Skip to main content

Quantum computing

 


Have I written anything about quantum computing in this blog?  I wrote so much here about so many things it is difficult to keep track. 

Ah, I just completed a survey of posts in the history of this blog that involve quantum mechanics  There is a fair number.  NONE of them address the question on my mind today -- whether humanity's understanding of quantum mechanics is about to set off a jump in our marketable computational power. So ... I will correct that lacuna. 

This could yet be the biggest disruption in the high-tech world since transistors replaced vacuum tubes. 

Existing computers, digital computers, work with a lot of on/off gates. Another way of saying this is that they calculate by “1” and “0.” Either number is called a “bit.” Quantum computers, first discussed theoretically by Richard Feynman and Yuri Manin in the early 1980s, have on/off/both gates. In numerical terms, a datum can still be a 1, or a 0, but can also be superposition of 1 and 0.

In essence, the superposition is a probability wave. When, at some point in the performance of a particular algorithm, the wave is collapsed, the value becomes either 1 or 0: until then, the wave represents the probability that it will be the one or the other when that point arrives. In terms of the cliched image: at some point in the execution of a program, the lid is opened and the “cat” is either alive or dead. Until then, it is both.

Superposition means that qubits store more data than bits, which allows for much greater computing power. Indeed, the difference in degree becomes a difference in kind. As John Loeffler, the managing editor of Interesting Engineering, has put it, a “trillion-year problem” can be reduced to a two- to five-year problem “with a quantum computer, and only with a quantum computer.”

Loeffler -- that is his image above -- wrote about the trillion-year problem five years ago, though. That editorial appeared in 2019. And even then there was a sense that a quantum revolution in engineering was hanging fire. It was a huge revolution that was "just about" to happen, but nobody could quantify just how quick "just about" could be. 

And here we are, five years since Loeffler's hopeful words, and the fire is still hanging. 

Now I've said so here. 

Comments

Post a Comment

Popular posts from this blog

A Story About Coleridge

This is a quote from a memoir by Dorothy Wordsworth, reflecting on a trip she took with two famous poets, her brother, William Wordsworth, and their similarly gifted companion, Samuel Taylor Coleridge.   We sat upon a bench, placed for the sake of one of these views, whence we looked down upon the waterfall, and over the open country ... A lady and gentleman, more expeditious tourists than ourselves, came to the spot; they left us at the seat, and we found them again at another station above the Falls. Coleridge, who is always good-natured enough to enter into conversation with anybody whom he meets in his way, began to talk with the gentleman, who observed that it was a majestic waterfall. Coleridge was delighted with the accuracy of the epithet, particularly as he had been settling in his own mind the precise meaning of the words grand, majestic, sublime, etc., and had discussed the subject with William at some length the day before. “Yes, sir,” says Coleridge, “it is a maj...
9 comments
Read more

Searle: The Chinese Room

John Searle has become the object of accusations of improper conduct. These accusations even have some people in the world of academic philosophy saying that instructors in that world should try to avoid teaching Searle's views. That is an odd contention, and has given rise to heated exchanges in certain corners of the blogosphere.  At Leiter Reports, I encountered a comment from someone describing himself as "grad student drop out." GSDO said: " This is a side question (and not at all an attempt to answer the question BL posed): How important is John Searle's work? Are people still working on speech act theory or is that just another dead end in the history of 20th century philosophy? My impression is that his reputation is somewhat inflated from all of his speaking engagements and NYRoB reviews. The Chinese room argument is a classic, but is there much more to his work than that?" I took it upon myself to answer that on LR. But here I'll tak...
17 comments
Read more

Recent Controversies Involving Nassim Taleb, Part I

I've written about Nassim Taleb on earlier occasions in this blog. I'll let you do the search yourself, dear reader, for the full background. The short answer to the question "who is Taleb?" is this: he is a 57 year old man born in Lebanon, educated in France, who has been both a hedge fund manager and a derivatives trader. He retired from active participation from the financial world sometime between 2004 and 2006, and has been a full-time writer and provocateur ever since. Taleb's writings for the general public began where one might expect -- in the field where he had made his money -- and he explained certain financial issues to a broad audiences in a very dramatic non-technical way. Since then, he has widened has fields of study, writing about just about everything, applying the intellectual tools he honed in that earlier work. As you might have gather from the above, I respect Taleb, though I have sometimes been critical of him when my own writing ab...
4 comments
Read more