scholarly journals Partial Bell-State Analysis with Parametric down Conversion in the Wigner Function Formalism

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
A. Casado ◽  
S. Guerra ◽  
J. Plácido
Keyword(s):  
Wigner Function ◽  
Beam Splitter ◽  
Bell State ◽  
Function Formalism ◽  
State Measurement ◽  
Parametric Down Conversion ◽  
Correlation Properties ◽  
Light Beams ◽  
Down Conversion ◽  
State Analysis

We apply the Wigner function formalism to partial Bell-state analysis using polarization entanglement produced in parametric down conversion. Two-photon statistics at a beam-splitter are reproduced by a wave-like description with zeropoint fluctuations of the electromagnetic field. In particular, the fermionic behaviour of two photons in the singlet state is explained from the invariance on the correlation properties of two light beams going through a balanced beam-splitter. Moreover, we show that a Bell-state measurement introduces some fundamental noise at the idle channels of the analyzers. As a consequence, the consideration of more independent sets of vacuum modes entering the crystal appears as a need for a complete Bell-state analysis.

scholarly journals Practical quantum teleportation of an unknown quantum state

2017 ◽  
Vol 95 (5) ◽  
pp. 498-503
Author(s):  
Syed Tahir Amin ◽  
Aeysha Khalique
Keyword(s):  
Quantum State ◽  
Quantum Teleportation ◽  
Bell State ◽  
Linear Optics ◽  
State Measurement ◽  
Dark Counts ◽  
Experimental Parameters ◽  
Unknown Quantum State ◽  
Down Conversion ◽  
Good Agreement

We present our model to teleport an unknown quantum state using entanglement between two distant parties. Our model takes into account experimental limitations due to contribution of multi-photon pair production of parametric down conversion source, inefficiency, dark counts of detectors, and channel losses. We use a linear optics setup for quantum teleportation of an unknown quantum state by the sender performing a Bell state measurement. Our theory successfully provides a model for experimentalists to optimize the fidelity by adjusting the experimental parameters. We apply our model to a recent experiment on quantum teleportation and the results obtained by our model are in good agreement with the experimental results.

scholarly journals From Stochastic Optics to theWigner Formalism: The Role of the Vacuum Field in Optical Quantum Communication Experiments

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 76 ◽  
Author(s):  
Alberto Casado ◽  
Santiago Guerra ◽  
José Plácido
Keyword(s):  
Quantum Cryptography ◽  
Physical Meaning ◽  
Quantum Communication ◽  
Bell State ◽  
Vacuum Field ◽  
Heisenberg Picture ◽  
Parametric Down Conversion ◽  
The Relationship ◽  
Down Conversion

TheWigner formalism in the Heisenberg picture constitutes a bridge that connects QuantumOptics to Stochastic Optics. The vacuum field appears explicitly in the formalism, and the wavelikeaspects of light are emphasised. In addition, the zeropoint intensity as a threshold for detection is acommon denominator in both theories. In this paper, after summarising the basic rules of the Wignerapproach and its application to parametric down-conversion, some new results are presented thatdelve into the physical meaning of the zeropoint field in optical quantum communication. Specifically,the relationship between Bell-state distinguishability and the number of sets of zeropoint modesthat take part in the experiment is analysed in terms of the coupling between the phases of thedifferent fields involved and the subtraction of the zeropoint intensity at the detectors. Additionally,the connection between the compatibility theorem in quantum cryptography and zeropoint fieldis stressed.

Parametric down-conversion for light beams possessing orbital angular momentum

1999 ◽  
Vol 59 (5) ◽  
pp. 3950-3952 ◽  
Author(s):  
J. Arlt ◽  
K. Dholakia ◽  
L. Allen ◽  
M. J. Padgett
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Parametric Down Conversion ◽  
Light Beams ◽  
Down Conversion

scholarly journals Non-classical Signature of Parametric Fluorescence and its Application in Metrology

2014 ◽  
Vol 14 (4) ◽  
pp. 227-236 ◽  
Author(s):  
M. Hamar ◽  
V. Michálek ◽  
A. Pathak
Keyword(s):  
Numerical Simulations ◽  
Photon Number ◽  
Theoretical Background ◽  
Iccd Camera ◽  
Parametric Down Conversion ◽  
Light Beams ◽  
Down Conversion ◽  
Theoretical Results ◽  
Multimode Beams

Abstract The article provides a short theoretical background of what the non-classical light means. We applied the criterion for the existence of non-classical effects derived by C.T. Lee on parametric fluorescence. The criterion was originally derived for the study of two light beams with one mode per beam. We checked if the criterion is still working for two multimode beams of parametric down-conversion through numerical simulations. The theoretical results were tested by measurement of photon number statistics of twin beams emitted by nonlinear BBO crystal pumped by intense femtoseconds UV pulse. We used ICCD camera as the detector of photons in both beams. It appears that the criterion can be used for the measurement of the quantum efficiencies of the ICCD cameras.

Spatiotemporal coherence properties of entangled light beams generated by parametric down-conversion

1994 ◽  
Vol 50 (4) ◽  
pp. 3349-3361 ◽  
Author(s):  
Adel Joobeur ◽  
Bahaa E. A. Saleh ◽  
Malvin C. Teich
Keyword(s):  
Parametric Down Conversion ◽  
Light Beams ◽  
Down Conversion

Coherence properties of entangled light beams generated by parametric down-conversion: Theory and experiment

1996 ◽  
Vol 53 (6) ◽  
pp. 4360-4371 ◽  
Author(s):  
Adel Joobeur ◽  
Bahaa E. A. Saleh ◽  
Todd S. Larchuk ◽  
Malvin C. Teich
Keyword(s):  
Parametric Down Conversion ◽  
Light Beams ◽  
Down Conversion ◽  
Theory And Experiment
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