Francesco Santagiustina | Università degli Studi di Padova (original) (raw)

Papers by Francesco Santagiustina

Dual capacity regions of the MAC and BC for two-users [7]. . 2.4 Expectation and variance of the ... more Dual capacity regions of the MAC and BC for two-users [7]. . 2.4 Expectation and variance of the maximum gain among K users 2.5 Expectation and variance of the maximum rate among K users 3.1 Average sum rate of the different linear precoding methods for K = 4 users as a function of the average SNR [8].. .. .. .. 3.2 Geometrical representation of the optimal, ZF and MRT transmit vectors with respect to the channel vectors [8]. .. .. .. 3.3 Block diagram of a RF chain connected to a phased array [9]. 3.4 Fully connected hybrid beamforming architecture [10]. .. .. 3.5 Féjer kernel of order 10, note zeros at multiples of 2 M. .. .. 4.1 Scheme of superposition coding combined to beamforming [11]

arXiv (Cornell University), Feb 13, 2023

Time-bin (TB) and energy-time (ET) entanglement are crucial resources for long-distance quantum i... more Time-bin (TB) and energy-time (ET) entanglement are crucial resources for long-distance quantum information processing. Recently, major efforts have been made to produce compact highquality sources of TB/ET entangled photons based on solid-state integrated technologies. However, these attempts failed to close the so-called "post-selection loophole". Here, we present an integrated photonic general Bell-test chip for genuine (i.e., free of the post-selection loophole) TB and ET entanglement certification. We report a violation of a Bell inequality by more than 10 standard deviations using our device based on the "hug" interferometric scheme. The experiment also demonstrates that the hug scheme, previously exploited for ET entanglement, can also be used for genuine TB entanglement.

Quantum 2.0 Conference and Exhibition, 2022

We present an FPGA-based, dual core system able to continuously operate with a true randomness so... more We present an FPGA-based, dual core system able to continuously operate with a true randomness source that fully provides the information to encode the qubits for a Quantum Key Distribution transmitter without expansion algorithms.

Quantum key distribution (QKD) is one of the most mature among the quantum technologies that allo... more Quantum key distribution (QKD) is one of the most mature among the quantum technologies that allows two remote users to generate secret keys with unconditional security. To increase its adoption, simple, low-cost, and robust systems are necessary, together with demonstrations in real environments. Here, we present a QKD field-trial over optical fibers deployed in the city center of Padua, Italy. Our system exploits two key technologies developed by our group: a low-error, self-stabilized polarization encoder, called iPOGNAC, and a novel synchronization technique, called Qubit4Sync, which allows us to minimize the experimental complexity of our system.

Journal of Lightwave Technology, Mar 15, 2022

Current technological progress is driving Quantum Key Distribution towards a commercial and world... more Current technological progress is driving Quantum Key Distribution towards a commercial and worldwide scale expansion. Its capability to deliver unconditionally secure communication will be a fundamental feature in the next generations of telecommunication networks. Nevertheless, demonstrations of QKD implementation in a real operating scenario and their coexistence with the classical telecom infrastructure are of fundamental importance for reliable exploitation. Here we present a Quantum Key Distribution application implemented over a classical fiber-based infrastructure. By exploiting just a single fiber cable for both the quantum and the classical channel and by using a simplified receiver scheme with just one single-photon detector, we demonstrate the feasibility of low-cost and ready-to-use Quantum Key Distribution systems compatible with standard classical infrastructure.

arXiv (Cornell University), Feb 13, 2023

Quantum 2.0 Conference and Exhibition

We present an FPGA-based, dual core system able to continuously operate with a true randomness so... more We present an FPGA-based, dual core system able to continuously operate with a true randomness source that fully provides the information to encode the qubits for a Quantum Key Distribution transmitter without expansion algorithms.

Quantum Computing, Communication, and Simulation II

Field-trials are of key importance for novel technologies seeking commercialization and wide-spre... more Field-trials are of key importance for novel technologies seeking commercialization and wide-spread adoption. This is certainly also the case for Quantum Key Distribution (QKD), which allows distant parties to distill a secret key with unconditional security. Typically, QKD demonstrations over urban infrastructures require complex stabilization and synchronization systems to maintain a low Quantum Bit Error (QBER) and high secret key rates over time. Here we present a field-trial which exploits a low-complexity self-stabilized hardware and a novel synchronization technique, to perform QKD over optical fibers deployed in the city center of Padua, Italy. In particular, two techniques recently introduced by our research group are evaluated in a real-world environment: the iPOGNAC polarization encoder was used for the preparation of the quantum states, while the temporal synchronization was performed using the Qubit4Sync algorithm. The results here presented demonstrate the validity and...

This work presents a hardware and software architecture which can be used in those systems that i... more This work presents a hardware and software architecture which can be used in those systems that implement practical Quantum Key Distribution (QKD) and Quantum Random Number Generation (QRNG) schemes. This architecture fully exploits the capability of a System-on-a-Chip (SoC) which comprehends both a Field Programmable Gate Array (FPGA) and a dual core CPU unit. By assigning the time-related tasks to the FPGA and the management to the CPU, we built a flexible system with optimized resource sharing on a commercial off-the-shelf (COTS) evaluation board which includes a SoC. Furthermore, by changing the dataflow direction, the versatile system architecture can be exploited as a QKD transmitter, QKD receiver and QRNG control-acquiring unit. Finally, we exploited the dual core functionality and realized a concurrent stream device to implement a practical QKD transmitter where one core continuously receives fresh data at a sustained rate from an external QRNG source while the other operate...

ArXiv, 2021

Andrea Stanco1,∗, Francesco B. L. Santagiustina1,2, Luca Calderaro1 Marco Avesani1, Tommaso Berta... more Andrea Stanco1,∗, Francesco B. L. Santagiustina1,2, Luca Calderaro1 Marco Avesani1, Tommaso Bertapelle1, Daniele Dequal3, Giuseppe Vallone1,4 and Paolo Villoresi1 Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Padova, via Gradenigo 6B, 35131 Padova, Italy Dipartimento di Matematica ”Tullio Leci-Civita”, Università degli Studi di Padova, Via Trieste 63, 35121 Padova, Italy Unità Telecomunicazioni e Navigazione, Agenzia Spaziale Italiana, contrada Terlecchia s.n.c., Matera, Italy Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy

Marco Avesani,1, ∗ Giulio Foletto,1, ∗ Matteo Padovan,1, ∗ Luca Calderaro,1, † Costantino Agnesi,... more Marco Avesani,1, ∗ Giulio Foletto,1, ∗ Matteo Padovan,1, ∗ Luca Calderaro,1, † Costantino Agnesi,1 Elisa Bazzani,1 Federico Berra,1 Tommaso Bertapelle,1 Francesco Picciariello,1 Francesco B.L. Santagiustina,1 Davide Scalcon,1 Alessia Scriminich,1 Andrea Stanco,1 Francesco Vedovato,1 Giuseppe Vallone,1, 2, 3 and Paolo Villoresi1, 3 1Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Padova, via Gradenigo 6B, IT-35131 Padova, Italy 2Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, via Marzolo 8, IT-35131 Padova, Italy 3Padua Quantum Technologies Research Center, Università degli Studi di Padova, via Gradenigo 6B, IT-35131 Padova, Italy

Cellular communications exploiting the mmWaves frequency range are com- ing within our technologi... more Cellular communications exploiting the mmWaves frequency range are com- ing within our technological reach. However the specificities of propagation at these frequencies calls for new transmission schemes. Concerning the downlink there are signs that opportunistic beamforming may be an effec- tive solution. This thesis aims to show that in mmWaves channels, schemes based on randomly-directional beamforming allow to harness both the spatial multiplexing and multiuser diversity characterizing the broadcast channel by using only limited feedback and a simple transmitter architecture. It is well- known that performances of random beamforming schemes become optimal when the number of users tends to infinity. Hence, the number of necessary users with respect to the number of transmitting antennas is investigated and the necessity of a linear relation between the two is confirmed. Opportunis- tic beamforming is furthermore analysed under the aspect of fairness. The possibility to combine i...

Optical Fiber Communication Conference (OFC) 2021

We describe a novel low-error and calibration-free polarization encoder for Quantum Key Distribut... more We describe a novel low-error and calibration-free polarization encoder for Quantum Key Distribution, called iPOGNAC. The device, together with the Qubit4Sync synchronization, has been used to realize a resource-effective QKD field-trial in Padua, Italy.

Dual capacity regions of the MAC and BC for two-users [7]. . 2.4 Expectation and variance of the ... more Dual capacity regions of the MAC and BC for two-users [7]. . 2.4 Expectation and variance of the maximum gain among K users 2.5 Expectation and variance of the maximum rate among K users 3.1 Average sum rate of the different linear precoding methods for K = 4 users as a function of the average SNR [8].. .. .. .. 3.2 Geometrical representation of the optimal, ZF and MRT transmit vectors with respect to the channel vectors [8]. .. .. .. 3.3 Block diagram of a RF chain connected to a phased array [9]. 3.4 Fully connected hybrid beamforming architecture [10]. .. .. 3.5 Féjer kernel of order 10, note zeros at multiples of 2 M. .. .. 4.1 Scheme of superposition coding combined to beamforming [11]

arXiv (Cornell University), Feb 13, 2023

Time-bin (TB) and energy-time (ET) entanglement are crucial resources for long-distance quantum i... more Time-bin (TB) and energy-time (ET) entanglement are crucial resources for long-distance quantum information processing. Recently, major efforts have been made to produce compact highquality sources of TB/ET entangled photons based on solid-state integrated technologies. However, these attempts failed to close the so-called "post-selection loophole". Here, we present an integrated photonic general Bell-test chip for genuine (i.e., free of the post-selection loophole) TB and ET entanglement certification. We report a violation of a Bell inequality by more than 10 standard deviations using our device based on the "hug" interferometric scheme. The experiment also demonstrates that the hug scheme, previously exploited for ET entanglement, can also be used for genuine TB entanglement.

Quantum 2.0 Conference and Exhibition, 2022

We present an FPGA-based, dual core system able to continuously operate with a true randomness so... more We present an FPGA-based, dual core system able to continuously operate with a true randomness source that fully provides the information to encode the qubits for a Quantum Key Distribution transmitter without expansion algorithms.

Quantum key distribution (QKD) is one of the most mature among the quantum technologies that allo... more Quantum key distribution (QKD) is one of the most mature among the quantum technologies that allows two remote users to generate secret keys with unconditional security. To increase its adoption, simple, low-cost, and robust systems are necessary, together with demonstrations in real environments. Here, we present a QKD field-trial over optical fibers deployed in the city center of Padua, Italy. Our system exploits two key technologies developed by our group: a low-error, self-stabilized polarization encoder, called iPOGNAC, and a novel synchronization technique, called Qubit4Sync, which allows us to minimize the experimental complexity of our system.

Journal of Lightwave Technology, Mar 15, 2022

Current technological progress is driving Quantum Key Distribution towards a commercial and world... more Current technological progress is driving Quantum Key Distribution towards a commercial and worldwide scale expansion. Its capability to deliver unconditionally secure communication will be a fundamental feature in the next generations of telecommunication networks. Nevertheless, demonstrations of QKD implementation in a real operating scenario and their coexistence with the classical telecom infrastructure are of fundamental importance for reliable exploitation. Here we present a Quantum Key Distribution application implemented over a classical fiber-based infrastructure. By exploiting just a single fiber cable for both the quantum and the classical channel and by using a simplified receiver scheme with just one single-photon detector, we demonstrate the feasibility of low-cost and ready-to-use Quantum Key Distribution systems compatible with standard classical infrastructure.

arXiv (Cornell University), Feb 13, 2023

Quantum 2.0 Conference and Exhibition

We present an FPGA-based, dual core system able to continuously operate with a true randomness so... more We present an FPGA-based, dual core system able to continuously operate with a true randomness source that fully provides the information to encode the qubits for a Quantum Key Distribution transmitter without expansion algorithms.

Quantum Computing, Communication, and Simulation II

Field-trials are of key importance for novel technologies seeking commercialization and wide-spre... more Field-trials are of key importance for novel technologies seeking commercialization and wide-spread adoption. This is certainly also the case for Quantum Key Distribution (QKD), which allows distant parties to distill a secret key with unconditional security. Typically, QKD demonstrations over urban infrastructures require complex stabilization and synchronization systems to maintain a low Quantum Bit Error (QBER) and high secret key rates over time. Here we present a field-trial which exploits a low-complexity self-stabilized hardware and a novel synchronization technique, to perform QKD over optical fibers deployed in the city center of Padua, Italy. In particular, two techniques recently introduced by our research group are evaluated in a real-world environment: the iPOGNAC polarization encoder was used for the preparation of the quantum states, while the temporal synchronization was performed using the Qubit4Sync algorithm. The results here presented demonstrate the validity and...

This work presents a hardware and software architecture which can be used in those systems that i... more This work presents a hardware and software architecture which can be used in those systems that implement practical Quantum Key Distribution (QKD) and Quantum Random Number Generation (QRNG) schemes. This architecture fully exploits the capability of a System-on-a-Chip (SoC) which comprehends both a Field Programmable Gate Array (FPGA) and a dual core CPU unit. By assigning the time-related tasks to the FPGA and the management to the CPU, we built a flexible system with optimized resource sharing on a commercial off-the-shelf (COTS) evaluation board which includes a SoC. Furthermore, by changing the dataflow direction, the versatile system architecture can be exploited as a QKD transmitter, QKD receiver and QRNG control-acquiring unit. Finally, we exploited the dual core functionality and realized a concurrent stream device to implement a practical QKD transmitter where one core continuously receives fresh data at a sustained rate from an external QRNG source while the other operate...

ArXiv, 2021

Andrea Stanco1,∗, Francesco B. L. Santagiustina1,2, Luca Calderaro1 Marco Avesani1, Tommaso Berta... more Andrea Stanco1,∗, Francesco B. L. Santagiustina1,2, Luca Calderaro1 Marco Avesani1, Tommaso Bertapelle1, Daniele Dequal3, Giuseppe Vallone1,4 and Paolo Villoresi1 Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Padova, via Gradenigo 6B, 35131 Padova, Italy Dipartimento di Matematica ”Tullio Leci-Civita”, Università degli Studi di Padova, Via Trieste 63, 35121 Padova, Italy Unità Telecomunicazioni e Navigazione, Agenzia Spaziale Italiana, contrada Terlecchia s.n.c., Matera, Italy Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy

Marco Avesani,1, ∗ Giulio Foletto,1, ∗ Matteo Padovan,1, ∗ Luca Calderaro,1, † Costantino Agnesi,... more Marco Avesani,1, ∗ Giulio Foletto,1, ∗ Matteo Padovan,1, ∗ Luca Calderaro,1, † Costantino Agnesi,1 Elisa Bazzani,1 Federico Berra,1 Tommaso Bertapelle,1 Francesco Picciariello,1 Francesco B.L. Santagiustina,1 Davide Scalcon,1 Alessia Scriminich,1 Andrea Stanco,1 Francesco Vedovato,1 Giuseppe Vallone,1, 2, 3 and Paolo Villoresi1, 3 1Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Padova, via Gradenigo 6B, IT-35131 Padova, Italy 2Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, via Marzolo 8, IT-35131 Padova, Italy 3Padua Quantum Technologies Research Center, Università degli Studi di Padova, via Gradenigo 6B, IT-35131 Padova, Italy

Cellular communications exploiting the mmWaves frequency range are com- ing within our technologi... more Cellular communications exploiting the mmWaves frequency range are com- ing within our technological reach. However the specificities of propagation at these frequencies calls for new transmission schemes. Concerning the downlink there are signs that opportunistic beamforming may be an effec- tive solution. This thesis aims to show that in mmWaves channels, schemes based on randomly-directional beamforming allow to harness both the spatial multiplexing and multiuser diversity characterizing the broadcast channel by using only limited feedback and a simple transmitter architecture. It is well- known that performances of random beamforming schemes become optimal when the number of users tends to infinity. Hence, the number of necessary users with respect to the number of transmitting antennas is investigated and the necessity of a linear relation between the two is confirmed. Opportunis- tic beamforming is furthermore analysed under the aspect of fairness. The possibility to combine i...

Optical Fiber Communication Conference (OFC) 2021

We describe a novel low-error and calibration-free polarization encoder for Quantum Key Distribut... more We describe a novel low-error and calibration-free polarization encoder for Quantum Key Distribution, called iPOGNAC. The device, together with the Qubit4Sync synchronization, has been used to realize a resource-effective QKD field-trial in Padua, Italy.