This
level-5 vital article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||
|
This article may be too technical for most readers to understand.(September 2010) |
What is this, some kind of sequel to Canticle for Liebowitz? Seriously, someone rewrite this article that knows what they are talking about. Otherwise I'm going to just assume that anyone selling me "quantum computers" is blowing smoke up my ass. — Preceding unsigned comment added by 198.233.187.6 ( talk) 18:56, 4 January 2018 (UTC)
Schumacher undoubtedly discovered Shumacher compression and is generally accepted as having introduced the term qubit in the 1995 Phys Rev paper Quantum Coding, but historically it is questionable whether one can say he discovered how to interpret states as information. I suspect that something like this may have been known to Feynman. Anyway I'm not a historian of science, but I would appreciate if somebody could look into this. CSTAR 18:18, 20 Jun 2004 (UTC)
So I was trying to learn a little bit more about quantum cryptography and I found this article to be kinda confusing. would someone run a copyedit? TitaniumDreads 10:11, 7 August 2005 (UTC)
Whether you wanna study Quantum Computing first learn basic physics and linear algebra, don't try to be a genius without a previous necessary background. — Preceding unsigned comment added by 181.54.169.243 ( talk) 03:32, 6 February 2013 (UTC)
I have heard of Schrodigner's cat in a box. So that cat is a qudit ... right? But I think physicists are confusing everybody. Can't imagine how a cat to be the superposition of two cats. The more I mull over this the more confused I am. Help!!!! Feb 2006 (HYK, Singapore) —Preceding unsigned comment added by 165.21.154.116 ( talk • contribs) 13:39, 28 February 2006
As per the requests on the talk page, I dove in and tried to make the Qubit page a little more readable. Any feedback would be greatly appreciated, as this is my first time doing any more than a minor edit on a page.-- Nate 20:49, 9 June 2006 (UTC)
I am a layperson trying to understand an article about using qubits to hide messages or information, ala steganography. After reading this definition, I have a fuzzy idea of some bit floating around in double space like the film, Maxtrix Reloaded. Can you make the concept a little easier to understand for nonphysics geeks like myself? Thanks. —Preceding unsigned comment added by Lorikeets ( talk • contribs) 17:38, 24 June 2006
If the limits in the article are the only ones there are, then you could no the probability amplitude of p without knowing the probability amplitude of not-p. That doesn't make sense.
why in a state of qbit e.g. a|0>+b|0> , a,b are complex number? why these are not just real number between -1,1? please send an e-mail: rastegari.mohammad@yahoo.com —Preceding unsigned comment added by 80.191.109.129 ( talk • contribs) 22:33, 11 June 2007
UnHoly 06:41, 12 June 2007 (UTC)
h,, — Preceding unsigned comment added by 60.225.75.60 ( talk) 06:52, 14 November 2013 (UTC)
I think this is a mistake: The use of entanglement in quantum computing has been referred to as "quantum parallelism", and offers a possible explanation for the power of quantum computing: because the state of the computer can be in a quantum superposition of many different classical computational paths, these paths can all proceed concurrently.
Paralelism: (|0>+|1>)(|0>|1>)=|0>|0>+|0>|1>+|1>|0>+|1>|1> (all combinations of 0 and 1)
Entanglement: |0>|0>+|1>|1> (Not all combinations!!!)
193.144.84.171 11:03, 26 June 2007 (UTC)
This article is almost worthless and unintelligible to me. Exactly what is the definition of a "two-level system"? Is it the same as a "two-state system"? Some examples of two-level systems should be given.
And I still don't understand how a quantum computer could work. If you don't know exactly which state the qubit is in, how can you continue into creating bytes, then words, then computer programs? Or if the article means the state can be disambiguated with probabilities, why doesn't the article state this fact, along with the equations/algorithm for doing so?
And I don't immediately understand the sphere of complex numbers. A complex number has a 2-dimensional representation, so normally two complex numbers would be represented with four dimensions, so why is a 3-dimensional sphere shown?
This article really needs to be rewritten to make quick, intuitive sense. I already know about the oddities of quantum mechanics, but this article does not explain how any of that relates to computer operation, as far as I can tell.
Simnia 21:59, 12 July 2007 (UTC)simnia
WHOA! Interleaved-comments in a talk page? USENET and email works with that, even forums. Here? Recipe for confusion! Tgm1024 ( talk) 23:56, 26 June 2019 (UTC)
In article Trapped_ion_quantum_computer#Components_of_a_quantum_computer, it mentioned there are two ways to form a qubit using the electronic states of an ion:
Are they also included in section 'Physical representation' of this article? I'm confused. - Justin545 ( talk) 10:08, 4 May 2008 (UTC)
The statement A quiet qubit refers to a qubit that can be efficiently decoupled from the environment. [1] is problematic since a quiet qubit was a particular superconducting qubit proposed by Ioffe et al but never realized as proposed. It is not a variation in the in the qubit, qutrit, qudit progression since it does not encode more or fewer states than a qubit. Moreover, a good qubit is decoupled from the environment. Suggest that this comment be removed. Shadesofgrey ( talk) 17:38, 14 December 2009 (UTC)
In the Bloch sphere paragraph: "Represented on such a sphere, a classical bit could only be on the z-axis at the top or (a single point) on the equator of the sphere." Surely a classical bit would be only on "North Pole" or "South Pole" of the sphere, and a point on the equator woud be a superposition with equal probabilities of being |0> or |1>? Should it be changed or am I being stupid?-- Hermajesty21 ( talk) 16:11, 22 December 2010 (UTC)
Kwantum is also a chain of stores in the Netherlands. (disambiguation) —Preceding unsigned comment added by 195.240.86.253 ( talk) 22:21, 16 April 2011 (UTC)
A qubit is an item of quantum data, not information.
I suggest that instead of saying "A qubit can be thought of as a superposition or two states", which is true but entirely confusing to non-physicists that the following statement is used instead "A qubit can be thought of as being an analogue value varying between two extremes, for example, polarisation angles from 0º to 90º."
I think we also need some simple statements describing how qubits relate to real world information. I suggest the following: Qubits can be used in an analogue manner, where the precise value of a qubit is a genuine analogue value. For example, polarisation angles between 0º and 90º may relate to a real world value if you multiply the angle by 4, which can result in a real angle between 0º and 360º. Qubits can also be used in a discrete manner, where the qubit takes one of a specific number of states. For example, polarisation angles of 0, 30, 60 and 90º. In this case, one qubit relates directly to 2 bits of data by assigning each of the four binary states associated with the 2 bits to one angle each. Yeatesi ( talk) 09:37, 5 June 2012 (UTC)
I find in the example the first part coherent where .
At part, the is correct too and computing we can observe that . Here is the explanation why it is pointing to the positive y axis.
I cited P. Shor's paper as it is on arXiv, is there a better place I should cite this from as arXiv isn't actually a journal? KM4JWL ( talk) 14:39, 15 April 2016 (UTC)
I admit that i have yet to grasp the very concept. My physics education ended with the rudiments of quantum physics. So my dumb question is: How is a quantum computer even possible if everything is probabilities? One presumes that computing requires exact results. How does a qubit, which can have probabilistic values, yield useful results? I don't see the answer to that, at least in non-expert terms, in this article. Tmangray ( talk) 00:35, 5 May 2016 (UTC)
Should this article include information about the current state of quantum computing? I'm trying to learn the concept, having not gotten past sophomore engineering physics, and what I'm reading confuses me. A recent Wired article says that Google is aiming to create a 50 qubit supercomputer this year [ [1]], yet the D-Wave Systems article says they had a 128 qubit chipset as far back as 2011. Who is using the term wrong? Timtempleton ( talk) 22:11, 23 June 2017 (UTC)
I wrote a draft article, Draft:Physical and logical qubits. Should we transclude or otherwise incorporate some of its text here? -- Daviddwd ( talk) 23:36, 15 October 2018 (UTC)
(even though this is a talk page)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
I would say "no". Could we replace this with a quoted or synthesized scientific definition? Asides from the word itself being inappropriate, it's just obscuring whatever actual information should go there.
I'm not saying overly technical. Just accurate and objective. Perhaps "weirdness" can be replaced with something like "special properties such as X". 71.179.84.225 ( talk) 00:45, 5 December 2018 (UTC)
when talking about the bloch sphere representation , it is unclear why overall phase of the state ei ψ has no physically observable consequences . Some details would be appreciated (or some links to another page) .
also the section standard representation is unclear on the way of building the four-dimensional vector basis from the two-dimensional vector basis . it's a tensor product right ? I had to figure it out but it's not obvious .
Stilgarnat ( talk) 09:43, 22 September 2019 (UTC)
I think that the Photon / Time-bin encoding / Time of arrival / Early-Late type of qubit should be removed from this list. These things are not full qubits because only the relative phase of the basis states is a tunable property. Superposition cannot be achieved with these because there is nearly always a 50/50% chance of a |0> or a |1> being detected. They have their place in quantum information science but not as qubits in a quantum computer. Polymath uk ( talk) 16:07, 7 July 2020 (UTC)
I think that the overall explanation of qudits should be rerouted or expanded into its own page considering the mathematics and theory behind higher order D-Dimensional states is somewhat different than standard qubit stuff, what does everyone think? Twiximus ( talk) 18:09, 16 Oct 2022 (UTC) — Preceding unsigned comment added by 98.97.58.13 ( talk)
The qubit itself is an exhibition of quantum entanglement. Yes, more than one of these can be entangled (as written in the article), but a selling point for using qubits is to reduce computational stress with the phenomenon of local simult processing. 72.174.131.123 ( talk) 02:25, 14 January 2024 (UTC)
This
level-5 vital article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||
|
This article may be too technical for most readers to understand.(September 2010) |
What is this, some kind of sequel to Canticle for Liebowitz? Seriously, someone rewrite this article that knows what they are talking about. Otherwise I'm going to just assume that anyone selling me "quantum computers" is blowing smoke up my ass. — Preceding unsigned comment added by 198.233.187.6 ( talk) 18:56, 4 January 2018 (UTC)
Schumacher undoubtedly discovered Shumacher compression and is generally accepted as having introduced the term qubit in the 1995 Phys Rev paper Quantum Coding, but historically it is questionable whether one can say he discovered how to interpret states as information. I suspect that something like this may have been known to Feynman. Anyway I'm not a historian of science, but I would appreciate if somebody could look into this. CSTAR 18:18, 20 Jun 2004 (UTC)
So I was trying to learn a little bit more about quantum cryptography and I found this article to be kinda confusing. would someone run a copyedit? TitaniumDreads 10:11, 7 August 2005 (UTC)
Whether you wanna study Quantum Computing first learn basic physics and linear algebra, don't try to be a genius without a previous necessary background. — Preceding unsigned comment added by 181.54.169.243 ( talk) 03:32, 6 February 2013 (UTC)
I have heard of Schrodigner's cat in a box. So that cat is a qudit ... right? But I think physicists are confusing everybody. Can't imagine how a cat to be the superposition of two cats. The more I mull over this the more confused I am. Help!!!! Feb 2006 (HYK, Singapore) —Preceding unsigned comment added by 165.21.154.116 ( talk • contribs) 13:39, 28 February 2006
As per the requests on the talk page, I dove in and tried to make the Qubit page a little more readable. Any feedback would be greatly appreciated, as this is my first time doing any more than a minor edit on a page.-- Nate 20:49, 9 June 2006 (UTC)
I am a layperson trying to understand an article about using qubits to hide messages or information, ala steganography. After reading this definition, I have a fuzzy idea of some bit floating around in double space like the film, Maxtrix Reloaded. Can you make the concept a little easier to understand for nonphysics geeks like myself? Thanks. —Preceding unsigned comment added by Lorikeets ( talk • contribs) 17:38, 24 June 2006
If the limits in the article are the only ones there are, then you could no the probability amplitude of p without knowing the probability amplitude of not-p. That doesn't make sense.
why in a state of qbit e.g. a|0>+b|0> , a,b are complex number? why these are not just real number between -1,1? please send an e-mail: rastegari.mohammad@yahoo.com —Preceding unsigned comment added by 80.191.109.129 ( talk • contribs) 22:33, 11 June 2007
UnHoly 06:41, 12 June 2007 (UTC)
h,, — Preceding unsigned comment added by 60.225.75.60 ( talk) 06:52, 14 November 2013 (UTC)
I think this is a mistake: The use of entanglement in quantum computing has been referred to as "quantum parallelism", and offers a possible explanation for the power of quantum computing: because the state of the computer can be in a quantum superposition of many different classical computational paths, these paths can all proceed concurrently.
Paralelism: (|0>+|1>)(|0>|1>)=|0>|0>+|0>|1>+|1>|0>+|1>|1> (all combinations of 0 and 1)
Entanglement: |0>|0>+|1>|1> (Not all combinations!!!)
193.144.84.171 11:03, 26 June 2007 (UTC)
This article is almost worthless and unintelligible to me. Exactly what is the definition of a "two-level system"? Is it the same as a "two-state system"? Some examples of two-level systems should be given.
And I still don't understand how a quantum computer could work. If you don't know exactly which state the qubit is in, how can you continue into creating bytes, then words, then computer programs? Or if the article means the state can be disambiguated with probabilities, why doesn't the article state this fact, along with the equations/algorithm for doing so?
And I don't immediately understand the sphere of complex numbers. A complex number has a 2-dimensional representation, so normally two complex numbers would be represented with four dimensions, so why is a 3-dimensional sphere shown?
This article really needs to be rewritten to make quick, intuitive sense. I already know about the oddities of quantum mechanics, but this article does not explain how any of that relates to computer operation, as far as I can tell.
Simnia 21:59, 12 July 2007 (UTC)simnia
WHOA! Interleaved-comments in a talk page? USENET and email works with that, even forums. Here? Recipe for confusion! Tgm1024 ( talk) 23:56, 26 June 2019 (UTC)
In article Trapped_ion_quantum_computer#Components_of_a_quantum_computer, it mentioned there are two ways to form a qubit using the electronic states of an ion:
Are they also included in section 'Physical representation' of this article? I'm confused. - Justin545 ( talk) 10:08, 4 May 2008 (UTC)
The statement A quiet qubit refers to a qubit that can be efficiently decoupled from the environment. [1] is problematic since a quiet qubit was a particular superconducting qubit proposed by Ioffe et al but never realized as proposed. It is not a variation in the in the qubit, qutrit, qudit progression since it does not encode more or fewer states than a qubit. Moreover, a good qubit is decoupled from the environment. Suggest that this comment be removed. Shadesofgrey ( talk) 17:38, 14 December 2009 (UTC)
In the Bloch sphere paragraph: "Represented on such a sphere, a classical bit could only be on the z-axis at the top or (a single point) on the equator of the sphere." Surely a classical bit would be only on "North Pole" or "South Pole" of the sphere, and a point on the equator woud be a superposition with equal probabilities of being |0> or |1>? Should it be changed or am I being stupid?-- Hermajesty21 ( talk) 16:11, 22 December 2010 (UTC)
Kwantum is also a chain of stores in the Netherlands. (disambiguation) —Preceding unsigned comment added by 195.240.86.253 ( talk) 22:21, 16 April 2011 (UTC)
A qubit is an item of quantum data, not information.
I suggest that instead of saying "A qubit can be thought of as a superposition or two states", which is true but entirely confusing to non-physicists that the following statement is used instead "A qubit can be thought of as being an analogue value varying between two extremes, for example, polarisation angles from 0º to 90º."
I think we also need some simple statements describing how qubits relate to real world information. I suggest the following: Qubits can be used in an analogue manner, where the precise value of a qubit is a genuine analogue value. For example, polarisation angles between 0º and 90º may relate to a real world value if you multiply the angle by 4, which can result in a real angle between 0º and 360º. Qubits can also be used in a discrete manner, where the qubit takes one of a specific number of states. For example, polarisation angles of 0, 30, 60 and 90º. In this case, one qubit relates directly to 2 bits of data by assigning each of the four binary states associated with the 2 bits to one angle each. Yeatesi ( talk) 09:37, 5 June 2012 (UTC)
I find in the example the first part coherent where .
At part, the is correct too and computing we can observe that . Here is the explanation why it is pointing to the positive y axis.
I cited P. Shor's paper as it is on arXiv, is there a better place I should cite this from as arXiv isn't actually a journal? KM4JWL ( talk) 14:39, 15 April 2016 (UTC)
I admit that i have yet to grasp the very concept. My physics education ended with the rudiments of quantum physics. So my dumb question is: How is a quantum computer even possible if everything is probabilities? One presumes that computing requires exact results. How does a qubit, which can have probabilistic values, yield useful results? I don't see the answer to that, at least in non-expert terms, in this article. Tmangray ( talk) 00:35, 5 May 2016 (UTC)
Should this article include information about the current state of quantum computing? I'm trying to learn the concept, having not gotten past sophomore engineering physics, and what I'm reading confuses me. A recent Wired article says that Google is aiming to create a 50 qubit supercomputer this year [ [1]], yet the D-Wave Systems article says they had a 128 qubit chipset as far back as 2011. Who is using the term wrong? Timtempleton ( talk) 22:11, 23 June 2017 (UTC)
I wrote a draft article, Draft:Physical and logical qubits. Should we transclude or otherwise incorporate some of its text here? -- Daviddwd ( talk) 23:36, 15 October 2018 (UTC)
(even though this is a talk page)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
I would say "no". Could we replace this with a quoted or synthesized scientific definition? Asides from the word itself being inappropriate, it's just obscuring whatever actual information should go there.
I'm not saying overly technical. Just accurate and objective. Perhaps "weirdness" can be replaced with something like "special properties such as X". 71.179.84.225 ( talk) 00:45, 5 December 2018 (UTC)
when talking about the bloch sphere representation , it is unclear why overall phase of the state ei ψ has no physically observable consequences . Some details would be appreciated (or some links to another page) .
also the section standard representation is unclear on the way of building the four-dimensional vector basis from the two-dimensional vector basis . it's a tensor product right ? I had to figure it out but it's not obvious .
Stilgarnat ( talk) 09:43, 22 September 2019 (UTC)
I think that the Photon / Time-bin encoding / Time of arrival / Early-Late type of qubit should be removed from this list. These things are not full qubits because only the relative phase of the basis states is a tunable property. Superposition cannot be achieved with these because there is nearly always a 50/50% chance of a |0> or a |1> being detected. They have their place in quantum information science but not as qubits in a quantum computer. Polymath uk ( talk) 16:07, 7 July 2020 (UTC)
I think that the overall explanation of qudits should be rerouted or expanded into its own page considering the mathematics and theory behind higher order D-Dimensional states is somewhat different than standard qubit stuff, what does everyone think? Twiximus ( talk) 18:09, 16 Oct 2022 (UTC) — Preceding unsigned comment added by 98.97.58.13 ( talk)
The qubit itself is an exhibition of quantum entanglement. Yes, more than one of these can be entangled (as written in the article), but a selling point for using qubits is to reduce computational stress with the phenomenon of local simult processing. 72.174.131.123 ( talk) 02:25, 14 January 2024 (UTC)