Recent comments from SciRate

Hsin-Yuan Huang Oct 10 2022 16:10 UTC

Thank you all for the nice work!

Should there be a constraint that the poly(n) Paulis must all be few-body (similar to random Pauli measurements) in the abstract? Prior works proved that we could not efficiently estimate many general Paulis using single-copy measurements.

Best regards,

Robert (Hs

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Weilei Zeng Oct 09 2022 06:47 UTC

Nice work! Can you give a short explanation for the name _Quark_ ?

Chinmay Nirkhe Oct 08 2022 18:18 UTC

We are withdrawing this note from the arXiv -- the withdrawal will update on arXiv at the next update.

The withdrawal is due to an uncorrectable error in the proof.

A detailed explanation of the error is hosted on my website at
https://nirkhe.github.io/simple_nlts_retraction.pdf

Apologie

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Marcos Crichigno Sep 29 2022 20:57 UTC

Thank you for your prompt reply, Seth! Once again, congratulations on your paper to both!

Seth Lloyd Sep 29 2022 16:27 UTC

First of all, congratulations on your (very recent!) excellent preprint on the QMA1-hardness of clique homology. Quite a few papers on quantum homology have appeared on the arXiv in the last week: we are still analyzing the overlaps, connected components, and voids in this `homological hundredth mo

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Marcos Crichigno Sep 29 2022 09:09 UTC

Dear Alexander and Seth,

Congratulations on your paper! Your comments on when exponential quantum advantage is possible are very interesting!

You may not be aware of this but I should point out that the result reported in your **Theorem 1** (*#P-hardness of exact Betti numbers of clique-dense com

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Chris Cade Sep 28 2022 18:07 UTC

Hi Ryan, I'll try to keep my reply short ;) (Also happy to take the discussion offline if it looks likely to continue indefinitely).

What you write is correct indeed. The hard-core fermion model on a graph considered in their paper is precisely the independence complex for that graph: i.e. the '

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Ryan Babbush Sep 28 2022 15:17 UTC

Thanks Ismail. I think the new version of your abstract that you've recently uploaded is much improved. I agree that the relaxation of the problem you describe in your most recent post is likely to admit a substantial quantum speedup for many data sets. I agree it's cool. But, as you mention, the ma

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Ismail Yunus Akhalwaya Sep 28 2022 07:10 UTC

Hi everyone, I'm tickled pink by the fascinating discussions here, thank you!

Just to let everyone know, we have uploaded a new version to arxiv incorporating the above suggestions (with acknowledgements). We're still happy to make further changes as they crop up.

One further thought combining

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Marcos Crichigno Sep 27 2022 19:21 UTC

Hi all,

Related to your question, Chris, I agree that it is not sufficient to just have “beta_k” growing exponentially but it should grow exactly like 2^n/poly(n), which indeed is fine-tuned. On the other hand, as you know well, one should keep in mind that the LGZ algorithm does not estimate the *

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Chris Cade Sep 27 2022 13:39 UTC

Hi all,

Nice that you are having this discussion! I agree with the sentiment of Ryan's comments, in that it feels unlikely that a real-world dataset will happen to be one for which we can obtain an exponential ('proved' or otherwise) advantage over classical algorithms.

On that note: you both

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Ryan Babbush Sep 24 2022 14:29 UTC

Thank you for your thoughtful reply. I think we’re basically in agreement about the facts of the matter. While these terms are a bit ambiguous, the requirement that data have exponentially many holes still seems pathological enough that I would hesitate to call it “arbitrary” and “non-handcrafted” w

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Marcos Crichigno Sep 23 2022 23:41 UTC

To clarify, the nice work by Gyurik-Cade-Dunjko that you mention does not claim to show DQC1-hardness of estimating normalized "Betti" numbers. What they establish, improving on work by Brandao, is DQC1-hardness of determining the low-lying spectrum of a general Hamiltonian, which has nothing to do

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Ismail Yunus Akhalwaya Sep 23 2022 17:43 UTC

Dear Ryan, Aram, and Travis

Thank you very much for this discussion and for sharing your precious time and insights. This is what we love about arxiv/scirate in that it allows us to improve our pre-print before publication.

Thank you for doing a great job of getting to the heart of what seem

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Earl Campbell Sep 21 2022 21:55 UTC

Thanks for your question. We did indeed so some experiments as you suggest, but decided to keep the message simple and omit them.

For a quantum memory experiment, we found you could roughly half the buffer region with no significant impact on the logical fidelity, but improving the decoding

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Ryan Babbush Sep 21 2022 21:01 UTC

As I mentioned in my comment, the DQC1 results from Dunjko and others pertain to estimating the normalized Betti number - a quantity that exponentially concentrates to zero unless the Betti number is exponentially large. Having exponentially large Betti number is a very unusual property that we shou

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Travis Scholten Sep 21 2022 15:10 UTC

There is this work from Dunjko et al: https://arxiv.org/abs/2005.02607

From the abstract:

"In this paper, we study the quantum-algorithmic methods behind the algorithm for topological data analysis of Lloyd, Garnerone and Zanardi through this lens. We provide evidence that the problem solved by th

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Aram Harrow Sep 21 2022 14:32 UTC

Is this problem known to be DQC1-complete? That would be one way to address Ryan's concern.

Ryan Babbush Sep 21 2022 03:24 UTC

The abstract of this paper suggests that the quantum topological data analysis algorithm provides a “provable exponential speedup on arbitrary classical (non-handcrafted) data”. This is a strong claim, especially in light of arguments, see e.g. [arXiv:1906.07673][1], that super-polynomial speedup is

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Krishanu Sankar Sep 20 2022 21:32 UTC

Did you experiment with varying the sizes of $n_{com}$ and $n_{buf}$? Intuitively, larger $n_{buf}$ means decreased error rate but increased overhead... and large $n_{com}$ decreases both but increases latency. Would be nice to see empirically the benefits or drawbacks of values other than d, especi

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Māris Ozols Sep 19 2022 16:16 UTC

A special case of your formula for the probability distribution $p(x | n, m, k, l)$ was obtained by Montanaro in [arXiv:0903.5466][1]. Namely, when $n = k$ and $m = l$ we have $p(x | k, l, k, l) = \mathrm{Pr}[x|l]$, where $\mathrm{Pr}[x|l]$ is given in Montanaro's Lemma 4. It denotes the probability

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Matt Hagan Sep 08 2022 14:40 UTC

Equation (25) appears to be incorrect to me, you are writing the second order Trotter formula as $U_2(dt) = \left[ U_1 (dt/2) U_1(dt/2)^T\right]^m$, but since $dt = t/m$ then this would correspond to a Trotter formula for $U_2(t)$ not $U_2(dt)$?

Enrique Cervero Sep 06 2022 07:29 UTC

Hey, thanks for your question.
So in our work, we find that for the ansatze we consider, the onset of barren plateaus is related to the width of the causal cone of an observable.
The width itself expands via entangling gates like CNOTs in the circuit architecture.

In the qMPS ansatz, the ent

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Bingzhi Zhang Sep 05 2022 19:13 UTC

Hi, congratulations to your work. From your work, you state that the barren plateau is absent for qMERA and qTTN, but exists for qMPS. From previous works, entanglement can induce barren plateau, and I assume the ensemble of states generated by qMPS has smaller entanglement than the other two and a

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Gilad Gour Sep 02 2022 20:03 UTC

Thanks! Indeed, there is a typo in the direction of the majorization symbol of Definition 1 in Appendix C.

Seok Hyung Lie Sep 02 2022 08:30 UTC

Outstanding work. Small typo?: It seems like the direction of majorization symbol in Definition 1 of Appendix C is reversed.

Blake Stacey Aug 28 2022 16:01 UTC

This paper refers to the version of RQM that existed before the introduction of "cross-perspective links" in [arXiv:2203.13342](http://arxiv.org/abs/2203.13342), a change that amounts to saying, "Well, we didn't want all those 'relative facts' anyway."

Pavel Panteleev Aug 12 2022 17:16 UTC

Hi, Anthony! Thank you for pointing out the Oded Goldreich survey. I think it's really neat! I haven't read it yet before since the original paper [30] was written so well that I never needed to look anywhere else. I believe you are referring to the comment on page 3, where he indeed considers somet

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Anthony Leverrier Aug 12 2022 14:57 UTC

Hi Pavel,
You're right that ref [30] doesn't use double covers, although the overview from Oded Goldreich that came out a few weeks later did
https://eccc.weizmann.ac.il/report/2021/175/
Of course, we'll be happy to give you proper credit when we update the manuscript.
Best,
Anthony & Gilles

Pavel Panteleev Aug 12 2022 12:41 UTC

Congratulations! A very nice result with much shorter proofs than ever before! It is great that with all these recent simplifications each next paper rapidly approaches the high standards of simplicity and elegancy set by Sipser and Spielman in 1996. However, with all due respect, I believe, you inc

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Dave Bacon Aug 05 2022 18:10 UTC

Note that Eqs. 7 through 14 in the arXiv version of this paper are not correct. The correct expressions appear in the published version in Physical Review Letters. It's pretty straightforward to fix these equations if you are following the paper by hand, but be warned!

Mark M. Wilde Aug 05 2022 12:49 UTC

This is an outstanding paper in quantum Shannon theory. Congratulations to the author.

Angus Lowe Aug 03 2022 06:31 UTC

Thanks for pointing this out! The PDF should be working now. Sorry about the initial error.

Felix Leditzky Aug 02 2022 19:34 UTC

The arXiv vanity version seems to work (to some extent): https://www.arxiv-vanity.com/papers/2207.14438/

Māris Ozols Aug 02 2022 07:46 UTC

Looks like arXiv is not able to produce the PDF file for this paper.

Diogo Cruz Jul 22 2022 10:36 UTC

Very interesting!

Alex Meiburg Jul 11 2022 18:18 UTC

It seems that our future AI overlords will have us all speaking Pirahã, then. :)

Stephen Bartlett Jul 07 2022 23:15 UTC

Very nice paper. You may be interested in this great paper by Montina:
https://arxiv.org/abs/1107.4647
that looks into the d>2 case that you mention in your discussion section. It seems this qubit case is quite exceptional and difficult to generalize.

Michal Oszmaniec Jul 01 2022 19:28 UTC

Thanks Mark! I'm also looking forward to read your paper in detail.

Mark M. Wilde Jul 01 2022 10:16 UTC

Thanks a lot for your comment and for pointing out your paper. We'll definitely add a citation to your work in a revision of our paper. We're reading your paper now and will email you if we have any questions about it.

Michal Oszmaniec Jul 01 2022 06:05 UTC

Congratulations for the nice result! I did not expect that estimation of multivariate trances (also known as Bargmann invariants) can be performed so easily. Still, I wanted to point out that in this earlier work https://scirate.com/arxiv/2109.10006 with Ernesto Galvao and Dan Brod we managed to co

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Xiao Yuan Jun 23 2022 03:22 UTC

Hi William, Thanks for pointing out the error. Indeed, it should be

..., then $|{H_{ji}}|^2 = \sum_{kk'}h_kh_{k'}p_{kk'}^i(j)$ with $p_{kk'}^i(j)=\mathrm{Re}\langle i|U^\dagger P_k U\Pi_jU^\dagger P_{k'} U|i \rangle$ satisfying $\sum_j |p_{kk'}^i(j)|\le 1$.

The key point here is that by regar

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William J. Huggins Jun 22 2022 17:53 UTC

I've been reading your paper with interest but I think that the claim (top left of page 4) that $p^i_{kk'}(j) \geq 0$ and $\sum_j p^i_{kk'}(j) =1$ is incorrect.

I'd also be curious to know how you expect your algorithm to perform in the presence of sampling noise.

Hsin-Yuan Huang Jun 16 2022 16:48 UTC

I think there is a mistake in the proof, which causes Theorem 2 to be incorrect. There should be an additional $2^n$ factor ($n$ is the number of qubits) in the number of experiments stated in Theorem 2. If Theorem 2 is true, then given any exponentially deep classical boolean circuits on $n$ bits,

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Richard Kueng Jun 08 2022 17:43 UTC

Thanks for pointing out this nice paper. Our main results relate to single copy measurements, not multi-copy measurements (e.g. Hillary's paper with noiseless circuits but also https://arxiv.org/abs/quant-ph/0111082, which we do cite). We have also entanglement conditions in terms of only the first

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Shu Kanno Jun 07 2022 21:35 UTC

Thank you for your reply, and I appreciate your revision in the next version.

Once Upon Jun 06 2022 21:10 UTC

Go right ahead! I'm glad you like it :D

Raul Santos Sanhueza Jun 06 2022 07:52 UTC

Thanks Shu for the clarification. We will revise that description in the next version of our work.

Aram Harrow Jun 05 2022 12:36 UTC

I think they're supposed to be arm-wrestling, not making a deal. :)

Daniel Bultrini Jun 03 2022 11:48 UTC

This is beautiful, thank you, hahaha! A deal with the devil it is :D
Also... do you mind if I use this in a talk some day?