Periodic Reporting for period 3 - COQCOoN (COntinuous variables Quantum COmplex Networks)
Berichtszeitraum: 2022-06-01 bis 2023-11-30
At different scales, from molecular systems to technological infrastructures, physical systems group in structures which are neither simply regular or random, but can be represented by networks with complex shape. This is the case for proteins in metabolic structures and the World Wide Web. In addition, individual elements of natural samples, like atoms or electrons, are quantum objects. The objective of this project is to theoretically study and experimentally implement complex networks with quantum features by using an all-optical platform based on non-linear optical process pumped by femtosecond lasers. This will help in simulating basic features of natural phenomena and also in optimizing future quantum technologies.
Up to the period covered by this report we have mainly worked along three lines: 1) implementing two different setups of non-linear optical process for producing multimode fields that can be arranged as complex quantum networks 2) Developing the theory of complex quantum systems in our particular framework, where the quantum effects are embedded in the continuous variables (amplitude and phase) of the electromagnetic fields. 3) Devising quantum information protocols.
On the first line: we have implemented a setup at near-infrared wavelengths for the production of quantum states of light that are multiplexed both in time and frequency. Moreover, we implemented a second experimental set-up at telecommunication wavelengths that produces states multiplexed in the frequency degree of freedom with large values of squeezing.
On the second line: we have studied, via typical complex networks measures, the complexity of the large multimode quantum states when affected by non-Gaussian operations. We have developed general theoretical tools for describing such operations and we have developed and applied an experimental technique to characterize their quantum features, Wigner negativity and entanglement properties via machine learning techniques.
On the third line: we have studied the reconfigurability of the quantum complex networks based on multimode optical resources and we have studied suitable quantum routing protocols in quantum communications tasks. We have also devised a particular quantum machine learning protocol (quantum reservoir computing) that can be implemented via our experimental resource. We have then implemented a first experimental protocol based on optical resources. We have finally implemented an experimental protocol for the simulation of quantum environment.
On the first line: we have implemented a setup at near-infrared wavelengths for the production of quantum states of light that are multiplexed both in time and frequency. Moreover, we implemented a second experimental set-up at telecommunication wavelengths that produces states multiplexed in the frequency degree of freedom with large values of squeezing.
On the second line: we have studied, via typical complex networks measures, the complexity of the large multimode quantum states when affected by non-Gaussian operations. We have developed general theoretical tools for describing such operations and we have developed and applied an experimental technique to characterize their quantum features, Wigner negativity and entanglement properties via machine learning techniques.
On the third line: we have studied the reconfigurability of the quantum complex networks based on multimode optical resources and we have studied suitable quantum routing protocols in quantum communications tasks. We have also devised a particular quantum machine learning protocol (quantum reservoir computing) that can be implemented via our experimental resource. We have then implemented a first experimental protocol based on optical resources. We have finally implemented an experimental protocol for the simulation of quantum environment.
Some of the results achieved so far are already beyond the state of the art. The experimental technique for characterizing Wigner negativity allows to process data for systems with number of components (up to 10) that couldn’t be processed with previous tomographic techniques (that allow a maximum of 3-4 components). The theoretical classification- via complex networks measures- of the large (100 components) multimode quantum states when affected by non-Gaussian operations represents a unique method for classifying such large and complex quantum states. Again, standard quantum optics techniques allow for the characterization of only few-modes (i.e. few-components) states. Also, we have revised specific protocols for quantum communication in a multiparty scenario in the continuous variable framework.
The experimental implementation of multiplexed quantum states is also already beyond the state of the art: we have implemented the first continuous variable (CV) multimode quantum state that is multiplexed both in time and frequency degree of freedom. Moreover the telecom setup demonstrated the first frequency multiplexed CV-quantum state with significant values of squeezing.
The result expected until the end of the project concerns the experimental implementation of large and totally reconfigurable CV quantum network multiplexed bot in time and frequency degree of freedom. According the actual state of the art, it can be generated large networks only involving temporal degree of freedom.
Such networks will be also furnished of specific quantum operations (that renders the probability distributions of their characteristic variables non-Gaussian) in order to device advanced protocols for quantum simulation ( simulation of quantum environment, quantum synchronization, quantum transport), for quantum information ( quantum machine learning) and quantum communication ( multiparty quantum communication at telecommunication wavelengths).
The experimental implementation of multiplexed quantum states is also already beyond the state of the art: we have implemented the first continuous variable (CV) multimode quantum state that is multiplexed both in time and frequency degree of freedom. Moreover the telecom setup demonstrated the first frequency multiplexed CV-quantum state with significant values of squeezing.
The result expected until the end of the project concerns the experimental implementation of large and totally reconfigurable CV quantum network multiplexed bot in time and frequency degree of freedom. According the actual state of the art, it can be generated large networks only involving temporal degree of freedom.
Such networks will be also furnished of specific quantum operations (that renders the probability distributions of their characteristic variables non-Gaussian) in order to device advanced protocols for quantum simulation ( simulation of quantum environment, quantum synchronization, quantum transport), for quantum information ( quantum machine learning) and quantum communication ( multiparty quantum communication at telecommunication wavelengths).