Showing papers by "Charles H. Bennett published in 2006"
TL;DR: In this article, a polynomial-time method for universal source coding is proposed for quantum state tomography, called "gentle tomography". But this method requires the quantum data to be preserved.
Abstract: Quantum-state tomography--the practice of estimating a quantum state by performing measurements on it - is useful in a variety of contexts. We introduce 'gentle tomography' as a version of tomography that preserves the measured quantum data. As an application of gentle tomography, we describe a polynomial-time method for universal source coding.
35 citations
IBM1
TL;DR: A hierarchy of capacity inequalities and open questions is given of quantum channels whose classical and quantum capacities, when assisted by classical feedback, exceed their unassisted classical Holevo capacity.
Abstract: We exhibit quantum channels whose classical and quantum capacities, when assisted by classical feedback, exceed their unassisted classical Holevo capacity. These channels are designed to be noisy in a way that can be corrected with the help of the output and a reference system entangled with part of the input. A similar construction yields quantum channels whose classical capacity, when assisted by two-way classical communication independent of the source, exceeds their classical capacity assisted by feedback alone. We give a hierarchy of capacity inequalities and open questions.
32 citations
Patent•
26 Jul 2006
9 citations
22 Nov 2006
TL;DR: The quantum principles of superposition and entanglement have led to a recasting of the foundations of information and computation theory, and are especially helpful in understanding the nature of privacy.
Abstract: The quantum principles of superposition and entanglement have led to a recasting of the foundations of information and computation theory, and are especially helpful in understanding the nature of privacy. The most private information, exemplified by a quantum eraser experiment, is best regarded as existing only conditionally and temporarily—after the experiment is over no trace remains. Less private is classically‐secret information—quantum information that has decohered, and thus become recoverable in principle, though not in practice, from portions of the environment. Finally there is public information, which has been replicated so thoroughly throughout the environment as to be infeasible to conceal. The Internet has caused an explosion of public information, with the beneficial side effect of making it harder for despots to rewrite the history of their misdeeds, and it is tempting to hope that all macroscopic information is permanent, making such cover‐ups impossible in principle if not in practice. ...
3 citations
TL;DR: The goals of cryptography are reviewed, how quantum laws allow some of these goals to be attained that could not be otherwise are explained, and the future of quantum cryptography and the nature of its security are commented on.
Abstract: We review the goals of cryptography, explain how quantum laws allow some of these goals to be attained that could not be otherwise, and comment on the future of quantum cryptography and the nature of its security. Wir geben einen Überblick über die Ziele der Kryptographie und erklären, wie mit Hilfe der Gesetze der Quantenmechanik einige dieser Ziele erreicht werden können, die andernfalls unerreichbar sind. Ferner diskutieren wir die Zukunft der Quantenkryptographie sowie den wesentlichen Ursprung ihrer Sicherheit.
1 citations