{"id":107188,"date":"2019-10-07T22:10:17","date_gmt":"2019-10-08T02:10:17","guid":{"rendered":"http:\/\/rbach.net\/index.php\/"},"modified":"2021-08-19T15:02:27","modified_gmt":"2021-08-19T19:02:27","slug":"quantum-supremacy","status":"publish","type":"post","link":"https:\/\/rbach.net\/index.php\/quantum-supremacy\/","title":{"rendered":"Quantum Supremacy"},"content":{"rendered":"

\"Quantum<\/a>There are reports are that Google<\/a> (GOOG<\/a>) has demonstrated quantum supremacy<\/a><\/strong>. In quantum computing<\/a>, quantum supremacy<\/a> means that a quantum computer is able to perform a calculation that is practically impossible for a classical computer.<\/strong> Before we fear and weep for the western dream, ScienceAlert<\/a><\/em> explains<\/a> that we can’t be sure of the claim.<\/p>\n

\"\"<\/a>Shortly after the research article was uploaded to the NASA<\/a><\/strong> site it was withdrawn for unknown reasons<\/strong>. The news was originally<\/a> broken by the paywalled Financial Times<\/em>, which reported both seeing the paper and also that it was subsequently taken down. Now there are only copies<\/a> of the original paper available online. Further, Google has not officially explained<\/strong> to anybody what’s going on, sparking no end of speculation online about what has or hasn’t happened.<\/p>\n

Assuming the briefly released paper, is real<\/strong> \u2013 why is this important? Wired<\/a><\/em> explains<\/a> that the Google researchers used a quantum processor called Sycamore, with 54 qubits<\/a><\/strong>. It tackled a random sampling problem<\/strong> \u2013 that is, checking that a set of numbers has a truly random distribution. ScienceAlert<\/em> says the experimental quantum processor took about 200 seconds<\/strong> to solve a particular computational problem.<\/p>\n

\"\"<\/a>As part of the experiment, they set a version of the same challenge to some powerful Google server clusters, as well as to the current world’s fastest supercomputer, the IBM-built Summit supercomputer<\/a> at Oak Ridge National Lab<\/a>. The state-of-the-art supercomputer <\/strong>would require approximately 10,000 years<\/strong> to perform the same task.<\/p>\n

According to copies<\/a> (PDF) of the vanished report,<\/p>\n

This dramatic speedup relative to all known classical algorithms provides an experimental realization of quantum supremacy on a computational task and heralds the advent of a much-anticipated computing paradigm<\/em><\/p>\n

\"Summit<\/a>In the Wired<\/em> article, John Preskill<\/a>, the Caltech<\/a> professor who coined the term “quantum supremacy,\u201d calls the breakthrough, if accurate, \u201dtruly impressive achievement in experimental physics.<\/em>\u201d But he and other experts, and even Google\u2019s own paper, caution that the result doesn\u2019t mean quantum computers are ready for practical work<\/strong>. Professor Preskill explains, \u201cThe problem their machine solves with astounding speed has been very carefully chosen just for the purpose of demonstrating the quantum computer\u2019s superiority.<\/em>\u201d<\/p>\n

Professor Preskill told Wired<\/em>,\u00a0 it\u2019s unclear how long it will take quantum computers to become commercially useful<\/strong>; breaking encryption\u2014a theorized use for the technology\u2014remains a distant hope. \u201cThat\u2019s still many years out,<\/em>\u201d says Jonathan Dowling<\/a>, a professor at Louisiana State University<\/a> and New Scientist<\/em> said<\/a> although that is impressive, there is no practical use<\/strong> for it.<\/p>\n

Will Oliver,<\/a> a quantum specialist at MIT<\/a>, told<\/a> Technology Review<\/em><\/a>, the computing milestone is similar to the first flight of the Wright brothers at Kitty Hawk<\/strong> in aviation. He said it would give added impetus to research in the field, which should help quantum machines achieve their promise more quickly.<\/p>\n

\"1904<\/a><\/p>\n

New Scientist<\/em><\/a> says<\/a> there are plenty of hurdles<\/strong> left to overcome before quantum computing hits the big time<\/strong>. The author cites a number of steps:<\/p>\n

For a start, the processors need to be more powerful<\/strong>. Google\u2019s Sycamore quantum computer, consisted of only 54 qubits. For quantum computers to really come into their own, they will probably need thousands<\/strong>. Scaling up the number of qubits won\u2019t be easy. Qubits must be isolated from vibrations as they can be easily disturbed.<\/p>\n

Next quantum computers need error-correcting<\/strong> codes. Classical computers have mechanisms to make sure that when little mistakes happen they are automatically rectified.<\/p>\n

The same will be needed for quantum computers, especially considering the delicate nature of qubits<\/strong>. The challenge now is to build a quantum computer that has quantum supremacy, as well as error-correcting codes<\/strong>.<\/p>\n

The final, biggest step is to actually do something useful. Google\u2019s quantum computer tackled a task specifically tailored\u00a0 to prove quantum supremacy, not do anything useful.<\/p>\n

New Scientist<\/a><\/em> called<\/a> the achievement impressive, there is no practical use for it. Ciar\u00e1n Gilligan-Lee<\/a> at University College London said, \u201cWe shouldn\u2019t get too carried away with this … but there\u2019s still a long way to go.<\/em>”<\/p>\n

rb-<\/em><\/strong><\/p>\n

This bench-marking task is a proof of concept. SkyNet is not coming –\u00a0 yet. <\/em><\/p>\n

Combining quantum with machine learning and AI may be a different story. But for a year or so we are probably safe. Unless of course, some TLA that is already using quantum computing made the paper disappear.<\/em><\/p>\n

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