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Communication via a quantum loop gravity string?
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Darth Beaver Send message Joined: 20 Aug 99 Posts: 6728 Credit: 21,443,075 RAC: 3 |
Quantum computing is still a target. But quantum cryptography is used today to transmit cryptographic keys in a secure way. Tullio this may sound stupid but anyway . Is not what they call Quantum cryptographic just maths and not really anything to do with Quantum computing seeing as they have the keys ? I guess what i'm asking is that it's not really anything to do with Quantum mechanics it's more just normal maths . |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
No, it is using one entanglement feature. If anybody tries to intercept the message (man in the middle) the receiver is immediately alerted by a quantum jump. Tullio |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
Though I think that we have commented before on Quantum Computing, let me reiterate some thoughts. The concept of the qubit was unknowingly introduced by Stephen Wiesner in 1983, in his proposal for unforgeable quantum money, which he had tried to publish for over a decade.[1][2] In quantum computing, a qubit (/ˈkjuËbɪt/) or quantum bit is a unit of quantum information—the quantum analogue of the classical bit. A qubit is a two-state quantum-mechanical system, such as the polarization of a single photon: here the two states are vertical polarization and horizontal polarization. In a classical system, a bit would have to be in one state or the other. However quantum mechanics allows the qubit to be in a superposition of both states at the same time, a property which is fundamental to quantum computing. An important distinguishing feature between a qubit and a classical bit is that multiple qubits can exhibit quantum entanglement. Entanglement is a nonlocal property that allows a set of qubits to express higher correlation than is possible in classical systems. http://en.wikipedia.org/wiki/Qubit |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
Quantum computing is still a target. But quantum cryptography is used today to transmit cryptographic keys in a secure way. Glenn:) In a predictive sense, quantum computers may become a technological reality; it is therefore important to study cryptographic schemes that are allegedly secure even against adversaries with access to a quantum computer. The study of such schemes is often referred to as post-quantum cryptography. http://en.wikipedia.org/wiki/Quantum_cryptography#Post-quantum_cryptography So you use both quantum cryptography and quantum mechanics strange phenomenas. Maybe we will see quantum Money in the future:) http://en.wikipedia.org/wiki/Quantum_money |
Darth Beaver Send message Joined: 20 Aug 99 Posts: 6728 Credit: 21,443,075 RAC: 3 |
Thank's Tuillio .... I didn't explain what i was asking properly . I understand what your saying about the entanglement as part of a moving particule , but with computers !! cryptography !!, code breaking , MATH is what i hear , TILT !!!!!!! |
Darth Beaver Send message Joined: 20 Aug 99 Posts: 6728 Credit: 21,443,075 RAC: 3 |
Janne they call it Quantum cryptography why Quantum ? cryptography is code breaking ..... why the word Quantum to me the 2 words are separate and have different meanings |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Cryptography is both crypting and decrypting. There was a "crypt" tool on UNIX, you had to choose a key. Then it was taken off to the request of FBI. In the RSA crypting scheme you have both a public and a private key. The problem is: how do you transmit the private key in a secure way? This is where quantum cryptography comes in. There is a method developed by Anton Zeilinger at the University of Vienna in which you can send a private key to a receiver. If somebody tries to intercept it, the receiver is immediately warned and he will not use the key. This was used in the Swiss Cantonal elections and is used by banks as routine. Tullio |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
Janne they call it Quantum cryptography why Quantum ? It was Stephen Wiesner who came up with the idea of Quantum information. As a graduate student at Columbia University in New York in the late 1960s and early 1970s, he discovered several of the most important ideas in quantum information theory, including quantum money (which led to quantum key distribution), quantum multiplexing [1] (the earliest example of oblivious transfer) and superdense coding[2] (the first and most basic example of entanglement-assisted communication). In physics and computer science, quantum information is information that is held in the state of a quantum system. Quantum information is the basic entity that is studied in the growing field of quantum information theory, and manipulated using the engineering techniques of quantum information processing. Much like classical information can be processed with digital computers, transmitted from place to place, manipulated with algorithms, and analyzed with the mathematics of computer science, so also analogous concepts apply to quantum information. http://en.wikipedia.org/wiki/Quantum_information |
KLiK Send message Joined: 31 Mar 14 Posts: 1304 Credit: 22,994,597 RAC: 60 |
1st OT: to have a FTL transmission over the Space distances, which might come in handy in missions like Cassini, Juno, Deep Horizons, Voyagers or Mars missions, you first have to find some paticle that is FTL...neutrinos & tachions are candidates! Then you have to constract a neutrino or tachion transmitter & receiver, which we don't have commercially awailable...only test subjects, which is supposed to be used for military, 'cause it avoids solid walls of stone or matter like water - so it would be perfect to communicate without surfacing, etc... list of NASA curent missions: http://www.jpl.nasa.gov/missions/?type=current Also, back to science...right now all communications to Mars mission is down, 'cause Mars is directly opposite to Earth right now...that means that with neutrino transmitter-receiver we might have rovers operational now & connection to orbiters - unless Suns dense matter would slow down & destroy neutrinos... When the Mars come back in contact it will be 22min away by communication! So having neutrinos to cut that down a little, would be also nice! Imagine how a mission like Voyager would be closer for communication? Now a signal fomr V1 takes over 18h to come to Earth...18h! ;) But so far, we don't have it...maybe soon? :) non-profit org. Play4Life in Zagreb, Croatia, EU |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Voyager1 is still sending and receiving messges due to its plutonium thermoelectricity generator. It should stop in 2025. Tullio |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
We need to revisit and remind ourselves what the definition of "Information" is. Next we need to ask ourselves if information can be transmitted faster than the speed of light. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
The first question is soon solved."A Mathematical Theory of Communication", by Claude E.Shannon, 1948. The second is more difficult . I personally believe that entanglement is not a way to communicate, but Quantum Theory has not beeen understood completely, and it is still under discussion, so I reserve my bet. Tullio |
KLiK Send message Joined: 31 Mar 14 Posts: 1304 Credit: 22,994,597 RAC: 60 |
We need to revisit and remind ourselves what the definition of "Information" is. Next we need to ask ourselves if information can be transmitted faster than the speed of light. I know what you mean...that we need a buffer & computer that is FTL inside it! Otherwise it would transmit only on light speed... non-profit org. Play4Life in Zagreb, Croatia, EU |
Vern Send message Joined: 24 May 15 Posts: 3 Credit: 16,826 RAC: 0 |
If we one day are able to send an quantum entangled somewhere at the speed of light, thus making entanglement more practical for communication. Also, entanglement would only be used between two places with intelligent beings being at both places. So one of them could easily take an entangled particle with them |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
We need to revisit and remind ourselves what the definition of "Information" is. I Think you can say that Information is the opposite of entropy. If you want to reconstruct something you need information, like a blue-print. Actually information can't be destroyed and the Information is still there even after those objects don't exist anymore. Next we need to ask ourselves if information can be transmitted faster than the speed of light. It doesnt need to be FTL since it useful in short distances as well. Military and finance like this idea very much. Impossible to break the keys and you cannot block communication. |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Information can be destroyed. Haven't you erased a ROM? But this increases entropy. Tullio |
janneseti Send message Joined: 14 Oct 09 Posts: 14106 Credit: 655,366 RAC: 0 |
Information can be destroyed. Haven't you erased a ROM? But this increases entropy. Nope. Leonard Susskind and Stephen Hawking has the answers. And others of course. For instance black hole. Every matter that get destroyed when falling in are "saved" as information in the event horizon. So that means that you can reconstruct the matter again. Just following the law of physics:) btw Leonard Susskind began working as a plumber at the age of 16. He use his experience from that time to explain what information is:) |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
There is a lecture at Cambridge University center of Quantum Computing tomorrow. Here is its abstract: The quantization of energy is of fundamental importance for quantum thermodynamics, even for macroscopic systems. The fragility of quantum coherence naturally makes it less so. However the scale of control of the dynamics of small systems in current experiments is such that understanding basic constraints on how quantum coherences can evolve/be manipulated in a thermodynamic setting is of interest. I will discuss a few such constraints that go beyond free-energy type relations, although the most general form of the problem remains open. Tullio |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
If you format your hard disk you will destroy all infornations contained in it and your computer will not boot, no matter what Hawking and Susskind may say. Tullio |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
It's energy that cannot be created or destroyed--only transformed. It also occurs to me that information can be destroyed by noise--that's the whole essence of Claud Shannon's Information Theory. If the information is there but nobody can see it anymore then I would call that destroyed. |
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