Prof. John Preskill
Scientists who work on theoretical aspects of quantum computation and information look forward each year to the Conference on Quantum Information Processing (QIP), an annual event since 1998. This year’s meeting, QIP 2019, was hosted this past week by the University of Colorado at Boulder. I attended and had a great time, as I always do. But this year, in addition to catching up with old friends and talking with colleagues about the latest research advances, I also accepted a humbling assignment: I was the after-dinner speaker at the conference banquet. Here is (approximately) what I said.
QIP 2019 After-Dinner Speech 16 January 2019
Thanks, it’s a great honor to be here, and especially to be introduced by Graeme Smith, my former student. I’m very proud of your success, Graeme. Back in the day, who would have believed it?
And I’m especially glad to join you for these holiday festivities. You do know this is a holiday, don’t you? Yes, as we do every January, we are once again celebrating Gottesman’s birthday! Happy Birthday, Daniel!
Look, I’m kidding of course. Yes, it really is Daniel’s birthday — and I’m sure he appreciates 500 people celebrating in his honor — but I know you’re really here for QIP. We’ve been holding this annual celebration of Quantum Information Processing since 1998 — this is the 22nd QIP. If you are interested in the history of this conference, it’s very helpful that the QIP website includes links to the sites for all previous QIPs. I hope that continues; it conveys a sense of history. For each of those past meetings, you can see what people were talking about, who was there, what they looked like in the conference photo, etc.
Some of you were there the very first time – I was not. But among the attendees at the first QIP, in Arhus in 1998, where a number of brilliant up-and-coming young scientists who have since then become luminaries of our field. Including: Dorit Aharonov, Wim van Dam, Peter Hoyer (who was an organizer), Michele Mosca, John Smolin, Barbara Terhal, and John Watrous. Also somewhat more senior people were there, like Harry Buhrman and Richard Cleve. And pioneers so eminent that we refer to them by their first names alone: Umesh … Gilles … Charlie. It’s nice to know those people are still around, but it validates the health of our field that so many new faces are here, that so many young people are still drawn to QIP, 21 years after it all began. Over 300 students and postdocs are here this year, among nearly 500 attendees.
QIP has changed since the early days. It was smaller and more informal then; the culture was more like a theoretical physics conference, where the organizing committee brainstorms and conjures up a list of invited speakers. The system changed in 2006, when for the first time there were submissions and a program committee. That more formal system opened up opportunities to speak to a broader community, and the quality of the accepted talks has stayed very high — only 18% of 349 submissions were accepted this year.
In fact it has become a badge of honor to speak here — people put it on their CVs: “I gave a QIP contributed talk, or plenary talk, or invited talk.” But what do you think is the highest honor that QIP can bestow? Well, it’s obvious isn’t it? It’s the after-dinner speech! That’s the talk to rule them all. So Graeme told me, when he invited me to do this. And I checked, Gottesman put it on his website, and everyone knows Daniel is a very serious guy. So it must be important. Look, we’re having a banquet in honor of his birthday, and he can hardly crack a smile!
I hear the snickers. I know what you’re thinking. “John, wake up. Don’t you see what Graeme was trying to tell you: You’re too washed up to get a talk accepted to QIP! This is the only way to get you on the program now!” But no, you’re wrong. Graeme told me this is a great honor. And I trust Graeme. He’s an honest man. What? Why are you laughing? It’s true.
I asked Graeme, what should I talk about? He said, “Well, you might try to be funny.” I said, “What do you mean funny? You mean funny Ha Ha? Or do you mean funny the way cheese smells when it’s been in the fridge for too long?” He said, “No I mean really, really funny. You know, like Scott.”
So there it was, the gauntlet had been thrown. Some of you are too young to remember this, but the most notorious QIP after-dinner speech of them all was Scott Aaronson’s in Paris in 2006. Were you there? He used props, and he skewered his more senior colleagues with razor sharp impressions. And remember, this was 2006, so everybody was Scott’s more senior colleague. He was 12 at the time, if memory serves.
He killed. Even I appreciated some of the jokes; for example, as a physicist I could understand this one: Scott said, “I don’t care about the fine structure constant, it’s just a constant.” Ba ding! So Scott set the standard back then, and though many have aspired to clear the bar since then, few have come close.
But remember, this was Graeme I was talking to. And I guess many of you know that I’ve had a lot of students through the years, and I’m proud of all of them. But my memory isn’t what it once was; I need to use mnemonic tricks to keep track of them now. So I have a rating system; I rate them according to how funny they are. And Graeme is practically off the chart, that’s how funny he is. But his is what I call stealth humor. You can’t always tell that he’s being funny, but you assume it.
So I said, “Graeme, What’s the secret? Teach me how to be funny.” I meant it sincerely, and he responded sympathetically. Graeme said, “Well, if you want to be funny, you have to believe you are funny. So when I want to be funny, I think of someone who is funny, and I pretend to be that person.” I said, “Aha, so you go out there and pretend to be Graeme Smith?” And Graeme said, “No, that wouldn’t work for me. I close my eyes and pretend I’m … John Smolin!” I said, “Graeme, you mean you want me to be indistinguishable from John Smolin to an audience of computationally bounded quantum adversaries?” He nodded. “But Graeme, I don’t know any plausible cryptographic assumptions under which that’s possible!”
Fortunately, I had another idea. “I write poems,” I said. “What if I recite a poem? This would set a great precedent. From now on, everyone would know: the QIP after-dinner speech will be a poetry slam!”
Graeme replied “Well, that sounds [long pause] really [pause] boring. But how about a limerick? People love limericks.” I objected, “Graeme, I don’t do limericks. I’m not good at limericks.” But he wouldn’t back down. “Try a limerick,” Graeme said. “People like limericks. They’re so [pause] short.”
But I don’t do limericks. You see:
I was invited to speak here by Graeme. He knows me well, just as I am. He was really quite nice When he gave this advice: Please don’t do a poetry slam.
Well, like I said, I don’t do limericks.
So now I’m starting to wonder: Why did they invite me to do this anyway? And I think I figured that out. See, Graeme asked me to speak just a few days ago. This must be what happened. Like any smoothly functioning organizing committee, they lined up an after-dinner speaker months in advance, as is the usual practice.
But then, just a few days before the conference began, they began to worry. “We better comb through the speaker’s Twitter feed. Maybe, years ago, our speaker said something offensive, something disqualifying.” And guess what? They found something, something really bad. It turned out that the designated after-dinner speaker had once made a deeply offensive remark about something called “quantum supremacy” … No, wait … that can’t be it.
Can’t you picture the panicky meeting of the organizers? QIP is about to start, and there’s no after-dinner speaker! So people started throwing out suggestions, starting with the usual suspects.
“How about Schroedinger’s Rat?” “No, he’s booked.” “Are you telling me Schroedinger’s Rat has another gig that same night?” “No, no, I mean they booked him. A high-profile journal filed a complaint and he’s in the slammer.” “Well, how about RogueQIPConference?” “No, same problem.”
“I’ve got it,” someone says: “How about the hottest quantum Twitter account out there? Yes, I’m talking about Quantum Computing Memes for QMA-Complete Teens!”
Are you all following that account? You should be. That’s where I go for all the latest fast-breaking quantum news. And that’s where you can get advice about what a quantumist should wear on Halloween. Your costume should combine Sexy with your greatest fear. Right, I mean Sexy P = BQP.
Hey does that worry you? That maybe P = BQP? Does it keep you up at night? It’s possible, isn’t it? But it doesn’t worry me much. If it turns out that P = BQP, I’m just going to make up another word. How about NISP? Noisy Intermediate-Scale Polynomial.
I guess they weren’t able to smoke out whoever is behind Quantum Computing Memes for QMA-Complete Teens. So here I am.
Aside from Limericks, Graeme had another suggestion. He said, “You can reminisce. Tell us what QIP was like in the old days.” “The old days?” I said. “Yes, you know. You could be one of those stooped-over white-haired old men who tells interminable stories that nobody cares about.” I hesitated. “Yeah, I think I could do that.”
Okay, if that’s what you want, I’ll tell a story about my first QIP; that was QIP 2000, which was actually in Montreal in December 1999. It was back in the BPC era — Before Program Committee — and I was an invited speaker (I talked about decoding the toric code). Attending with me was Michael Nielsen, then a Caltech postdoc. Michael’s good friend Ike Chuang was also in the hotel, and they were in adjacent rooms. Both had brought laptops (not a given in 1999), and they wanted to share files. Well, hotels did not routinely offer Internet access back then, and certainly not wireless. But Ike had brought along a spool of Ethernet cable. So Ike and Mike both opened their windows, even though it was freezing cold. And Ike leaned out his window and made repeated attempts to toss the cable though Michael’s window before he finally succeeded, and they connected their computers.
I demanded to know, why the urgent need for a connection? And that was the day I found what most of the rest of the quantum world already knew: Mike and Ike were writing a book! By then they were in the final stages of writing, after some four years of effort (they sent the final draft of the book off to Cambridge University Press the following June).
So, QIP really has changed. The Mike and Ike book is out now. And it’s no longer necessary to open your window on a frigid Montreal evening to share a file with your collaborator.
Boy, it was cold that week in Montreal. [How cold was it?] Well, we went to lunch one day during the conference, and were walking single file down a narrow sidewalk toward the restaurant, when Harry Buhrman, who was right behind me, said: “John, there’s an icicle on your backpack!” You see, I hadn’t screwed the cap all the way shut on my water bottle, water was leaking out of the bottle, soaking through the backback, and immediately freezing on contact with the air; hence the icicle. And ever since then I’ve always been sure to screw my bottle cap shut tight. But over the years since then, lots of other things have spilled in my backpack just the same, and I’d love to tell you about that, but …
Well, my stories may be too lacking in drama to carry the evening …. Look, I don’t care what Graeme says, I’m gonna recite some poems!
I can’t remember how this got started, but some years ago I started writing a poem whenever I needed to introduce a speaker at the Caltech physics colloquium. I don’t do this so much anymore. Partly because I realized that my poetry might reveal my disturbing innermost thoughts, which are best kept private.
Actually, one of my colleagues, after hearing one of my poems, suggested throwing the poem into a black hole. And when we tried it … boom …. it bounced right back, but in a highly scrambled form! And ever since then I’ve had that excuse. If someone says “That’s not such a great poem,” I can shoot back, “Yeah, but it was better before it got scrambled.”
But anyway, here’s one I wrote to honor Ben Schumacher, the pioneer of quantum information theory who named the qubit, and whose compression theorem you all know well.
Ben. He rocks. I remember When He showed me how to fit A qubit In a small box. I wonder how it feels To be compressed. And then to pass A fidelity test. Or does it feel At all, and if it does Would I squeal Or be just as I was? If not undone I’d become as I’d begun And write a memorandum On being random. Had it felt like a belt Of rum? And might it be predicted That I’d become addicted, Longing for my session Of compression? I’d crawl To Ben again. And call, “Put down your pen! Don’t stall! Make me small!”
Yeah that’s the response I usually get when I recite this poem — embarrassed silence, followed by a few nervous titters.
So, as you can see, as in Ben Schumacher’s case, I use poetry to acknowledge our debt to the guiding intellects of our discipline. It doesn’t always work, though. I once tried to write a poem about someone I admire very much, Daniel Gottesman, and it started like this:
When the weather’s hottest, then I call for Daniel Gottesman. My apples are less spotted when Daniel eats the rottenest ten …
It just wasn’t working, so I stopped there. Someday, I’ll go back and finish it. But it’s tough to rhyme “Gottesman.”
More apropos of QIP, some of you may recall that about 12 years ago, one of the hot topics was quantum speedups for formula evaluation, a subject ignited by a brilliant paper by Eddie Farhi, Jeffrey Goldstone, and Sam Gutmann. They showed there’s a polynomial speedup if we use a quantum computer to, say, determine whether a two-player game has a winning strategy. That breakthrough inspired me to write an homage to Eddie, which went:
We’re very sorry, Eddie Farhi Your algorithm’s quantum. Can’t run it on those mean machines Until we’ve actually got ‘em. You’re not alone, so go on home, Tell Jeffrey and tell Sam: Come up with something classical Or else it’s just a scam. Unless … you think it’s on the brink A quantum-cal device. That solves a game and brings you fame. Damn! That would be nice!
Now, one thing that Graeme explained to me is that the white-haired-old-man talk has a mandatory feature: It must go on too long. Maybe I have met that criterion by now. Except …
There’s one thing Graeme neglected to say. He never told me that I must not sing at QIP.
You see, there’s a problem: Tragically, though I like to sing, I don’t sing very well at all. And unfortunately, I am totally unaware of this fact. So I sometimes I sing in public, despite strongly worded advice not to do so.
When I was about to leave home on my way to QIP, my wife Roberta asked me, “When are you going to prepare your after-dinner talk?” I said, “Well, I guess I’ll work on it on the plane.” She said, “LA to Denver, that’s not a long enough flight.” I said, “I know!”
What I didn’t say, is that I was thinking of singing a song. If I had, Roberta would have tried to stop me from boarding the plane.
So I guess it’s up to you, what do you think? Should we stop here while I’m (sort of) ahead, or should we take the plunge. Song or no song? How many say song?
All right, that’s good enough for me! This is a song that I usually perform in front of a full orchestra, and I hoped the Denver Symphony Orchestra would be here to back me up. But it turns out they don’t exist anymore. So I’ll just have to do my best.
If you are a fan of Rodgers and Hammerstein, you’ll recognize the tune as a butchered version of Some Enchanted Evening, But the lyrics have changed. This song is called One Entangled Evening.
One entangled evening We will see a qubit And another qubit Across a crowded lab. And somehow we’ll know We’ll know even then This qubit’s entangled Aligned with its friend. One entangled evening We’ll cool down a circuit See if we can work it At twenty milli-K. A circuit that cold Is worth more than gold For qubits within it. Will do as they’re told. Quantum’s inviting, just as Feynman knew. The future’s exciting, if we see it through One entangled evening Anyons will be braiding And thereby evading The noise that haunts the lab. Then our quantum goods Will work as they should Solving the problems No old gadget could! Once we have dreamt it, we can make it so. Once we have dreamt it, we can make it so!
The song lyrics are meant to be uplifting, and I admit they’re corny. No one can promise you that, in the words of another song, “the dreams that you dare to dream really do come true.” That’s not always the case.
At this time in the field of quantum information processing, there are very big dreams, and many of us worry about unrealistic expectations concerning the time scale for quantum computing to have a transformative impact on society. Progress will be incremental. New technology does not change the world all at once; it’s a gradual process.
But I do feel that from the perspective of the broad sweep of history, we (the QIP community and the broader quantum community) are very privileged to be working in this field at a pivotal time in the history of science and technology on earth. We should deeply cherish that good fortune, and the opportunities it affords. I’m confident that great discoveries lie ahead for us.
It’s been a great privilege for me to be a part of a thriving quantum community for more than 20 years. By now, QIP has become one of our venerable traditions, and I hope it continues to flourish for many years ahead. Now it’s up to all of you to make our quantum dreams come true. We are on a great intellectual adventure. Let’s savor it and enjoy it to the hilt!
Thanks for putting up with me tonight.
This is also posted on our partner website www.quantumfrontiers.com