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Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 60 (from laksa005)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa060.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.jyu.fi/en/blog/the-truth-about-quantum-superposition\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.jyu.fi/en/blog/the-truth-about-quantum-superposition\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition","crawl_time":1770215057,"first_indexed_time":1738774653,"http_code":200,"src_unparsed":"fi,jyu!www,\/en\/blog\/the-truth-about-quantum-superposition s443","src_root_hash":"13321573151364776460","history_drop_reason":null,"meta_title":"The truth about quantum superposition | University of Jyväskylä","meta_descriptions":["This science blog starts a series of three blogs where Teiko Heinosaari explains the essential terms of quantum physics."],"attrs_boilerpipe_text":"Quantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential. \nA central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos?\n I will try to explain the matter by means of an illustrative story.\nThe superposition state is like Singapore in between the poles\nAntti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole. \nAntti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time. \nBertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair. \nAntti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth.\nThe story illustrates the difference between a quantum-physical system and an everyday system as follows:\nIn the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits. \nIn a sense, though, superposition states are between the bit states of 0 and 1. \nThis state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1.\nAlso in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky).\nA superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states. \nLet’s make it even clearer: a quantum system is only in one state at a time!\nQuantum mechanics says nothing about the location of a particle\nPerceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not. \nIf we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted. \nIf we determine the location of a particle by measuring it, we can find it in exactly one place.\n“Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.”\nWhile writing this column, I may have slipped into the role of quantum pedant. \nIn my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory\n. We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics.","attrs_markdown":"[Skip to main content](https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition#main-content)\n\nSwitch language, current language: EN\n\n- [EN - English](https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition)\n- [FI - Suomeksi](https:\/\/www.jyu.fi\/fi\/blogikirjoitus\/totuus-kvanttisuperpositiosta)\n\nSearch\n\n### Site search\nClose search\n\n### Advanced searches\n- [Education search](https:\/\/www.jyu.fi\/en\/search\/education)\n- [Person search](https:\/\/www.jyu.fi\/en\/search\/person)\n- [Research search](https:\/\/www.jyu.fi\/en\/search\/research)\n\n- [Search](https:\/\/www.jyu.fi\/en\/search)\n- [Contact](https:\/\/www.jyu.fi\/en\/contact)\n- [Tools](https:\/\/www.jyu.fi\/en\/tools)\n\n[![Home page](https:\/\/www.jyu.fi\/themes\/custom\/jyu\/images\/logos\/jyu-logo-en.svg)](https:\/\/www.jyu.fi\/en \"Home page\")\n\n- [Study with us](https:\/\/www.jyu.fi\/en\/study-with-us)\n- [Research](https:\/\/www.jyu.fi\/en\/research)\n- [Science for All](https:\/\/www.jyu.fi\/en\/science-for-all)\n- [For students](https:\/\/www.jyu.fi\/en\/for-students)\n- [Collaboration](https:\/\/www.jyu.fi\/en\/collaboration)\n- [Faculties and departments](https:\/\/www.jyu.fi\/en\/faculties-and-departments)\n- [About us](https:\/\/www.jyu.fi\/en\/about-us)\n\nMenu\n\nClose the menu\n\n- [Study with us](https:\/\/www.jyu.fi\/en\/study-with-us)\n  Expand submenu forStudy with us\n  - 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[Home](https:\/\/www.jyu.fi\/en)\n2. The truth about quantum superposition\n\n[Listen](https:\/\/app-eu.readspeaker.com\/cgi-bin\/rsent?customerid=10980&lang=en_uk&readid=content-area&url=https%3A%2F%2Fwww.jyu.fi%2Fen%2Fblog%2Fthe-truth-about-quantum-superposition \"Listen to this page using ReadSpeaker (opens in a new window)\")\n\n# The truth about quantum superposition\nProfessor in Quantum Computing Teiko Heinosaari corrects the most common misunderstanding related to quantum-physical systems – what is the quantum state superposition all about? To answer this question, we must visit the North Pole and the South Pole. This science blog starts a series of three blogs where Heinosaari explains the essential terms of quantum physics.\n\n![Teiko Heinosaari ja noppa](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_1440px\/public\/2025-02\/Heinosaari_Teiko_053.jpg?h=ed1d0588&itok=cNmH9D7H)\n\nPublished\n\n3\\.2.2025\n\n**Text**: Teiko Heinosaari \\| **Photos**: Petteri Kivimäki\n\nQuantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential.\n\nA central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos?  \n  \n I will try to explain the matter by means of an illustrative story.\n\n## The superposition state is like Singapore in between the poles\nAntti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole.\n\nAntti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time.\n\nBertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair.\n\n> Antti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth.\n\nThe story illustrates the difference between a quantum-physical system and an everyday system as follows:\n\nIn the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits.\n\n> In a sense, though, superposition states are between the bit states of 0 and 1.\n\nThis state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1.\n\nAlso in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky).\n\nA superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states.\n\nLet’s make it even clearer: a quantum system is only in one state at a time\\!\n\n## Quantum mechanics says nothing about the location of a particle\nPerceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not.\n\nIf we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted.\n\n> If we determine the location of a particle by measuring it, we can find it in exactly one place.\n\n“Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.”\n\nWhile writing this column, I may have slipped into the role of quantum pedant. In my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory. We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics.\n\n## Share this article\n- [![Linkedin](https:\/\/www.jyu.fi\/\/themes\/custom\/jyu\/images\/icons\/icon-linkedin.svg)](https:\/\/www.linkedin.com\/shareArticle?mini=true&url=https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition&title=The%20truth%20about%20quantum%20superposition&source=https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition \"Linkedin (opens in a new window)\")\n- [![Facebook](https:\/\/www.jyu.fi\/themes\/custom\/jyu\/images\/icons\/icon-facebook-share.svg)](https:\/\/www.facebook.com\/share.php?u=https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition&title=The%20truth%20about%20quantum%20superposition \"Facebook (opens in a new window)\")\n\n[![Teiko Heinosaari](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/1_1_90px\/public\/profiles\/Teiko_Heinosaari_01caa72dad81120817ec40da5047849b_1764615358.jpg?itok=5t0Qc30U) Teiko Heinosaari Professor](https:\/\/www.jyu.fi\/en\/people\/teiko-heinosaari)\n\n## Subscribe to the research newsletter of the University of Jyväskylä\nSubscribe to our newsletter to receive current science news and articles directly to your inbox. You can unsubscribe at any time.\n\n[Privacy notice](https:\/\/www.jyu.fi\/en\/node\/134954)\n\n## Related content\n[![Hanwool Lee (vas.), Andrés Muñoz Moller ja Teiko Heinosaari keskustelevat pöydän ääressä Agorassa.](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2025-02\/Heinosaari_Teiko_007.jpg?h=dbe99178&itok=EUzcwkEV) Feature article 5.2.2025 Teiko Heinosaari: “More is known about quantum phenomena these days” The professor of quantum computing Teiko Heinosaari is constantly seeking new ways to reach new audiences.](https:\/\/www.jyu.fi\/en\/feature-article\/teiko-heinosaari-more-is-known-about-quantum-phenomena-these-days)\n\n[![Kvanttilippulaivassa ryhmänjohtajia ovat Joel Mero (vas.), Ilari Maasilta, Robert van Leeuwen, Teiko Heinosaari, Kezilebieke Shawulienu, Tero Heikkilä (lippulaivan vastuututkija Jyväskylän yliopistossa) ja Juha Muhonen.](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2024-03\/Kvanttilippulaiva_008B.jpg?h=e4b6811f&itok=_-aCzPyM) Project The Finnish Quantum Flagship The Finnish Quantum Flagship consolidate and expand the national ecosystem, promote cutting-edge research that boosts the emergence of new businesses, and secure our position as a leading quantum-enabled society.](https:\/\/www.jyu.fi\/en\/projects\/the-finnish-quantum-flagship)\n\n[![](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2023-03\/Medium_2021-06-10-JYU-img-JK-0921.jpg?h=62868edf&itok=HyfGlmfU) Faculty of Information Technology The Faculty of Information Technology is creating a digital future through science, research and education. It combines the perspectives of technology, business and people.](https:\/\/www.jyu.fi\/en\/it)\n\n[![Kuvassa on näkymä päärakennuksen portaikkoon ja läpikulkuhalliin..](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2024-11\/Seminaarinmaki_paarakennus.jpg?h=56d0ca2e&itok=QlifEnrC) Tiedonportti - University of Jyväskylä's Online Science Magazine Read more science articles and science blogs](https:\/\/www.jyu.fi\/en\/current\/tiedonportti-university-of-jyvaskylas-online-science-magazine)\n\n[![qowl](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2025-05\/Qowl-oranssi-sininen-3.png?h=2d7a1265&itok=jlw4WLHw) Research group Quantum Information and Computation Team Quantum Information and Computation Team is on a mission to decode the quantum realm's computational power and to push the boundaries of what's ultimately possible in computing and communication.](https:\/\/www.jyu.fi\/en\/research-groups\/quantum-information-and-computation-team)\n\n## Other news\n[![Noppa Teiko Heinosaaren kädessä](https:\/\/www.jyu.fi\/sites\/default\/files\/styles\/16_9_max_320px\/public\/2025-04\/Heinosaari_Teiko_054.jpg?h=6987d0c3&itok=ngypc5vp) Blog post 9.4.2025 Quantum entanglement surpasses even a magician’s tricks Teiko Heinosaari describes how a magician with dice could make his trick more impressive using quantum entanglement.](https:\/\/www.jyu.fi\/en\/blog\/quantum-entanglement-surpasses-even-a-magicians-tricks)\n\n[![Logo of the JYU](https:\/\/www.jyu.fi\/themes\/custom\/jyu\/images\/logos\/jyu-torch-white.svg)](https:\/\/www.jyu.fi\/en \"Home page\")\n\n[Back to top](https:\/\/www.jyu.fi\/en\/blog\/the-truth-about-quantum-superposition#top)\n\n## University of Jyväskylä\nSeminaarinkatu 15   \n(Registry office and archive)  \nPO Box 35  \nFI-40014 University of Jyväskylä  \nFinland  \nSwitchboard +358 (14) 260 1211\n\n[Contact information](https:\/\/www.jyu.fi\/en\/contact) \\| [Maps](https:\/\/www.jyu.fi\/en\/about-us\/maps-and-visitor-information)  \n[HelpJYU Service Portal](https:\/\/help.jyu.fi\/jp)  \n[Send feedback on the website](https:\/\/link.webropolsurveys.com\/S\/F7F72AC87492A672 \"(opens in a new window)\")\n\nVAT number FI02458947  \n[Invoicing address for the University of Jyväskylä](https:\/\/www.jyu.fi\/en\/invoicing-address-for-the-university-of-jyvaskyla)\n\nCookie settings\n\n## Follow us\n- [Follow us on Youtube (Opens in a new tab)](https:\/\/www.youtube.com\/user\/jyvaskylauniversity \"(Follow us on Youtube Opens in a new tab, opens in a new window)\")\n- [Follow us on Instagram (Opens in a new tab)](https:\/\/www.instagram.com\/uniofjyvaskyla \"(Follow us on Instagram Opens in a new tab, opens in a new window)\")\n- [Follow us on LinkedIn (Opens in a new tab)](https:\/\/www.linkedin.com\/school\/166642\/ \"(Follow us on LinkedIn Opens in a new tab, opens in a new window)\")\n- [Follow us on Facebook (Opens in a new tab)](https:\/\/www.facebook.com\/uniofjyvaskyla \"(Follow us on Facebook Opens in a new tab, opens in a new window)\")\n\n- [Privacy notice](https:\/\/www.jyu.fi\/en\/data-privacy-at-the-university-of-jyvaskyla)\n- [Accessibility specification](https:\/\/www.jyu.fi\/en\/accessibility-specification)\n- [Intranet Uno](https:\/\/uno.jyu.fi\/en)\n- [Log in (for staff)](https:\/\/www.jyu.fi\/en\/user\/login)","attrs_readable_markdown":"Quantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential.\n\nA central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos?\n\nI will try to explain the matter by means of an illustrative story.\n## The superposition state is like Singapore in between the poles\nAntti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole.\n\nAntti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time.\n\nBertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair.\n\n> Antti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth.\n\nThe story illustrates the difference between a quantum-physical system and an everyday system as follows:\n\nIn the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits.\n\n> In a sense, though, superposition states are between the bit states of 0 and 1.\n\nThis state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1.\n\nAlso in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky).\n\nA superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states.\n\nLet’s make it even clearer: a quantum system is only in one state at a time\\!\n\n## Quantum mechanics says nothing about the location of a particle\nPerceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not.\n\nIf we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted.\n\n> If we determine the location of a particle by measuring it, we can find it in exactly one place.\n\n“Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.”\n\nWhile writing this column, I may have slipped into the role of quantum pedant. In my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory. We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics.","meta_canonical":null}

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Meta Title	The truth about quantum superposition \| University of Jyväskylä
Meta Description	This science blog starts a series of three blogs where Teiko Heinosaari explains the essential terms of quantum physics.
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Boilerpipe Text	Quantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential. A central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos? I will try to explain the matter by means of an illustrative story. The superposition state is like Singapore in between the poles Antti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole. Antti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time. Bertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair. Antti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth. The story illustrates the difference between a quantum-physical system and an everyday system as follows: In the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits. In a sense, though, superposition states are between the bit states of 0 and 1. This state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1. Also in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky). A superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states. Let’s make it even clearer: a quantum system is only in one state at a time! Quantum mechanics says nothing about the location of a particle Perceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not. If we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted. If we determine the location of a particle by measuring it, we can find it in exactly one place. “Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.” While writing this column, I may have slipped into the role of quantum pedant. In my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory . We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics.
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[Home](https://www.jyu.fi/en) 2. The truth about quantum superposition [Listen](https://app-eu.readspeaker.com/cgi-bin/rsent?customerid=10980&lang=en_uk&readid=content-area&url=https%3A%2F%2Fwww.jyu.fi%2Fen%2Fblog%2Fthe-truth-about-quantum-superposition "Listen to this page using ReadSpeaker (opens in a new window)") # The truth about quantum superposition Professor in Quantum Computing Teiko Heinosaari corrects the most common misunderstanding related to quantum-physical systems – what is the quantum state superposition all about? To answer this question, we must visit the North Pole and the South Pole. This science blog starts a series of three blogs where Heinosaari explains the essential terms of quantum physics. ![Teiko Heinosaari ja noppa](https://www.jyu.fi/sites/default/files/styles/16_9_max_1440px/public/2025-02/Heinosaari_Teiko_053.jpg?h=ed1d0588&itok=cNmH9D7H) Published 3\.2.2025 Text: Teiko Heinosaari \\| Photos: Petteri Kivimäki Quantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential. A central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos? I will try to explain the matter by means of an illustrative story. ## The superposition state is like Singapore in between the poles Antti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole. Antti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time. Bertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair. > Antti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth. The story illustrates the difference between a quantum-physical system and an everyday system as follows: In the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits. > In a sense, though, superposition states are between the bit states of 0 and 1. This state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1. Also in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky). A superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states. Let’s make it even clearer: a quantum system is only in one state at a time\! ## Quantum mechanics says nothing about the location of a particle Perceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not. If we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted. > If we determine the location of a particle by measuring it, we can find it in exactly one place. “Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.” While writing this column, I may have slipped into the role of quantum pedant. In my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory. We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics. ## Share this article - [![Linkedin](https://www.jyu.fi//themes/custom/jyu/images/icons/icon-linkedin.svg)](https://www.linkedin.com/shareArticle?mini=true&url=https://www.jyu.fi/en/blog/the-truth-about-quantum-superposition&title=The%20truth%20about%20quantum%20superposition&source=https://www.jyu.fi/en/blog/the-truth-about-quantum-superposition "Linkedin (opens in a new window)") - [![Facebook](https://www.jyu.fi/themes/custom/jyu/images/icons/icon-facebook-share.svg)](https://www.facebook.com/share.php?u=https://www.jyu.fi/en/blog/the-truth-about-quantum-superposition&title=The%20truth%20about%20quantum%20superposition "Facebook (opens in a new window)") [![Teiko Heinosaari](https://www.jyu.fi/sites/default/files/styles/1_1_90px/public/profiles/Teiko_Heinosaari_01caa72dad81120817ec40da5047849b_1764615358.jpg?itok=5t0Qc30U) Teiko Heinosaari Professor](https://www.jyu.fi/en/people/teiko-heinosaari) ## Subscribe to the research newsletter of the University of Jyväskylä Subscribe to our newsletter to receive current science news and articles directly to your inbox. 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Readable Markdown	Quantum technology is a general term for new technologies where quantum properties have been harnessed for technological applications. Quantum sensors and quantum random number generators are already commercial products, whereas quantum computers, for instance, are still at a stage of development where we are waiting to see their real potential. A central phenomenon pertaining to quantum technologies is the superposition of quantum states, which is, unfortunately, associated with unnecessary mysticism. I was once asked what the most common misunderstanding related to quantum physics is. I said that in my opinion it is that “an object is in several places at the same time”, or the closely related notion that “in superposition a system is simultaneously in multiple states”. After that, many people have asked me what I actually meant. Isn’t that exactly how superposition is explained in YouTube videos? I will try to explain the matter by means of an illustrative story. ## The superposition state is like Singapore in between the poles Antti and Bertta are two friends who like to travel. Antti knows only two possible destinations: the North Pole and the South Pole. His favourite activity is to stare at stars in the sky, and the polar regions are well suited for such an activity. At the North Pole, he admires the Big Dipper in particular. The Big Dipper cannot be seen from the South Pole at all, and for Antti, seeing it in the sky is evidence of being at the North Pole. In turn, Antti goes to the South Pole to admire the Southern Cross, which cannot be seen from the North Pole. Antti is not only fascinated by these two destinations, but he is not even aware of the possibility of travelling to any other place. Bertta is more open-minded and decides to travel to Singapore near the Equator. One night, Bertta sees both the Big Dipper and the Southern Cross in the sky at the same time. Bertta gives Antti a call and tells him that she is admiring these two constellations at the same time while resting on her deck chair. > Antti finds this impossible – it would mean that Bertta would be simultaneously at the North and South Poles! Bertta’s statement is in conflict with what Antti knows about the position of the stars and the movement of the Earth. The story illustrates the difference between a quantum-physical system and an everyday system as follows: In the information world a bit has exactly two states, 0 (North Pole) and 1 (South Pole). A quantum-physical bit or qubit has in addition to these states also all superpositions of these. The superpositions can be compared to the fact that there are plenty of other places than just the two Poles. Just as Singapore is not the North and South Pole at the same time, nor is the superposition state simultaneously 0 and 1. Superposition states are a new kind of state that we don’t encounter in the world of bits. > In a sense, though, superposition states are between the bit states of 0 and 1. This state of being in between is manifested so that observations made about the states through measurements are something in between the observations we would get in similar measurements respectively for the states 0 and 1. Also in this sense, it is comparable to the notion that the observations in Singapore (with the Big Dipper and the Southern Cross both visible in the sky) have certain similarity with the observations made both at the North Pole and at the South Pole, but also some difference (the constellations are in different places in the sky). A superposition state is not a vague one by any means, and neither is Bertta’s resting position in Singapore. Each superposition state is exactly as valid as 0 and 1. In fact, for qubits these two latter states have no special significance. We could pick any two states and present all other states as their superposition states. Let’s make it even clearer: a quantum system is only in one state at a time\! ## Quantum mechanics says nothing about the location of a particle Perceiving superposition as simultaneous states is closely linked with the misconception that before measurement, a quantum particle can be everywhere simultaneously. Though it would also be problematic to argue that a particle is always in one place, whether we measure it or not. If we must say something about it, the closest to the truth would be that a particle has no specific location until it is measured. But we need not say even this. The point is that quantum mechanics is indifferent in this regard. Quantum mechanics gives the probability of a given measurement result when the measurement is conducted. > If we determine the location of a particle by measuring it, we can find it in exactly one place. “Well”, you might say, “now you've taken everything interesting out of the subject by nitpicking about the meanings of words. Being everywhere at the same time was the coolest thing about quantum mechanics.” While writing this column, I may have slipped into the role of quantum pedant. In my opinion, the idea that a particle can exist everywhere at once is so mystical that it hinders any effort to gain insight into quantum theory. We should take a cue from Bertta in the story and broaden our perspectives, which can be accomplished by studying quantum physics.
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