Publications

@article{Sgroi2024,

title = {Efficient excitation-transfer across fully connected networks via local-energy optimization},

author = {S. Sgroi and G. Zicari and A. Imparato and M. Paternostro},

doi = {10.1140/epjqt/s40507-024-00238-w},

issn = {2196-0763},

year  = {2024},

date = {2024-12-00},

journal = {EPJ Quantum Technol.},

volume = {11},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractWe study the excitation transfer across a fully connected quantum network whose sites energies can be artificially designed. Starting from a simplified model of a broadly-studied physical system, we systematically optimize its local energies to achieve high excitation transfer for various environmental conditions, using an adaptive Gradient Descent technique and Automatic Differentiation. We show that almost perfect transfer can be achieved with and without local dephasing, provided that the dephasing rates are not too large. We investigate our solutions in terms of resilience against variations in either the network connection strengths, or size, as well as coherence losses. We highlight the different features of a dephasing-free and dephasing-driven transfer. Our work gives further insight into the interplay between coherence and dephasing effects in excitation-transfer phenomena across fully connected quantum networks. In turn, this will help designing optimal transfer in artificial open networks through the simple manipulation of local energies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Braidotti2024,

title = {Amplification of electromagnetic fields by a rotating body},

author = {M. C. Braidotti and A. Vinante and M. Cromb and A. Sandakumar and D. Faccio and H. Ulbricht},

doi = {10.1038/s41467-024-49689-w},

issn = {2041-1723},

year  = {2024},

date = {2024-12-00},

journal = {Nat Commun},

volume = {15},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractIn 1971, Zel’dovich predicted the amplification of electromagnetic (EM) waves scattered by a rotating metallic cylinder, gaining mechanical rotational energy from the body. This phenomenon was believed to be unobservable with electromagnetic fields due to technological difficulties in meeting the condition of amplification that is, the cylinder must rotate faster than the frequency of the incoming radiation. Here, we measure the amplification of an electromagnetic field, generated by a toroid LC-circuit, scattered by an aluminium cylinder spinning in the toroid gap. We show that when the Zel’dovich condition is met, the resistance induced by the cylinder becomes negative implying amplification of the incoming EM fields. These results reveal the connection between the concept of induction generators and the physics of this fundamental physics effect and open new prospects towards testing the Zel’dovich mechanism in the quantum regime, as well as related quantum friction effects.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gundhi2024,

title = {Decoherence due to the Casimir effect?},

author = {Anirudh Gundhi},

doi = {10.1103/physrevd.110.116001},

issn = {2470-0029},

year  = {2024},

date = {2024-12-00},

journal = {Phys. Rev. D},

volume = {110},

number = {11},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lenler-Eriksen2024,

title = {Testing continuous spontaneous localization model with charged macromolecules},

author = {Emil Lenler-Eriksen and Michael Drewsen and Matteo Carlesso},

doi = {10.1088/1367-2630/ad904a},

issn = {1367-2630},

year  = {2024},

date = {2024-11-01},

journal = {New J. Phys.},

volume = {26},

number = {11},

publisher = {IOP Publishing},

abstract = {Abstract

               In the last decade, a growing interest has been devoted to models of spontaneous collapse of the wavefunction, known also as collapse models. They coherently solve the well-known quantum measurement problem by suitably modifying the Schrödinger evolution. Quantum experiments are now finally within the reach of testing such models (and thus testing the limits of quantum theory). Here, we propose a method based on a two-ions confined in a linear Paul trap to possibly enhance the testing capabilities of such experiments. The combination of an atomic and a macromolecular ion provide a good match for the cooling of the motional degrees of freedom and a non-negligible insight in the collapse mechanism, respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Figurato2024c,

title = {On the effectiveness of the collapse in the Diósi–Penrose model},

author = {Laria Figurato and Marco Dirindin and José Luis Gaona-Reyes and Matteo Carlesso and Angelo Bassi and Sandro Donadi},

doi = {10.1088/1367-2630/ad8c77},

issn = {1367-2630},

year  = {2024},

date = {2024-11-01},

journal = {New J. Phys.},

volume = {26},

number = {11},

publisher = {IOP Publishing},

abstract = {Abstract

               The possibility that gravity plays a role in the collapse of the quantum wave function has been considered in the literature, and it is of relevance not only because it would provide a solution to the measurement problem in quantum theory, but also because it would give a new and unexpected twist to the search for a unified theory of quantum and gravitational phenomena, possibly overcoming the current impasse. The Diósi–Penrose model is the most popular incarnation of this idea. It predicts a progressive breakdown of quantum superpositions when the mass of the system increases; as such, it is susceptible to experimental verification. Current experiments set a lower bound 

                     

                     

                        

                           

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                   Å  for the free parameter of the model, excluding some versions of it. In this work we search for an upper bound, coming from the request that the collapse is effective enough to guarantee classicality at the macroscopic scale: we find out that not all macroscopic systems collapse effectively. If one relaxes this request, a reasonable (although to some degree arbitrary) bound is found to be: 

                     

                     

                        

                           

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                   Å. This will serve to better direct future experiments to further test the model.},

keywords = {},

pubstate = {published},

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}

@article{Hanif2024,

title = {Testing Whether Gravity Acts as a Quantum Entity When Measured},

author = {Farhan Hanif and Debarshi Das and Jonathan Halliwell and Dipankar Home and Anupam Mazumdar and Hendrik Ulbricht and Sougato Bose},

doi = {10.1103/physrevlett.133.180201},

issn = {1079-7114},

year  = {2024},

date = {2024-10-00},

journal = {Phys. Rev. Lett.},

volume = {133},

number = {18},

publisher = {American Physical Society (APS)},

abstract = {A defining signature of classical systems is “in principle measurability” without disturbance: a feature manifestly violated by quantum systems. We describe a multi-interferometer experimental setup that can, in principle, reveal the nonclassicality of a spatial superposition-sourced gravitational field if an irreducible disturbance is caused by a measurement of gravity. While one interferometer sources the field, the others are used to measure the gravitational field created by the superposition. This requires neither any specific form of nonclassical gravity, nor the generation of entanglement between any relevant degrees of freedom at any stage, thus distinguishing it from the experiments proposed so far. This test, when added to the recent entanglement-witness based proposals, enlarges the domain of quantum postulates being tested for gravity. Moreover, the proposed test yields a signature of quantum measurement induced disturbance for any finite rate of decoherence, and is device independent.

          

            

            

              

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                2024

              

            

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keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vischi2024,

title = {Simulating photonic devices with noisy optical elements},

author = {Michele Vischi and Giovanni Di Bartolomeo and Massimiliano Proietti and Seid Koudia and Filippo Cerocchi and Massimiliano Dispenza and Angelo Bassi},

doi = {10.1103/physrevresearch.6.033337},

issn = {2643-1564},

year  = {2024},

date = {2024-09-00},

journal = {Phys. Rev. Research},

volume = {6},

number = {3},

publisher = {American Physical Society (APS)},

abstract = {Quantum computers are inherently affected by noise. While in the long term, error correction codes will account for noise at the cost of increasing physical qubits, in the near term, the performance of any quantum algorithm should be tested and simulated in the presence of noise. As noise acts on the hardware, the classical simulation of a quantum algorithm should not be agnostic on the platform used for the computation. In this paper, we apply the recently proposed noisy gates approach to efficiently simulate noisy optical circuits described in the dual rail framework. The evolution of the state vector is simulated directly, without requiring the mapping to the density matrix framework. Notably, we test the method on both the gate-based and measurement-based quantum computing models, showing that the approach is very versatile. We also evaluate the performance of a photonic variational quantum algorithm to solve the MAX-2-CUT problem. In particular we design and simulate an ansatz, which is resilient to photon losses up to p∼10−3 making it relevant for near-term applications.

          

            

            

              

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                2024

              

            

          },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Timberlake2024,

title = {Linear cooling of a levitated micromagnetic cylinder by vibration},

author = {Chris Timberlake and Elliot Simcox and Hendrik Ulbricht},

doi = {10.1103/physrevresearch.6.033345},

issn = {2643-1564},

year  = {2024},

date = {2024-09-00},

journal = {Phys. Rev. Research},

volume = {6},

number = {3},

publisher = {American Physical Society (APS)},

abstract = {We report feedback cooling of translational and librational degrees of freedom of a levitated m icromagnet cylinder, utilizing a piezoelectric actuator to apply linear feedback to high-Q mechanical modes. The normal modes are measured with a superconducting pick-up coil coupled to a dc SQUID, and phase information is fed back to the piezoelectric actuator to feedback cool a center-of-mass mode to ∼7K, and a librational mode to 830±200mK. Q-factors of 1.0×107 are evaluated for the center-of-mass mode. We find that it is plausible to achieve ground state cooling of the center-of-mass mode by introducing vibration isolation, optimizing the geometry of the pick-up coil to focus on the specific mode of interest and utilizing a state-of-the-art SQUID for detection.

          

            

            

              

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                2024

              

            

          },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wu2024,

title = {Squeezing below the ground state of motion of a continuously monitored levitating nanoparticle},

author = {Qiongyuan Wu and Diana A Chisholm and Rafael Muffato and Tiberius Georgescu and Jack Homans and Hendrik Ulbricht and Matteo Carlesso and Mauro Paternostro},

doi = {10.1088/2058-9565/ad7284},

issn = {2058-9565},

year  = {2024},

date = {2024-08-22},

journal = {Quantum Sci. Technol.},

publisher = {IOP Publishing},

abstract = {Abstract

               Squeezing is a crucial resource for quantum information processing and quantum sensing. In levitated nanomechanics, squeezed states of motion can be generated via temporal control of the trapping frequency of a massive particle. However, the amount of achievable squeezing typically suffers from detrimental environmental effects. We analyze the performance of a scheme that, by embedding careful time-control of trapping potentials and fully accounting for the most relevant sources of noise – including measurement backaction – achieves significant levels of mechanical squeezing. The feasibility of our proposal, which is close to experimental state-of-the-art, makes it a valuable tool for quantum state engineering.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Altamura2024,

title = {Noninterferometric rotational test of the continuous spontaneous localization model: Enhancement of the collapse noise through shape optimization},

author = {Davide Giordano Ario Altamura and Matteo Carlesso and Sandro Donadi and Angelo Bassi},

doi = {10.1103/physreva.109.062212},

issn = {2469-9934},

year  = {2024},

date = {2024-06-00},

journal = {Phys. Rev. A},

volume = {109},

number = {6},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piscicchia2024,

title = {X-Ray Emission from Atomic Systems Can Distinguish between Prevailing Dynamical Wave-Function Collapse Models},

author = {Kristian Piscicchia and Sandro Donadi and Simone Manti and Angelo Bassi and Maaneli Derakhshani and Lajos Diósi and Catalina Curceanu},

doi = {10.1103/physrevlett.132.250203},

issn = {1079-7114},

year  = {2024},

date = {2024-06-00},

journal = {Phys. Rev. Lett.},

volume = {132},

number = {25},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DiBartolomeo2024,

title = {Experimental bounds on linear-friction dissipative collapse models from levitated optomechanics},

author = {Giovanni Di Bartolomeo and Matteo Carlesso},

doi = {10.1088/1367-2630/ad3842},

issn = {1367-2630},

year  = {2024},

date = {2024-04-01},

journal = {New J. Phys.},

volume = {26},

number = {4},

publisher = {IOP Publishing},

abstract = {Abstract

               Collapse models constitute an alternative to quantum mechanics that solve the well-know quantum measurement problem. In this framework, a novel approach to include dissipation in collapse models has been recently proposed, and awaits experimental scrutiny. Our work establishes experimental bounds on the so-constructed linear-friction dissipative Diósi-Penrose (dDP) and Continuous Spontaneous localisation (dCSL) models by exploiting experiments in the field of levitated optomechanics. Our results in the dDP case exclude collapse temperatures below 10−13 K and 

                     

                     

                        

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                   K respectively for values of the localisation length smaller than 10−6 m and 10−8 m. In the dCSL case the entire parameter space is excluded for values of the temperature lower than 

                     

                     

                        

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                   K.},

keywords = {},

pubstate = {published},

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}

@article{Suprano2024,

title = {Experimental Property Reconstruction in a Photonic Quantum Extreme Learning Machine},

author = {Alessia Suprano and Danilo Zia and Luca Innocenti and Salvatore Lorenzo and Valeria Cimini and Taira Giordani and Ivan Palmisano and Emanuele Polino and Nicolò Spagnolo and Fabio Sciarrino and G. Massimo Palma and Alessandro Ferraro and Mauro Paternostro},

doi = {10.1103/physrevlett.132.160802},

issn = {1079-7114},

year  = {2024},

date = {2024-04-00},

journal = {Phys. Rev. Lett.},

volume = {132},

number = {16},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barr2024,

title = {Spectral density classification for environment spectroscopy},

author = {J Barr and G Zicari and A Ferraro and M Paternostro},

doi = {10.1088/2632-2153/ad2cf1},

issn = {2632-2153},

year  = {2024},

date = {2024-03-01},

journal = {Mach. Learn.: Sci. Technol.},

volume = {5},

number = {1},

publisher = {IOP Publishing},

abstract = {Abstract

               Spectral densities encode the relevant information characterizing the system–environment interaction in an open-quantum system problem. Such information is key to determining the system’s dynamics. In this work, we leverage the potential of machine learning techniques to reconstruct the features of the environment. Specifically, we show that the time evolution of a system observable can be used by an artificial neural network to infer the main features of the spectral density. In particular, for relevant examples of spin-boson models, we can classify with high accuracy the Ohmicity parameter of the environment as either Ohmic, sub-Ohmic or super-Ohmic, thereby distinguishing between different forms of dissipation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fuchs2024,

title = {Measuring gravity with milligram levitated masses},

author = {Tim M. Fuchs and Dennis G. Uitenbroek and Jaimy Plugge and Noud van Halteren and Jean-Paul van Soest and Andrea Vinante and Hendrik Ulbricht and Tjerk H. Oosterkamp},

doi = {10.1126/sciadv.adk2949},

issn = {2375-2548},

year  = {2024},

date = {2024-02-23},

journal = {Sci. Adv.},

volume = {10},

number = {8},

publisher = {American Association for the Advancement of Science (AAAS)},

abstract = {Gravity differs from all other known fundamental forces because it is best described as a curvature of space-time. For that reason, it remains resistant to unifications with quantum theory. Gravitational interaction is fundamentally weak and becomes prominent only at macroscopic scales. This means, we do not know what happens to gravity in the microscopic regime where quantum effects dominate and whether quantum coherent effects of gravity become apparent. Levitated mechanical systems of mesoscopic size offer a probe of gravity, while still allowing quantum control over their motional state. This regime opens the possibility of table-top testing of quantum superposition and entanglement in gravitating systems. Here, we show gravitational coupling between a levitated submillimeter-scale magnetic particle inside a type I superconducting trap and kilogram source masses, placed approximately half a meter away. Our results extend gravity measurements to low gravitational forces of attonewton and underline the importance of levitated mechanical sensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gaona-Reyes2024,

title = {Spontaneous collapse models lead to the emergence of classicality of the Universe},

author = {José Luis Gaona-Reyes and Lucía Menéndez-Pidal and Mir Faizal and Matteo Carlesso},

doi = {10.1007/jhep02(2024)193},

issn = {1029-8479},

year  = {2024},

date = {2024-02-00},

journal = {J. High Energ. Phys.},

volume = {2024},

number = {2},

publisher = {Springer Science and Business Media LLC},

abstract = {Abstract

                     Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can one then describe the emergence of the classical, well-defined geometry that we observe? Considering that the decoherence-driven quantum-to-classical transition relies on external physical entities, this process cannot account for the emergence of the classical behaviour of the Universe. Here, we show how models of spontaneous collapse of the wavefunction can offer a viable mechanism for explaining such an emergence. We apply it to a simple General Relativity dynamical model for gravity and a perfect fluid. We show that, by starting from a general quantum superposition of different geometries, the collapse dynamics leads to a single geometry, thus providing a possible mechanism for the quantum-to-classical transition of the Universe. Similarly, when applying our dynamics to the physically-equivalent Parametrised Unimodular gravity model, we obtain a collapse on the basis of the cosmological constant, where eventually one precise value is selected, thus providing also a viable explanation for the cosmological constant problem. Our formalism can be easily applied to other quantum cosmological models where we can choose a well-defined clock variable.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wardak2024,

title = {Nanoparticle Interferometer by Throw and Catch},

author = {Jakub Wardak and Tiberius Georgescu and Giulio Gasbarri and Alessio Belenchia and Hendrik Ulbricht},

doi = {10.3390/atoms12020007},

issn = {2218-2004},

year  = {2024},

date = {2024-02-00},

journal = {Atoms},

volume = {12},

number = {2},

publisher = {MDPI AG},

abstract = {Matter wave interferometry with increasingly larger masses could pave the way to understanding the nature of wavefunction collapse, the quantum to classical transition, or even how an object in a spatial superposition interacts with its gravitational field. In order to improve upon the current mass record, it is necessary to move into the nanoparticle regime. In this paper, we provide a design for a nanoparticle Talbot–Lau matter wave interferometer that circumvents the practical challenges of previously proposed designs. We present numerical estimates of the expected fringe patterns that such an interferometer would produce, considering all major sources of decoherence. We discuss the practical challenges involved in building such an experiment, as well as some preliminary experimental results to illustrate the proposed measurement scheme. We show that such a design is suitable for seeing interference fringes with 106 amu SiO2 particles and that this design can be extended to even 108 amu particles by using flight times below the typical Talbot time of the system.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Blair2024,

title = {Nonequilibrium quantum probing through linear response},

author = {S. Blair and G. Zicari and A. Belenchia and A. Ferraro and M. Paternostro},

doi = {10.1103/physrevresearch.6.013152},

issn = {2643-1564},

year  = {2024},

date = {2024-02-00},

journal = {Phys. Rev. Research},

volume = {6},

number = {1},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Figurato2024,

title = {On the testability of the Károlyházy model},

author = {Laria Figurato and Angelo Bassi and Sandro Donadi},

doi = {10.1088/1367-2630/ad1499},

issn = {1367-2630},

year  = {2024},

date = {2024-01-01},

journal = {New J. Phys.},

volume = {26},

number = {1},

publisher = {IOP Publishing},

abstract = {Abstract

               Károlyházy’s original proposal, suggesting that space-time fluctuations could be a source of decoherence in space, faced a significant challenge due to an unexpectedly high emission of radiation (13 orders of magnitude more than what was observed in the latest experiment). To address this issue, we reevaluated Károlyházy’s assumption that the stochastic metric fluctuation must adhere to a wave equation. By considering more general correlation functions of space-time fluctuations, we resolve the problem and consequently revive the aforementioned proposal.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Das2024,

title = {Mass-Independent Scheme to Test the Quantumness of a Massive Object},

author = {Debarshi Das and Dipankar Home and Hendrik Ulbricht and Sougato Bose},

doi = {10.1103/physrevlett.132.030202},

issn = {1079-7114},

year  = {2024},

date = {2024-01-00},

journal = {Phys. Rev. Lett.},

volume = {132},

number = {3},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hernández-Gómez2023,

title = {Experimental signature of initial quantum coherence on entropy production},

author = {Santiago Hernández-Gómez and Stefano Gherardini and Alessio Belenchia and Andrea Trombettoni and Mauro Paternostro and Nicole Fabbri},

doi = {10.1038/s41534-023-00738-0},

issn = {2056-6387},

year  = {2023},

date = {2023-12-00},

journal = {npj Quantum Inf},

volume = {9},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractWe report on the experimental quantification of the contribution to non-equilibrium entropy production stemming from the quantum coherence content in the initial state of a qubit exposed to both coherent driving and dissipation. Our experimental demonstration builds on the exquisite experimental control of the spin state of a nitrogen-vacancy defect in diamond and is underpinned, theoretically, by the formulation of a generalized fluctuation theorem designed to track the effects of quantum coherence. Our results provide significant evidence of the possibility to pinpoint the genuinely quantum mechanical contributions to the thermodynamics of non-equilibrium quantum processes in an open quantum systems scenario.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Innocenti2023,

title = {Potential and limitations of quantum extreme learning machines},

author = {L. Innocenti and S. Lorenzo and I. Palmisano and A. Ferraro and M. Paternostro and G. M. Palma},

doi = {10.1038/s42005-023-01233-w},

issn = {2399-3650},

year  = {2023},

date = {2023-12-00},

journal = {Commun Phys},

volume = {6},

number = {1},

publisher = {Springer Science and Business Media LLC},

abstract = {AbstractQuantum extreme learning machines (QELMs) aim to efficiently post-process the outcome of fixed — generally uncalibrated — quantum devices to solve tasks such as the estimation of the properties of quantum states. The characterisation of their potential and limitations, which is currently lacking, will enable the full deployment of such approaches to problems of system identification, device performance optimization, and state or process reconstruction. We present a framework to model QELMs, showing that they can be concisely described via single effective measurements, and provide an explicit characterisation of the information exactly retrievable with such protocols. We furthermore find a close analogy between the training process of QELMs and that of reconstructing the effective measurement characterising the given device. Our analysis paves the way to a more thorough understanding of the capabilities and limitations of QELMs, and has the potential to become a powerful measurement paradigm for quantum state estimation that is more resilient to noise and imperfections.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DiBartolomeo2023b,

title = {Noisy gates for simulating quantum computers},

author = {Giovanni Di Bartolomeo and Michele Vischi and Francesco Cesa and Roman Wixinger and Michele Grossi and Sandro Donadi and Angelo Bassi},

doi = {10.1103/physrevresearch.5.043210},

issn = {2643-1564},

year  = {2023},

date = {2023-12-00},

journal = {Phys. Rev. Research},

volume = {5},

number = {4},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gianani2023,

title = {Diagnostics of quantum-gate coherences deteriorated by unitary errors via end-point-measurement statistics},

author = {Ilaria Gianani and Alessio Belenchia and Stefano Gherardini and Vincenzo Berardi and Marco Barbieri and Mauro Paternostro},

doi = {10.1088/2058-9565/acedca},

issn = {2058-9565},

year  = {2023},

date = {2023-10-01},

journal = {Quantum Sci. Technol.},

volume = {8},

number = {4},

publisher = {IOP Publishing},

abstract = {Abstract

               Quantum coherence is a central ingredient in quantum physics with several theoretical and technological ramifications. We consider a figure of merit encoding the information on how the coherence generated on average by a quantum gate is affected by unitary errors (coherent noise sources) in the form of rotation-angle and rotation-axis errors. We provide numerical evidences that such information is well captured by the statistics of local energy measurements on the output states of the gate. These findings are then corroborated by experimental data taken in a quantum optics setting.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Chisholm2023,

title = {The meaning of redundancy and consensus in quantum objectivity},

author = {Diana A. Chisholm and Luca Innocenti and G. Massimo Palma},

doi = {10.22331/q-2023-08-03-1074},

issn = {2521-327X},

year  = {2023},

date = {2023-08-03},

journal = {Quantum},

volume = {7},

publisher = {Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften},

abstract = {While the terms "redundancy" and "consensus" are often used as synonyms in the context of quantum objectivity, we show here that these should be understood as two related but distinct notions, that quantify different features of the quantum-to-classical transition. We show that the two main frameworks used to measure quantum objectivity, namely spectrum broadcast structure and quantum Darwinism, are best suited to quantify redundancy and consensus, respectively. Furthermore, by analyzing explicit examples of states with nonlocally encoded information, we highlight the potentially stark difference between the degrees of redundancy and consensus. In particular, this causes a break in the hierarchical relations between spectrum broadcast structure and quantum Darwinism. Our framework provides a new perspective to interpret known and future results in the context of quantum objectivity, paving the way for a deeper understanding of the emergence of classicality from the quantum realm.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{LoMonaco2023,

title = {Quantum scrambling via accessible tripartite information},

author = {Gabriele Lo Monaco and Luca Innocenti and Dario Cilluffo and Dario A Chisholm and Salvatore Lorenzo and G Massimo Palma},

doi = {10.1088/2058-9565/accd92},

issn = {2058-9565},

year  = {2023},

date = {2023-07-01},

journal = {Quantum Sci. Technol.},

volume = {8},

number = {3},

publisher = {IOP Publishing},

abstract = {Abstract

               Quantum information scrambling (QIS), from the perspective of quantum information theory, is generally understood as local non-retrievability of information evolved through some dynamical process, and is often quantified via entropic quantities such as the tripartite information. We argue that this approach comes with a number of issues, in large part due to its reliance on quantum mutual informations, which do not faithfully quantify correlations directly retrievable via measurements, and in part due to the specific methodology used to compute tripartite informations of the studied dynamics. We show that these issues can be overcome by using accessible mutual informations, defining corresponding ‘accessible tripartite informations’, and provide explicit examples of dynamics whose scrambling properties are not properly quantified by the standard tripartite information. Our results lay the groundwork for a more profound understanding of what QIS represents, and reveal a number of promising, as of yet unexplored, venues for further research.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DiBartolomeo2023,

title = {Linear-friction many-body equation for dissipative spontaneous wave-function collapse},

author = {Giovanni Di Bartolomeo and Matteo Carlesso and Kristian Piscicchia and Catalina Curceanu and Maaneli Derakhshani and Lajos Diósi},

doi = {10.1103/physreva.108.012202},

issn = {2469-9934},

year  = {2023},

date = {2023-07-00},

journal = {Phys. Rev. A},

volume = {108},

number = {1},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gundhi2023,

title = {Motion of an electron through vacuum fluctuations},

author = {Anirudh Gundhi and Angelo Bassi},

doi = {10.1103/physreva.107.062801},

issn = {2469-9934},

year  = {2023},

date = {2023-06-00},

journal = {Phys. Rev. A},

volume = {107},

number = {6},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Donadi2023,

title = {Collapse Dynamics Are Diffusive},

author = {Sandro Donadi and Luca Ferialdi and Angelo Bassi},

doi = {10.1103/physrevlett.130.230202},

issn = {1079-7114},

year  = {2023},

date = {2023-06-00},

journal = {Phys. Rev. Lett.},

volume = {130},

number = {23},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wu2023,

title = {Quantifying protocol efficiency: A thermodynamic figure of merit for classical and quantum state-transfer protocols},

author = {Qiongyuan Wu and Mario A. Ciampini and Mauro Paternostro and Matteo Carlesso},

doi = {10.1103/physrevresearch.5.023117},

issn = {2643-1564},

year  = {2023},

date = {2023-05-00},

journal = {Phys. Rev. Research},

volume = {5},

number = {2},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Brown2023,

title = {Optimal quantum control via genetic algorithms for quantum state engineering in driven-resonator mediated networks},

author = {Jonathon Brown and Mauro Paternostro and Alessandro Ferraro},

doi = {10.1088/2058-9565/acb2f2},

issn = {2058-9565},

year  = {2023},

date = {2023-04-01},

journal = {Quantum Sci. Technol.},

volume = {8},

number = {2},

publisher = {IOP Publishing},

abstract = {Abstract

               We employ a machine learning-enabled approach to quantum state engineering based on evolutionary algorithms. In particular, we focus on superconducting platforms and consider a network of qubits—encoded in the states of artificial atoms with no direct coupling—interacting via a common single-mode driven microwave resonator. The qubit-resonator couplings are assumed to be in the resonant regime and tunable in time. A genetic algorithm is used in order to find the functional time-dependence of the couplings that optimise the fidelity between the evolved state and a variety of targets, including three-qubit GHZ and Dicke states and four-qubit graph states. We observe high quantum fidelities (above 0.96 in the worst case setting of a system of effective dimension 96), fast preparation times, and resilience to noise, despite the algorithm being trained in the ideal noise-free setting. These results show that the genetic algorithms represent an effective approach to control quantum systems of large dimensions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bassi2023,

title = {Collapse Models: A Theoretical, Experimental and Philosophical Review},

author = {Angelo Bassi and Mauro Dorato and Hendrik Ulbricht},

doi = {10.3390/e25040645},

issn = {1099-4300},

year  = {2023},

date = {2023-04-00},

journal = {Entropy},

volume = {25},

number = {4},

publisher = {MDPI AG},

abstract = {In this paper, we review and connect the three essential conditions needed by the collapse model to achieve a complete and exact formulation, namely the theoretical, the experimental, and the ontological ones. These features correspond to the three parts of the paper. In any empirical science, the first two features are obviously connected but, as is well known, among the different formulations and interpretations of non-relativistic quantum mechanics, only collapse models, as the paper well illustrates with a richness of details, have experimental consequences. Finally, we show that a clarification of the ontological intimations of collapse models is needed for at least three reasons: (1) to respond to the indispensable task of answering the question ’what are collapse models (and in general any physical theory) about?’; (2) to achieve a deeper understanding of their different formulations; (3) to enlarge the panorama of possible readings of a theory, which historically has often played a fundamental heuristic role.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Marchese2023,

title = {Optomechanics-Based Quantum Estimation Theory for Collapse Models},

author = {Marta Maria Marchese and Alessio Belenchia and Mauro Paternostro},

doi = {10.3390/e25030500},

issn = {1099-4300},

year  = {2023},

date = {2023-03-00},

journal = {Entropy},

volume = {25},

number = {3},

publisher = {MDPI AG},

abstract = {We make use of the powerful formalism of quantum parameter estimation to assess the characteristic rates of a continuous spontaneous localization (CSL) model affecting the motion of a massive mechanical system. We show that a study performed in non-equilibrium conditions unveils the advantages provided by the use of genuinely quantum resources—such as quantum correlations—in estimating the CSL-induced diffusion rate. In stationary conditions, instead, the gap between quantum performance and a classical scheme disappears. Our investigation contributes to the ongoing effort aimed at identifying suitable conditions for the experimental assessment of collapse models.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ribezzo2022,

title = {Deploying an Inter‐European Quantum Network},

author = {Domenico Ribezzo and Mujtaba Zahidy and Ilaria Vagniluca and Nicola Biagi and Saverio Francesconi and Tommaso Occhipinti and Leif K. Oxenløwe and Martin Lončarić and Ivan Cvitić and Mario Stipčević and Žiga Pušavec and Rainer Kaltenbaek and Anton Ramšak and Francesco Cesa and Giorgio Giorgetti and Francesco Scazza and Angelo Bassi and Paolo De Natale and Francesco Saverio Cataliotti and Massimo Inguscio and Davide Bacco and Alessandro Zavatta},

doi = {10.1002/qute.202200061},

issn = {2511-9044},

year  = {2023},

date = {2023-02-00},

journal = {Adv Quantum Tech},

volume = {6},

number = {2},

publisher = {Wiley},

abstract = {AbstractAround 40 years have passed since the first pioneering works introduced the possibility of using quantum physics to enhance communications safety. Nowadays, quantum key distribution (QKD) exited the physics laboratories to become a mature technology, triggering the attention of States, military forces, banks, and private corporations. This work takes on the challenge of bringing QKD closer to a consumer technology: deployed optical fibers by telecommunication companies of different States have been used to realize a quantum network, the first‐ever connecting three different countries. This work also emphasizes the necessity of networks where QKD can come up besides classical communications, whose coexistence currently represents the main limitation of this technology. This network connects Trieste to Rijeka and Ljubljana via a trusted node in Postojna. A key rate of over 3 kbps in the shortest link and a 7‐hour‐long measurement demonstrate the system's stability and reliability. The network has been used to present the QKD at the G20 Digital Ministers' Meeting in Trieste. The experimental results, together with the interest that one of the most important events of international politics has attracted, showcase the maturity of the QKD technology bundle, placing it in the spotlight for consumer applications in the near term.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Piscicchia2023,

title = {A Novel Approach to Parameter Determination of the Continuous Spontaneous Localization Collapse Model},

author = {Kristian Piscicchia and Alessio Porcelli and Angelo Bassi and Massimiliano Bazzi and Mario Bragadireanu and Michael Cargnelli and Alberto Clozza and Luca De Paolis and Raffaele Del Grande and Maaneli Derakhshani and Diósi Lajos and Sandro Donadi and Carlo Guaraldo and Mihai Iliescu and Matthias Laubenstein and Simone Manti and Johann Marton and Marco Miliucci and Fabrizio Napolitano and Alessandro Scordo and Francesco Sgaramella and Diana Laura Sirghi and Florin Sirghi and Oton Vazquez Doce and Johann Zmeskal and Catalina Curceanu},

doi = {10.3390/e25020295},

issn = {1099-4300},

year  = {2023},

date = {2023-02-00},

journal = {Entropy},

volume = {25},

number = {2},

publisher = {MDPI AG},

abstract = {Models of dynamical wave function collapse consistently describe the breakdown of the quantum superposition with the growing mass of the system by introducing non-linear and stochastic modifications to the standard Schrödinger dynamics. Among them, Continuous Spontaneous Localization (CSL) was extensively investigated both theoretically and experimentally. Measurable consequences of the collapse phenomenon depend on different combinations of the phenomenological parameters of the model—the strength λ and the correlation length rC—and have led, so far, to the exclusion of regions of the admissible (λ−rC) parameters space. We developed a novel approach to disentangle the λ and rC probability density functions, which discloses a more profound statistical insight.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Napolitano2023,

title = {Underground Tests of Quantum Mechanics by the VIP Collaboration at Gran Sasso},

author = {Fabrizio Napolitano and Andrea Addazi and Angelo Bassi and Massimiliano Bazzi and Mario Bragadireanu and Michael Cargnelli and Alberto Clozza and Luca De Paolis and Raffaele Del Grande and Maaneli Derakhshani and Sandro Donadi and Carlo Fiorini and Carlo Guaraldo and Mihail Iliescu and Matthias Laubenstein and Simone Manti and Antonino Marcianò and Johann Marton and Marco Miliucci and Edoardo Milotti and Kristian Piscicchia and Alessio Porcelli and Alessandro Scordo and Francesco Sgaramella and Diana Laura Sirghi and Florin Sirghi and Oton Vazquez Doce and Johann Zmeskal and Catalina Curceanu},

doi = {10.3390/sym15020480},

issn = {2073-8994},

year  = {2023},

date = {2023-02-00},

journal = {Symmetry},

volume = {15},

number = {2},

publisher = {MDPI AG},

abstract = {Modern physics lays its foundations on the pillars of Quantum Mechanics (QM), which has been proven successful to describe the microscopic world of atoms and particles, leading to the construction of the Standard Model. Despite the big success, the old open questions at its very heart, such as the measurement problem and the wave function collapse, are still open. Various theories consider scenarios which could encompass a departure from the predictions of the standard QM, such as extra-dimensions or deformations of the Lorentz/Poincaré symmetries. At the Italian National Gran Sasso underground Laboratory LNGS, we search for evidence of new physics proceeding from models beyond standard QM, using radiation detectors. Collapse models addressing the foundations of QM, such as the gravity-related Diósi–Penrose (DP) and Continuous Spontaneous Localization (CSL) models, predict the emission of spontaneous radiation, which allows experimental tests. Using a high-purity Germanium detector, we could exclude the natural parameterless version of the DP model and put strict bounds on the CSL one. In addition, forbidden atomic transitions could prove a possible violation of the Pauli Exclusion Principle (PEP) in open and closed systems. The VIP-2 experiment is currently in operation, aiming at detecting PEP-violating signals in Copper with electrons; the VIP-3 experiment upgrade is foreseen to become operative in the next few years. We discuss the VIP-Lead experiment on closed systems, and the strong bounds it sets on classes of non-commutative quantum gravity theories, such as the θ–Poincaré theory.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zicari2023,

title = {On the role of initial coherence in the spin phase-space entropy production rate},

author = {Giorgio Zicari and Barış Çakmak and Özgür E Müstecaplıoğlu and Mauro Paternostro},

doi = {10.1088/1367-2630/acb45b},

issn = {1367-2630},

year  = {2023},

date = {2023-01-01},

journal = {New J. Phys.},

volume = {25},

number = {1},

publisher = {IOP Publishing},

abstract = {Abstract

               Recent studies have pointed out the intrinsic dependence of figures of merit of thermodynamic relevance—such as work, heat and entropy production—on the amount of quantum coherences that is made available to a system. However, whether coherences hinder or enhance the value taken by such quantifiers of thermodynamic performance is yet to be ascertained. We show that, when considering entropy production generated in a process taking a finite-size bipartite quantum system out of equilibrium through local non-unitary channels, no general monotonicity relationship exists between the entropy production and degree of quantum coherence in the state of the system. A direct correspondence between such quantities can be retrieved when considering specific forms of open-system dynamics applied to suitably chosen initial states. Our results call for a systematic study of the role of genuine quantum features in the non-equilibrium thermodynamics of quantum processes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Laneve2022,

title = {A scheme for multipartite entanglement distribution via separable carriers},

author = {Alessandro Laneve and Hannah McAleese and Mauro Paternostro},

doi = {10.1088/1367-2630/aca499},

issn = {1367-2630},

year  = {2022},

date = {2022-12-01},

journal = {New J. Phys.},

volume = {24},

number = {12},

publisher = {IOP Publishing},

abstract = {Abstract

               The ability to reliably distribute entanglement among the nodes of a network is an essential requirement for the development of effective quantum communication protocols and the realization of useful quantum networks. It has been demonstrated, in different contexts, that two remote systems can be entangled via local interactions with a carrier system that always remains in a separable state with respect to such distant particles. We develop a strategy for entanglement distribution via separable carriers that can be applied to any number of network nodes to achieve various entanglement distribution patterns. We show that our protocol results in multipartite entanglement, while the carrier mediating the process is always in a separable state with respect to the network. We provide examples showcasing the flexibility of our approach and propose a scheme of principle for the experimental demonstration of the protocol.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Vinante2022,

title = {Levitated Micromagnets in Superconducting Traps: A New Platform for Tabletop Fundamental Physics Experiments},

author = {Andrea Vinante and Chris Timberlake and Hendrik Ulbricht},

doi = {10.3390/e24111642},

issn = {1099-4300},

year  = {2022},

date = {2022-11-00},

journal = {Entropy},

volume = {24},

number = {11},

publisher = {MDPI AG},

abstract = {Magnetically levitated microparticles have been proposed as mechanical sensors with extreme sensitivity. In particular, micromagnets levitated above a superconductor can achieve very low levels of dissipation and thermal noise. In this paper, we review recent initial experiments and discuss the potential for using these systems as sensors of magnetic fields and rotational motion, as well as possible applications to fundamental physics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}