Recent comments from SciRate

Frédéric Grosshans Oct 25 2019 09:50 UTC

Is this a NISQy algorithm breaking lattice-based postquantum crypotography (if the numerical evidence are confirmed)? That’s how I read the abstract and the paper, but I’m neither a specialist of AQC, nor of postquantum cryptography.

Noon van der Silk Oct 23 2019 03:27 UTC

Now this is useful work! Awesome!

Noon van der Silk Oct 23 2019 03:21 UTC

If this is the best ML can do with respect to climate change; we're in big trouble.

I think that at a place like NeurIPS, and in a _workshop_ on _tackling climate change_, the kinds of things we as the ML community focus on should be much larger-ticket items.

Arthur Pesah Oct 18 2019 20:58 UTC

Very nice paper! Is the Supplementary Material available somewhere? :)

Marco Tomamichel Oct 10 2019 03:20 UTC

Congratulations on the first use of "quantum pwenage" (as far as I am aware). Although, should it not be "quantum pwnage"?

Joschka Roffe Oct 09 2019 09:47 UTC

Review now published in Contemporary physics. Available at
https://www.tandfonline.com/doi/full/10.1080/00107514.2019.1667078

Marcel Fröhlich Oct 08 2019 09:57 UTC

https://www.researchers.one/article/2019-10-7

Ish Dhand Oct 08 2019 06:22 UTC

The main text ends with a parable: "We close with a story. Alice and Bob, having successfully run their randomized boson-sampling experiment, are in Stockholm to pick up the Nobel Prize in Physics for the first demonstration of quantum supremacy. As the King of Sweden approaches to present the Nobel

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Marcel Fröhlich Oct 02 2019 17:16 UTC

See also https://scirate.com/arxiv/1901.07471

Daniel Brod Sep 29 2019 20:21 UTC

Also, the statement that "It is known that arbitrary n-qubit gate can be generated by arbitrary 1-qubit gates and the CNOT gates on any two qubits in time O((log d)^3)", where d = 2^n, is wrong, no?

Mankei Tsang Sep 27 2019 13:20 UTC

If you look at the transverse spatial wavefunction of a photon in a Laguerre-Gaussian mode, it has a radial index $p \in \mathbb N_0$ and an azimuthal index $l \in \mathbb Z$. The beam width, as measured by the standard deviation in space, grows as $\sim \sqrt{2p+|l|+1}W_0$, where $W_0$ is the width

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Māris Ozols Sep 26 2019 10:03 UTC

How is one supposed to evaluate the Slater determinant in Eq. (20)? It is clearly not a square matrix since M is typically larger than N.

Jerry Finkelstein Sep 25 2019 20:50 UTC

I do not understand why "standard quantum mechanics predicts that *none* of the photons should arrive early". E.g. in fig. 5, would not photons along the diagonal path arrive earlier than photons along the right-angle path, in standard quantum mechanics just as in Bohmian mechanics?

Steve Flammia Sep 24 2019 01:25 UTC

If you're wondering how this is possible, the exponential savings comes from using photon states with orbital angular momentum $\ell = 2^{\Omega(n)}$.

Ewout van den Berg Sep 23 2019 13:26 UTC

Dear Michel, thank you very much for bringing this to our attention. We will add an appropriate citation in the updated version of our paper.

Planat Sep 19 2019 07:51 UTC

Dear authors,
I suggest you read
https://arxiv.org/abs/1009.3858
"Pauli graphs when the Hilbert space dimension contains a square: why the Dedekind psi function ?"
for commuting Paulis, also the related papers.
Michel Planat.

Lingling Lao Sep 18 2019 12:57 UTC

Hi Eddie, thanks for your comments. Indeed, this information is too difficult to find. We will make improvements in a future version.

Travis Scholten Sep 02 2019 11:53 UTC

Noticed I forgot to include a corresponding author's email! If you have questions or comments, you can reach me at [first name].[last name] using the ibm.com domain.

Noon van der Silk Aug 30 2019 08:30 UTC

Wow!

Anthony Leverrier Aug 30 2019 08:05 UTC

interesting figure:
Estimated climate footprint of the computations presented in this paper = 992 kg

Narayanan Rengaswamy Aug 17 2019 15:16 UTC

Now published in PRA!

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.100.022304

Mark Everitt Aug 16 2019 07:56 UTC

Thank you to everyone who helped - because of your help and good questions we had a smooth refereeing process.

https://journals.aps.org/pra/accepted/d207eNe9R6210217390c06a5282cb5fb55447473c

Noon van der Silk Aug 14 2019 03:00 UTC

Uncharacteristically readable paper involving Terry Tao! More about this [over on his blog](https://terrytao.wordpress.com/2019/08/13/eigenvectors-from-eigenvalues/).

Eddie Schoute Aug 13 2019 13:36 UTC

For other readers who are also interested in what a MOVE operation is: It's defined in Fig. 6.

Guanyu Zhu Aug 10 2019 05:16 UTC

Great paper! Non-abelian quantum error correction is still a quite unexplored territory. Needs more attention from the QEC community. Going beyond stabilizer models leads to much more opportunities.

Noon van der Silk Aug 07 2019 23:02 UTC

What a great idea! This is very exciting! Who's going to try implementing it as a quantum algorithm!?

Joschka Roffe Aug 02 2019 09:27 UTC

Hi Arthur. Very happy to hear you've found my review useful! Feel free to email me if you have any more questions about QEC or quantum computing :)

Arthur Pesah Aug 01 2019 10:52 UTC

I'm currently learning quantum error correction (as a grad student) and found your guide to be an incredibly useful resource, very clear and well written! Thanks a lot for sharing it :)

Michal Oszmaniec Jul 25 2019 16:34 UTC

Thanks a lot for your comment. Well, doing full Gate Set Tomography certainly gives a lot of information about your devices (assuming you can actually perform it). However, as far as I understand one cannot use this data directly to mitigate the errors. The point of our work is to use tomography of

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Noon van der Silk Jul 25 2019 04:45 UTC

Most unexpected paper title of the year?

Swarnadeep Majumder Jul 24 2019 16:39 UTC

Exciting work! Could you comment on how using your technique will be different than doing a full Gate Set Tomography?

Colm Ryan Jul 23 2019 05:09 UTC

Should probably have a reference to the original NMR experimental implementation: [Benchmarking Quantum Computers: The Five-Qubit Error Correcting Code
](http://dx.doi.org/10.1103/PhysRevLett.86.5811)

Jalex Stark Jul 12 2019 13:54 UTC

Thanks for your detailed comments. I'm now convinced that the questions addressed in your two papers are interesting, and I currently have nothing to add to the discussion of these questions.

Bradley Foreman Jul 10 2019 02:29 UTC

The statement in your first paragraph is partially correct, but also misleading. Part of the problem is that the word "measurement" has too many meanings. For the present purposes, let us say that a measurement consists of what Peres has called a "premeasurement" (i.e., a unitary interaction that

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Jalex Stark Jul 09 2019 18:29 UTC

Okay, now I understand that equations 10 and 13 are mathematically different, where before I had not. Is it correct to say that one of your key points here is something like "one must always set aside a subsystem of nontrivial dimension to be considered as inaccessible / unmeasured?"

A view that I

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Bradley Foreman Jul 09 2019 03:29 UTC

The equivalence relation you describe is the standard one given in equation (10). It is not quite the same as the one I am proposing to use, which is the one given in equations (12) and (13). You are correct that the crucial question is which observables are allowed. Your circuit-size criterion i

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Jalex Stark Jul 09 2019 02:58 UTC

In your title you suggest that we should quotient the state of density matrices by an appropriate equivalence relation. Is your equivalence relation exactly

$\sigma \sim \rho \iff \operatorname{Tr}(P_i\sigma) = \operatorname{Tr}(P_i\rho)$ for all
"projections" $P_i$ which are part of the spectr

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Blake Stacey Jul 01 2019 20:58 UTC

I'm happy to see that the bibliography I compiled for [arXiv:1703.07901][1] is becoming more and more out of date!

[1]: https://scirate.com/arxiv/1703.07901

rrtucci Jun 27 2019 11:38 UTC

https://qbnets.wordpress.com/2019/06/27/comments-on-quant-ph-arxiv1906-10726-quantum-causal-models-by-jonathan-barrett-robin-lorenz-ognyan-oreshkov/

Barbara Terhal Jun 12 2019 07:31 UTC

Interesting work! Are the authors aware that there is other recent work which has formulated and examined the question of curing the sign problem from complexity and algorithmic perspectives: https://arxiv.org/abs/1802.03408 and https://arxiv.org/abs/1806.05405

Blake Stacey Jun 04 2019 13:37 UTC

Reference 2, which is used to define QBism, is to Caves, Fuchs and Schack (2002). This is an incorrect attribution; Caves does not call himself a QBist and disagrees with some turns that the other two authors made in the following years. (One migh

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Robert Raussendorf May 24 2019 23:55 UTC

Regarding your first point, the blocking strategy *can* be applied. See our reply to Earl Campbell's comment.

Ryan Babbush May 24 2019 18:30 UTC

See the first sentence of the main text..

Robert Raussendorf May 24 2019 15:31 UTC

=> A similar block decomposition as in the stabilizer case can be applied. Namely, for a total of n copies of |H>, one can expand the first set of k copies with respect to the robustness of our paper, and the other n/k -1 sets of k copies w.r.t. the (stabilizer) robustness of magic. For such very r

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Robert Raussendorf May 24 2019 15:29 UTC

=> There is nothing else to consider for classical simulation of QC with magic states. There may a priori be Clifford unitaries, but they can all be propagated past the last measurement, conjugating the measurements in this process. The measurement statistics are the same, for instance, see [20]. F

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Martin Ekerå May 24 2019 10:59 UTC

All of these results are for Shor's algorithms. More specifically, the results are for various derivatives of Shor's original algorithms. These derivatives are specialized for problems that are relevant in cryptography. They provide various constant factor improvements with respect to the number of

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Pixir Dust May 24 2019 08:43 UTC

How about using shor's algorithm?

Markus Heinrich May 23 2019 08:48 UTC

Regarding your first point, I have had exactly the same thoughts. It seems that the "blocking strategy" cannot be applied to the Raussendorf et. al robustness measure and I would be interested if there is a different way of extending low-dimensional solutions. Simulating a quantum circuit with $n$ m

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Earl Campbell May 23 2019 08:24 UTC

Opp.... I wrote a reply yesterday but as a separate comment (see below). My main question is essentially the same as Patrick's above: these LPs are typically only tractable up to 5 qubits so you need some suboptimal method to perform larger simulations.

Patrick Rall May 22 2019 19:49 UTC

The last point confuses me somewhat: if I understand correctly your algorithm only supports potentially non-classical input states followed by Pauli measurements. How can this be used to simulate an arbitrary quantum circuit? With an MBQC approach, the initial state would have to scale with the size

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