Giorgio Milani

• Sapienza University of Rome

The exploitation of certification tools by end users represents a fundamental aspect of the development of quantum technologies as the hardware scales up beyond the regime of classical simulatability. Certifying quantum networks becomes even more crucial when the privacy of their users is exposed to malicious quantum nodes or servers as in the case...

Blind quantum computing (BQC) was only demonstrated in single-client scenarios. Here, we design a versatile multi-client BQC on a linear network and demonstrate it in a two-client setting on an adaptive photonic platform.

Universal blind quantum computing allows users with minimal quantum resources to delegate a quantum computation to a remote quantum server, while keeping intrinsically hidden input, algorithm, and outcome. State-of-art experimental demonstrations of such a protocol have only involved one client. However, an increasing number of multi-party algorith...

Universal blind quantum computing allows users with minimal quantum resources to delegate a quantum computation to a remote quantum server, while keeping intrinsically hidden input, algorithm, and outcome. State-of-art experimental demonstrations of such a protocol have only involved one client. However, an increasing number of multi-party algorith...

In a Bell experiment, it is natural to seek a causal account of correlations wherein only a common cause acts on the outcomes. For this causal structure, Bell inequality violations can be explained only if causal dependencies are modeled as intrinsically quantum. There also exists a vast landscape of causal structures beyond Bell that can witness n...

We implement triangle causal structures in photonics platforms and detect different forms of nonlocality. In particular, we focused on the Genuine Multipartite Non-locality and on the nonlocality exhibited in a network without freedom of choice.

In a Bell experiment, it is natural to seek a causal account of correlations wherein only a common cause acts on the outcomes. For this causal structure, Bell inequality violations can be explained only if causal dependencies are modelled as intrinsically quantum. There also exists a vast landscape of causal structures beyond Bell that can witness...

Since Bell’s theorem, it is known that local realism fails to explain quantum phenomena. Bell inequality violations manifestly show the incompatibility of quantum theory with classical notions of cause and effect. As recently found, however, the instrumental scenario—a pivotal tool in causal inference—allows for nonclassicality signatures going bey...

We implement a binary-variable instrumental scenario on a photonic setup. Despite no Bell-like inequality exists for this model, we detect non-classical correlations by quantifying causal influences, which allows demonstrating discrepancies between quantum and classical predictions.

Since Bell's theorem, it is known that the concept of local realism fails to explain quantum phenomena. Indeed, the violation of a Bell inequality has become a synonym of the incompatibility of quantum theory with our classical notion of cause and effect. As recently discovered, however, the instrumental scenario -- a tool of central importance in...

Using a flexible and scalable photonic platform, we implement a star-shaped quantum network with five nodes and truly independent sources, and we violate a n -locality inequality to device-independently witness nonlocal correlations in the whole network.

The incompatibility between the quantum and classical notion of causality is a well known result in quantum theory. Using a photonic platform we show that, going beyond Bell's scenario, we can detect nonclassicality even when no violation is possible, by intervening in our experimental apparatus.

The launch of a satellite capable of distributing entanglement through long distances and the first loophole-free violation of Bell inequalities are milestones indicating a clear path for the establishment of quantum networks. However, nonlocality in networks with independent entanglement sources has only been experimentally verified in simple trip...

The wave or particle duality has long been considered a fundamental signature of the nonclassical behavior of quantum phenomena, especially in a delayed choice experiment, where the experimental setup revealing either the particle or the wave nature of the system is decided after the system has entered the apparatus. However, as counterintuitive as...

We implement adaptive machine learning techniques to enhance the sensitivity in the estimation of a relative phase shift between two paths of an interferometer. The estimation is realized through single photons measured shot by shot.

Wave-particle duality has long been considered a fundamental signature of the non-classical behavior of quantum phenomena, specially in a delayed choice experiment (DCE), where the experimental setup revealing either the particle or wave nature of the system is decided after the system has entered the apparatus. However, as counter-intuitive as it...

Phase estimation protocols provide a fundamental benchmark for the field of quantum metrology. The latter represents one of the most relevant applications of quantum theory, potentially enabling the capability of measuring unknown physical parameters with improved precision over classical strategies. Within this context, most theoretical and experi...

Phase estimation protocols provide a fundamental benchmark for the field of quantum metrology. The latter represents one of the most relevant applications of quantum theory, potentially enabling the capability of measuring unknown physical parameters with improved precision over classical strategies. Within this context, most theoretical and experi...

A boson sampling device is a specialised quantum computer that solves a problem which is strongly believed to be computationally hard for classical computers. Recently a number of small-scale implementations have been reported, all based on multi-photon interference in multimode interferometers. In the hard-to-simulate regime, even validating the d...

Full characterization of quantum states and processes is a fundamental requirement for verification and benchmarking of quantum devices. It has been realized in systems with few components, but for larger systems it becomes unfeasible because of the exponential growing with the system size of the number of measurements and the amount of computation...

In the last years the attention of the scientific community on the generation of entangled states has constantly increased both for their importance in the foundation of quantum mechanics and for their application in the quantum computation and communication field. To these aims high quality of generated states is required. A standard procedure to...

We demonstrate the potentialities of a deformable mirror for closed-loop control of a two-photon path-entangled state subject to phase fluctuations. A custom-made membrane mirror is used to set a relative phase shift between the arms of an interferometric apparatus. The control algorithm estimates the phase of the quantum state by measurements of t...

We report the experimental realization of a recently discovered quantum-information protocol by Peres implying an apparent nonlocal quantum mechanical retrodiction effect. The demonstration is carried out by a quantum optical method by which each singlet entangled state is physically implemented by a two-dimensional subspace of Fock states of a mod...

The realization of the optical stochastic (or nonstationary) field interferometer (Sto-IF) is reported. By this device, whose properties are determined by those of the stochastic beam splitter (Sto-BS), relevant Bose-Einstein correlations are generated within the investigated particle field. A very general quantum theory of Sto-BS and Sto-IF is rep...