"8" . "Experimental observations are usually described using theoretical models that make assumptions about the dimensionality of the system under consideration. However, would it be possible to assess the dimension of a completely unknown system only from the results of measurements performed on it, without any extra assumption? The concept of a dimension witness(1-6) answers this question, as it allows bounding the dimension of an unknown system only from measurement statistics. Here, we report on the experimental demonstration of dimension witnesses in a prepare and measure scenario(6). We use photon pairs entangled in polarization and orbital angular momentum(7-9) to generate ensembles of classical and quantum states of dimensions up to 4. We then use a dimension witness to certify their dimensionality as well as their quantum nature. Our work opens newavenues in quantum information science, where dimension represents a powerful resource(10-12), especially for device-independent estimation of quantum systems(13-16) and quantum communications(17,18)."@en . . . "15310" . "000307223900008" . "GB - Spojen\u00E9 kr\u00E1lovstv\u00ED Velk\u00E9 Brit\u00E1nie a Severn\u00EDho Irska" . "1745-2473" . . "6"^^ . . "135554" . . "Experimental estimation of the dimension of classical and quantum systems"@en . . "8" . "Experimental estimation of the dimension of classical and quantum systems"@en . "4"^^ . "Experimental estimation of the dimension of classical and quantum systems" . . . "Experimental observations are usually described using theoretical models that make assumptions about the dimensionality of the system under consideration. However, would it be possible to assess the dimension of a completely unknown system only from the results of measurements performed on it, without any extra assumption? The concept of a dimension witness(1-6) answers this question, as it allows bounding the dimension of an unknown system only from measurement statistics. Here, we report on the experimental demonstration of dimension witnesses in a prepare and measure scenario(6). We use photon pairs entangled in polarization and orbital angular momentum(7-9) to generate ensembles of classical and quantum states of dimensions up to 4. We then use a dimension witness to certify their dimensionality as well as their quantum nature. Our work opens newavenues in quantum information science, where dimension represents a powerful resource(10-12), especially for device-independent estimation of quantum systems(13-16) and quantum communications(17,18)." . . "RIV/61989592:15310/12:33140470!RIV13-MSM-15310___" . "Experimental estimation of the dimension of classical and quantum systems" . . . "Z(MSM6198959213)" . "Hendrych, Martin" . . "Acin, Antonio" . "Nature Physics" . . "Torres, Juan P." . . "10.1038/NPHYS2334" . "RIV/61989592:15310/12:33140470" . "Mi\u010Duda, Michal" . "Brunner, Nicolas" . "PHOTONS; ENTANGLEMENT; BELL INEQUALITIES; ORBITAL ANGULAR-MOMENTUM"@en . . . . "1"^^ . "Gallego, Rodrigo" . "[A613745896EC]" .