@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}

}