Theory and Experiment

The Quantum Optics Group of INRIM performs research both experimental and theoretical, devoted to the investigation of entanglement in quantum mechanics and its application to quantum technologies, such as quantum information processing and quantum metrology. More in detail, many experiments, based on the use of entangled pairs of photons, are being performed, using the "Carlo Novero " eight laboratories (devoted to the memory of Carlo Novero, who began this activity). Among them:

1. We have carried out some experiments concerning Foundations of Quantum Mechanics. In particular, we tested specific local realistic models with Bell inequalities-like experiments. We also performed research aimed at the study of the bounds of quantum correlations. An experiment on wave-particle duality was realized with various optical states as well. This activity was done in part in collaboration with Turin University. Experiments on single-photon quantumness has been carried on in collaboration with NIST and University of Geneva. Finally, an experiment aimed at visualizing Page-Wootters emergence of time phenomenon has been realized in collaboration with Pavia and Pisa Universities.

2. We partecipated to the realization of the first Italian prototype of an entanglement based quantum cryptography link in the framework of a national research program leaded by Elsag Datamat. In this context we investigated quantum key distribution and quantum secure direct communication protocols both theoretically and experimentally based on entangled photon pairs. Furthermore, we realised QKD protocols based on orthogonal states (Goldberg-Vaidman's and controfactual ones). At the moment, we are studying both quantum communication channel (fibre/open air) effects and the realisation of innovative protocols. We participate in the ETSI work group on QKD standardization.

3. Our group also investigates absolute photodector calibration using correlated photons. Beyond studies on the traditional PDC scheme, alternative methods have been developed in collaboration with Moscow University. More recently researches dealt with the calibration of analog detectors.

4. We carried out the study of quantum states engineering, such as the realisation and characterisation of PDC sources with specific properties (also realised in microstructured materials, such as PPLN crystals and waveguides), and the study of entanglement coupling and propagation in fiber. We are also studying entanglement measures and other quantumness quantifiers of quantum optical states. Also specific investigations on peculiar properties of Gaussian states have been carried on. These activities were partially realized in collaboration with Max Planck Institute for the Science of Light and with Milan University.

5. We studied and realised single photon detection systems prototypes with reduced deadtime, exploiting multiplexing based on active optical switch (in collaboration with NIST). We worked on the characterisation of TES detectors (in collaboration with Milan University). Ancilla assisted calibration of photon-number-resolving detector characterisation has been performed in collaboration with NIST.

6. We addressed the reconstruction of photon statistic and, more recently, of the full density matrix by using on/off detectors (in collaboration with Milan and Insubria Universities). Studies on the optimality of tomographic protocols and on the tomography of POVM were realized in collaboration with Moscow and Milan Universities. A novel method for optical field modes reconstruction was developed in collaboration with NIST.

7. We performed studies on the connection between Quantum Imaging and entanglement. After having realized the first Sub-Shot-Noise Quantum Imaging experiment, we also built the first setup in which Quantum Illumination was achieved. Also activities on ghost imaging have been carried out. Now we are considering the advantages of these techniques in interferometry (e. g. for the holometer, i.e. a double Michelson interferometer aimed at testing quantum gravity). Some of these works were in collaboration with Milano University and Insubria University.

8. We realized an extremely low-noise heralded-single-photon-source (based on PPLN crystal) that does not need temporal post-selection for the emitted single-photon in collaboration with NIST and Polytechnic of Milano. Coupling enhancement of single photon sources based on impurities in diamonds by micro- and nano-structures is an on-going activity carried on in collaboration with Turin University.

9. From a theoretical point of view we worked on multidimensional QKD, application of mesons to local realism tests and quantification of quantum correlations (with Torino University, Politecnico and ISI).


Strada delle Cacce 91


Center for Artificial Intelligence and RObotics (CAIRO), Aswan University

The "Vienna Center for Quantum Science and Technology" is a joint initiative of the University of Vienna, the Vienna University of Technology, and the Austrian Academy of Sciences. It unites quantum physicists of Vienna's research institutions in one collaborative center. The VCQ will set new impulses for research and teaching in quantum science on the basis of the 2nd quantum revolution through its unique spectrum of research topics - from fundamental quantum physics to novel quantum technologies.

The VCQ combines expertise in an exceptional mix of research areas from fundamental quantum physics to new quantum technologies, i.e. technologies that rely on the application of genuine quantum effects or that enable such applications. Currently covered research areas include Matter-wave interferometry, Quantum Micromechanics, Microscale quantum optics, Cold atoms & atom chips, Many-body quantum theory, Quantum information & Foundations of physics.

The "Vienna Center for Quantum Science and Technology" is a joint initiative of the University of Vienna, the Vienna University of Technology, and the Austrian Academy of Sciences, which unites quantum physicists of Vienna's research institutions in one collaborative center. The VCQ covers fundamental quantum physics and novel quantum technologies.

The research groups comprise
Arndt Group:Quantum Nanophysics and Molecular Quantum Optics
Aspelmeyer Group: Quantum Foundations and Quantum Information on the Nano- and Microscale
Brukner Group: Quantum foundations and quantum information theory
Verstraete Group: Many-Body Quantum Theory
Walther Group: Quantum information sciences and quantum computation

Rabl Group: Quantum Optics Theory
Rauschenbeutel Group: Nano-Fiber Photonics and Quantum Optics
Schmiedmayer Group: Cold Atoms and Atom Chips
Schumm Group: Quantum-enhanced measurement and metrology

IQOQI VIENNA, Austrian Academy of SCIENCES
Ursin Group: Quantum Physics and Quantum Communication
Zeilinger Group: Quantum Information and Foundations of Physics


Boltzmanngasse 5

Research Focus: Hybrid Simulation Techniques for Experimental QKD , Hybrid Quantum - Digital Cryptography Schemes & Quantum Internet




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