38 research outputs found
A Talk on Quantum Cryptography, or How Alice Outwits Eve
Alice and Bob wish to communicate without the archvillainess Eve
eavesdropping on their conversation. Alice, decides to take two college
courses, one in cryptography, the other in quantum mechanics. During the
courses, she discovers she can use what she has just learned to devise a
cryptographic communication system that automatically detects whether or not
Eve is up to her villainous eavesdropping. Some of the topics discussed are
Heisenberg's Uncertainty Principle, the Vernam cipher, the BB84 and B92
cryptographic protocols. The talk ends with a discussion of some of Eve's
possible eavesdropping strategies, opaque eavesdropping, translucent
eavesdropping, and translucent eavesdropping with entanglement.Comment: 31 pages, 8 figures. Revised version of a paper published in "Coding
Theory, and Cryptography: From Geheimscheimschreiber and Enigma to Quantum
Theory," (edited by David Joyner), Springer-Verlag, 1999 (pp. 144-174). To be
published with the permission of Springer-Verlag in an AMS PSAPM Short Course
volume entitled "Quantum Computation.
Distributed quantum computing: A distributed Shor algorithm
We present a distributed implementation of Shor's quantum factoring algorithm
on a distributed quantum network model. This model provides a means for small
capacity quantum computers to work together in such a way as to simulate a
large capacity quantum computer. In this paper, entanglement is used as a
resource for implementing non-local operations between two or more quantum
computers. These non-local operations are used to implement a distributed
factoring circuit with polynomially many gates. This distributed version of
Shor's algorithm requires an additional overhead of O((log N)^2) communication
complexity, where N denotes the integer to be factored.Comment: 13 pages, 12 figures, extra figures are remove
Entanglement Criteria - Quantum and Topological
This paper gives a criterion for detecting the entanglement of a quantum
state, and uses it to study the relationship between topological and quantum
entanglement. It is fundamental to view topological entanglements such as
braids as entanglement operators and to associate to them unitary operators
that are capable of creating quantum entanglement. The entanglement criterion
is used to explore this connection. The paper discusses non-locality in the
light of this criterion.Comment: 8 pages, LaTeX, to appear in proceedings of Spie Conference, Orlando,
Fla, April 200