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Theory on detection of multipartite entanglement
https://ir.soken.ac.jp/records/1237
https://ir.soken.ac.jp/records/1237c5348b50462747b88bd3cc071e915203
名前 / ファイル  ライセンス  アクション 

要旨・審査要旨 / Abstract, Screening Result (351.4 kB)

Item type  学位論文 / Thesis or Dissertation(1)  

公開日  20100222  
タイトル  
タイトル  Theory on detection of multipartite entanglement  
タイトル  
タイトル  Theory on detection of multipartite entanglement  
言語  en  
言語  
言語  eng  
資源タイプ  
資源タイプ識別子  http://purl.org/coar/resource_type/c_46ec  
資源タイプ  thesis  
著者名 
長田, 宏二
× 長田, 宏二 

フリガナ 
ナガタ, コウジ
× ナガタ, コウジ 

著者 
NAGATA, Kouji
× NAGATA, Kouji 

学位授与機関  
学位授与機関名  総合研究大学院大学  
学位名  
学位名  博士（理学）  
学位記番号  
内容記述タイプ  Other  
内容記述  総研大甲第712号  
研究科  
値  先導科学研究科  
専攻  
値  22 光科学専攻  
学位授与年月日  
学位授与年月日  20030324  
学位授与年度  
値  2002  
要旨  
内容記述タイプ  Other  
内容記述  Since the 1980s, there has been a physical problem relating to the detection of multipartite entangled states that helps us to investigate fundamental point of view on interpretations of quantum mechanics. On the other hand, information theories based on the mathematical structure of quantum mechanics, for example, quantum cryptography and quantum computation, have been investigated by researchers whose number has been increasing day by day in the world. This field became to be called quantum information theories. A practical experimental realization of quantum information processing needs that we detect experimentally multipartite entangled states. The number of researchers for multipartite entangled states is increasing rapidly. Especially, GreenbergerHorneZeilinger (GHZ) states are useful for quantum information processing information processing using quantum mechanics, which improves the conventional information processing ability which had been based on classical theories. However, practical experimental realization of the theories and controlling quantum states have inevitable difficulties due to the interaction with environments. The requirement in maintaining multipartite entangled states in relation to the time that takes to make a practical experiment is also a problem. Many experimentalists are tackling this problem, and recently, several groups have reported that multipartite entangled states have been physically detected in their laboratories. The main difficulty is how to judge whether or not the observed quantum state is indeed a multipartite entangled state. For this purpose, it is necessary to construct theoretical models to analyze such experimental data.<br /> In this thesis, we apply a mathematical structure as to density operators described in a highdimensional Hilbert space, and we employ mathematical theories to prove if the corresponding density operator represents a multipartite entangled state or not. The main aim for constructing such models is to analyze the raw experimental data. Moreover, this model helps experimentalists in the sense that it allows them to see how to confirm that observed states are indeed the desired state. With mathematical theories developed before this thesis, only limited applications for this purpose were allowed. Some theories cover twodimensional Hilbert space only. It has not been even discussed how to analyze the fidelity to GHZ states of the observed state. This has led to some doubt of that experimental data might not always confirm threepartite entangled states. However, by using the method of this thesis, statistical check based on such experimental data of the existence of three particleentangled states is possible under appropriate assumptions. This example symbolizes that our analytical knowledge has improved very much in the last few years. This thesis gives us an advanced mathematical model for analyzing experimental data.  
所蔵  
値  有 