Recent comments from SciRate

Marco Piani Apr 01 2016 08:00 UTC

I had answered in a similar fashion (a second answer after a first answer), but also my comment is floating around :-)

Robin Blume-Kohout Mar 31 2016 17:25 UTC

Note: Because I hit the wrong button, there's a stray comment (by me) floating around that answers this question. It's just not in this thread...

Robin Blume-Kohout Mar 31 2016 17:23 UTC

Good point about sorting ...but it wouldn't have been an issue if I'd used the site correctly! I intended my comment to be a reply to Tom's, but (due to incompetence) it ended up standalone instead. Oops. Anyway, SciRate does keep threads together, which should go some way to helping with organiz

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Felix Leditzky Mar 31 2016 11:43 UTC

That would indeed be helpful - you should definitely email the developers about this! Not sure if they read every comment ;-)

Tom Wong Mar 31 2016 10:15 UTC

Thanks, Robin!

I like this use of SciRate as a "reading group." It's a collaborative and friendly use of the comments.

Perhaps SciRate can add a feature to "sort by date" rather than by rating/points, which would be useful for such discussions?

Robin Blume-Kohout Mar 30 2016 22:31 UTC

@Tom: They're considering the case where U's eigenvalues are not discrete, but (instead) take values that are dense on the complex unit circle. So for every $\phi\in[0,2\pi]$, U has an eigenvalue $e^{i\phi}$. Which means that the spectrum isn't just *contained* in [-2,2], it *is* [-2,2]. The who

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Joe Fitzsimons Mar 30 2016 04:58 UTC

Sure, but if you don't rule out super-determinism, then you haven't closed the loophole, you are merely splitting it in two and then closing one of those. There is no way to do what you are suggesting without introducing an additional assumption. Even in a universe that is not super-deterministic, h

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Bill Plick Mar 29 2016 16:13 UTC

Hi Joe,

Well, yes and no. It really depends on whether or not you say the measurement choices can be pre-determined from the beginning of the universe (superdeterminism), or whether they are - for example - potentially determined from the moment of entanglement creation. In the later case the loo

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Ivan Coulamy Mar 28 2016 18:40 UTC

I would like to bring to your attention that fig 2.(a) is inconsistent with it's caption. Is T=50 or T=20?

Joe Fitzsimons Mar 28 2016 05:18 UTC

It's fundamentally impossible to close. There is never a way to rule out super-determinism.

Bill Plick Mar 23 2016 10:51 UTC

Also, there is still no mention of the freedom of choice loophole. But maybe this is even something that is impossible to close in their setup?

Māris Ozols Mar 19 2016 16:34 UTC

This result has caused quite a lot of excitement in number theory (see the articles in [Quanta Magazine][1] and [Nature News][2]).

It turns out that the last digits of consecutive primes are not uniformly distributed but rather tend to be anti-correlated. For example, in base 10 the last digit of

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Māris Ozols Mar 09 2016 14:59 UTC

Wow, that's really great! I wasn't expecting that progress on this will be made any time soon, so it's great to hear that somebody is already working on this and trying to change things!

Lidia del Rio Mar 09 2016 14:36 UTC

Marcus Huber, Christian Gogolin and I are actually in the process of setting up an arXiv overlay journal for quant-ph. We are finalizing a draft with the initial proposal and guidelines, and will soon reach out to form an editorial board and open the idea to discussion by the community. More news on

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Noon van der Silk Mar 09 2016 00:29 UTC

I don't even really see the point of a journal. Maybe we could adapt SciRate to have a little collection of longer reviews/editorials/etc associated to each article (like comments).

What do you think a journal would offer over SciRate itself? I.e. if the potential paper reviewers would just inste

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Juani Bermejo-Vega Mar 08 2016 12:50 UTC

Gower's [earlier post][1] on this arXiv overlay initiative is also very inspiring.

[1]: https://gowers.wordpress.com/2015/09/10/discrete-analysis-an-arxiv-overlay-journal/

Tom Wong Mar 08 2016 11:21 UTC

An arXiv overlay journal was also started for [astrophysics][1], and their source is available on [GitHub][2]. All we need to do is find/replace "astrophysics" with "quantum information" in the source code, and we have a platform.

[1]: http://astro.theoj.org/about
[2]: https://github.com/o

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Māris Ozols Mar 08 2016 05:57 UTC

This article just got published in [Discrete Analysis][1], a new arXiv overlay journal that was launched last week (by "published" I simply mean that you can read it for free on arXiv as you would normally do anyway). Just like in any other journal, this article was peer-reviewed, revised, accepted,

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Juan Miguel Arrazola Mar 08 2016 02:37 UTC

A dream that started during my PhD keeps getting closer and closer to reality! :-)

Laura Mančinska Mar 04 2016 11:10 UTC

Looks like we have our first scirate reading group :)

Marco Piani Mar 04 2016 07:49 UTC

Hi Tom, again not 100% sure, but if you take literally the part

"It is argued there that the unitary evolution U associated to the evolution of a computer (classical or quantum) capable of universal computation has invariant subspaces with discrete spectrum (roots of unity) and other invariant su

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Tom Wong Mar 03 2016 15:00 UTC

Thanks, Marco! That makes sense. Continuing with the paper, why would that imply that the spectral gap is always 0?

Marco Piani Mar 03 2016 14:33 UTC

Not sure 100% what is meant, but it could be that they are referring to the fact that, since $H = U + U^\dagger$, the eigenvalues have the form $e^{i\phi}+e^{-i\phi} = 2 \cos (\phi) \in [-2,2]$

Tom Wong Mar 03 2016 11:27 UTC

I haven't done any research in this area, so this is probably a silly question. After Result 6, why is the spectrum of the Hamiltonian always [-2,2]?

Aram Harrow Feb 29 2016 03:37 UTC

Thanks for the reply. (3) is an interesting case to think about and it does seem that these attacks could be very significant then. And of course it's always good to improve the theoretical guarantees even if this is only relevant against future attacks.

For (2) it still does seem that if the l

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Anthony Leverrier Feb 28 2016 16:59 UTC

There are 3 interesting time scales to consider:

1) As long as nobody has a quantum computer, our results don't have any practical relevance. That's clear.

2) When malicious parties start having access to quantum computers, the situation becomes more shady. For the reasons you mention, if the

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Aram Harrow Feb 27 2016 18:06 UTC

This result really surprised me! But I don't understand how it could be used in practice.

Let's say Alice and Bob are communicating over the internet using AES and Eve records all their messages. She's not making any queries and can't break anything.

Let's say Alice is a web server who retur

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Māris Ozols Feb 18 2016 14:29 UTC

"...structures seen in the universe today, from clusters of galaxies to Donald Trump."

Joel Klassen Feb 07 2016 17:57 UTC

The conversation amongst philosophers about the notion of free will and its relationship to determinism has a rich and nuanced history. It's disappointing to see someone who should know better be so flippantly dismissive of that conversation.

Noon van der Silk Jan 27 2016 03:39 UTC

Great institute name ...

Varun Narasimhachar Jan 20 2016 22:58 UTC

Sciting for the funny title (not judging the work, on which I am no expert). Science needs more of creative writing.

Perplexed Platypus Jan 15 2016 21:14 UTC

This review concerns v3 on arXiv.

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As evidenced by the changes in the title and abstract, the revised version is much more cautions with interpreting the results. The main message is no longer that spatial quantum search with multiple marked elements breaks down. Instead, it is phras

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Perplexed Platypus Jan 12 2016 15:45 UTC

This paper studies two variants of random access codes (RACs): parity-oblivious and even-parity-oblivious. The main result is a construction of a parity-oblivious quantum RAC and a proof showing that its bias is optimal and asymptotically better than that of a classical code. The construction is bas

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Cedric Lin Jan 11 2016 22:38 UTC

Er, not in any way I know of. Maybe we could've picked a better name...

Māris Ozols Jan 11 2016 20:53 UTC

Is your $\mathsf{QMA_{exp}}$ in any way related to $\mathsf{QMA_{EXP}}$ in [arXiv:0905.2419][1] (see Definition 2.3)?

[1]: http://arxiv.org/abs/0905.2419

Zoltán Zimborás Jan 07 2016 06:50 UTC

Interesting, both the 2nd and the 4th author is called Yuanping Chen... :)

Alessandro Dec 09 2015 01:12 UTC

Hey, I've already seen this title! http://arxiv.org/abs/1307.0401

Kenneth Goodenough Dec 01 2015 09:38 UTC

Thank you very much for your comment, Hari. Currently we don't have the analytical form of the bound from Pirandola et al. to compare with our results. However, judging by the graph in their paper it is clear that their bound is tighter than our bound for all eta for the case of n = 1. We do expect

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Hari Krovi Nov 30 2015 20:26 UTC

Very nice results. I was wondering how your improvement to Takeoka et al for the thermal noise channel compares to the improvement of Pirandola et al (which uses relative entropy of entanglement - ref 34). Sorry if I missed it in your paper.

Mile Gu Nov 20 2015 05:04 UTC

Good question! There shouldn't be any contradiction with the correspondence principle. The reason here is that the quantum models are built to simulate the output behaviour of macroscopic, classical systems, and are not necessarily macroscopic themselves. When we compare quantum and classical comple

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hong Nov 20 2015 00:40 UTC

Interesting results. But, just wondering, does it contradict to the correspondence principle?

Marco Tomamichel Nov 17 2015 21:05 UTC

Thanks for pointing this out, this is an unintended omission and we will certainly fix it. I thought Koashi was first to use entropic uncertainty relations for QKD but apparently I was wrong.

Raul Garcia-Patron Nov 17 2015 14:42 UTC

Nice work, congratulations!
Please correct me if I am wrong, but there seems to be an important reference missing in the manuscript, the 2003 paper by Frederic Grosshans and Nicolas Cerf using uncertainty relations to prove the security of individual attacks against CV-QKD: arXiv:quant-ph/0311006

Marco Tomamichel Nov 12 2015 06:07 UTC

Okay, so my scite should not be considered as an endorsement. The only interesting part of this paper is Table I and II (minus the caption, which is wrong).

Chris Ferrie Nov 12 2015 05:36 UTC

Feels a bit like numerology, but the simple point that the setting choices are far from uniform is worrisome.

Marco Tomamichel Nov 12 2015 05:13 UTC

And looking forward to the response as well!

Tom Wong Nov 09 2015 11:12 UTC

This resolves an open problem of whether the procedure of Emms et al (2006), which is based on quantum walks, can distinguish all non-isomorphic strongly regular graphs. Their conclusion: no, because they came up with an example where the procedure fails.

Frédéric Grosshans Nov 02 2015 11:51 UTC

Nice work !

This paper answers a question which has obsessed me since 2002, and I’m more than happy to see that the answer is the one I would have guessed since 2004, but with no way to prove it! (Some people kept thinking I’m a bit too much obsessed by these 1.44 bits ;-) )

At that time ( ht

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Aram Harrow Oct 21 2015 02:56 UTC

clearly that should be the last TODO to be removed.

Māris Ozols Oct 20 2015 23:50 UTC

There's a TODO note missing on page 24 saying: "Remove TODO notes"