Direct calibration of click-counting detectors

We study the Kimble-Braunstein continuous-variable quantum teleportation with the quantum channel physically realized in the turbulent atmosphere. In this context, we examine the applicability of different strategies preserving the Gaussian entanglement [Bohmann et al., Phys. Rev. A 94, 010302(R) (2016)] for improving the fidelity of the coherent-state teleportation. First, we demonstrate that increasing the squeezing parameter characterizing the entangled state is restricted by its optimal value, which we derive for realistic experimentally-verified examples. Further, we consider the technique of adaptive correlations of losses and show its performance for channels with large squeezing parameters. Finally, we investigate the efficiencies of postselection strategies in dependence on the stochastic properties of the channel transmittance.

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“…Furthermore, post-selection scenarios can improve the entanglement transfer. Similar results were also reported for non-Gaussian states [49].…”

Section: Introductionsupporting

confidence: 89%

Quantum teleportation through atmospheric channels

et al. 2019

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“…This is the expected result for a coherent-state reference [50], and we can conclude that our detection scheme works appropriately and does not herald false nonclassicality. Note that a similar measurement with varying intensities has been recently applied to accurately calibrate the used detection device [52], which additionally determines the quantum efficiency. As the eigenvalue is consistent with zero for all measurements, our detection scheme works as expected.…”

Section: B Constant Lossesmentioning

confidence: 99%

Probing free-space quantum channels with laboratory-based experiments

et al. 2017

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Atmospheric channels are a promising candidate to establish secure quantum communication on a global scale. However, due to their turbulent nature, it is crucial to understand the impact of the atmosphere on the quantum properties of light and examine it experimentally. In this paper, we introduce a method to probe atmospheric free-space links with quantum light on a laboratory scale. In contrast to previous works, our method models arbitrary intensity losses caused by turbulence to emulate general atmospheric conditions. This allows us to characterize turbulent quantum channels in a well-controlled manner. To implement this technique, we perform a series of measurements with different constant attenuations and simulate the fluctuating losses by combining the obtained data. We directly test the proposed method with an on-chip source of nonclassical light and a time-binmultiplexed detection system. With the obtained data, we characterize the nonclassicality of the generated states for different atmospheric noise models and analyze a post-selection protocol. This general technique in atmospheric quantum optics allows for studying turbulent quantum channels and predicting their properties for future applications.

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“…(9) for P (α) = δ(α − α 0 ). For a binary outcome, K + 1 = 2, we retrieve a binomial distribution [9,77], which applies, for example, to avalanche photodiodes in the Geiger mode [47,51,73] or superconducting nanowire detectors [29,78].…”

Section: E Discussionmentioning

confidence: 99%

Identification of nonclassical properties of light with multiplexing layouts

et al. 2017

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In Sperling et al. [Phys. Rev. Lett. 118, 163602 (2017)], we introduced and applied a detector-independent method to uncover nonclassicality. Here, we extend those techniques and give more details on the performed analysis. We derive a general theory of the positive-operator-valued measure that describes multiplexing layouts with arbitrary detectors. From the resulting quantum version of a multinomial statistics, we infer nonclassicality probes based on a matrix of normally ordered moments. We discuss these criteria and apply the theory to our data which are measured with superconducting transition-edge sensors. Our experiment produces heralded multiphoton states from a parametric down-conversion light source. We show that the known notions of sub-Poisson and sub-binomial light can be deduced from our general approach, and we establish the concept of sub-multinomial light, which is shown to outperform the former two concepts of nonclassicality for our data.

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Direct calibration of click-counting detectors

Cited by 27 publications

References 59 publications

Quantum teleportation through atmospheric channels

Quantum teleportation through atmospheric channels

Probing free-space quantum channels with laboratory-based experiments

Identification of nonclassical properties of light with multiplexing layouts

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