Quantum information or quantum coding? - Philsci
... to transmit the messages generated by the source with vanishing error is given by NS (ρ ) . Schumacher designs the proof of the theorem by close analogy with the corresponding Shannon’s theorem. Again, the idea is that all the possible states α (representing the messages of N letters produced by the ...
... to transmit the messages generated by the source with vanishing error is given by NS (ρ ) . Schumacher designs the proof of the theorem by close analogy with the corresponding Shannon’s theorem. Again, the idea is that all the possible states α (representing the messages of N letters produced by the ...
Quantum Factorization of 143 on a Dipolar
... tried for the different combinations. Here we just demonstrate an example case where p and q has the same width and set each factor’s first bit (i.e., most significant bit) to be 1. In a realistic problem, the width of p or q could not be known a priori. Thus one need to verify the answer (i.e., pq ...
... tried for the different combinations. Here we just demonstrate an example case where p and q has the same width and set each factor’s first bit (i.e., most significant bit) to be 1. In a realistic problem, the width of p or q could not be known a priori. Thus one need to verify the answer (i.e., pq ...
The Quantum Mechanical Model of the Atom
... The smaller spaces between colored lines, however, suggested that there were enough. The many-electron problem called for a new model to explain smaller energy differences within energy levels. It was fairly straightforward modify Bohr’s model to include theanother idea spectra of all types of atoms ...
... The smaller spaces between colored lines, however, suggested that there were enough. The many-electron problem called for a new model to explain smaller energy differences within energy levels. It was fairly straightforward modify Bohr’s model to include theanother idea spectra of all types of atoms ...
Solving Schrödinger`s equation around a desired energy
... large molecules and solids are generally cast in terms of solutions to some effective single-particle Schrodinger equation ...
... large molecules and solids are generally cast in terms of solutions to some effective single-particle Schrodinger equation ...
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... there are point particles with definite positions, and the distribution of these particles agrees with the probabilities predicted by the quantum state. Granted that the de Broglie-Bohm theory does in fact solve the measurement problem, what is its motivation? A quick perusal of the literature indic ...
... there are point particles with definite positions, and the distribution of these particles agrees with the probabilities predicted by the quantum state. Granted that the de Broglie-Bohm theory does in fact solve the measurement problem, what is its motivation? A quick perusal of the literature indic ...
Quantum error correction
... other systems give rise to a full set of quantum phenomena, many of which have no correspondence in classical information theory. These phenomena include decoherence, as a consequence of entanglement. Decoherence can also be understood as “information leakage”, i.e., knowledge of an event is transfe ...
... other systems give rise to a full set of quantum phenomena, many of which have no correspondence in classical information theory. These phenomena include decoherence, as a consequence of entanglement. Decoherence can also be understood as “information leakage”, i.e., knowledge of an event is transfe ...
2006-11-14-RAL-Wang - Indico
... in terms of the conformal field A and the rescaled metric γαβ . We shall work in a standard laboratory frame where the direction of time is perpendicular to space. Accordingly, we set γ00 = −1 and γ0a = 0 (using a, b = 1, 2, 3 as spatial coordinate indices.) The spatial part of the metric γαβ is den ...
... in terms of the conformal field A and the rescaled metric γαβ . We shall work in a standard laboratory frame where the direction of time is perpendicular to space. Accordingly, we set γ00 = −1 and γ0a = 0 (using a, b = 1, 2, 3 as spatial coordinate indices.) The spatial part of the metric γαβ is den ...
Full text in PDF form
... In quantum information, the elementary unit is the quantum bit (or qubit), a coherent superposition of the two basis states 0 and 1. The underlying logic is non-Boolean. Different from classical bits, a qubit is contextual [20], and cannot be copied, or "cloned" [21]. The emerging fields of quantum ...
... In quantum information, the elementary unit is the quantum bit (or qubit), a coherent superposition of the two basis states 0 and 1. The underlying logic is non-Boolean. Different from classical bits, a qubit is contextual [20], and cannot be copied, or "cloned" [21]. The emerging fields of quantum ...
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.