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... Bob a random bit string r and to send Charlie the modulo-2 sum, r ⊕ m, of the random bit string r and her message m. If Bob and Charlie act together, they can recover Alice’s message m simply by adding their bit strings together. Of course, this protocol presumes that Bob cannot monitor Alice’s tran ...
... Bob a random bit string r and to send Charlie the modulo-2 sum, r ⊕ m, of the random bit string r and her message m. If Bob and Charlie act together, they can recover Alice’s message m simply by adding their bit strings together. Of course, this protocol presumes that Bob cannot monitor Alice’s tran ...
Quantum Computing Lecture 1 What is Quantum Computing?
... Quantum mechanics tells us that any such system can exist in a superposition of states. In general, the state of a quantum bit (or qubit for short) is described by: α|0i + β|1i where, α and β are complex numbers, satisfying ...
... Quantum mechanics tells us that any such system can exist in a superposition of states. In general, the state of a quantum bit (or qubit for short) is described by: α|0i + β|1i where, α and β are complex numbers, satisfying ...
N 2
... Now consider the group of atoms in exactly the same excited state, and most are effectively within the stimulation range of a passing photon. We also will assume that t is very long, and that the probability for stimulated emission is 100 percent. The incoming (stimulating) photon interacts with the ...
... Now consider the group of atoms in exactly the same excited state, and most are effectively within the stimulation range of a passing photon. We also will assume that t is very long, and that the probability for stimulated emission is 100 percent. The incoming (stimulating) photon interacts with the ...
Document
... Quantum Mechanics and Atomic Orbitals Orbitals and Quantum Numbers • Schrödinger’s equation requires 3 quantum numbers: 1. Principal Quantum Number, n. This is the same as Bohr’s n. As n becomes larger, the atom becomes larger and the electron is further from the nucleus. ( n = 1 , 2 , 3 , 4 , …. ) ...
... Quantum Mechanics and Atomic Orbitals Orbitals and Quantum Numbers • Schrödinger’s equation requires 3 quantum numbers: 1. Principal Quantum Number, n. This is the same as Bohr’s n. As n becomes larger, the atom becomes larger and the electron is further from the nucleus. ( n = 1 , 2 , 3 , 4 , …. ) ...
Quantum Notes (Chapter 16)(Powerpoint document)
... Y2, however, represents the probability of finding an electron at a particular point around the H nucleus. A three dimensional plot of 2 vs. distance from the nucleus, r, represents a volume of space. ...
... Y2, however, represents the probability of finding an electron at a particular point around the H nucleus. A three dimensional plot of 2 vs. distance from the nucleus, r, represents a volume of space. ...
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... The deterministic complexity of the Deutsch-Josza problem is 2n−1 +1. This is because if the function is actually constant, then we need to know its value at at least that many points to be sure that it is constant. The randomized complexity of the Deutsch-Josza problem is constant, in the sense tha ...
... The deterministic complexity of the Deutsch-Josza problem is 2n−1 +1. This is because if the function is actually constant, then we need to know its value at at least that many points to be sure that it is constant. The randomized complexity of the Deutsch-Josza problem is constant, in the sense tha ...
Calculating the Charging Energy of a Non Neutral
... Quantum dots are nanometer scale semiconductor devices. Their small size leads to unique behavior different from that of macroscopic semiconductors. Our objective is to generalize the Thomas-Fermi method of atomic physics to understand the electronic structure of quantum dots. The problems we wish t ...
... Quantum dots are nanometer scale semiconductor devices. Their small size leads to unique behavior different from that of macroscopic semiconductors. Our objective is to generalize the Thomas-Fermi method of atomic physics to understand the electronic structure of quantum dots. The problems we wish t ...
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.