Frontiers of quantum physics

Abstract:

We apply the axiomatic approach to thermodynamics presented by Giles to derive a unique measure of entanglement for bipartite pure states. This implies that local manipulations of entanglement in quantum information theory and adiabatic transformations of states in thermodynamics have the same underlying mathematical structure. We discuss possible extensions of our results to mixed and multipartite states.

Abstract:

We propose an entanglement concentration scheme which uses only the effects of quantum statistics of indistinguishable particles. This establishes the fact that useful quantum information processing can be accomplished by quantum statistics alone. Because of the basis independence of statistical effects, our protocol requires less knowledge of the initial state than most entanglement concentration schemes. Moreover, no explicit controlled operation is required at any stage.

Abstract:

A comparison of the query complexity analysis of quantum algorithms was presented. Two different ways of representing a permutation in terms of a black box quantum oracle were provided. A simple promise problem that minimal quantum oracles could solve faster that the classical oracles was discussed. Results showed that the possibility of efficiently solving nonautomorphic graph isomorphism (NAGI) could be excluded by simulating a simpler oracle using standard oracle for a one-to-one function. © Oxford University Press 2002.