Category Archives: Quantum

The Argument Against Quantum Computers – A Very Short Introduction

Left: Gowers’s book Mathematics a very short introduction. Right C. elegans; Boson Sampling can be seen as the C. elegans of quantum computing. (See, this paper.) Update (January 6, 2021): Tomorrow January, 7, 8:30 AM Israel time, I give a … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Physics, Probability, Quantum | Tagged , | 7 Comments

Photonic Huge Quantum Advantage ???

This is a quick and preliminary post about a very recent announcement in a Science Magazine paper: Quantum computational advantage using photons by a group of researchers leaded by Jianwei Pan and Chao-Yang Lu. (Most of the researchers are from … Continue reading

Posted in Combinatorics, Physics, Probability, Quantum | Tagged , | 12 Comments

Quantum Matters

A comparison between the Google estimator U for the fidelity and two improved estimators that we studied  MLE (maximum likelihood estimator) and V (a variant of U). (More figures at the end of the post.) Here are some links on … Continue reading

Posted in Quantum, Statistics | Tagged , | 6 Comments

Trees not Cubes! Memories of Boris Tsirelson

This post is devoted to a few memories of Boris Tsirelson who passed away at the end of January. I would like to mention that a few days ago graph theorist Robin Thomas passed away after long battle with ALS. … Continue reading

Posted in Combinatorics, Obituary, Probability, Quantum | Tagged | 3 Comments

Amazing: Zhengfeng Ji, Anand Natarajan, Thomas Vidick, John Wright, and Henry Yuen proved that MIP* = RE and thus disproved Connes 1976 Embedding Conjecture, and provided a negative answer to Tsirelson’s problem.

A few days ago an historic 160-page paper with a very short title MIP*=RE was uploaded to the arXive by Zhengfeng Ji, Anand Natarajan, Thomas Vidick, John Wright, and Henry Yuen.  I am thankful to Dorit Aharonov and Alon Rosen … Continue reading

Posted in Algebra, Analysis, Combinatorics, Computer Science and Optimization, Physics, Quantum | Tagged , , , , | 13 Comments

The Google Quantum Supremacy Demo and the Jerusalem HQCA debate.

Below are 10 annotated slides from a spontaneous informal talk that I gave at the school on mathematics of quantum computing a weak ago. (Power point presentation.) Later in the afternoon we had  a panel/debate on quantum supremacy (click for … Continue reading

Posted in Controversies and debates, Quantum | Tagged , , , , , , , , , , | 4 Comments

Gil’s Collegial Quantum Supremacy Skepticism FAQ

The first 15 samples of Google’s  53 qubit  flagship quantum supremacy experiment!   After the sensationally successful Scott’s Supreme Quantum Superiority FAQ and Boaz’s inferior classical inferiority FAQ let me add my contribution, explaining my current skeptical view. (I was actually … Continue reading

Posted in Combinatorics, Physics, Quantum | Tagged | 23 Comments

The story of Poincaré and his friend the baker

Update: After the embargo update (Oct 25): Now that I have some answers from the people involved let me make a quick update: 1) I still find the paper unconvincing, specifically, the few verifiable experiments (namely experiments that can be … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Probability, Quantum, Statistics | Tagged , , | 25 Comments

Noisy quantum circuits: how do we know that we have robust experimental outcomes at all? (And do we care?)

In a recent post we discussed Google’s claim of achieving “quantum supremacy” and my reasons to think that these claims will not stand. (See also this comment for necessary requirements from a quantum supremacy experiment.) This debate gives a good … Continue reading

Posted in Computer Science and Optimization, Quantum | Tagged , , | 10 Comments

Quantum computers: amazing progress (Google & IBM), and extraordinary but probably false supremacy claims (Google).

A 2017 cartoon from this post. After the embargo update (Oct 25): Now that I have some answers from the people involved let me make a quick update: 1) I still find the paper  unconvincing, specifically, the verifiable experiments (namely experiments … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Quantum, Updates | Tagged | 67 Comments