Coherence and entanglement are the two key concepts that distinguish quantum
mechanics from classical mechanics. Many novel phenomena occuring in the quantum
world are due to these two Âphysical quantitiesÂ. They also play essential roles in
quantum computation and quantum information. For example, coherence, which
says that a quantum mechanical system could be in a superposition state, makes the
quantum parallel computing scheme possible; and entanglement, which says that two
quantum systems separated in space could be in an intervened state, is the key factor
in various quantum teleportation algorithms.
We have studied entanglement generation in various systems. We found that with
atomic coherence, entanglement could be generated between two thermal fields with
arbitrarily high temperatures. We also found that temperature difference instead of
the purity of state is essential for the entanglement generation between an atom and
a thermal field. We discovered that correlated spontaneous emission lasers (CELs)
could be used to generate bright entanglement laser beams. As a special case of CEL
systems, we studied entanglement generation in Non-degenerate Optical Parametric
Amplifiers (NOPAs). We performed the input-output calculations for a NOPA system
and showed that the two output optical beams are still entangled. This justifies our idea that CEL (or NOPA) systems can be used as an ideal entanglement source
for various quantum information schemes. From an experimental point of view, we
considered the effects of pumping fluctuations on entanglement generation in CEL
and NOPA systems. We found that these fluctuations, especially the phase diffusion
processes, in the pump laser would greatly reduce the entanglement generated in such
systems.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/3797 |
| Date | 16 August 2006 |
| Creators | Xiong, Han |
| Contributors | Scully, Marlan O., Zubairy, M. Suhail |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 745732 bytes, electronic, application/pdf, born digital |
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