ppt - IIT Kanpur
... (1) If signal photon has horizontal (vertical) polarization, idler photon is guaranteed to have horizontal (vertical) polarization --- Is this entanglement ?? NO --- Two independent classical sources can also produce such correlations ...
... (1) If signal photon has horizontal (vertical) polarization, idler photon is guaranteed to have horizontal (vertical) polarization --- Is this entanglement ?? NO --- Two independent classical sources can also produce such correlations ...
4tuesCosmo
... What physics operated before the Planck time? What is gravity? Higgs? Graviton? Other? What is dark matter? Neutrino mass? Wimps? What is dark energy? Why does universe’s expansion accelerate? ...
... What physics operated before the Planck time? What is gravity? Higgs? Graviton? Other? What is dark matter? Neutrino mass? Wimps? What is dark energy? Why does universe’s expansion accelerate? ...
Quantum Electronics
... wave of energy, or a mere probability of being at any one place. This ties in with the uncertainty principal that says we cannot know both the position and the velocity of a particle at the same time. And quantum computing takes advantage of the infinite number of possible states that a property of ...
... wave of energy, or a mere probability of being at any one place. This ties in with the uncertainty principal that says we cannot know both the position and the velocity of a particle at the same time. And quantum computing takes advantage of the infinite number of possible states that a property of ...
The Learnability of Quantum States
... Unforgeable money (and copy-protected software, etc.) remains one of the most striking potential applications of quantum mechanics to computer science So we’ve been revisiting this 40-year-old idea using the arsenal of modern CS theory Biggest challenge: Secure quantum money that anyone can verify ( ...
... Unforgeable money (and copy-protected software, etc.) remains one of the most striking potential applications of quantum mechanics to computer science So we’ve been revisiting this 40-year-old idea using the arsenal of modern CS theory Biggest challenge: Secure quantum money that anyone can verify ( ...
Uncertainty not so certain after all Early formulation
... relationship can be written out mathematically. But Heisenberg first came up with the idea in a slightly different fashion using slightly different mathematics. That version says the more you disturb a particle, the less precisely you can measure a particular property of it, and vice versa. As an ex ...
... relationship can be written out mathematically. But Heisenberg first came up with the idea in a slightly different fashion using slightly different mathematics. That version says the more you disturb a particle, the less precisely you can measure a particular property of it, and vice versa. As an ex ...
What Have I Learned From Physicists / Computer Scientists
... Repetition Theorem and didn’t know it Play such a game n times in parallel. Does the probability of winning all n games decrease exponentially in n? Asked by physicists in the case of the CHSH game Parallel Repetition Theorem: Yes. For the CHSH game, best known result comes from Feige-Lovasz semidef ...
... Repetition Theorem and didn’t know it Play such a game n times in parallel. Does the probability of winning all n games decrease exponentially in n? Asked by physicists in the case of the CHSH game Parallel Repetition Theorem: Yes. For the CHSH game, best known result comes from Feige-Lovasz semidef ...
Classical and Quantum Gases
... – Hence, since the average separation of particles in a gas of density n is ~n-1/3 – If n << nQ , the average separation is greater than and the gas is classical rather than quantum ...
... – Hence, since the average separation of particles in a gas of density n is ~n-1/3 – If n << nQ , the average separation is greater than and the gas is classical rather than quantum ...
Presentación de PowerPoint
... "Divergent series are on the whole devil's work, and it is a shame that one dares to found any proof on them. One can get out of them what one wants if one uses them, and it is they which have made so much unhappiness and so many paradoxes. Can one think of anything more appalling than to say that ...
... "Divergent series are on the whole devil's work, and it is a shame that one dares to found any proof on them. One can get out of them what one wants if one uses them, and it is they which have made so much unhappiness and so many paradoxes. Can one think of anything more appalling than to say that ...
Quantum key distribution
Quantum key distribution (QKD) uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages. It is often incorrectly called quantum cryptography, as it is the most well known example of the group of quantum cryptographic tasks.An important and unique property of quantum key distribution is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key. This results from a fundamental aspect of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the key must in some way measure it, thus introducing detectable anomalies. By using quantum superpositions or quantum entanglement and transmitting information in quantum states, a communication system can be implemented which detects eavesdropping. If the level of eavesdropping is below a certain threshold, a key can be produced that is guaranteed to be secure (i.e. the eavesdropper has no information about it), otherwise no secure key is possible and communication is aborted.The security of encryption that uses quantum key distribution relies on the foundations of quantum mechanics, in contrast to traditional public key cryptography which relies on the computational difficulty of certain mathematical functions, and cannot provide any indication of eavesdropping at any point in the communication process, or any mathematical proof as to the actual complexity of reversing the one-way functions used. QKD has provable security based on information theory, and forward secrecy.Quantum key distribution is only used to produce and distribute a key, not to transmit any message data. This key can then be used with any chosen encryption algorithm to encrypt (and decrypt) a message, which can then be transmitted over a standard communication channel. The algorithm most commonly associated with QKD is the one-time pad, as it is provably secure when used with a secret, random key. In real world situations, it is often also used with encryption using symmetric key algorithms like the Advanced Encryption Standard algorithm. In the case of QKD this comparison is based on the assumption of perfect single-photon sources and detectors, that cannot be easily implemented.