Quantum - Caltech Particle Theory
... It is difficult to construct a theory that is consistent with both the principles of quantum mechanics and the principles of special relativity. Therefore quantum field theories are highly constrained. They are built on the notion that the algebra of observables should have a natural decomposition a ...
... It is difficult to construct a theory that is consistent with both the principles of quantum mechanics and the principles of special relativity. Therefore quantum field theories are highly constrained. They are built on the notion that the algebra of observables should have a natural decomposition a ...
Degradable Quantum Channels - Quantum Theory Group at CMU
... channel Q(N ) is the supremum of all achievable R. This is also called the subspace transmission capacity. • The entanglement transmission capacity is denoted by ...
... channel Q(N ) is the supremum of all achievable R. This is also called the subspace transmission capacity. • The entanglement transmission capacity is denoted by ...
Why genetic information processing could have a quantum basis
... repeating what is already conveyed before. So the information contained in a message is increased by removing correlations amongst its parts; as messages become more efficient, they appear more and more random. Information thus lives in randomness, but it is not randomness. What distinguishes it fro ...
... repeating what is already conveyed before. So the information contained in a message is increased by removing correlations amongst its parts; as messages become more efficient, they appear more and more random. Information thus lives in randomness, but it is not randomness. What distinguishes it fro ...
Quantum Computing Applications
... One of the most basic problems in computer science is unstructured search. Imagine we have access to a function f : {0, 1}n → {0, 1} which we treat as a black box. We want to find an x such that f (x) = 1. ...
... One of the most basic problems in computer science is unstructured search. Imagine we have access to a function f : {0, 1}n → {0, 1} which we treat as a black box. We want to find an x such that f (x) = 1. ...
Theory of Open Quantum Systems - ITP Lecture Archive
... instrument there is a unique POVM Π(E) = EE∗ (1) that gives statistics consistent with the law of transformation. The converse is not true, for each POVM there are infinitely many instruments that gives that particular statistics. More physical discussion of the latter statement might be helpful at ...
... instrument there is a unique POVM Π(E) = EE∗ (1) that gives statistics consistent with the law of transformation. The converse is not true, for each POVM there are infinitely many instruments that gives that particular statistics. More physical discussion of the latter statement might be helpful at ...
File
... mechanics is the quantization of observable quantities, since quantum numbers are discrete sets of integers or half-integers, although they could approach infinity in some cases. This is distinguished from classical mechanics where the values can range continuously. Quantum numbers often describe sp ...
... mechanics is the quantization of observable quantities, since quantum numbers are discrete sets of integers or half-integers, although they could approach infinity in some cases. This is distinguished from classical mechanics where the values can range continuously. Quantum numbers often describe sp ...
Numerical Methods Project: Feynman path integrals in quantum
... To test the program, the harmonic potential was chosen. It has good proporties such as being smooth and well confined, which means that the discrepancies around the endpoints become unimportant. Also the analytical solution for this problem is well known, which means that error estimating will be st ...
... To test the program, the harmonic potential was chosen. It has good proporties such as being smooth and well confined, which means that the discrepancies around the endpoints become unimportant. Also the analytical solution for this problem is well known, which means that error estimating will be st ...
2 is
... Compare the wavelength of a photon produced from a transition from o n=3 3 to n=2 with w t that t at of o a photon p oto produced p oduced from o a transition ...
... Compare the wavelength of a photon produced from a transition from o n=3 3 to n=2 with w t that t at of o a photon p oto produced p oduced from o a transition ...
Exercise Sheet 9 - Institute for Quantum Information
... bit strings of length r which are not identically 0. This parity check matrix defines a linear code with n = 2r − 1 and k = 2r − r − 1, known as a Hamming code. Show that all Hamming codes have distance 3, and thus can correct an error on a single bit. 4) Gilbert-Varshamov bound. This bound is one o ...
... bit strings of length r which are not identically 0. This parity check matrix defines a linear code with n = 2r − 1 and k = 2r − r − 1, known as a Hamming code. Show that all Hamming codes have distance 3, and thus can correct an error on a single bit. 4) Gilbert-Varshamov bound. This bound is one o ...
Phase Shifting of an Interferometer using Nonlocal Quantum-State Correlations
... the horizontal, and with a rotating half-wave plate 共H兲 in between them 关22兴. When the half-wave plate was turned by an angle  + / 4 the horizontal component acquired a geometric phase +2 and the vertical component acquired a geometric phase −2. Thus the phase difference between the two polari ...
... the horizontal, and with a rotating half-wave plate 共H兲 in between them 关22兴. When the half-wave plate was turned by an angle  + / 4 the horizontal component acquired a geometric phase +2 and the vertical component acquired a geometric phase −2. Thus the phase difference between the two polari ...
On How to Produce Entangled States Violating Bell’s Inequalities in... Apoorva Patel Dx by discretising the time interval:
... to see that a unitary matrix with only real and positive matrix elements has to be the identity matrix (or its row-wise permutation corresponding to a shuffling of the states). The Euclidean time transition kernel is less restricted—it does not preserve the norm, though it maintains orthogonality of ...
... to see that a unitary matrix with only real and positive matrix elements has to be the identity matrix (or its row-wise permutation corresponding to a shuffling of the states). The Euclidean time transition kernel is less restricted—it does not preserve the norm, though it maintains orthogonality of ...
Quantum Optics - Department of Physics and Astronomy
... that electrons behaved like waves. This wave-particle duality was at the heart of quantum mechanics, which would support a mathematical model to explain both properties. ...
... that electrons behaved like waves. This wave-particle duality was at the heart of quantum mechanics, which would support a mathematical model to explain both properties. ...
Quantum information and quantum computation
... Andromeda. This phenomenon|information that cannot be accessed through localized measurements but is instead encoded as nonlocal correlations|is what we call quantum entanglement, and it is a very important feature of quantum information. It is important to appreciate how weird these nonlocal correl ...
... Andromeda. This phenomenon|information that cannot be accessed through localized measurements but is instead encoded as nonlocal correlations|is what we call quantum entanglement, and it is a very important feature of quantum information. It is important to appreciate how weird these nonlocal correl ...
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.