Citation
Gingrich, Robert M. (2002) Entanglement of multipartite quantum states and the generalized quantum search. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:01202012104927686
Abstract
In chapter 2 various parameterizations for the orbits under local unitary transformations of threequbit pure states are analyzed. It is shown that the entanglement monotones of any multipartite pure state uniquely determine the orbit of that state. It follows that there must be an entanglement monotone for threequbit pure states which depends on the Kempe invariant defined in [1]. A form for such an entanglement monotone is proposed. A theorem is proved that significantly reduces the number of entanglement monotones that must be looked at to find the maximal probability of transforming one multipartite state to another.
In chapter 3 Grover's unstructured quantum search algorithm is generalized to use an arbitrary starting superposition and an arbitrary unitary matrix. A formula for the probability of the generalized Grover's algorithm succeeding after n iterations is derived. This formula is used to determine the optimal strategy for using the unstructured quantum search algorithm. The speedup obtained illustrates that a hybrid use of quantum computing and classical computing techniques can yield a performance that is better than either alone. The analysis is extended to the case of a society of k quantum searches acting in parallel.
In chapter 4 the positive map Г : p → (Trρ)  ρ is introduced as a separability criterion. Any separable state is mapped by the tensor product of Г and the identity in to a nonnegative operator, which provides a necessary condition for separability. If Г acts on a twodimensional subsystem, then it is equivalent to partial transposition and therefore also sufficient for 2 x 2 and 2 x 3 systems. Finally, a connection between this map for two qubits and complex conjugation in the "magic" basis [2] is displayed.
Item Type:  Thesis (Dissertation (Ph.D.)) 

Subject Keywords:  Physics 
Degree Grantor:  California Institute of Technology 
Division:  Physics, Mathematics and Astronomy 
Major Option:  Physics 
Thesis Availability:  Restricted to Caltech community only 
Research Advisor(s): 

Thesis Committee: 

Defense Date:  23 August 2001 
Record Number:  CaltechTHESIS:01202012104927686 
Persistent URL:  http://resolver.caltech.edu/CaltechTHESIS:01202012104927686 
Default Usage Policy:  No commercial reproduction, distribution, display or performance rights in this work are provided. 
ID Code:  6769 
Collection:  CaltechTHESIS 
Deposited By:  Benjamin Perez 
Deposited On:  23 Jan 2012 19:34 
Last Modified:  26 Dec 2012 04:39 
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