The simulation of open quantum dynamics has recently allowed the direct investigation features system-environment interaction and their consequences on evolution a system. Such threatens properties system, spoiling them causing phenomenon decoherence. Sometimes however coherent exchange information takes place between system environment, memory effects arise becomes non-Markovian. Here we report experimental realisation non-Markovian process where environment are coupled through simulated...

We present a novel optical device based on an integrated system of microlenses and single-mode fibers. It allows us to collect direct into many modes two photons generated by spontaneous parametric down-conversion. By this multiqubit entangled states and/or multilevel qudit photons, encoded in the longitudinal momentum degree freedom, are created. The multipath photon entanglement realized is expected find important applications modern quantum information technology.

Quantum mechanics is a nonlocal theory, but not as the no-signalling principle allows. However, there exist quantum correlations that exhibit maximal nonlocality: they are any nonsignalling correlation and thus have local content, quantified by fraction ${p}_{L}$ of events admitting description, equal to zero. We exploit known link between Kochen-Specker Bell theorems derive violation inequality from every proof. then show these inequalities lead experimental bounds on content significantly...

Decoherence is a manifestation of the coupling system with its environment. The resulting loss information can hamper functioning quantum devices, hence need understanding origin and dynamics. stem from entanglement, but it also be classical in nature. Indeed, methods have been developed to understand whether qubit-environment entanglement (QEE) actually present some important classes channels - pure dephasing. Their practicality resides fact they only require accessing qubit. In this...

Abstract Quantum sensing is a rapidly growing branch of research within the area quantum science and technology offering key resources, beyond classical ones, with potential for commercialization novel (quantum) sensors. The exploitation resources offered by photons can boost performance sensors innovative challenging applications. In this paper, we build on idea that ghost spectroscopy (QGS), i.e. counterpart in frequency domain imaging (QGI), target specific applications detection possible...

We present the experimental realization of optimal estimation protocol for a Pauli noisy channel. The method is based on generation 2-qubit Bell states and introduction quantum noise in controlled way one state subsystems. efficiency estimation, achieved by measurement, shown to outperform process tomography.

We report the experimental demonstration of two quantum networking protocols, namely $1\ensuremath{\rightarrow}3$ telecloning and open-destination teleportation, implemented using a four-qubit register whose state is encoded in high-quality two-photon hyperentangled Dicke state. The resource characterized criteria based on multipartite entanglement witnesses. explore characteristic entanglement-sharing structure by implementing high-fidelity projections onto lower-dimensional states. Our...

We report on an experimental violation of the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality using energy-time-entangled photons. The experiment is not free locality and detection loopholes but first Bell-CHSH energy-time entangled photons which postselection loophole described by Aerts et al. [Phys. Rev. Lett. 83, 2872 (1999)].

A recently introduced family of multipartite entangled states, the 4-qubit phased Dicke has been created by 2-photon hyperentanglement. Our experimental method allows high state fidelity and generation rate. By introducing quantum noise in system a controlled way, we have tested robustness these states. To this purpose entanglement resulting mixed states verified using new kind structural witness.

Assessing the presence of chemical, biological, radiological, and nuclear threats is a crucial task which usually dealt with in spectroscopic measurements by analyzing spectral features measured absorption profile. The use quantum ghost spectroscopy opens up enticing perspective to perform these remotely without compromising measurement accuracy. However, order have necessary signal-to-noise ratio, long acquisition times are typically required, hence subtracting from benefits provided remote...

Quantum interference is a central resource in many quantum-enhanced tasks, from computation to communication. While usually occurring between identical photons, it can also be enabled by performing projective measurements that render the photons indistinguishable, process known as quantum erasing. Structured light forms another hallmark of photonics, achieved manipulating degrees freedom light, and enables multitude applications both classical regimes. By combining these ideas, we design...

We present a device that exploits spatial and spectral correlations in parametric down-conversion at once. By using ghost imaging arrangement, we were able to remotely reconstruct the frequency profile of composite system. Our can detect presence distinct regions, each them characterized by different absorption. This is enabled model-independent analysis, making it possible identify component based uniquely on collected data without recurring priori information. Such an approach be...

We describe the first experimental realization of Deutsch-Jozsa quantum algorithm to evaluate properties a 2-bit boolean function in framework one-way computation. For this purpose novel two-photon six-qubit cluster state was engineered. Its peculiar topological structure is basis original measurement pattern allowing realization. The good agreement results with theoretical predictions, obtained at $\sim$1kHz success rate, demonstrate correct implementation algorithm.

We explore experimentally the space of two-qubit quantum correlated mixed states, including frontier ones as defined by use discord and von Neumann entropy. Our experimental setup is flexible enough to allow for high-quality generation a vast variety states. address quantitatively relation between recently suggested alternative measure correlations.

Frequency correlations are a versatile and powerful tool which can be exploited to perform spectral analysis of objects whose direct measurement might unfeasible. This is achieved through so-called ghost spectrometer, that implemented with quantum classical resources alike. While there some known advantages associated either choice, an their metrological capabilities has not yet been performed. Here we report on the comparison between spectrometer. We estimation transmittivity bandpass...

We experimentally demonstrate the achievement of entanglement-assisted capacity for classical information transmission over a depolarizing channel. The implementation is based on generation and local manipulation two-qubit Bell states, which are finally measured at receiver by realizing projective measurements in basis. channel realized introducing quantum noise controlled way one two qubits. This work represents an investigation into amount that can be shared presence noise.

An innovative hyperspectral LIDAR instrument has been developed for applications in marine environment monitoring research activities, remotely detecting the fluorescence spectra produced spectral interval between 400 nm and 720 nm. The detection system is composed by a custom made photomultiplier charge integrating measuring (CIM) unit, which makes automatic background signal subtraction, liquid crystal tunable filter (LCTF). new therefore resolution allows subtraction; it compact automated...

We propose a paradigmatic demonstration of the potentialities deformable mirror for closed-loop control two-photon momentum-entangled state, subject to phase fluctuations. A custom-made membrane is used set relative shift between arms an interferometric apparatus. The algorithm estimates quantum by measurements coincidence events at output ports interferometer, and uses results provide feedback signal mirror. Stabilization rate within 1.5 standard deviation Poissonian noise demonstrated over...

Starting from a four-partite photonic hyper-entangled Dicke resource, we report the full tomographic characterization of three-, two- and one-qubit states obtained by projecting out part computational register. The reduced thus correspond to fidelities with expected larger than 87%, therefore certifying faithfulness entanglement-sharing structure within original four-qubit resource. high quality three-qubit state allows for experimental verification Koashi–Winter relation monogamy...

Characterization of quantum objects, being them states, processes, or measurements, complemented by previous knowledge about is a valuable approach, especially as it leads to routine procedures for real-life components. To this end, Machine Learning algorithms have demonstrated successfully operate in presence noise, estimating specific physical parameters. Here we show that neural network (NN) can improve the tomographic estimate parameters including convolutional stage. We applied our...

Quantum Sensing is a rapidly growing branch of research within the area quantum science and technology offering key resources, beyond classical ones, with potential for commercialisation novel (quantum) sensors. The exploitation resources offered by photons can boost performance sensors innovative challenging applications. In this paper we build on idea Ghost Spectroscopy (QGS), i.e. counterpart in frequency domain Imaging (QGI), targeting specific applications detection possible threats....

Identification of chemical species using eye-safe laser pulses is becoming wide interest for both biology and security purposes. Many instruments are designed to this purpose exploiting the high selectivity sensitivity Raman spectroscopy. A pulse sent a target, its echo (usually from Stokes band) collected by some optics, dispersed analyzed detector. Being cross sections usually very small, when compliance with regulations about exposure radiations requested, each step acquisition chain must...