NUCLEAR MAGNETIC RESONANCE QUANTUM COMPUTATION
... NMR signal detection is best described using a classical view [8]. The ensemble average of the spins behaves like a classical magnetisation rotating at the Larmor frequency, and the NMR detector is a coil of wire wrapped around the sample. As the magnetisation cuts across the wires it induces an EMF ...
... NMR signal detection is best described using a classical view [8]. The ensemble average of the spins behaves like a classical magnetisation rotating at the Larmor frequency, and the NMR detector is a coil of wire wrapped around the sample. As the magnetisation cuts across the wires it induces an EMF ...
Shor state
... Quantum computers offer revolutionary improvement in computing power due to the ability of qubits to be in superposition states and to become entangled. Powerful quantum algorithms already known include Shor’s algorithm to factor large numbers and Grover’s fast database searches Careful explorati ...
... Quantum computers offer revolutionary improvement in computing power due to the ability of qubits to be in superposition states and to become entangled. Powerful quantum algorithms already known include Shor’s algorithm to factor large numbers and Grover’s fast database searches Careful explorati ...
Introduction to the Bethe Ansatz II
... work on quantum spin chains from the early sixties until the present. Some of the advances achieved via the Bethe ansatz emerged in direct response to experimental data which had remained unexplained by standard approximations used in many-body theory. In Part I of this series1 we introduced the Bet ...
... work on quantum spin chains from the early sixties until the present. Some of the advances achieved via the Bethe ansatz emerged in direct response to experimental data which had remained unexplained by standard approximations used in many-body theory. In Part I of this series1 we introduced the Bet ...
Aalborg Universitet The effect of time-dependent coupling on non-equilibrium steady states
... subsystems {Ha , Ha } and {Hb , Hb } are called left- and right-hand reservoirs. The middle system {HI , HI } is identified with a closed quantum well. We assume that all three subsystems are at thermal equilibrium; according to Definition 12, the corresponding sub-states must be functions of their ...
... subsystems {Ha , Ha } and {Hb , Hb } are called left- and right-hand reservoirs. The middle system {HI , HI } is identified with a closed quantum well. We assume that all three subsystems are at thermal equilibrium; according to Definition 12, the corresponding sub-states must be functions of their ...
Corrals and Critical Behavior of the Distribution of Fluctuational Paths
... with quantum mechanics, where e.g., observation of a path passing through a slit destroys the interference in a two-slit experiment. We note that the Landau theory of critical behavior applies exactly to the present system, since the soft mode is localized and there is a gap between its energy and t ...
... with quantum mechanics, where e.g., observation of a path passing through a slit destroys the interference in a two-slit experiment. We note that the Landau theory of critical behavior applies exactly to the present system, since the soft mode is localized and there is a gap between its energy and t ...
HBNI Th65 - The Institute of Mathematical Sciences
... A state that cannot be written in this form is called an entangled state. The set of separable states form a convex subset of the bipartite state space. The qualitative detection and quantitative estimation of entanglement have proved to be non-trivial. To this end, there have been many approaches t ...
... A state that cannot be written in this form is called an entangled state. The set of separable states form a convex subset of the bipartite state space. The qualitative detection and quantitative estimation of entanglement have proved to be non-trivial. To this end, there have been many approaches t ...
Public-Key Cryptosystems from the Worst
... of Rn .) Since then, basic cryptographic primitives such as one-way functions and collision-resistant hash functions, along with other notions from “Minicrypt” [Imp95], have been based on the conjectured hardness of important and well-studied lattice problems. Perhaps the most well-known of these, t ...
... of Rn .) Since then, basic cryptographic primitives such as one-way functions and collision-resistant hash functions, along with other notions from “Minicrypt” [Imp95], have been based on the conjectured hardness of important and well-studied lattice problems. Perhaps the most well-known of these, t ...
Mathematical foundation of quantum annealing
... problems and statistical physics.4,5 In SA, the cost function to be minimized is identified with the energy of a statistical-mechanical system. The system is then given a temperature, an artificially introduced control parameter, which, by reducing slowly from a high value to zero, we hope to drive ...
... problems and statistical physics.4,5 In SA, the cost function to be minimized is identified with the energy of a statistical-mechanical system. The system is then given a temperature, an artificially introduced control parameter, which, by reducing slowly from a high value to zero, we hope to drive ...
Interferometry beyond the Standard Quantum Limit using a Sagnac
... Ü If you want to join this exciting project with your expertise you are more than welcome! Ü There is quite a lot of work involved in this project, - definitely more than my team on its own will be able to manage. Ü So everybody is welcome to join. Send us your interested students and postdoc ...
... Ü If you want to join this exciting project with your expertise you are more than welcome! Ü There is quite a lot of work involved in this project, - definitely more than my team on its own will be able to manage. Ü So everybody is welcome to join. Send us your interested students and postdoc ...
Classical Simulation of Quantum Systems
... could simulate another quantum system in a fruitful manner [Fey82]. Hence, to advance our understanding of all varieties of quantum systems, a computing device that “works” in the full volume of its quantum-mechanical Hilbert space and not just in its classical states [Fey85], would be a tool of tre ...
... could simulate another quantum system in a fruitful manner [Fey82]. Hence, to advance our understanding of all varieties of quantum systems, a computing device that “works” in the full volume of its quantum-mechanical Hilbert space and not just in its classical states [Fey85], would be a tool of tre ...
ABSTRACT RANDOM ROUTING AND CONCENTRATION IN QUANTUM SWITCHING NETWORKS
... on the first (log n − 1) stages and bit controlled self-routing on the last log n stages of a quantum Beneš network, the output packet pattern corresponding to routing with no blocking is always present in the output quantum state with a non-zero probability. We give a lower bound on the probability ...
... on the first (log n − 1) stages and bit controlled self-routing on the last log n stages of a quantum Beneš network, the output packet pattern corresponding to routing with no blocking is always present in the output quantum state with a non-zero probability. We give a lower bound on the probability ...
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.