
Review of Vivek Wadhwa’s Washington Post Column on Quantum Computing - jashkenas
https://www.scottaaronson.com/blog/?p=3645
======
kirrent
Interestingly, Vivek Wadhwa said that his source for quantum computing being
useful for travelling salesman by trying all possibilities in parallel was
from the researcher Michelle Simmons in a Ted talk. I decided to watch it to
see how he'd misinterpreted it and he hadn't!

From 4:30 Simmons brings out the laundry list of quantum computing
misconceptions. These are that the TSP scales poorly for classical computers
and implies it doesn't for QC, implies that there's an efficient quantum
algorithm for list lookups because the list can be read in parallel, and says
the power of QC is partially because you can store so much information in the
superposition (which is, at the very least, misleading). Then she starts
comparing the power of QC and classical computers, saying that a 300 bit QC
would be more powerful than all the computers in the world put together. In a
section that's about what quantum computers will be useful for she includes as
examples economic and climate modelling, which is news to me. The slides even
include the phrase - 'Quantum computer- can check many different possibilities
in parallel'.

All in all, I'm not surprised that Wadhwa was confused.

[https://www.youtube.com/watch?v=cugu4iW4W54](https://www.youtube.com/watch?v=cugu4iW4W54)

~~~
shaki-dora
> useful for she includes as examples economic and climate modelling, which is
> news to me

These are just rather generic examples of computationally-expensive fields of
study.

~~~
OscarCunningham
I don't think that there's any evidence at all that quantum computers will
provide a speedup on generic problems.

------
shaki-dora
I think the comments show a real desire on the author's part to learn about
any possible inaccuracies in his editorial, and I would have wished for a
slightly more constructive response by Scott.

As it is, his main points seem to be:

\- The Y2K comparison, which, eventually, he seems to agree may indeed be
accurate.

\- The "trying all possible solutions simultaneously" explanation of qc. This
is a very common explanation, and from what I gather from Scott's comments is
that it's inaccurate for TSP, but possibly right for problems that are better
structured to use the technology(?)

\- An off-topic criticism of the author's previous article calling bitcoin a
Ponzi scheme. That article may have been premature in its predictions, but
seems accurate on the facts. Who would be miffed of being warned of a ponzi
scheme _too early_?

\- That matrix multiplication bit, which indeed appears to be mostly
gibberish. Although my take-away from the sentence would mostly be the
_existence_ of "quantum-resistant" algorithms, which seems accurate (and would
also hint at the non-universality of the claims of speedups.)

I guess Scott may be unwilling to "do the author's work for them", so to
speak. And it's laudable that he mentions some of the good work the WP has
been doing, instead of succumbing to the nihilistic cynicism so common these
days.

But for as long as someone is showing a good-faith effort to improve, I think
it's worth for experts in a field to engage constructively with them. Quantum
Computing is niche enough that it's entirely plausible that someone with
plenty of expertise on computing and the best intentions could end up writing
such an article just from a few misunderstandings in their communications with
the experts they found.

~~~
rspeer
> The "trying all possible solutions simultaneously" explanation of qc. This
> is a very common explanation, and from what I gather from Scott's comments
> is that it's inaccurate for TSP, but possibly right for problems that are
> better structured to use the technology(?)

From what I gather from Scott's comments (and the tagline of his entire blog),
this common explanation is basically always incorrect. Quantum algorithms do
not try all solutions simultaneously.

That's a description of the theoretical model of nondeterministic computing
(like where "NP" comes from), not of quantum computing.

~~~
OscarCunningham
In fact both quantum computers and nondeterministic computers can perform a
computation on all possible inputs simultaneously. The difference is in what
happens afterwards.

A nondeterministic computer halts in the "success" state if _any_ of the
individual threads halted succesfully. This turns out to be tremendously
useful.

A quantum computer run on a quantum superposition of all possible inputs gives
you a superposition of the outputs. If you we're to measure it directly you
would just get one of the outputs chosen at random. This not useful. But
sometimes (on particular problems with a suitable structure) further work can
be done on the superposed state before measuring it, in such a way that the
results of the measurement are useful.

~~~
kgwgk
> If you we're to measure it directly you would just get one of the outputs
> chosen at random.

The point is that not all the outputs are equally probable and (in the
interesing cases) you will get the “right” answer with high probability.

~~~
OscarCunningham
My point is that if you do it the naive way then they are all equally likely.
You need to do something extra to make the ones you want more likely. And this
only works in some cases. (I guess Grover's algorithm works in all cases, but
it's not a exponential speedup.)

~~~
kgwgk
I thought that something extra was part of “running a quantum computer”.

------
RyanZAG
_> Do you, like me, consider them one of the most important venues on earth
for people to be able to trust right now? How does it happen that the
Washington Post publishes a quantum computing piece filled with errors that
would embarrass a high-school student doing a term project (and we won’t even
count the reference to Stephen “Hawkings”—that’s a freebie)?_

I'd recommend reading the Washington Post with a bit more skepticism. You're
only noticing their mistakes on this article because it's something you're
familiar with, but they make many mistakes in their other articles too. You
probably just don't pick it up as you're not an expert in those other fields,
and it sticks out in this one like a sore thumb because you are.

~~~
ClintEhrlich
You've just described the Gell-Man Amnesia effect:

"Briefly stated, the Gell-Mann Amnesia effect works as follows. You open the
newspaper to an article on some subject you know well. In Murray’s case,
physics. In mine, show business. You read the article and see the journalist
has absolutely no understanding of either the facts or the issues. Often, the
article is so wrong it actually presents the story backward-reversing cause
and effect. I call these the “wet streets cause rain” stories. Paper’s full of
them. In any case, you read with exasperation or amusement the multiple errors
in a story-and then turn the page to national or international affairs, and
read with renewed interest as if the rest of the newspaper was somehow more
accurate about far-off Palestine than it was about the story you just read.
You turn the page, and forget what you know." \- Michael Crichton, Why
Speculate (26 April 2002)

~~~
baking
What's particularly interesting is that Scott specifically says that "the
Washington Post has been a leader in investigative journalism exposing Trump’s
malfeasance" but anyone who has been following Seth Abramson knows that the
Washington Post and the New York Times are still a huge part of the problem in
keeping up with the whole Russia investigation.

~~~
bcoates
Wait, Seth Abramson's problem with the Washingon Post is that they're not
willing _enough_ to believe batshit Russians-under-our-beds stories?

~~~
curuinor
I think the summary of Seth Abramson's contributions is:

1\. He's insane

2\. 2016-2018 has been insane

3\. They've often been materially insane in the same way. But sometimes not.

Russians are, in fact, under our collective beds, getting at our voting.

~~~
bcoates
But is he keeping track of their plot to sap and impurify our precious bodily
fluids?

You ever see a Putin drink a glass of water?

~~~
curuinor
Steele report hinges on a few things, among them some women's precious bodily
fluids...

------
Animats
Oh, Wadhwa again. He promotes himself as an expert on a huge range of
subjects. His real business was automatically upgrading COBOL programs for Y2K
fixes; he did a startup for that.[1] Now he's a pundit. He has vague
affiliations with various academic institutions, but he's not a real academic.

The traveling salesman problem isn't hard. It's one of those things that's NP-
hard only for pathological cases, as is linear programming. Solutions to the
TSP which produce a near-optimum result, and the optimal result most of the
time, are easy. (Connect nodes arbitrarily. Then randomly cut two links to
split path into three sections, try all ways to reconnect the three sections,
pick the best. Repeat until no improvement for a while. Bell Labs, 1960s.)

Now, if quantum computing could help with factoring, we'd have a problem.

[1]
[https://books.google.com/books?id=tTkEAAAAMBAJ&pg=PA40&lpg=P...](https://books.google.com/books?id=tTkEAAAAMBAJ&pg=PA40&lpg=PA40#v=onepage&q&f=false)

~~~
MrMoenty
Well, funnily enough, quantum computing CAN help with factoring, and likely
not with TSP. Factoring is one of those rare problems in NP that is not known
to be NP-complete, but for which we also don't know a polynomial algorithm. In
1994, Peter Shor came up with a quantum algorithm that solves factoring in
polynomial time [1].

On the other hand, it is generally not believed that quantum computers would
be able to solve NP-complete problems such as TSP in polynomial time.

[1]
[https://en.wikipedia.org/wiki/Shor%27s_algorithm](https://en.wikipedia.org/wiki/Shor%27s_algorithm)

~~~
randomsearch
I think that was a joke...

~~~
jacquesm
I think he improved on it.

------
whack
Copy-pasting most of Vivek's response (from the above article's comments):

\-------------

 _Scott, I just watched your fascinating and excellent TedX talk and really
appreciate your perspectives. I’ll start by admitting that I struggle with the
concepts of quantum computing and found it very hard to simplify these. I have
read your criticisms of journalists who have had the same issue and your
frustrations with the deficiency.

As far as the traveling salesman problem goes, the person I learned of this
from, a few years ago is Michelle Simmons, director of the Centre for Quantum
Computation & Communication Technology, University of NSW. This TedX talk that
she gave was brilliant and I wrote to her to thank her for opening my eyes:
[https://www.youtube.com/watch?v=cugu4iW4W54](https://www.youtube.com/watch?v=cugu4iW4W54).
She repeated this example in a recent piece in ZDNet:
[http://www.zdnet.com/article/australias-ambitious-plan-to-
wi...](http://www.zdnet.com/article/australias-ambitious-plan-to-win-the-
quantum-race/) I also consulted a couple of other gurus and no one raised
issue with this example.

If you give me a better way of explaining how quantum computers work I will
surely use that. But I find your comparison of this to my criticism of
Bitcoin’s demise as a digital currency to be unprofessional and petty. Surely
you don’t have to resort to such nastiness._

\-------------

That was a pretty great response, and he's right. Scott does come across as
petty, and as someone you would never want to work with. Vivek might have been
wrong, but he had done a reasonable amount of homework on this - far more than
Scott had mistakenly assumed. This discussion would have been far more
productive if Scott had dedicated a thousand words towards educating people
about QC, rather than belittling someone personally.

~~~
gone35
_Scott does come across as petty, and as someone you would never want to work
with._

Please don't let his (admittedly sometimes aggressive, unabashed) writing
style detract from the man himself. From personal experience, he's unfailingly
generous, kind, and amazing to work with.

------
dvfjsdhgfv
A very interesting exchange in the comments section. I actually find Vivek
Wadhwa's explanations (in the comments) reasonable and convincing. He seems
like a honest guy who did the homework and asked the right people (contrary to
what he's accused of) BUT he didn't give them the final version of the article
to read so that they could correct errors and misunderstandings. This is
actually common practice and I hate it - they interview you, you do your best
explaining what you're asked, and then you see it in print completely skewed.
Technically, sometimes these are your own words, but taken out of context they
make little sense or can just be completely wrong. That's the case here, I
think.

In light of Vivek Wadhwa's responses, Aaronson's attack seems really petty.
I'd love to read a technical summary of all mistakes made by Wadhwa though.

~~~
emtel
Here is a direct quote from one of Vivek's comments:

"Please give me 1-2 sentences that your children could understand that
explains the possibilities of quantum computing and I will use these in future
articles. I acknowledge that I am not as smart as most of you are. I struggle
with the concepts of quantum computing, these just don’t make sense to me."

Is there any other field in which someone would profess complete ignorance
about a topic, and go on to write about it in a national newspaper anyway?

~~~
shaki-dora
I would take Vivek's line to indicate not "ignorance" but humility, or,
possibly, a slightly sarcastic jab at what he may perceive as arrogance from
his critics.

There's also a difference between complete ignorance, and the ability to
perfectly frame a field's possible impact in language that the general public
can understand.

Considering that he is unlikely to be so humbled by this experience to
immediately change careers, the wish to improve journalism may be best
channeled not at trying to take this guy down, but to actually acquiesce and
simply provide him that summary he is asking for. I, for one, would be
interested.

~~~
eru
They have provided those summaries multiple times over. And Wikipedia has some
of them too.

------
cs702
Well-run media outlets like the Washington Post face a _difficult_ challenge:
how to explain science to the general public, when both most editors and
journalists and a majority of the general public are _extremely poorly
educated_ in the ways and language of science.

This broad lack of education opens the door for people like Mr. Wadhwa to
write articles about subjects like quantum computing that are wrong in many
important ways, rankling people who actually know a lot about the subject,
like Aaronson.

Every article in a mainstream publication I've read on a technical subject
about which I actually know something is wrong in important ways.

I doubt there's a short-term solution for this problem.

~~~
smitherfield
I’ve been impressed (read: found few/no obvious factual errors, which puts it
in a minority of one among non-industry-specific news services I read) by
Bloomberg’s technology reporting lately.

------
bobthechef
To quote the ornery David Bentley Hart, “Journalism is the art of translating
abysmal ignorance into execrable prose.” I find it odd that Scott holds the
Pravda on the Potomac in such high esteem [0], though I have no personal
animus toward Vivek, only the usual confusion about why journalists insist on
expounding on topics they have no basic comprehension of. The mass media must
always be read in the same spirit one might read a less vulgar version of the
National Inquirer. In this regard, Vivek’s article does not depart in terms of
quality from the standard fare of popular science books and magazines.

[0] Crichton’s “Gell-Mann Amnesia” quote is fantastically apropos in this
regard, and certain kinds of specialists ought to recall it so that it might
temper snobbery and inspire a more charitable response. I can’t tell you how
often specialists, often competent in their own narrow areas of expertise,
produce some of the most absurd and ignorant nonsense ever put to paper when
they falsely presume to have anything of value to say about topics outside of
their fields.

------
rdtsc
Now I was wondering about TSP why it was mentioned at all and if there were
any new results since I dabbled in quantum computing. It seems with some
constraints on vertex degrees, which seems to be practical, it's possible to
do have some speedup (not polynomial of course). For example
[https://arxiv.org/abs/1612.06203](https://arxiv.org/abs/1612.06203) claims
O(1.3^N) for 4 nodes vs O(1.6^N) for classical. For example with N=500 that's
1e57 vs 1e102. But yeah still wouldn't have picked it as _the_ example to use.

Not on topic but since Scott had to mention it...

> Would you agree that the Washington Post has been a leader in investigative
> journalism exposing Trump’s malfeasance? Do you, like me, consider them one
> of the most important venues on earth for people to be able to trust right
> now?

No, no, I don't. They are better then MSNBC and CNN in that they do some
actual legwork as opposed to talking about ice-cream scoops and extra long
hand shakes, but certainly have gotten the "Russian hackers" fever and can't
let go of it: [https://theintercept.com/2017/01/04/washpost-is-richly-
rewar...](https://theintercept.com/2017/01/04/washpost-is-richly-rewarded-for-
false-news-about-russia-threat-while-public-is-deceived/)

