The Hindu Business Line : Rules in ‘the world of the very small’

Any computer should be able to do two things: store information in the form of bits (0s and 1s), and offer a way to alter the bits in accordance with instructions (using logic gates. Thus writes Vishal Sahni in Quantum Computing ( www.tatamcgrawhill.com).

“Everything a computer does — whether synthesising speech, calculating the billionth digit of pi or beating Garry Kasparov at chess — ultimately comes about through the transformation of bits by gates,” he explains.

“Could subatomic particles store bits? Could they form gates?” To find answers to these questions, you need to enter the world of quantum computers, which operate according to the rules of quantum mechanics governing ‘the world of the very small: the waves and particles of subatomic physics’.

A startling discovery of twentieth century physicists that gave ‘enormous incentive to apply quantum mechanics to computing’ was that elementary particles such as protons, neutrons, and electrons could exist in two or more states at once, the author narrates.

Conventional electronics has depended on the advancements in miniaturisation and the pronouncement by Gordon Moore (that performance per unit cost increases by a factor of two every 18 months). How long can Moore’s law continue to hold, the author asks? “Can we continue to expect an exponential improvement in performance 20 or more years from now?”

Perhaps, quantum computing is the alternative. Quantum computers are still in labs, but researchers are never tired of describing the possibilities.

“We are writing the software for a device that does not yet exist. Yet, on paper, the prospects are stunning,” says Sahni.

Scenarios include: “An algorithm that could factor 140-digit-long numbers a billion times faster than is currently possible… a search engine that could examine every nook and cranny of the Internet in half an hour, a brute-force decoder that could unscramble a DES (data encryption standard) transmission in five minutes…”

Well, a home quantum computer is among ‘five ideas that will reinvent computing’, according to PC Magazine. The other ideas are IMAX-quality movies at home with new projectors, a mid-air mouse that requires no flat surfa ce, a router-based peer-to-peer system, and a man-made brain, as a recent posting on http://it.slashdot.org states.

The fundamental unit of information in quantum computing is qubit, short for quantum bit. “A qubit can exist not only in a state corresponding to the logical state 0 or 1 as in a classical bit, but also in states corresponding to a blend or superposition of these classical states.” For 500 particles, say, we could create a quantum system that is a superposition of as many as 2 to the power 500 states, explains Sahni. “With one machine cycle, one tick of the computer clock, a quantum operation could compute not just on one machine state, as serial computers do, but on 2 to the power 500 machine states at once.”

As a result, quantum computers would be able to solve problems that classical computers cannot touch. “If functioning quantum computers can be built, harnessing their potential will be just a matter of creating algorithms that carry out the right operations in the right order.”

Ready for the ‘quantum’ leap?

Lousy lounges and laser printers

Intel had to spend more to produce an inferior chip.

Ever wondered why the departure lounges in most airports are shoddy? “If the free departure areas became comfortable, then airlines would no longer be able to sell business-class tickets on the strength of their ‘executive’ lounges,” reasons Tim Harford in The Undercover Economist ( www.penguinbooksindia.com). He finds the phenomenon in supermarkets, too; the own-brand ‘value’ range may display ̵ 6;crude designs’… only “to put off customers who are willing to pay more.” A surprising example from the world of computers, on similar lines, is IBM’s LaserWriter E – a low-end laser printer, which “turned out to be exactly the same piece of equipment as their high-end LaserWriter – except that there was an additional chip in the cheaper version to slow it down.”

To get anyone to buy the expensive printer, IBM had to slow down the cheap one, explains Harford. “It seems wasteful, but presumably it was cheaper for IBM to do this than design and manufacture two completely different printers.” Likewise, Intel had to spend more to produce an inferior chip: “it was made by taking the superior chip and doing extra work to disable one of its features.”

In a chapter on ‘the men who knew the value of nothing’, Harford writes about John von Neumann’s game theory work. “A game, to a game theorist, is any activity in which your prediction of what another person will do affects what you decide to do. Such games include poker, nuclear war, love, or bidding for thin air in an auction.”

Take for instance poker, a game full of spirals of second-guessing, where you need to analyse your opponent’s moves. “Is a small bet a sign of weakness, or a trick to tempt you to raise the stakes against hidden strength? And do big bets mean a big hand — or a bluff? At the same time you must recognise that your opponents will be trying to interpret your own bets, and you must be careful not to be predictable.” In business, spectrum auction in which telecom companies participate is an example of game at play. “Every bidder has some idea of how profitable it would be to own a licence but nobody knows precisely how profitable. The government’s challenge is to find out some secrets: to determine which of the telecom companies can best use the licences, and how much the licences are worth to them.”

Elementary economic inputs that you would always need!

To cupid thru clicks

“Can you really find love through a machine?”

Booting up his laptop, he Googles the words ‘Internet’ and ‘dating’. Who? Sean Thomas in Millions of Women Are Waiting to Meet You ( www.landmarkonthenet.com). Wh at does he get? “Wow. Seven million hits!” He decides to narrow down the search. “But ‘Online dating’, in quotes, still gets nearly three million hits. And ‘Internet romance’ gets seven hundred thousand…”

Thomas has his doubts. “Can you really find love through a machine? Via a screen? With a click of a mouse? Surely any romance born this way would be marred from the start? Surely it would feel manufactured, contrived, artificial, digitised, the Dolly the Sheep of love affairs?”

Entertaining.

Tailpiece

“He bungled up on the date field when dating online.”

“Misdated, you mean?”

“Yes, and that got him a retrospective rejection!”

dmurali@thehindu.co.in