13 research outputs found

    Bell-type inequalities for cold heteronuclear molecules

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    We introduce Bell-type inequalities allowing for non-locality and entanglement tests with two cold heteronuclear molecules. The proposed inequalities are based on correlations between each molecule spatial orientation, an observable which can be experimentally measured with present day technology. Orientation measurements are performed on each subsystem at diferent times. These times play the role of the polarizer angles in Bell tests realized with photons. We discuss the experimental implementations of the proposed tests, which could also be adapted to other high dimensional quantum angular momenta systems.Comment: 4 page

    Bell inequalities with continuous angular variables

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    International audienceWe consider bipartite quantum systems characterized by a continuous angular variable θ ∈ [−π, π[, representing, for instance, the position of a particle on a circle. We show how to reveal non-locality on this type of system using inequalities similar to CHSH ones, originally derived for bipartite spin 1/2 like systems. Such inequalities involve correlated measurement of continuous angular functions and are equivalent to the continuous superposition of CHSH inequalities acting on bidimensional subspaces of the infinite dimensional Hilbert space. As an example, we discuss in detail one applica- tion of our results, and we derive inequalities based on orientation correlation measurements. The introduced Bell-type inequalities open the perspective of new and simpler experiments to test non locality on a variety of quantum systems described by continuous variables

    Metrological advantage at finite temperature for Gaussian phase estimation

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    In the context of phase estimation with Gaussian states, we introduce a quantifiable definition of metrological advantage that takes into account thermal noise in the preparation procedure. For a broad set of states, \textit{isotropic non-pure Gaussian states}, we show that squeezing is not only necessary, but sufficient, to achieve metrological advantage. We interpret our results in the framework of resource theory, and discuss possible sources of advantage other than squeezing. Our work is a step towards using phase estimation with pure and mixed state to define and quantify nonclassicality. This work is complementary with studies that defines nonclassicality using quadrature displacement estimation.Comment: Changes to wording, figures replace

    Bell-type inequalities for cold heteronuclear molecules

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    4 pagesWe introduce Bell-type inequalities allowing for non-locality and entanglement tests with two cold heteronuclear molecules. The proposed inequalities are based on correlations between each molecule spatial orientation, an observable which can be experimentally measured with present day technology. Orientation measurements are performed on each subsystem at diferent times. These times play the role of the polarizer angles in Bell tests realized with photons. We discuss the experimental implementations of the proposed tests, which could also be adapted to other high dimensional quantum angular momenta systems

    Generation of quantum states of light in nonlinear AlGaAs chips: engineering and applications

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    Photonic quantum technologies represent a promising platform for applications ranging from long-distance secure communications to the simulation of complex phenomena. Among the different material platforms, direct bandgap semiconductors offer a wide range of functionalities opening promising perspectives for the implementation of future quantum technologies. In this paper, we review our progress on the generation and manipulation of quantum states of light in nonlinear AlGaAs chips and their use in quantum networks

    Bell-type inequalities for cold heteronuclear molecules

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    4 pagesWe introduce Bell-type inequalities allowing for non-locality and entanglement tests with two cold heteronuclear molecules. The proposed inequalities are based on correlations between each molecule spatial orientation, an observable which can be experimentally measured with present day technology. Orientation measurements are performed on each subsystem at diferent times. These times play the role of the polarizer angles in Bell tests realized with photons. We discuss the experimental implementations of the proposed tests, which could also be adapted to other high dimensional quantum angular momenta systems

    Metrological advantage at finite temperature for Gaussian phase estimation

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    The use of pure classical probes in a metrological experiment gives precision limited by the standard quantum limit. This limit may be circumvented using nonclassical probes. Since the onset of quantum metrology, numerous papers have studied the standard quantum limit in various contexts. This allowed to better understand the resources needed to surpass this limit, achieving a metrological advantage. However, a general characterization of said resources is still missing. Moreover, the standard quantum limit itself can be unattainable at the classical level due to noise in the preparation procedure. Here, in the context of phase estimation, we introduce a quantifiable definition of metrological advantage that takes into account noise in the preparation procedure. We characterize all Gaussian states that possess this metrological advantage, and show that squeezing is not only necessary, but sufficient, to have an advantage. Finally, we compare our results to the framework of resource theory; interestingly, we find that some, but not all, properties of our metrological advantage can be recast in this language
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