| 1. |
- Badziag, Piotr, et al.
(author)
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Experimentally friendly geometrical criteria for entanglement
- 2008
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:14, s. 140403-
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Journal article (peer-reviewed)abstract
- A simple geometrical criterion gives experimentally friendly sufficient conditions for entanglement. Its generalization gives a necessary and sufficient condition. It is linked with a family of entanglement identifiers, which is strictly richer than the family of entanglement witnesses.
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| 2. |
- Kaltenbaek, Rainer, et al.
(author)
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Macroscopic Quantum Resonators (MAQRO) : 2015 update
- 2016
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In: EPJ Quantum Technology. - : Springer Berlin/Heidelberg. - 2196-0763. ; 3:1
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Research review (peer-reviewed)abstract
- Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schrodinger's cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments.
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| 3. |
- Trojek, Pavel, et al.
(author)
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Experimental multipartner quantum communication complexity employing just one qubit
- 2013
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In: Natural Computing. - : Springer Science and Business Media LLC. - 1567-7818 .- 1572-9796. ; 12:1, s. 19-26
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Journal article (peer-reviewed)abstract
- Most proposals for quantum solutions of information-theoretic problems rely on the usage of multi-partite entangled states which are still difficult to produce experimentally with current state-of-the-art technology. Here, we analyze a scheme to simplify a particular kind of multiparty communication protocols for the experiment. We prove that the fidelity of two communication complexity protocols, allowing for an N - 1 bit communication, can be exponentially improved by N - 1 (unentangled) qubit communication. Taking into account, for a fair comparison, all inefficiencies of state-of-the-art set-up, the experimental implementation for N = 5 outperforms the best classical protocol, making it the candidate for multi-party quantum communication applications.
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