Criticality and Phase Diagram of Classical and Quantum Long-Range Systems

Andrea Trombettoni

(University of Trieste)

Several recent experiments in atomic, molecular and optical systems motivated a huge interest in the study of quantum long-range spin systems. The goal of the talk is to present a general description of their critical behavior and phases, devising a treatment valid in d dimensions with an exponent d+σ for the power-law decay of the couplings in the presence of an O(N) symmetry. I will first start by reminding results on classical long-range systems. Then, by introducing a convenient ansatz for the effective action, one can determine the phase diagram for the N-component quantum rotor model with long-range interactions, with N=1 corresponding to the Ising model. The phase diagram in the σ− d plan shows a non trivial dependence on σ. As a consequence of the fact that the model is quantum, the correlation functions are genuinely strongly anisotropic in the spatial and time coordinates for σ smaller than a critical value and in this region the isotropy is not restored even at the criticality. Results for the correlation length exponent & the dynamical critical exponent and a comparison with numerical findings for them are presented.

Description of the research activity of my group

Andrea Trombettoni

(University of Trieste)

The research activity of Andrea Trombettoni currently focuses on the use of ultracold atoms for quantum simulations and quantum devices. Starting from the modelization of ultracold atoms in optical lattices, the group works on the determination of the effects of temperature, interaction, noise and coupling with other quantum systems on the performance of quantum devices such as ultracold Josephson junctions and quantum interferometers, and on the design of new quantum simulation schemes. The role of long-range interactions as useful tool to control the properties of ultracold quantum devices and in quantum simulations is as well investigated.

An Entire Nuclear Quantum Optics Lab inside a Fiber

Devang Sumantrai Naik

（LP2N Institut d’Optique d’Aquitaine）

Laboratory-based quantum sensors (clocks, accelerometers, gyroscopes, magnetometers) feature performances hardly beaten in terms of precision, accuracy and stability. This is highlighted by the high profile accorded to compact atomic clocks, gravimeters and magnetometers at the major international metrology institutions. Despite two-decades long efforts, these phenomenal instruments are hardly operated outside dedicated laboratories with their physical footprint being the size of a room and requiring complex optical and ultra-high vacuum (UHV) setups as the quantum sensors, i.e. individual atoms, work at their best in vacuum and cooled to micro-kelvin temperatures. Nowadays, atom-based commercial sensors of accelerations can be utilized to map local variations of gravity relevant for geodesy (oceans currents, magma flows, ice thickness) as well as for mineral, oil and archaeological explorations, but these sophisticated instruments, produced by a few companies worldwide, are still bulky and expensive, with unit prices in the range of € 1 million. I propose replacing the bulky and fragile vacuum setups with hollow-core photonic crystal fibers (HCPCF) filled with atomic vapours and hermetically sealed, coined Photonic Microcell (PMC). The result is a highly versatile atomic and photonic component for it is both an optical fiber, and an atomic system whose quantum functionality can be engineered via fiber-coupled light allowing for unprecedented atom-light interactions. In a leap, the size of the sensor head will be reduced from 1000 cm3 to 0.1 cm3, with a volume gain of 4 orders of magnitude, and the additional benefit of the wave-guide providing versatile modes to spatially structure the light field. By confining the atoms together with light over modal areas of as small as a few , whilst keeping them in interaction over length scales a million times longer than the Rayleigh range, the best of two worlds can be achieved: an unprecedented gas phase-laser interaction efficiency and friendly compactness. Granting strong coupling between atoms and light, the envisioned technology will open the possibility for future sensors to operate with Heisenberg scaling, i.e. scaling as 1/N with respect to either atom and/or photon number N, in place of the standard quantum limit 1/ . Importantly, the hollow-core fiber technology, being passive, will reduce the power consumption of atom-based sensors, further facilitating their use in real-world applications.

Research Activity - Atom Photonics: My research activity centers on merging the fields of ultra-cold atomic physics with hollow-core fibers to create the next generation of atomic technologies that are minituarized, portable and all-fibered. In the past my work was focused on degenerat quantum gases cooled down to 10s of nK inside large vacuum system. These ultra-cold atoms were mainly used in quantum simulation (Bose-Hubbard Model and Superradiance) and quantum sensing (gravitational and magnetic sensing). The university of Limoges is a world leader in hollow-core fiber technology. Together we have won an EU FET-Open grant that has allowed us found the Quantum Technologies division at GLOPhotonics and CNRS. The main goal is to bring quantum sensing and quantum simulation to the everyday commercial world by creating techniques to fill hollow-core fiber with various atoms and cool and probe these atoms inside the hollow-core fiber. By using the light guidance properties of the fiber with the optical cooling strategies developed with my previous groups, I plan to surpass the enhanced atom-light interactions in cavity QED without the need for complex cavity overhead leading to protable, turn-key atomic technologies. We focus now on quantum simulation of superradiance, quantum magnetometry, and nuclear quantum optics. My works are international collaborations between various EU countries and the US and I would love to extend my collaborations to China.

Generalized spin squeezing with limited measurements

Irene García Martínez

(Universitat de València)

An important and widely used tool in quantum metrology is the spin squeezing parameter. Its development was mainly motivated by two applications: the improvement of precision measurements beyond the classical limit and the study of particle correlations and entanglement [1]. In quantum metrology, the spin squeezing parameter determines the sensitivity that can be achieved through the measurement of a fixed, possibly suboptimal observable. It therefore determines a lower bound on the quantum Fisher information, which expresses the maximal sensitivity achievable with an optimal observable.

However, these sensitivities can only be achieved for an asymptotically large number of measurements. Since these are a limited resource, it is crucial to explore precision bounds in the low data regime. Guided by the recently derived hierarchy of quantum metrology bounds [2], we investigate approximations to generalized quantum information functions beyond the Fisher information that are of relevance in the presence of low data. We present a family of generalized bounds that includes the relation between standard spin squeezing and Fisher information as a particular case.

Our generalized spin squeezing type of bounds are analytically derived from averages and variances of arbitrary measurement observables. We study the families of quantum bounds that may involve higher-order derivatives (Bhattacharyya) and others that avoid the use of differentials altogether (Barankin), as well as combinations of both of them (Hybrid).

We derive analytical expressions for the bounds and for the coefficients that optimize them. For a single qubit, the derived generalized bounds show saturation (see Fig. 1).

Figure 1: Comparison of the generalized spin squeezing bounds and the generalized quantum information functions that include the Fisher information as a special case. All three families saturate the bound for all values of the single free parameter λ. The Bhattacharyya type of bound coincides with the quantum Cramér-Rao bound for all λ, while the other bounds recover it as λ→ 0.

Reference

[1] L. Pezzè et al., Quantum metrology with nonclassical states of atomic ensembles, Rev. Mod. Phys. 90, 035005 (2018)

[2] M. Gessner and A. Smerzi, Hierarchies of Frequentist Bounds for Quantum Metrology: From Cramér-Rao to Barankin, Phys. Rev. Lett. 130, 260801 (2023).

Organic Molecules for Photonic Quantum Technologies

Maja Colautti*

(National Institute of Optics – CNR-INO, Largo E. Fermi 6, Florence, Italy; Euopean Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara 1, Sesto Fiorentino (FI), Italy)

Quantum optics and photonics have advanced applications in quantum technologies, especially in the fields of communication [1], sensing and metrology [2], computing [3], and simulation [4]. In many of these contexts, two-photon interference (TPI stands as a fundamental quantum process [5]. In terms of physical systems, different solid-state platforms provide key components in quantum photonics, as non-classical light sources [6,7], quantum-circuits [8], -sensors [9], and detectors [10], everything potentially miniaturized in integrated optical chips [8,11]. However, environmental noise significantly impacts the first-order coherence of single-photon wave packets from solid-state quantum emitters, reducing the visibility of TPI and thus affecting the quality of these quantum resources. Considering single-photon pulses from distinct emitters in particular, besides dephasing, quantum interference is sensitive to frequency fluctuations occurring on the minute-long time scale of the measurement, also known as spectral diffusion.

Molecular quantum emitters embedded in crystalline host matrices exhibit excellent photophysical properties [12-14], with bright, pure and indistinguishable emission at cryogenic temperature, and offer great potential for integration in photonic circuits [15-16]. In this work, we study the problem of TPI from distinct molecular emitters on chip, attaining and combining together the following milestones: simultaneously addressing on the same sample several single molecules operating as on-demand single-photon sources, tuning independently their relative zero-phonon line (ZPL) frequency with an all-optical approach, measuring in semi-real-time TPI from such distinct sources, and extracting information about joint properties of the photon pairs, using hence TPI as an exquisite probing tool [17]. In particular, the all-optical tuning approach is a technique recently discovered by the group [18] and based on laser-induced charge-separated states which migrate in the matrix and remain separated also after the laser is switched off, inducing a local Stark shift effect which allows to manipulate the single-emitter frequency in a controlled way and with spatial resolution at the micron-scale.
Latest results on the combination of this all-optical approach with the electric field generated by electrodes will be also presented [19]. Thanks to the anisotropy of the molecule’s polarizability and on the combination of the electric and optical approaches we can demonstrate a two-dimensional control of the local electric field which allows not only to tune the emitter’s frequency but also to sensibly suppress its spectral diffusion. These results are promising to mitigate the practical limitations on the TPI among distinct emitters via the actual control of the electrical environment at the nanoscale and to unlock the full potential of solid-state quantum emitters for a quantum advantage in photonics, where tunable sources of indistinguishable photons should be ideally available in a single chip.

Biography and Research activity

Dr. Maja Colautti is a permanent staff researcher at the National Institute of Optics (CNR-INO) in Florence, Italy, since 2023. She graduated in the University of Padua, Italy, in Experimental Physics in 2016 and finished her PhD in Atomic and Molecular Photonics in Florence in 2020. Currently, she is carrying her research alongside with several international collaborations and supervising PhD Students. Her line of research focuses on organic single-photon emitters for quantum photonic applications, with a focus on nano-fabrication strategies for the smart manipulation of light-matter interaction at the nanoscale and on quantum communication applications. The results of her research have been presented in international conferences and in PhD Schools, and published in international peer-review journals. Dr. Maja Colautti has also recently been granted as co-PI in a national EU-funded project on the development of a transportable atom-based single-photon source in the telecom for quantum communication experiments, based on nano-fabricated fiber-based optical tweezer technology. Maja Colautti is also actively involved in outreach and science dissemination activities and is expert on technology transfer in the field of photonics and quantum photonics, with past experience also in working as business developer and technology expert in a start-up developing quantum-dot single-photon sources for quantum computation.

References

[1] J. Yin, Y.-H. Li, S.-K. Liao, et al., “Entanglement-based secure quantum cryptography over 1,120 kilometres,” Nature 582, 501–505 (2020).

[2] V. Giovannetti, S. Lloyd, and L. Maccone, “Advances in quantum metrol- ogy,” Nat. Photonics 5, 222–229 (2011).

[3] J. L. O’Brien, A. Furusawa, and J. Vuckovic, “Photonic quantum technologies,” Nat. Photonics 3, 687–695 (2009).

[4] A. Aspuru-Guzik and P. Walther, “Photonic quantum simulators,” Nat. Phys. 8, 285–291 (2012).

[5] F. Bouchard, A. Sit, Y. Zhang, R. Fickler, F. M. Miatto, Y. Yao, F. Sciarrino, and E. Karimi, “Two-photon interference: the Hong–Ou–Mandel effect,” Rep. Prog. Phys. 84, 012402 (2021).

[6] I. Aharonovich, D. Englund, and M. Toth, “Solid-state single-photon emitters,” Nat. Photonics 10, 631–641 (2016).

[7] B. Lounis and M. Orrit, “Single-photon sources,” Rep. Prog. Phys. 68, 1129–1179 (2005).

[8] A. Politi, M. J. Cryan, J. G. Rarity, S. Yu, and J. L. O’Brien, “Silica- on-silicon waveguide quantum circuits,” Science 320, 646–649 (2008).

[9] D. M. Jackson, D. A. Gangloff, J. H. Bodey, L. Zaporski, C. Bachorz, E. Clarke, M. Hugues, C. Le Gall, and M. Atatüre, “Quantum sensing of a coherent single spin excitation in a nuclear ensemble,” Nat. Phys. 17, 585–590 (2021).

[10] W. Pernice, C. Schuck, O. Minaeva, M. Li, G. Goltsman, A. Sergienko, and H. Tang, “High-speed and high-efficiency travelling wave single- photon detectors embedded in nanophotonic circuits,” Nat. Commun. 3, 1325 (2012).

[11] P. Lodahl, S. Mahmoodian, and S. Stobbe, “Interfacing single photons and single quantum dots with photonic nanostructures,” Rev. Mod. Phys. 87, 347–400 (2015).

[12] S. Pazzagli, P. Lombardi, D. Martella, M. Colautti, B. Tiribilli, F. S. Cataliotti, and C. Toninelli, “Self-assembled nanocrystals of polycyclic aromatic hydrocarbons show photostable single-photon emission,” ACS Nano 12, 4295–4303 (2018).

[13] P. Lombardi, M. Colautti, R. Duquennoy, G. Murtaza, P. Majumder, and C. Toninelli, “Triggered emission of indistinguishable photons from an organic dye molecule,” Appl. Phys. Lett. 118, 204002 (2021).

[14] C. Toninelli, I. Gerhardt, A. S. Clark, A. Reserbat-Plantey, S. Götzinger, Z. Ristanovic,M.Colautti,P.Lombardi,K.D.Major,I.Deperasin ́ska,W.H. Pernice, F. H. L. Koppens, B. Kozankiewicz, A. Gourdon, V. Sandoghdar, and M. Orrit, “Single organic molecules for photonic quantum technolo- gies,” Nat. Mater. 20, 1615–1628 (2021).

[15] M. Colautti, P. Lombardi, M. Trapuzzano, F. S. Piccioli, S. Pazzagli, B. Tiribilli, S. Nocentini, F. S. Cataliotti, D. S. Wiersma, and C. Toninelli, “A 3D polymeric platform for photonic quantum technologies,” Adv. Quantum Technol. 3, 2000004 (2020).

[16] P. Lombardi, A. P. Ovvyan, S. Pazzagli, G. Mazzamuto, G. Kewes, O. Neitzke, N. Gruhler, O. Benson, W. H. P. Pernice, F. S. Cataliotti, and C. Toninelli, “Photostable molecules on chip: integrated sources of nonclassical light,” ACS Photon. 5, 126–132 (2017).

[17] Rocco Duquennoy, Maja Colautti, Ramin Emadi, Prosenjit Majumder, Pietro Lombardi, and Costanza Toninelli, "Real-time two-photon interference from distinct molecules on the same chip," Optica 9, 731-737 (2022).

[18] M.Colautti,F.S.Piccioli,Z.Ristanovic ́,P.Lombardi,A.Moradi,S. Adhikari, I. Deperasinska, B. Kozankiewicz, M. Orrit, and C. Toninelli, “Laser-induced frequency tuning of Fourier-limited single-molecule emitters,” ACS Nano 14, 13584–13592 (2020).

[19] R. Duquennoy et al., to be submitted soon.

A Quantum Toolbox for Neurobiology Sensory Systems

Marilù Chiofalo

(Department of Physics, University of Pisa and INFN-Pisa)

The quantum-like paradigm has emerged over the last decade to describe non-linear, dynamical, complex phenomena using quantum mechanics as a tool. In essence, it takes advantage of the linearity of quantum information processing, allowing for complex correlations through entanglement.

In a quantum- and neuroscience truly interdisciplinary research in collaboration with the neuroscientist's group of Concetta Morrone, we found that an open quantum spin network, mapping a neural system, can simulate the human sense of number as a global dynamical property. This numerosity perception ability is ubiquitous and challenging to be simulated, since its only about 15% error-rate is proportional to the number of perceived items (up to 200), known as Weber's law, while the items uncertainty is Poissonian. Our quantum model succeeded well, in contrast with the poor performance of conventional Artificial Neural Networks. Here, we aim to extend the simulation to other important complex perceptual phenomena like the perception of space, time, and numbers. It is well known that perturbing one of these perceptual dimensions will alter the others, suggesting that a shared neuronal mechanism is operating in the brain.

Based on this research, in this talk I will discuss the potential of a new research program, named QoolNeSS, aimed at creating a quantum toolbox to simulate this integrated space-time-number sensory ability of our brain, with open-quantum systems methods. We will explore the implications of more general quantum-matter paradigms, and their possible coding into a quantum technology.

Brief description of the research-group activity

My way in research is imprinted by a substantial interdisciplinary, international, and collaborative character, and the conduction of the group by setting up inclusive environments, no matter how complex they are. My research now focuses on conceiving and engineering quantum technologies - mainly in quantum gases platforms - by means of quantum theoretical and simulation methods, along three directions:

A. Quantum simulators for condensed matter or fundamental physics, biology and neurobiology, also within the driven-dissipative open quantum systems framework. Examples of current investigated problems are: the QoolNeSS program (see proposed talk) in collaboration with Concetta Morrone; the BCS-BEC crossover; out-of-equilibrium superfluidity in optical cavities in collaboration with Andrew Daley (Oxford, UK); quantum phases of trapped ions systems in collaboration with Vladan Vuletic (MIT) and Giovanna Morigi (Saarbrucken University); analogue gravity and black holes in collaboration with Massimo Mannarelli (LNGS), Dario Grasso (INFN) and Stefano Liberati (SISSA), quantum time in collaboration with Nicola Pranzini and Sabrina Maniscalco (Helsinki). I recently started a program on quantum computing for biological systems within NEXT-Gen EU funded Italian Center for Quantum Computing, also being the PI of a EU-PON funded RTDA grant, and I'm part of ELLIS- European Lab for Learning&Intelligent Systems.

B. Quantum metrology, also contributing to the cross-disciplinary and international networks AEDGE (Atomic Experiments for Dark Matter and Gravity Exploration in Space) and STE-QUEST (Space Time Explorer and QUantum Equivalence principle Space Test) aimed at designing a roadmap for tests of general relativity and foundations of quantum mechanics either in space or - more recently - with terrestrial very-long baseline atomic interferometers. In addition, I dedicate some time as internal reviewer in the VIRGO-LIGO collaboration.

C. Physics Education and Physics Outreach Research, the latter being a field that I have initiated, with special attention to research-based methods and tools for effective quantum physics training aimed at school teachers and education aimed at general public and school-students. In this context, I've co-coordinated the pilot project Quantum Technology Education for Everyone (QUTE4E) for the European Quantum Flagship and I'm part of the European project DIGIQ -Digitally-Enhanced Master in Quantum Technologies.

The above research interests are well represented by the following selected more recent publications:

References

[1] J. Yago Malo, L. Lepori, L. Gentini, and M. Chiofalo, Atomic Quantum Technologies for Quantum Matter and Fundamental Physics Applications, Technologies 12(5), 64 (2024).

[2] A. Civolani, V. Stanzione, M. Chiofalo and J. Yago Malo, Engineering Transport via Collisional Noise: a Toolbox for Biology Systems, Entropy 26(1), 20 (2024).

[3] S. Abend et al. (AEDGE coll.), Terrestrial Very-Long-Baseline Atom Interferometry: Workshop Summary, AVS QUANTUM SCIENCE 6(2), 24701 (2024).

[4] M. Chiofalo, D. Grasso, M. Mannarelli and S. Trabucco, Dissipative processes at the acoustic horizon, New Journal of Physics (in press).

[5] J. Yago Malo, M. Cicchini, C. Morrone and M Chiofalo, Quantum spin models for numerosity perception, PLOS ONE 18(4), e0284610 (2023) .

[6] M. L. Chiofalo, C. Foti, M. Michelini, L. Santi, A. Stefanel, Games for Teaching/Learning Quantum Mechanics: A Pilot Study with High-School Students, Education Sciences 12(7), 446 (2022).

[7] S. Goorney, C. Foti, L. Santi, J. Sherson, J. Yago Malo and M. Chiofalo, Culturo-scientific storytelling, Education Sciences 12(7), 474 (2022).

Quantum optics with acoustic phonons

Matteo Fadel

（ETH Zürich, Switzerland）

High-overtone bulk acoustic wave resonators are emerging as a new platform for hybrid quantum technologies. Compared to microwave cavities, acoustic resonators host a high density of long-lived modes, making them suitable for hardware-efficient quantum memories and quantum information processors. Moreover, acoustic modes with large effective mass could be useful for performing fundamental tests of quantum mechanics. To unlock these applications, a sophisticated toolbox for preparing, controlling, and measuring acoustic resonators in the quantum regime needs to be developed. In my presentation, I will present our most recent results on preparing mechanical Schrödinger cat states, one- and two-mode squeezed states, and show the realisation of a gaussian boson sampler with phonons.

Group interests: Our research interests focus on using acoustic resonators coupled to superconducting qubits as new hybrid quantum technologies for the study of quantum correlations (entanglement, EPR-steering and Bell nonlocality) in multipartite/macroscopic systems, for realising novel protocols for quantum-enhanced sensing, for bosonic quantum simulations, and for fundamental tests of quantum mechanics.

Exploring the shot-noise-level operation of mid-infrared semiconductor lasers and detection systems

Tecla Gabbrielli*

（CNR-INO – Istituto Nazionale di Ottica, Via Carrara 1 – 50019 Sesto Fiorentino FI, Italy）

The mid-infrared (MIR) spectral region, with its abundance of light molecules’ rovibrational transitions and nice transparency windows (e.g., the one spanning from 3 to 5 µm), is nowadays highly investigated for plenty of applications with a direct impact on relevant topics for modern society, such as sustainability and environmental monitoring [Del22], safety and security [Hin10], telecommunications [Sem22] and medical diagnostics [Pet01]. In this scenario, the availability of high-performance MIR laser sources, such as quantum cascade and interband cascade lasers (QCLs and ICLs), has boosted the research and technological development of plenty of applications, ranging from spectroscopy and sensing [Bor19] to communications [Cor22].

Following the demand for increasingly high-performance systems to favour the ongoing quantum revolution, the availability of shot-noise-limited or even sub-shot-noise intensity features in mid-infrared coherent sources is crucial for inaugurating a new season of high-precision MIR applications down to the standard quantum limit.

In this work, different ad-hoc MIR-balanced setups built up to measure intensity noise features down to the shot-noise level are presented. In general, these setups allow for a direct comparison between the intensity noise of the tested radiation and the shot-noise level in a wide frequency range up to 100 MHz, approximately, paving the way for unveiling possible sub-shot-noise features. In particular, we applied these setups to test different MIR state-of-the-art laser sources in single-mode and multimodal emission [Gab21, Gab24, Mar24].

Interestingly, both QCLs and ICLs also have the possibility of direct frequency comb emission. This emission regime is triggered by the third-order non-linearity of their active medium. Non-linear processes, such as the four-wave mixing happening in cascade lasers, are at the basis of many quantum experiments exploiting different photonic platforms [Mel22]. As a natural consequence, the presence of this non-linear process in these devices has encouraged their investigation from a quantum technology perspective. By adapting the developed balanced setups, we were able to measure the correlation in their multimodal frequency emission [Gab22]. This result demonstrates the robustness of the correlations triggered by the high third-order non-linearity of their waveguide, pushing MIR technological research through the development of potential laser-based chip-scale direct non-classical-light emitters.

References:

[Bor19] Borri, S., Insero, G., Santambrogio, G., Mazzotti, D., Cappelli, F., Galli, I., Galzerano, G., Marangoni, M., Laporta, P., Di Sarno, V., Santamaria, L., Maddaloni, P., and De Natale, P., “High-precision molecular spectroscopy in the mid-infrared using quantum cascade lasers,” Appl. Phys. B 125, 18 (Jan 2019).

[Cor22] Corrias, N., Gabbrielli, T., Natale, P. D., Consolino, L., and Cappelli, F., “Analog FM free-space optical communication based on a mid-infrared quantum cascade laser frequency comb,” Optics Express 30, 10217–10228 (Mar 2022).

[Del22] elli Santi, M. G., Insero, G., Bartalini, S., Cancio, P., Carcione, F., Galli, I., Giusfredi, G., Mazzotti, D., Bulgheroni, A., Martinez Ferri, A. I., Alvarez-Sarandes, R., Aldave de Las Heras, L., Rondinella, V., and De Natale, P., “Precise radiocarbon determination in radioactive waste by a laser-based spectroscopic technique,” PNAS 119(28), e2122122119 (2022).

[Gab21] Gabbrielli, T., Cappelli, F., Bruno, N., Corrias, N., Borri, S., De Natale, P., and Zavatta, A., “Mid-infrared homodyne balanced detector for quantum light characterization,” Optics Express 29(10), 14536–14547 (2021).

[Gab22] Gabbrielli, T., Bruno, N., Corrias, N., Borri, S., Consolino, L., Bertrand, M., Shahmohammadi, M., Franckié, M., Beck, M., Faist, J., Zavatta, A., Cappelli, F., and De Natale, P., “Intensity correlations in quantum cascade laser harmonic frequency combs,” Advanced Photonics Research 3(10), 2200162 (2022).

[Gab24] Gabbrielli, T., Pelini, J.; Marschick, G., Consolino, L., La Penna, I., Faist, J., Bertrand, M., Kapsalidis, F., Weih, R., Höfling, S., Akikusa, N., Hinkov, B., Cappelli, F., De Natale, P. and Borri, S. “Shot-noise limited emission from interband and quantum cascade lasers: a comparison," submitted (under peer- review).

[Hin10] Hinkov, B., Fuchs, F., Yang, Q. K., Kaster, J. M., Bronner, W., Aidam, R., Köhler, K., and Wagner, J.,

“Time-resolved spectral characteristics of external-cavity quantum cascade lasers and their application to

stand-off detection of explosives,” Appl. Phys. B Lasers Opt. 100, 253–260 (2010).

[Hin22] Hinkov, B., Pilat, F., Lux, L., Souza, P. L., David, M., Schwaighofer, A., Ristani ́c, D., Schwarz, B.,

Detz, H., Andrews, A. M., Lendl, B., and Strasser, G., “A mid-infrared lab-on-a-chip for dynamic reaction

monitoring,” Nat. Commun. 13(1), 4753 (2022).

[Mar24] Marschick, G., Pelini, J., Gabbrielli, T., Cappelli, F., Weih, R., Knötig, H., Koeth, J., Höfling, S., De Natale, P., Strasser, G., Borri, S., & Hinkov, B. “Mid-infrared Ring Interband Cascade Laser: Operation at the Standard Quantum Limit.” ACS Photonics, 11(2), 395-403 (2024).

[Mel22] Melalkia, M. F, Gabbrielli, T., Petitjean, A., Brunel, L., Zavatta, A., Tanzilli, S., Etesse, J., and D’Auria, V., "Plug-and-play generation of non-Gaussian states of light at a telecom wavelength," Opt. Express 30, 45195-45201 (2022).

[Pet01] Petrich, W., “Mid-infrared and Raman spectroscopy for medical diagnostics,” Applied Spectroscopy Reviews 36(2-3), 181–237 (2001).

[Sem22] Seminara, M., Gabbrielli, T., Corrias, N., Borri, S., Consolino, L., Meucci, M., Natale, P. D., Cappelli, F., and Catani, J., “Characterization of noise regimes in mid-IR free-space optical communication based on quantum cascade lasers,” Optics Express 30, 44640–44656 (Dec 2022).

Entanglement, Bell nonlocality and the dawn of Quantum Technologies

Julyo Smerzi

(INO-CNR, LENS, University of Florence, Italy)

• Classical and quantum entanglement

• Non-locality, realism and free will: the Bell inequality

• How flaws can advance physics: the FLASH protocol

• No-cloning theorem, teleportation and no-signalling

The aim of the course is to discuss a few building blocks of quantum information and quantum technologies. The course requires the previous knowledge of quantum mechanics and is therefore addressed to Researchers, PhD and Master students.

Bibliography:

Lecture notes

Do we really understand Quantum Mechanics?, Laloë, Cambridge (2019)

Quantum theory: concepts and methods, Peres, Kluwer (1995)

Quantum paradoxes, Aharanov and Rohrilch, Wiley (2005)

Introduction to quantum interferometry

Luca Pezzè

（INO-CNR, LENS, University of Florence, Italy）

• Basic mathematical description of a quantum interferometer: from the bosonic modes to the Schwinger formalism of angular momentum

• The Mach-Zehnder interferometer

• Frequentist and Bayesian phase estimation methods

• Sensitivity bounds: the quantum and classical Cramer-Rao bound, the standard quantum limit, the Heisenberg limit

• Phase sensitivity and entanglement.

The aim of the course is to discuss the basis of quantum interferometry by introducing key concepts and methods. The course requires the previous knowledge of quantum mechanics and is therefore addressed to Researchers, PhD and Master students.

Bibliography:

Lecture notes

L. Pezzè and A. Smerzi, arXiv:1411.5164, 2014

L. Pezzè et al. Rev. Mod Phys. 90, 035005 (2018)