Detail Project and Funding

Abstract: Quantum noise is unavoidably present in any realistic implementation of quantum tasks, ranging from quantum communication protocols to quantum information processing devices and quantum metrology. The performance and the optimization of quantum tasks quite often depend on the level of noise which is present in the physical realization considered. It is therefore of great interest to develop experimental methods to estimate the level of noise in the system under examination as precisely as possible and design strategies that allow the optimizion of the flow of information transmitted in the presence of noise. In the most general scenario information can be transmitted by quantum states, and several notions of efficiency can be defined according to the considered task and the resource available along the transmission channel. Furthermore, to experimentally realize a quantum channel may become an extremely challenging task, because of the presence of noise. Generally, one possible way to check how well this has been performed is to make a full tomography of the process. This nevertheless is known to be very expensive in terms of the number of measurements to be performed, and, in many practical situations one is only interested to know whether it has some entangling power, in order for the channel to be useful for a specific task, such as, e.g., quantum communication. Quantum channel detection has been recently proposed as a powerful method to solve this problem.
Another important aspect is represented by quantum networking, where a given task is pursued by a lattice of local nodes sharing (possibly entangled) quantum channels, is emerging as a realistic scenario for the implementation of quantum protocols requiring medium or large registers. In this scenario, photonics is playing an important role: the high reconfigurability of photonic setups and outstanding technical improvements have facilitated the birth of a new generation of experiments that have demonstrated multiphoton quantum control towards high-fidelity computing with registers of a size inaccessible until only recently. The design of complex interferometers and the exploitation of multiple degrees of freedom of a single photonic information carrier have enabled the production of interesting states, among others Dicke state, a potentially useful resource for the implementation of protocols for distributed quantum communication such as quantum secret sharing, quantum telecloning, and open destination teleportation.

All these aspects and problems represent the essence of this project.

INO’s Experiments/Theoretical Study correlated:
Quantum light state engineering