Quantum Universal Estimator

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Quantum Universal Estimator

• L.C. Kwek

NIE, NanyangTechnological University Local
Driver, QIT Lab (NUS, Singapore) Talk presented
at First Asia-Pacific Conference on Quantum
Computation, Tainan, 13 December 2004
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Collaborators

• Choo Keng Wah
• Do Jiangfeng
• Artur Ekert
• Pawel Horodecki
• Michal Horodecki
• Dagomir Kaszlikowski
• Carolina Moura-Aves
• Daniel Oi
• C.H. Oh
• C.H. Lai
• Zou Ping

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Scope of the talk

• Introduction
• A quantum network
• Applications
• Experimental realization
• References
• Acknowledgment

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Quantum Network
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Application 2 Direct measure of purity if r1
r2 r Visibility Tr (r2)
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visibility
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Application 4 Estimation of extremal
eigenvalues and eigenvectors of r2.
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• Quantum tomography can be done in many other ways
• This scheme is based on a fixed architecture
  controlled by input data

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Application Evaluation of Tr(rd) Tomography
evaluation of the spectrum of any density
matrix
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Direct estimation of shared bipartitite state
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Experimental

• Bruker Avance DMR 400 spectrometer
• 9.4 T
• 5mm probe
• C13 sample of alanine
• Resonant frequency of alanine 100 MHz

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References

• A.K. Ekert, C. Moura-Aves, D.K.L. Oi, M.
  Horodecki, P. Horodecki and L.C. Kwek. Direct
  estimations of linear and non-linear functionals
  of a quantum state, Phys. Rev. Lett., 88, 217901
  (2002)
• C. Moura Aves, P. Horodecki, Daniel K.L. Oi, L.C.
  Kwek and A. Ekert, Direct estimation of
  functionals of density operators by local
  operations and classical communication, Phys.
  Rev. A 68, 032306 (2003)
• A.K. Ekert, C. Moura-Aves, D.K.L. Oi, M.
  Horodecki, P. Horodecki and L.C. Kwek, .Direct
  Detection of entanglement, The Physics of
  Communication, Proceedings of the XXII Solvay
  Conference on Physics, Delphi Lamia, Greece,
  24-29 November 2001, edited by  I. Antoniu, V.A.
  Sadovnichy, and H. Walther, (World Scientific,
  Singapore, 2003)
• J.F. Du, P. Zou, M. Shi, L.C. Kwek, J.W. Pan,
  C.H. Oh, A. Ekert, D.K.L. Oi and M. Ericsson, An
  experimental observation of geometric phases for
  mixed states using interferometry, Phys. Rev.
  Lett. 91, 100403 (2003) , eprint
  arXivquant-ph/0305054

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Acknowledgement http//www.phdcomics.com