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https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.15.044033

Hi Igor,

I am not sure you or your coauthors will read this message. Anyway, very nice work!

I think I agree with all your arguments and your way of reasoning. In fact, considering also the thesis of Baym and Ozawa [10], we also did not claim that the Gedankenexperiment in our work [9] was a

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Probably just a bug.

Published 01 Apr 2021

This work is now published. https://iopscience.iop.org/article/10.1088/1367-2630/ac0755

Just before posting we realised Sandy Irani and Dorit Aharonov found similar results to ours independently. Their work is posted simultaneously here: https://scirate.com/arxiv/2107.06201

There is a new version of this work in which we consider, additionally to the routing protocol, a BB84-like single qubit protocol for position verification and prove that it is secure under the same conditions as the routing protocol (Section 4). Both protocols have their pros and cons regarding app

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Dear Jacques,

It is - as usually - a huge and tasty piece of food for thought! As for now I have 2 comments I dare to leave here:

First, the line of reasoning from IVC seems misleading - or rather, it is not a dead-end corridor as you seem to picture it. Let me recapitulate IVC in the light o

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You have done some actions - and those had to be done *by yourself* - so now sth exists. Could this meet ,,one of the common [sic] definitions of solipsism''?

BTW, what if such things with arXiv are not just some trivial arXiv-engine bugs but a kind of truly profound glitches? Perhaps a sign that

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No, it'll surely fail to spot it. It isn't even capable to consistently spot arxiv citations in bibliographies. For instance, [arXiv:2006.02790][1] had cited [arXiv:1810.13401][2] and [arXiv:1912.07554][3] but Google Scholar didn't spot that.

[1]: https://arxiv.org/abs/2006.02790
[2]: http

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This will be an interesting test case for Google Scholar: Will it be clever enough to spot the pointer to [arXiv:2107.00670](https://scirate.com/arxiv/2107.00670) that is given in the text but not the bibliography?

Well, regarding the possibility we have become smarter I have plenty of evidence to the contrary (for both of us!)

Whats going on in terms of the explicit constructions we use is simple enough I'm reasonably sure its correct. But when I think of viewing this kind of computation from 30000 feet

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But suppose that you have become even smarter in the last 15 years. Then your old conjecture was correct! Does this really prove "STP=BQP"? If so, amazing!

We've revisted this Matt and shown that even with only a source of maximally mixed single qubit states its possible to generate a resource sufficient for the rest of our construction to go through: https://scirate.com/arxiv/2107.03239

Sometimes, if you're quick, you can catch the paper before it's been compiled by arXiv (I think they do it at least partially on-demand); but I've never seen a true error before (pretty good comment on the arXiv's technical implementation, to be honest!)

I couldn't compile it from arXiv either, but arXiv vanity worked: https://arxiv-vanity.com/papers/2107.00670. Now the PDF works too! I think I might have seen this before but I forget when/where.

When I first tried to open this, the arXiv gave me a "could not compile the LaTeX" error message that I'd never seen before. I downloaded the source myself and compiled it to PDF without any trouble, and it seems to be working on the arXiv now too. Has anyone seen an error like that before?

Hi Michal,

Thank you very much for sharing your great work, which we were unfortunately not aware of. The route you followed towards universality by studying fermionic linear optics + non-quadratic Hamiltonian is one we actually considered initially before deciding to shift strategies, so this is

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A very interesting work! I wanted to point out however that in

https://scirate.com/arxiv/1705.11188

we studied generic universal gate sets for particle-conserving fermionic unitaries. In particular, we classified all unitary transformations that promote the so-called passive fermionic linear

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Beautiful work, bravo!

Glad I could bring a little fun to your day! :-)

Thanks for sharing your notes Blake! It's always fun to read you ;)

I'd had some notes kicking around a bit before someone mentioned that *Helgoland* had been translated into English and said some pertinent things. Maybe the book was a nudge for them, too.

But this time it seems there could be a pretty obvious - even if hidden - (Reichenbachian) common cause: Helgoland (esp. its recent English edition) by Rovelli. No mysterious synchronicity in here...

Hey, nice work! I'd like to advertise to the community a little cute fact, first found in https://link.springer.com/article/10.1007/s00220-021-03988-1 and re-discovered here (with credit given to the above paper): *feed into a 50:50 beam splitter a product state -- any product state; trace out one o

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Well, this is a fun bit of synchronicity! On Wednesday, I had posted some [informal notes about RQM](https://www.sunclipse.org/?p=3016) that grew out of a recent discussion group. The issues of consistency between observers and of how to define measurement timing stuck out to me.

In that paper we conjectured:

*It is possible that via a smarter encoding than these authors are capable of finding, it might be possible to perform quantum computation with J-measurements and only one or two different types of initial state.*

It wouldn't surprise me if this model isn't equiv

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Link to github: [https://github.com/saforem2/l2hmc-qcd](https://github.com/saforem2/l2hmc-qcd)

Thanks for that reference. It relies on having a source of many copies of 3 different states. It is much closer to our model, but still seems not to answer the question.

Yes definitely different than the exchange interaction only work (though clearly the representation theory of the symmetric group is both our friend). But doesn’t this paper answer the question about the power of the model https://arxiv.org/abs/quant-ph/0503151 ?

This time no fisherman's story?

Thank you for the reference, btw. We used in our paper a particular encoding of a qubit as part of proving PostSTP=PostBQP, but perhaps the reference you mentioned gives another encoding that can be used as well. I need to look at it in more detail.

Hi Matt, yes, right, thanks for clarifying.

If I understand correctly, that paper considers unitary evolution under the exchange interaction with controllable time-dependent couplings. In particular, unitary gates exp(i J \vec S_1 \cdot \vec S_2), with J controllable. We consider only a much smaller set of operations: just measuring in s/t

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There are early papers which show that the SU(2)-invariant exchange interaction suffices for universal QC (and measuring in the singlet-triplet basis), see https://arxiv.org/pdf/quant-ph/0005116.pdf so would that work not answer the conjecture?

What a fantastically written review! Very much enjoyed reading this.

This has been an incredibly helpful guide! I very much recommend it.

Makes sense, thanks! In the future I expect we'll try to publish some more code for using and analyzing the THC qubitization approach via OpenFermion, in order to at least make that technique a bit more accessible.

I recently came across this interesting paper (and subsequent work by Aharonov et al. on quantum algorithmic measurements). I wonder if the idea (in this 1610.09619) is in any way similar to the theory in Higgins et al., Nature 450, 393 (2007) (https://www.nature.com/articles/nature06257), which als

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Hey Ryan, thanks for the questions!

(1) Here we considered _all_ of the electrons, including core electrons. It's true that core electrons are not the primary factor in determining the chemical bondings, and thus including them to calculate ground state energies is neither necessary nor the most

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Thanks for your thoughtful comment, Dave. You're right, my one-liner was not particularly considerate and constructive. I did have my doubts about posting it and I'm still not sure how to properly react to this paper. But I also didn't want it to go unnoticed.

What triggered me is the wide gap be

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Thanks for the message and setting the tone Dave. I completely agree with you and, speaking for the moderating team, we will aim to do a better job.

I've been thinking a lot about this comment (probably more than I should!) Certainly it's funny, "quant-hype" is a laugh out loud line. It reminds me of calling the US food retailer "Whole Foods" by the name "Whole Paycheck".

But I would also point out that if we want a community that is kind

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This looks like a very thorough study with multiple substantial contributions, especially on the error-correction side. I have two questions:

(1) Are you simulating active spaces here, like other prior fault-tolerant studies using molecular orbitals, or are you including all the electrons (includ

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I'm having trouble understanding the definitions of "reasonable" and "connected" given at the top of p.3 in this paper, maybe someone can help. The easiest, in order to clarify it, would be to say explicitly what is the graph $G_{supp(S)}$ for $S = Z_1$ and also for $S = Z_1 Z_2$ (in the example giv

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This should have been posted under [quant-hype].

Thanks to a careful reader (thanks to him!), we realized there were a typo in the affiliations: so no breaking news, Elham is not moving to Maryland ;-) I'm not sure how we missed that typo, but a v2 is waiting approval and should appear tomorrow to fix this.

Dear Ramis,

Thanks so much for your kind words. Thank you also for your insightful comments. Indeed, your beautiful work very nicely complements ours, in particular in the way you look at the asymptotic limits of large bond or physical dimensions. We have now discussed and cited your work in the

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Hello,

I wish I could understand it more...
so I have a question about Fig. 3 (Fig. 2 in New J. Phys.-version) and all the argumentation from p. 4 hinged upon:

What if the proces depicted is not about some particle decay, but about some fully (FAPP) deterministic clock-gun mechanism that is s

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Thank you for clarifying! The history of this subject is complicated by independent rediscoveries, different terminologies being used by different fields, etc. We wrote [a review article](https://scirate.com/arxiv/1703.07901) four years ago that is already in some respects outdated!