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Protected quantum bits and Josephson junction arrays
Descriptive
TypeOfResource
Text
TitleInfo
(ID = T-1)
Title
Protected quantum bits and Josephson junction arrays
Identifier
ETD_2859
Identifier
(type = hdl)
http://hdl.rutgers.edu/1782.1/rucore10001600001.ETD.000056810
Language
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eng
Genre
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theses
Subject
(ID = SBJ-1);
(authority = RUETD)
Topic
Physics and Astronomy
Subject
(ID = SBJ-2);
(authority = ETD-LCSH)
Topic
Josephson junctions
Subject
(ID = SBJ-3);
(authority = ETD-LCSH)
Topic
Symmetry (Physics)
Subject
(ID = SBJ-4);
(authority = ETD-LCSH)
Topic
Quantum computers
Abstract
(type = abstract)
In this thesis we consider a Josephson junction device whose symmetry is described by the point group Td. It can be visualized as a tetrahedron that contains two Josephson junctions on each edge. We find the conditions under which the ground state of the system is degenerate or almost degenerate. In this case, the low-energy degrees of freedom can be mapped to the Hilbert space of a quantum spin 1/2. We evaluate effects of different physical perturbations on the degenerate ground state and find that they are small for most perturbations. We argue that this system can be considered as a very promising candidate for a protected quantum bit with built-in error correction. We propose and discuss an experimental method that allows to test validity of some of the theoretical results obtained for the tetrahedral Josephson junction array and other similar symmetric circuits. We have chosen a simpler pyramidal array to demonstrate the main ideas of our method. Even though the noise resistance and theoretical decoherence time of the pyramidal array are worse than those of the more complex tetrahedral systems, it is much easier to realize the pyramid experimentally. The proposed design can be used with any symmetric Josephson junction circuit. We explore a natural generalization of the tetrahedral quantum bit and consider devices whose symmetry can be described by one of the higher-order permutation groups Sn. We study the level structure and the associated built-in protection of some conceptually simple circuits and show that these circuits have many interesting properties. In particular, their ground state can be highly degenerate and stable with respect to perturbations violating the symmetry. Unfortunately, these highly symmetric systems consist of a large number of identical Josephson junctions. This makes them too complicated for experimental realization.
PhysicalDescription
Form
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electronic resource
Extent
vii, 106 p. : ill.
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application/pdf
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text/xml
Note
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Ph.D.
Note
(type = bibliography)
Includes bibliographical references
Note
(type = vita)
Includes vita
Note
(type = statement of responsibility)
by Ruslan Usmanov
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Usmanov
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Ruslan
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1980-
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author
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Ruslan Usmanov
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(type = family)
Ioffe
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(type = given)
Lev
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chair
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Advisory Committee
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Lev Ioffe
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(type = personal)
NamePart
(type = family)
Zimmermann
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(type = given)
Frank
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internal member
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Advisory Committee
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Frank Zimmermann
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NamePart
(type = family)
Gershenson
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Michael
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internal member
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Advisory Committee
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Michael Gershenson
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(type = family)
Yuzbashyan
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Emil
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internal member
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Advisory Committee
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Emil Yuzbashyan
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NamePart
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Frolov
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Sergey
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outside member
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Advisory Committee
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Sergey Frolov
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NamePart
Rutgers University
Role
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degree grantor
Name
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NamePart
Graduate School - New Brunswick
Role
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school
OriginInfo
DateCreated
(qualifier = exact)
2010
DateOther
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2010-10
Place
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(type = code)
xx
RelatedItem
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TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier
(type = RULIB)
ETD
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(type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier
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rucore19991600001
Location
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NjNbRU
Identifier
(type = doi)
doi:10.7282/T3XK8F8B
Genre
(authority = ExL-Esploro)
ETD doctoral
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Rights
RightsDeclaration
(AUTHORITY = GS);
(ID = rulibRdec0006)
The author owns the copyright to this work.
Copyright
Status
Copyright protected
Availability
Status
Open
Reason
Permission or license
RightsHolder
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Name
FamilyName
Usmanov
GivenName
Ruslan
Role
Copyright Holder
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Type
Permission or license
DateTime
2010-09-14 01:55:41
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Role
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Name
Ruslan Usmanov
Affiliation
Rutgers University. Graduate School - New Brunswick
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Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.
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Technical
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ETD
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application/pdf
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application/x-tar
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798720
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