Topic
Coherent information
About: Coherent information is a research topic. Over the lifetime, 1225 publications have been published within this topic receiving 46672 citations.
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TL;DR: In this article, the entanglement of pair coherent states in the phase damping channel was investigated and a scheme for teleportation via pair-consistent coherent states was proposed, and the fidelity of the scheme was analyzed.
Abstract: We investigate the entanglement of pair coherent states in the phase damping channel by adopting the relative entropy of entanglement and propose a protocol of teleportation via pair coherent states The fidelity of the protocol is then analyzed and the influence of phase damping on the teleportation fidelity examined
8 citations
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TL;DR: In this paper, the optimal tradeoff between the amount of information retrieved by a quantum measurement in estimating an unknown spin coherent state and the disturbance on the state itself is quantified.
Abstract: We show how to quantify the optimal tradeoff between the amount of information retrieved by a quantum measurement in estimating an unknown spin coherent state and the disturbance on the state itself, and how to derive the corresponding minimum-disturbing measurement.
8 citations
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TL;DR: It is shown that a simple BB84 protocol indeed distributes a binary sequence between Alice and Bob that looks almost random for Eve with a probability exponentially close to 1.
Abstract: We discuss the Bennett-Brassard 1984 (BB84) quantum key distribution protocol in the light of quantum algorithmic information. While Shannon's information theory needs a probability to define a notion of information, algorithmic information theory does not need it and can assign a notion of information to an individual object. The program length necessary to describe an object, Kolmogorov complexity, plays the most fundamental role in the theory. In the context of algorithmic information theory, we formulate a security criterion for the quantum key distribution by using the quantum Kolmogorov complexity that was recently defined by Vit\'anyi. We show that a simple BB84 protocol indeed distributes a binary sequence between Alice and Bob that looks almost random for Eve with a probability exponentially close to 1.
8 citations
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TL;DR: If the main essence of the above approaches taken together are accepted, each of them can provide a different part of a teleportation mechanism.
Abstract: The feasibility of wave function collapse in the human brain has been the subject of vigorous scientific debates since the advent of quantum theory. Scientists like Von Neumann, London, Bauer and Wigner (initially) believed that wave function collapse occurs in the brain or is caused by the mind of the observer. It is a legitimate question to ask how human brain can receive subtle external visual quantum information intact when it must pass through very noisy and complex pathways from the eye to the brain? There are several approaches to investigate information processing in the brain, each of which presents a different set of conclusions. Penrose and Hameroff have hypothesized that there is quantum information processing inside the human brain whose material substrate involves microtubules and consciousness is the result of a collective wavefunction collapse occurring in these structures. Conversely, Tegmark stated that owing to thermal decoherence there cannot be any quantum processing in neurons of the brain and processing in the brain must be classical for cognitive processes. However, Rosa and Faber presented an argument for a middle way which shows that none of the previous authors are completely right and despite the presence of decoherence, it is still possible to consider the brain to be a quantum system. Additionally, Thaheld, has concluded that quantum states of photons do collapse in the human eye and there is no possibility for collapse of visual quantum states in the brain and thus there is no possibility for the quantum state reduction in the brain. In this paper we conclude that if we accept the main essence of the above approaches taken together, each of them can provide a different part of a teleportation mechanism.
8 citations
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TL;DR: It is shown that it is not possible to attain a proper generalization of the quantum conditional mutual information by optimizing the distance in terms of quantum α-Renyi divergences over the set of all Markov states.
Abstract: We study the relation between the quantum conditional mutual information and the quantum $\alpha$-Renyi divergences. Considering the totally antisymmetric state we show that it is not possible to attain a proper generalization of the quantum conditional mutual information by optimizing the distance in terms of quantum $\alpha$-Renyi divergences over the set of all Markov states. The failure of the approach considered arises from the observation that a small quantum conditional mutual information does not imply that the state is close to a quantum Markov state.
8 citations