![arXiv:1312.4758v2 [quant-ph] 10 Apr 2014](http://s1.studyres.com/store/data/021352507_1-d587dd4045ccae4ae6a47bb17173f358-300x300.png)
Quantum Heat Engines and Refrigerators: Continuous Devices
... of hypothetical quantum heat engines and refrigerators to address these issues. Once understood, these models serve as a template for real devices. Gedanken heat engines are an integral part of thermodynamical theory. In 1824, Carnot (1) set the stage by analyzing an ideal engine. His analysis prece ...
... of hypothetical quantum heat engines and refrigerators to address these issues. Once understood, these models serve as a template for real devices. Gedanken heat engines are an integral part of thermodynamical theory. In 1824, Carnot (1) set the stage by analyzing an ideal engine. His analysis prece ...
Emergence of a classical world from within quantum theory
... by the opponents of this epistemic interpretation, it is difficult to reconcile this point of view with our common notion of “physical reality”, which exists independently of our monitoring, and can be discovered without disturbance. Indeed, if quantum theory is correct, it should apply to classical ...
... by the opponents of this epistemic interpretation, it is difficult to reconcile this point of view with our common notion of “physical reality”, which exists independently of our monitoring, and can be discovered without disturbance. Indeed, if quantum theory is correct, it should apply to classical ...
Finite-temperature mutual information in a simple phase transition
... review). Here, following recent works in two-dimensional quantum spin systems [14]–[16], we wish to investigate the same problem at finite temperature. Concerning the LMG model, the concurrence [37] (which characterizes the entanglement between two spins in an arbitrary state) is up to now the only e ...
... review). Here, following recent works in two-dimensional quantum spin systems [14]–[16], we wish to investigate the same problem at finite temperature. Concerning the LMG model, the concurrence [37] (which characterizes the entanglement between two spins in an arbitrary state) is up to now the only e ...
A Priori Probability and Localized Observers
... how to model many physical situations, at a given moment, by an appropriate wavefunction. The problem is that the wave-function appropriate at one moment appears to change abruptly whenever an act of measurement or an observation occurs. There is no widely-accepted detailed theory of such acts. In t ...
... how to model many physical situations, at a given moment, by an appropriate wavefunction. The problem is that the wave-function appropriate at one moment appears to change abruptly whenever an act of measurement or an observation occurs. There is no widely-accepted detailed theory of such acts. In t ...
Czech Technical University in Prague Faculty of Electrical
... quantum physics. Quantum computing can be seen as a special intermediate case between digital and real analog computing. Importantly, there is a threshold theorem for error correction, as opposed to the pure analog case. Alternatively, quantum computing can be viewed as generalized probabilistic com ...
... quantum physics. Quantum computing can be seen as a special intermediate case between digital and real analog computing. Importantly, there is a threshold theorem for error correction, as opposed to the pure analog case. Alternatively, quantum computing can be viewed as generalized probabilistic com ...
Including quantum effects in the dynamics of complex „i.e., large
... In the 1970s it was shown how semiclassical theory could be generalized to describe inelastic and reactive scatterings.14,15 共The challenge here was to learn how numerically computed classical trajectories could be used as input into a multidimensional generalization of the WKB approximation.兲 Since ...
... In the 1970s it was shown how semiclassical theory could be generalized to describe inelastic and reactive scatterings.14,15 共The challenge here was to learn how numerically computed classical trajectories could be used as input into a multidimensional generalization of the WKB approximation.兲 Since ...
arXiv:quant-ph/9710044 v1 20 Oct 1997 - UQ eSpace
... Despite these heroic experimental achievements, the quantum motion of a single trapped ion is obviously limited by sources of decoherence. Decoherence arises from random and unknown perturbations of the Hamiltonian. If these perturbations cannot be followed exactly, experiments must average over the ...
... Despite these heroic experimental achievements, the quantum motion of a single trapped ion is obviously limited by sources of decoherence. Decoherence arises from random and unknown perturbations of the Hamiltonian. If these perturbations cannot be followed exactly, experiments must average over the ...
Decoherence of a Quantum Bit Circuit
... Figure 2: Kane’s proposal: nuclear spins of phosphorus impurities form the qubits. The control is provided by the hyperfine interaction with a bound electron around each impurity. Each qubit is controlled by applying a voltage to an A gate electrode that displaces slightly the wavefunction of the bo ...
... Figure 2: Kane’s proposal: nuclear spins of phosphorus impurities form the qubits. The control is provided by the hyperfine interaction with a bound electron around each impurity. Each qubit is controlled by applying a voltage to an A gate electrode that displaces slightly the wavefunction of the bo ...
Bose-Glass Phases of Ultracold Atoms due to Cavity Backaction Hessam Habibian,
... diffraction of light by atoms in optical lattices was measured for various geometries and settings, from gratings of laser-cooled atoms [2–5] to ultracold bosons in the Mottinsulator (MI) phase [6]. In most of these setups, the mechanical effect of the scattered light on the density distribution of ...
... diffraction of light by atoms in optical lattices was measured for various geometries and settings, from gratings of laser-cooled atoms [2–5] to ultracold bosons in the Mottinsulator (MI) phase [6]. In most of these setups, the mechanical effect of the scattered light on the density distribution of ...
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.