One- and two-photon states for quantum information

Using correlated photons from parametric downconversion, we extend the boundaries of experimentally explored one- and two-qubit Hilbert space. These states are used to explore a variety of topics in quantum information. Specifically, we have created and characterized arbitrary single-qubit states and maximally entangled mixed states (MEMS) that lie above the Werner-state boundary in the linear entropy-tangle plane. In addition, we demonstrate that such states can be efficiently concentrated via a “Procrustean method,” simultaneously increasing both the purity and the degree of entanglement. Our experimental MEMS creation directed us to examine several ways of benchmarking states in the presence of perturbations, comparing the relative sensitivity between the common state measures–fidelity, trace distance, concurrence, tangle, von Neumann entropy, and linear entropy. In particular, we illustrate a sensitivity imbalance between three of these measures for depolarized MEMS and nonmaximally entangled states. Surprisingly, the size of the imbalance depends on the state’s tangle and linear entropy. Using maximally entangled states, we experimentally demonstrate the first remote state preparation of arbitrary single-qubit states, at two wavelengths. Further, we derive theoretical bounds on the states that may be remotely prepared for given two-qubit resources. By using methods for directly and remotely preparing arbitrary single-qubit states, we make the first optical mixed-state geometric phase measurement via single-photon interferometry. Finally, we present experimental progress on the remote preparation of single-photon number states, created deterministically out of a non-deterministic spontaneous parametric downconversion source.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Peters, Nicholas A.

Contributors dc:contributor

• Kwiat, Paul G.

• Single-photon polarization states
• Two-qubit creation
• Maximally entangled mixed states (MEMS)

Statement dc:rights

• ©2006 Nicholas A. Peters

Language dc:language

en

Identifier

5633253

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/34829