So, from vast data cen­ters to mobile phones, the pow­er of com­put­ers con­tin­ues to trans­form our lives. But there are some prob­lems across arti­fi­cial intel­li­gence, in the design of new mate­ri­als, phar­ma­ceu­ti­cals, and clean ener­gy devices that they will sim­ply nev­er solve. So even if we turned our entire plan­et into a giant super­com­put­er we would­n’t be able to solve these and many oth­er impor­tant prob­lems. The good news is that if we could build a com­put­ing device based on fun­da­men­tal quan­tum prin­ci­ples, we could. 

Cover of New Scientist magazine, with the headline "Quantum Computing: the power of parallel worlds"

New Scientist, Issue 1944, September 241994

And so back when I was a long-haired under­grad­u­ate stu­dent, I lent this mag­a­zine to every­one in my quan­tum mechan­ics class. And the idea that we could build an unimag­in­ably pow­er­ful com­put­er by har­ness­ing the bizarre laws of quan­tum physics seemed crazy. And I nev­er got the mag­a­zine back, but I no longer think it’s crazy. And so in 2001 I was real­ly amazed to tack­le this prob­lem of how we get from the few com­po­nents that we have in the lab to the mil­lions that we need to build a use­ful quan­tum computer. 

And back then in 2001, I was inspired by a real­ly break­through pro­pos­al which showed that actu­al­ly we can quan­tum com­pute with light. What we’ve come to today is the abil­i­ty to man­u­fac­ture a quan­tum com­put­er based on light, using the semi­con­duc­tor indus­try as we know it today

Photo from behind of two people holding large silicon wafers from which computer chips will be cut; their faces are reflected in the wafers

So these sil­i­con wafers con­tain mil­lions of com­put­er chips, and each of those chips con­tains bil­lions of com­put­ers. And so back to the begin­ning of the sto­ry, the idea of using light is a very appeal­ing one. Although it’s fly­ing around at the speed of light these sys­tems exhib­it almost no noise. So they’re not plagued by the noise that almost all oth­er quan­tum sys­tems are sub­ject to. 

And so I switched from a matter-based approach to quan­tum com­put­ing and spent the next two years align­ing and design­ing and assem­bling this for­est of opti­cal ele­ments on a huge lab­o­ra­to­ry table. And this sys­tem imple­ment­ed the key build­ing block, a log­ic gate.

Now, an impres­sive proof of prin­ci­ple? Sure. Manufacturable by the mil­lions? Absolutely not. And that sim­ply was­n’t good enough for us. 

And so by 2008, we’d tak­en that entire lab­o­ra­to­ry bench full of opti­cal com­po­nents and put it onto a sil­i­con chip mea­sured in cen­time­ters. Now, that was real­ly excit­ing progress, and bode well for the future of quan­tum com­put­ing, but there was still plen­ty more work to be done. 

And so just two years ago, we were able to take those same build­ing blocks and make them one mil­lion times small­er. But even more impor­tant­ly, we used the stan­dard tools of a man­u­fac­tur­ing line of a big chip mak­er. And so this brought the prospect of large scale quan­tum com­put­ing into sharp focus. 

And so we’ve spent the two years since devel­op­ing and refin­ing this blue­print, which peo­ple are start­ing to get very excit­ed about. I’m sure it won’t be obvi­ous in a quick glance, but all of the com­po­nents are stan­dard and no exot­ic fab­ri­ca­tion or oper­at­ing con­di­tions are required. And this blue­print will enable us to build the first quan­tum machine capa­ble of tack­ling impor­tant prob­lems across arti­fi­cial intel­li­gence, genomics, and genet­ic engi­neer­ing. In finance, and in the design of new mate­ri­als, phar­ma­ceu­ti­cals, and clean ener­gy devices. 

It’s also true that if you look any­where across sci­ence and tech­nol­o­gy, you’ll find prob­lems that a quan­tum com­put­er can solve. And solv­ing these prob­lems will enable us to tack­le some of the great chal­lenges that we face today in cli­mate change, in eco­nom­ics, in Big Data, in cyber­se­cu­ri­ty, and so the list goes on.

And so to con­clude, with­out a real­is­tic plan of how to man­u­fac­ture the mil­lions of com­po­nents that we need for a quan­tum com­put­er, schemes are worth noth­ing. The only way that humankind cur­rent­ly knows how to make sys­tems with that many com­po­nents is using sil­i­con chip man­u­fac­tur­ing tech­nol­o­gy. And we’re in the process of doing that to bring it to bear on some of these grand chal­lenges. And I think just as the com­put­er is now at the cen­ter of our lives, so to a quan­tum com­put­er will ignite a new tech­nol­o­gy rev­o­lu­tion that will trans­form almost every aspect of our lives, soci­ety, and economy.

We’ll build this device by the end of this decade. And so I’d like to fin­ish by ask­ing you, how would you like to har­ness it to improve your life and your busi­ness? And most impor­tant­ly how can we help you do that?

Further Reference

Professor Jeremy O’Brien’s pro­file at the University of Bristol School of Physics site.