1,721,005 research outputs found
Endurance of mesoscopic twin-beam states propagating in noisy channels
No full textQuantum resources can improve the quality and security of data
transmission. Here we prove, both theoretically and experimentally, that mesoscopic twin-beam states of light are robust against loss and noise sources, thus opening new
perspectives in the implementation of Quantum Communication protocols
Preserving nonclassical correlations in strongly unbalanced conditions
No full textIt is well known that optical losses represent the main obstacle to the real exploitation of quantum optical systems for quantum technology. Here we investigate to what extent the presence of unbalanced losses between the two parties of a mesoscopic twin-beam state can prevent or not the observation of nonclassical correlations. Moreover, we focus on the survival of nonclassicality in the presence of asymmetric lossy channels modeled according to specific statistical distributions
Effect of noisy channels on the transmission of mesoscopic twin-beam states
Full text linkQuantum properties of light, which are crucial resources for quantum technologies, are quite fragile in nature and can be degraded and even concealed by the environment. We show, both theoretically and experimentally, that mesoscopic twin-beam states of light can preserve their nonclassicality even in the presence of major losses and different types of noise, thus suggesting their potential usefulness to encode information in quantum communication protocols. We develop a comprehensive general analytical model for a measurable nonclassicality criterion and find thresholds on noise and losses for the survival of entanglement in the twin beam
Thermal and superthermal noise signals as resources for underwater quantum communication
No full textQuantum technologies have opened new perspectives for enhancing communication speed and security, particularly in challenging underwater environments, where conventional protocols rely on acoustic wave propagation. In this study, we introduce an innovative communication protocol built upon the utilization of mesoscopic twin-beam (TWB) states, entangled in the number of photons, and photon-number-resolving detectors. Our approach involves transmitting information by mixing the part of TWB that propagates through water with two signals having identical mean values but different statistical distributions. Specifically, we explore the advantages and limitations associated with employing pseudothermal states and two distinct types of superthermal states in our communication protocol. Through both theoretical analysis and experimental investigation, we assess the feasibility of accurately discriminating which state has been superimposed onto the TWB by evaluating the noise reduction factor. Our findings demonstrate promis- ing outcomes, suggesting the practical implementation of this protocol in real-world underwater communication scenarios
Effects of nonideal features of silicon photomultiplier on the measurements of quantum correlations
No full textWe analyze the effects of some stochastic deviations from the ideal response in silicon photomultipliers that prove to be detrimental for the measurement of quantum properties of light. We demonstrate that an optimized operation mode can overcome some limitations of the detectors allowing the characterization of entanglement in mesoscopic twin-beam states
Conditional measurements with silicon photomultipliers
Full text linkNonclassical states of light can be efficiently generated by performing conditional measure-ments. An experimental setup including Silicon Photomultipliers can currently be implemented for this purpose. However, these devices are affected by correlated noise, the optical cross talk in the first place. Here we explore the effects of cross talk on the conditional states by suitably expanding our existing model for conditional measurements with photon-number-resolving detectors. We assess the nonclassicality of the conditional states by evaluating the Fano factor and provide experimental evidence to support our results
Hybrid discrimination strategy in quantum communication based on photon-number-resolving detectors and mesoscopic twin-beam states
Full text linkState discrimination is a key challenge in the implementation of quantum communication protocols. Most optical communication protocols rely on either coherent states of light or fragile single-photon states, making it often difficult to achieve robustness and security simultaneously. In this work, we propose a hybrid strategy that operates in the mesoscopic intensity regime, leveraging robust quantum states of light. Our approach combines classical and quantum features: reliable state discrimination based on a classical property of light, and security stemming from nonclassical correlations. Specifically, the receiver uses photon-number-resolving detectors to access the mean photon number of the binary thermal signals encoding the information. The communication channel exploits twin-beam states, inherently sensitive to eavesdropping attacks, to provide a layer of security. This strategy is scalable, allowing for straightforward extension to more complex signal alphabets, and offers a promising route for robust and secure quantum communication in the mesoscopic intensity domain
Second-harmonic generation as a source of nonclassical light
No full textWe investigate the transformation of light statistics due to a second-harmonic generation process and address a quantum perturbative approach to retrieve the moments of the output light distribution for given input light states
Photon-number statistics measured with a noncounting PMT
No full textWe measure photon-number statistics of pulsed fields containing mesoscopic photon numbers in a time duration shorter than any feasible measuring time. As the detector we use a photomultiplier tube delivering anodic outputs in whose pulse-height spectrum only the zero detected-photon peak is resolved. We demonstrate that we can reconstruct the correct detected-photon statistical distribution provided the maximum number of detected photons falls within the range of linear response of the photomultiplier tube
Statistical characterization of discrete amplitude-modulated coherent states at telecom wavelengths by means of an up-conversion-based photon-number-resolving detector
Full text linkThe successful implementation of quantum communication protocols relies on the proper encoding of information in the degrees of freedom of the employed optical states. Particular interest is devoted to amplitude-phase-shift keying coherent states, which can provide robust solutions in satellite communication systems and guarantee high values of channel capacity. In this work, we implement a sum-frequency-based photon-number-resolving detector, capable of revealing discrete amplitude modulation of coherent states produced at telecom wavelengths. The detection is performed in the visible spectral range and in the photon-number-resolving domain, thus encouraging the use of more complex alphabets in which both amplitude and phase vary
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