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Q-ESSENCE

Precision Quantum Metrology and Nonclassicality in Linear and Nonlinear Detection Schemes

Wed, 2011-03-30 23:07 - Q-Essence Coordinator
Date: 
2010-06-30
Author(s): 

Ángel Rivas and Alfredo Luis

Reference: 

Phys. Rev. Lett. 105, 010403 (2010)

URL: 

http://prl.aps.org/abstract/PRL/v105/i1/e010403

We examine whether metrological resolution beyond coherent states is a nonclassical effect. We show that this is true for linear detection schemes but false for nonlinear schemes, and propose a very simple experimental setup to test it. We find a nonclassicality criterion derived from quantum Fisher information.

Loss-resistant state teleportation and entanglement swapping using a quantum-dot spin in an optical microcavity

Wed, 2011-03-30 22:58 - Q-Essence Coordinator
Date: 
2011-03-04
Author(s): 

C. Y. Hu and J. G. Rarity

Reference: 

Phys. Rev. B 83, 115303 (2011)

URL: 

http://prb.aps.org/abstract/PRB/v83/i11/e115303

We present schemes for efficient state teleportation and entanglement swapping using a single quantum-dot spin in an optical microcavity based on giant circular birefringence. State teleportation or entanglement swapping is heralded by the sequential detection of two photons and is finished after the spin measurement. The spin-cavity unit works as a complete Bell-state analyzer with a built-in spin memory allowing loss-resistant repeater operation.

Heralded generation of entangled photon pairs

Wed, 2011-03-30 22:47 - Q-Essence Coordinator
Date: 
2010-06-27
Author(s): 

Stefanie Barz, Gunther Cronenberg, Anton Zeilinger and Philip Walther

Reference: 

Nature Photonics 4, 553 - 556 (2010)

URL: 

http://www.nature.com/nphoton/journal/v4/n8/full/nphoton.2010.156.html

Entangled photons are a crucial resource for quantum communication and linear optical quantum computation. Unfortunately, the applicability of many photon-based schemes is limited due to the stochastic character of the photon sources. Therefore, a worldwide effort has focused on overcoming the limitation of probabilistic emission by generating two-photon entangled states conditioned on the detection of auxiliary photons.

Lossy phase estimation, by J. Kołodyński (UWAW)

Fri, 2011-03-04 17:52 - Q-Essence Coordinator
Date: 
2010-06-06
Author(s): 

J. Kołodyński, R. Demkowczi-Dobrzański, K. Banaszek

Conference/Workshop/Place: 
7th Central European Quantum Information Processing Workshop, Valtice, Czech Republic

Presenter: Jan Kołodyński

Contributed talk

Q-ESSENCE WP1.1: Quantum metrology in real-world environments

Q-ESSENCE press release 1st March 2010

Fri, 2011-03-04 10:45 - Q-Essence Coordinator

The first press release for Q-ESSENCE wich appeared on 1st March 2010.

Author: Dr Kamna Pruvost, University of Oxford (UOXF.DU).

Sense and sensitivity: robust quantum phase estimation, by R. Demkowicz-Dobrzanski (UWAW)

Thu, 2011-03-03 17:17 - Q-Essence Coordinator
Date: 
2010-08-04
Author(s): 

R. Demkowicz-Dobrzański, K. Banaszek, U. Dorner, I. A. Walmsley, W. Wasilewski, B. Smith, J. Lundeen, M. Kacprowicz, J. Kołodyński

Conference/Workshop/Place: 
SPIE Conference, Quantum Communications and Quantum Imaging VIII, San Diego, USA

Presenter: R. Demkowicz-Dobrzański

Contributed talk

Q-ESSENCE WP1.1: Quantum metrology in real-world environments

 

Taming the non-equilibrium, J. Eisert (UP)

Thu, 2011-03-03 17:13 - Q-Essence Coordinator
Date: 
2010-04-12
Author(s): 

J. Eisert

Conference/Workshop/Place: 
Colloquium of Dahlem Center for Complex Quantum Systems, FU Berlin, Germany

Lecture

Q-ESSENCE WP3.5: Entanglement-based quantum information processing

Tensor network description of quantum many-body systems, by J. Eisert (UP)

Thu, 2011-03-03 17:11 - Q-Essence Coordinator
Date: 
2010-11-15
Author(s): 

J. Eisert

Conference/Workshop/Place: 
Simons Conference on New Trends in Quantum Computation, Stony Brook, USA

Invited talk

Q-ESSENCE WP3.5: Entanglement-based quantum information processing

Computing by measuring, by J. Eisert (UP)

Thu, 2011-03-03 17:07 - Q-Essence Coordinator
Date: 
2010-10-28
Author(s): 

J. Eisert

Conference/Workshop/Place: 
Nordita Programme on Quantum Information, Stockholm, Sweden

Invited talk

Q-ESSENCE WP3.2: New protocols

Speed limits of information propagation, by J. Eisert (UP)

Thu, 2011-03-03 17:04 - Q-Essence Coordinator
Date: 
2010-09-06
Author(s): 

J. Eisert

Conference/Workshop/Place: 
Workshop: Hamiltonians and Gaps, Cambridge, UK

Invited talk

Q-ESSENCE WP3.2: New protocols

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