Lieb-Robinson bounds and the speed of light from topological order
... principle seriously: if object A causes a change on object B, there must be changes involving the points in between. The field is exactly what changes. In addition, if something is “happening” at all the intermediate points, then the interaction between the objects must propagate with a finite speed ...
... principle seriously: if object A causes a change on object B, there must be changes involving the points in between. The field is exactly what changes. In addition, if something is “happening” at all the intermediate points, then the interaction between the objects must propagate with a finite speed ...
L14alternative - Particle Physics and Particle Astrophysics
... emit photons, losing energy constantly and eventually spiralling into the nucleus. This doesn’t happen!! ...
... emit photons, losing energy constantly and eventually spiralling into the nucleus. This doesn’t happen!! ...
Shamsul Kaonain
... Einstein's theory of relativity. The resolution of this problem turns out to hinge on whether it is possible to clone an unknown quantum state, that is, construct a copy of a quantum state. Cloning turns out not to be possible in general in quantum mechanics. This no cloning theorem , discovered in ...
... Einstein's theory of relativity. The resolution of this problem turns out to hinge on whether it is possible to clone an unknown quantum state, that is, construct a copy of a quantum state. Cloning turns out not to be possible in general in quantum mechanics. This no cloning theorem , discovered in ...
The Physical Implementation of Quantum Computation David P. DiVincenzo
... will be too slow for the needs of error correction and a “conveyor belt” scheme would be required. Cooling by projection, in which the Hamiltonian of the system and its environment are necessarily perturbed strongly, will have a time scale dependent on the details of the setup, but potentially much ...
... will be too slow for the needs of error correction and a “conveyor belt” scheme would be required. Cooling by projection, in which the Hamiltonian of the system and its environment are necessarily perturbed strongly, will have a time scale dependent on the details of the setup, but potentially much ...
Δk/k
... A process/system is called coherent when interference is possible. Interference is possible within the same cell volume 3 x 3 p x V 3 of phase space (x, p). Whether a beam of particles is coherent or not depends only on its divergence and spot size. ...
... A process/system is called coherent when interference is possible. Interference is possible within the same cell volume 3 x 3 p x V 3 of phase space (x, p). Whether a beam of particles is coherent or not depends only on its divergence and spot size. ...
The Foundational Significance of Leggett`s Non-Local Hidden
... more limited ones. In other words, if Laudisa’s arguments fail with respect to Leggett’s original models, they will fail even more dramatically with respect to the more general models developed later. I therefore restrict my discussion to the original Leggett models except for some brief side remark ...
... more limited ones. In other words, if Laudisa’s arguments fail with respect to Leggett’s original models, they will fail even more dramatically with respect to the more general models developed later. I therefore restrict my discussion to the original Leggett models except for some brief side remark ...
Do Quantum Objects Have Temporal Parts? - Philsci
... subspaces. According to classical mereology, the relation of parthood is (minimally) reflexive (everything is part of itself), transitive (if p is part of q and q is part of r then p is part of r) and antisymmetric (no two distinct things can be part of each other). As is well known, the subspaces o ...
... subspaces. According to classical mereology, the relation of parthood is (minimally) reflexive (everything is part of itself), transitive (if p is part of q and q is part of r then p is part of r) and antisymmetric (no two distinct things can be part of each other). As is well known, the subspaces o ...
An information-theoretic perspective on the foundations of
... experimental verification of QM violating Bell's inequalities. Given to entangled particles with spin, the correlation between the outcomes of the spin measurements on these particles when they are separated were too strong to be local. As it will be explained later , the ...
... experimental verification of QM violating Bell's inequalities. Given to entangled particles with spin, the correlation between the outcomes of the spin measurements on these particles when they are separated were too strong to be local. As it will be explained later , the ...
What quantum computers may tell us about quantum mechanics
... identical to the same state in the usual coupled basis |J = 0, mJ = 0. Many therefore dismiss the whole notion of entanglement as simply a choice of basis. However, entanglement should not only reflect a nonseparable quantum state, but one in which independent quantum measurements on the individual ...
... identical to the same state in the usual coupled basis |J = 0, mJ = 0. Many therefore dismiss the whole notion of entanglement as simply a choice of basis. However, entanglement should not only reflect a nonseparable quantum state, but one in which independent quantum measurements on the individual ...
Preferred Basis in a Measurement Process
... is now exp(−∆x2 π/2λ2d). One can see that for ∆x >> λd , this factor is very small and hence the elements of the density matrix corresponding to these two off-diagonal peaks are negligible in magnitude. Thus, position seems to emerge as an approximate preferred basis, which works well only when one ...
... is now exp(−∆x2 π/2λ2d). One can see that for ∆x >> λd , this factor is very small and hence the elements of the density matrix corresponding to these two off-diagonal peaks are negligible in magnitude. Thus, position seems to emerge as an approximate preferred basis, which works well only when one ...
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.