Modern techniques allow experiments on a single atom or system, with new
phenomena and new challenges for the theoretician. We discuss what quantum
mechanics has to say about a single system. The quantum jump approach as well
as the role of quantum trajectories are outlined and a rather sophisticated
example is given.Comment: Fundamental problems in quantum theory workshop, invited lecture. 11
  pages Latex + 7 figures. To appear in Fortschr. d. Physi

Benson, O

Englert, B-G

Löffler, M

Varcoe, B

Walther, H

Weidinger, M

English

arXiv

A novel quantum optical interference experiment based on a delayed correlation technique and involving photons prepared in a polarization-entangled state is presented. The resulting phenomenology is found to be determined by the simultaneous realization of several non-classical interference processes of distinct nature albeit strictly interrelated. A formal interpretation of the results is attempted by a standard quantum analysis and by the adoption of a set of interfering Feynman diagrams. In addition, a physical interpre-tation at a deeper level is undertaken by introducing for the system the basic theoretical background of a new concept in quantum optics: entangled interferometry. As a relevant application of this new paradigm, a novel two-photon welcher-weg argument within a delayed-choice experiment is presented. It leads to an unexpected complementarity puzzle which expresses the manifestation of the EPR non-locality within the general context of interferometry. PACS numbers: 03.65.Bz, 42.50.-p, 42.50.Wm

DI GIUSEPPE, Giovanni

F. De Martini

D. Boschi

S. Branca

Archivio istituzionale della ricerca - Università di Camerino

Entangled Non-Local Quantum Interferometry

We propose an experimental procedure, based on homodyne tomography,
for measuring the matrix elements of the Liouvillian of optical
devices. After describing the proposed experimental setup, we give a
numerical Monte Carlo simulation of the measurement of the Liouvillian of
a laser

D'ARIANO, GIACOMO

MACCONE, LORENZO

Archivio Istituzionale della Ricerca - Università degli Studi di Pavia

Quantum  characterization of optical devices

The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made

Hughes, Richard J.

UNT Digital Library

Cryptography, quantum computation and trapped ions