale of the question is beyond him.

Vidyasagar says to him, "No matter what you say, you will look like a fool. Every statement about the future turns out to be foolish. All this, from heat-into-electricity? I have a word sequence which turns heat directly into light. I have one which creates kinetic energy from nothing at all." Hatt's mind boggles at these new claims. "Yes, I have a slight idea of what's begun. But I don't know. You don't know, neither of us knows!"

"You're right." Hatt pinches the bridge of his nose, the visions in his mind's eye now too bright and fast-changing to unscramble. "You're right."

"Before anything else, there is a huge amount of work to be done," Vidyasagar tells him.

The visions in Hatt's mind's eye are formless, as if waiting for him to move in and shape them.

"By us," he says.