Recent comments from SciRate

Scotland has a strong record of inspiring and inspired physicists ;-)

It is amazing that G. Nadurra has contributed to your research despite being just 16 years old!

Interesting work... Could you please comment on possible connections of your work with those of Hayden and May (http://arxiv.org/abs/1210.0913) and of Portmann et al. (http://arxiv.org/abs/1512.02240)?

This is a beautiful set of lecture notes.

What I mean is that merely separating the process by which you choose each measurement setting and the entangling event does not actually close even this restricted version of the loophole. You need a further assumption that this choosing process produces a distribution of outcomes which are uncorre

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No worries at all! I think I pressed the wrong button :-) And it is good to see that my answer was not totally off!

Okay, I don't disagree. You seem to be implying that making this split is artificial? Why should this be the case for setting dependence (freedom of choice) but not for outcome dependence?

Oops! I see your answer now. Didn't mean to dupe it...

I put in a feature request for sorting comments by date.
https://github.com/scirate/scirate/issues/328

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

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...

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

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?

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

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

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?

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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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!

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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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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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/

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

Looks like we have our first scirate reading group :)

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

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 $e^{i\phi}+e^{-i\phi} = 2 \cos (\phi) \in [-2,2]$

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]?

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

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.

Great institute name ...

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

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

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

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

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

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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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.

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