{"id":3604,"date":"2019-03-19T23:17:33","date_gmt":"2019-03-19T23:17:33","guid":{"rendered":"https:\/\/mohamedh.ml\/blog\/?p=3604"},"modified":"2022-04-19T01:59:47","modified_gmt":"2022-04-19T01:59:47","slug":"what-is-quantum-computer","status":"publish","type":"post","link":"https:\/\/mohamedh.me\/blog\/what-is-quantum-computer\/","title":{"rendered":"what is a Quantum computer?"},"content":{"rendered":"\n<p>Hello and\nwelcome to my blog!<\/p>\n\n\n\n<p>In this\narticle I will try cover the following.<br>\nPlease note I use the term QC(s) as an abbreviation for \u201cquantum computer(s)\u201d<\/p>\n\n\n\n<ul><li><strong>[Introduction\/context] How traditional\ncomputers work and how are quantum computers different)<\/strong><\/li><li><strong>Why do we need QCs? And why traditional\ncomputers can\u2019t do the job instead of QCs?<\/strong><\/li><li><strong>How fast could quantum computers be?<\/strong><\/li><li><strong>Who\u2019s currently developing QCs?<\/strong><\/li><li><strong>What is the current usage of the existing QCs?<\/strong><\/li><li><strong>What is the intended usage in the future?<\/strong><\/li><li><strong>What are the limitations\/issues? Why we don\u2019t\nhave large scale production of QCs yet?<\/strong><\/li><li><strong>When will we have a commercial (&amp; consumer\ngrade) QCs for sale on large scale?<\/strong><\/li><li><strong>Will They replace current computers?<\/strong><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Introduction<\/h2>\n\n\n\n<p>In a world full of data and information, the\namount of calculations on them keeps increasing and it\u2019s getting even more and\nmore complex. A way to store data and perform actions on this stored data is\nthe classical computers that we all know.<\/p>\n\n\n\n<p>As I explained, Computers are there to answer\nour demand for data and calculations. In simple terms, we store data as bits,\nelectronic signals that can be either High or Low, only one value at a time. We\nrepresent these two statuses with the famous binary model consisting of\nsequences of 1&#8217;s and 0&#8217;s. <br>\nWe perform operations on these data thanks to a CPU, the central processing\nunit (aka. processor) that allows us to perform operations. The faster your CPU\nis the more calculations per second it can perform. Fast here refers the CPU\nfrequency and the number of cores. <strong>This translates physically to the quantity\nof transistors the CPU has.<\/strong><\/p>\n\n\n\n<p>In quantum computing, we store data as quantum-qubit\n(qubits). Those qubits can possibly be on (1) or off (0) or they can even be\nboth 1 and 0 at the same time. Data are processed through a quantum processing\nunit (QPU). The more qubits the QPU has the faster the computer will perform operations.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Why do we need QCs? And\nwhy traditional computers can\u2019t do the job instead of QCs?<\/h2>\n\n\n\n<p>So Why bother developing those QCs? Why can\u2019t we\nsimply keep improving our computers and create 1024 cores processors with 10GHz\neach core? Well here\u2019s the thing. Remember when I said: &nbsp;better performance = more transistors? Here\nlies the issue. Unfortunately, the number of transistors we can keep adding is\nlimited by some physical constraints. Like the amount of heat for example. Higher\nfrequency CPUs will generate more heat, and this will be an issue to keep them\ncool. Also, there\u2019s a law called: Moore\u2019s law. This law explains the\nlimitations of the transistors we can keep adding to our CPUs. According to\nthis law, we almost reached the limit. This means that we can hardly make\ncomputers any faster. <br>\nSo that\u2019s it? Is it the end? We still need faster computers to accommodate for\nthe increasing demand of data processing. Luckily, we came with a couple of\nworkarounds like cloud computing and parallelism. And another possible\nsolutions to this problem is quantum computing. <\/p>\n\n\n\n<p>Quantum computing still can\u2019t break Moore\u2019s law. But since it is a law\nabout transistors in a dense integrated circuit it simply does not even apply\nto Quantum computers (QCs). QCs are not affected by it. However, another law\nexists for QCs, it\u2019s called rose\u2019s law but we\u2019re still far from reaching its\nlimitations.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How fast could quantum\ncomputers be?<\/h2>\n\n\n\n<p>In theory, they\u2019re million times faster than\nour traditional computers. The performance of QCs depends on the number qubits.\nA 30 qubits machine might offer the same performance expected from current\ncomputers. &nbsp;Here\u2019s a quote from <a href=\"http:\/\/quantumly.com\/quantum-computer-speed.html\">quantumly<\/a><\/p>\n\n\n\n<blockquote class=\"wp-block-quote\"><p>In 2015, Google and NASA reported that their new 1097-qubit D-Wave quantum computer had solved an optimization problem in a few seconds. That\u2019s&nbsp;100 million times faster&nbsp;than a regular computer chip. They claimed that a problem their D-Wave 2X machine processed inside one second would take a classical computer 10,000 years to solve.<\/p><\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">Who\u2019s currently developing\nQCs?<\/h2>\n\n\n\n<p>The number\nof companies, labs and universities working on quantum computers keeps\nincreasing every day. Here\u2019s a non-exhaustive list of the ones I know in\nvarious Countries:<\/p>\n\n\n\n<ul><li>North America<ul><li>USA:<ul><li>Google<\/li><\/ul><ul><li>Nasa\/ QuAIL<\/li><\/ul><ul><li>IBM<\/li><\/ul><ul><li>Microsoft<\/li><\/ul><ul><li>Intel<\/li><\/ul><ul><li>Mit<\/li><\/ul><ul><li>Caltech<\/li><\/ul><ul><li>UC berkley<\/li><\/ul><\/li><\/ul><ul><li>Canada<ul><li>D-wave<\/li><\/ul><ul><li>IQC<\/li><\/ul><\/li><\/ul><\/li><li>Europe<ul><li>European non country-specific:<ul><li>OpenSuperQ (Germany,\nSpain, Sweden, Switzerland)<\/li><\/ul><ul><li>Quantum\nTechnologies Flagship<\/li><\/ul><\/li><\/ul><ul><li>United Kingdom<ul><li>Cambridge\nQuantum Computing<\/li><\/ul><ul><li>UKNQTP<\/li><\/ul><ul><li>UCLQ<\/li><\/ul><\/li><\/ul><ul><li>Ireland<ul><li>Accenture<\/li><\/ul><\/li><\/ul><ul><li>France<ul><li>Atos<\/li><\/ul><ul><li>Pcqc (\/cnrs)<\/li><\/ul><\/li><\/ul><ul><li>Switzerland<ul><li>NCCR QSIT<\/li><\/ul><\/li><\/ul><ul><li>Netherlands<ul><li>Tu delft\/ qutech<\/li><\/ul><\/li><\/ul><ul><li>Germany<ul><li>TUM university<\/li><\/ul><\/li><\/ul><\/li><li>Asia<ul><li>China<ul><li>Baidu<\/li><\/ul><\/li><\/ul><ul><li>Japan:<ul><li>&nbsp;Tokyo Tech laboratory<\/li><\/ul><ul><li>University of\nTokyo<\/li><\/ul><ul><li>RIKEN, <\/li><\/ul><ul><li>The National Institute\nof Advanced Industrial Science and Technology<\/li><\/ul><\/li><\/ul><ul><li>Honk-Kong: <ul><li>HKUST &nbsp;<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n<p>There\u2019s\nstill much more of course and the list will keep increasing but these are the\nones I found at the time of writing.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What is the current usage\nof the existing QCs?<\/h2>\n\n\n\n<p>Quantum\ncomputers are great for solving optimization problems and they can do even much\nmore. Due to the limited access, we still didn\u2019t fully utilize them, they\u2019re\nonly used for a limited number of tasks like the following:<\/p>\n\n\n\n<ul><li>machine learning,\npattern recognition, mission planning and scheduling, distributed\nnavigation and coordination, and system diagnostics and anomaly detection (according to <a href=\"https:\/\/www.nas.nasa.gov\/projects\/quantum.html\">NASA<\/a>).<\/li><li>Volkswagen recently\nused QC from D-wave to help optimize traffic routing. (<a href=\"https:\/\/www.greencarcongress.com\/2019\/12\/20191206-vwquantum.html\">source<\/a>)<\/li><li>Most other uses at\nthe time being are not real-world use cases, they\u2019re mostly research oriented making\nuse of quantum computing to run scientific simulations.<\/li><\/ul>\n\n\n\n<p><a href=\"https:\/\/builtin.com\/hardware\/quantum-computing-applications\">Here\u2019s an\narticle <\/a>talking about some uses of the existing quantum computers.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What is the intended usage\nin the future?<\/h2>\n\n\n\n<p>In the future, if large-scale fully usable quantum\ncomputers are built, they will be able to solve certain problems exponentially\nfaster than our current classical computers (for example Shor&#8217;s algorithm). Quantum\ncomputers may be used to break all the cryptographic encryptions we have today.\nSimilarly, they can be used to create \u201cunbreakable\u201d encryption systems that are\nmuch more secure and almost impossible to break even with another quantum\ncomputer. That said, quantum computer can help introduce a huge improvement in various\ndomains that require calculations such as:<\/p>\n\n\n\n<ul><li>Cybersecurity<\/li><li>Much more accurate weather forecast<\/li><li>Drugs development.<\/li><li>Banking and financial modelling <\/li><li>Artificial Intelligence and machine learning<\/li><li>Physical simulations of scientific experiments.<\/li><\/ul>\n\n\n\n<p>However, it\u2019s\nworth noting quantum computers may not be beneficial (or at least have not been\nproven of use) to all domains. For example, domains like sound\/video editing,\ngraphic designing and video games won\u2019t see any improvement. Video encoding and\ncompression might be however improved since it\u2019s an algorithm-based process.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What are the\nlimitations\/issues? Why we don\u2019t have large scale production of QCs yet?<\/h2>\n\n\n\n<p>In the\nmeantime, we have a couple of issues that we still need to solve in order to\nattain a reliable QC. To do this, we need to find an optimal \u201cquantum error\ncorrection\u201d, it\u2019s the mechanism used to prevent <strong>Quantum decoherence<\/strong> and <strong>Quantum\nnoise<\/strong>. It\u2019s worth noting that noise may be caused by temperature\nfluctuations, mechanical vibrations or stray electromagnetic fields. In All\ncases the noise weakens the correlations between qubits and may result in\nerrors in the data. To increase reliability, QCs are cooled with huge cooling\nsystems making them room-size computers. The size of the D-wave 2000q is around\n10&#8242; x 7&#8242; x 10&#8242;.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">When will we have a\ncommercial (&amp; consumer grade) QCs for sale on large scale?<\/h2>\n\n\n\n<p>I luckily had the chance to talk to some\nresearchers from CNRS and I asked them this question. According to them, we expect\nto reach production ready quantum computers on much larger scale by 2030. I\nshould mention that since 2017 we already have access to IBM\u2019s network of quantum\ncomputers via their cloud services.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Will They replace current\ncomputers?<\/h2>\n\n\n\n<p>As I said earlier, domains like sound\/video editing, graphic designing and video games won\u2019t benefit from quantum computing (except for the computational part but not the visual part). QCs might be even worse than classical ones at some tasks. The current quantum computers we have are all hybrid so they can communicate with our normal computers. This means that the quantum computer containing the QPU is connected to another conventional computer that is programmed specially with all necessary functionalities to control the quantum computer connected to it. Access to the quantum computer is done by accessing the conventional one connected to it (locally or remotely) and the computer will then perform the calculations on the QC that is attached to it.<\/p>\n\n\n\n<p>In short, QCs were never meant to replace today\u2019s computers and they won\u2019t replace them.<br> <br> <br> <br> <\/p>\n\n\n\n<p><strong>Disclaimer<\/strong>: I try to put references to my sources as much I can, but a lot of what I write is based on my understanding of what I read in various articles. My articles should not be used as a source of information for any research projects or thesis as they may possibly contain some mistakes. If you ever spot any mistake in any of my articles, please do not hesitate to let me know!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Hello and welcome to my blog! In this article I will try cover the following. Please note I use the term QC(s) as an abbreviation [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10,16],"tags":[14],"_links":{"self":[{"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/posts\/3604"}],"collection":[{"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/comments?post=3604"}],"version-history":[{"count":5,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/posts\/3604\/revisions"}],"predecessor-version":[{"id":3820,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/posts\/3604\/revisions\/3820"}],"wp:attachment":[{"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/media?parent=3604"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/categories?post=3604"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohamedh.me\/blog\/wp-json\/wp\/v2\/tags?post=3604"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}