Publications old

@article{di_liberto_finite-momentum_2011,

title = {Finite-momentum Bose-Einstein condensates in shaken two-dimensional square optical lattices},

author = {M. Di_Liberto and O. Tieleman and V. Branchina and C. Morais Smith},

doi = {10.1103/PhysRevA.84.013607},

issn = {10502947},

year  = {2011},

date = {2011-07-01},

urldate = {2011-07-01},

journal = {Physical Review A - Atomic, Molecular, and Optical Physics},

volume = {84},

number = {1},

abstract = {We consider ultracold bosons in a two-dimensional square optical lattice described by the Bose-Hubbard model. In addition, an external time-dependent sinusoidal force is applied to the system, which shakes the lattice along one of the diagonals. The effect of the shaking is to renormalize the nearest-neighbor-hopping coefficients, which can be arbitrarily reduced, can vanish, or can even change sign, depending on the shaking parameter. Therefore, it is necessary to account for higher-order-hopping terms, which are renormalized differently by the shaking, and to introduce anisotropy into the problem. We show that the competition between these different hopping terms leads to finite-momentum condensates with a momentum that may be tuned via the strength of the shaking. We calculate the boundaries between the Mott insulator and the different superfluid phases and present the time-of-flight images expected to be observed experimentally. Our results open up possibilities for the realization of bosonic analogs of the Fulde, Ferrel, Larkin, and Ovchinnikov phase describing inhomogeneous superconductivity. © 2011 American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{branchina_mapping_2010,

title = {Mapping fermion and boson systems onto the Fock space of harmonic oscillators},

author = {Vincenzo Branchina and Marco Di_Liberto and Ivano Lodato},

doi = {10.1103/PhysRevE.81.011120},

issn = {15393755},

year  = {2010},

date = {2010-01-01},

urldate = {2010-01-01},

journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics},

volume = {81},

number = {1},

abstract = {The fluctuation-dissipation theorem (FDT) is very general and applies to a broad variety of different physical phenomena in condensed matter physics. With the help of the FDT and following the famous work of Caldeira and Leggett, we show that, whenever linear response theory applies, any generic bosonic or fermionic system at finite temperature T can be mapped onto a fictitious system of free-harmonic oscillators. To the best of our knowledge, this is the first time that such a mapping is explicitly worked out. This finding provides further theoretical support to the phenomenological harmonic oscillator models commonly used in condensed matter. Moreover, our result helps in clarifying an interpretation issue related to the presence and physical origin of the Bose-Einstein factor in the FDT. © 2010 The American Physical Society.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{branchina_dark_2009,

title = {Dark energy and Josephson junctions},

author = {Vincenzo Branchina and Marco Di_Liberto and Ivano Lodato},

doi = {10.1088/1475-7516/2009/08/011},

issn = {14757516},

year  = {2009},

date = {2009-01-01},

urldate = {2009-01-01},

journal = {Journal of Cosmology and Astroparticle Physics},

volume = {2009},

number = {8},

abstract = {It has been recently claimed that dark energy can be (and has been) observed in laboratory experiments by measuring the power spectrum S I(ω) of the noise current in a resistively shunted Josephson junction and that in new dedicated experiments, which will soon test a higher frequency range, S I(ω) should show a deviation from the linear rising observed in the lower frequency region because higher frequencies should not contribute to dark energy. Based on previous work on theoretical aspects of the fluctuation-dissipation theorem, we carefully investigate these issues and show that these claims are based on a misunderstanding of the physical origin of the spectral function S I(ω). According to our analysis, dark energy has never been (and will never be) observed in Josephson junctions experiments. We also predict that no deviation from the linear rising behavior of S I(ω) will be observed in forthcoming experiments. Our findings provide new (we believe definite) arguments which strongly support previous criticisms. © 2009 IOP Publishing Ltd and SISSA.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zuliani2021,

title = {SUPP INF: Quantum-inspired Machine Learning on high-energy physics data},

author = {Davide Zuliani and Timo Felser and Marco Trenti and Lorenzo Sestini and Alessio Gianelle and Donatella Lucchesi and Simone Montangero},

pages = {931},

abstract = {One of the most challenging big data problems in high energy physics is the analysis and classification of the data produced by the Large Hadron Collider at CERN. Recently, machine learning techniques have been employed to tackle such challenges, which, despite being very effective, rely on classification schemes that are hard to interpret. Here, we introduce and apply a quantum-inspired machine learning technique and, exploiting tree tensor networks, we show how to efficiently classify b-jet events in proton-proton collisions at LHCb and to interpret the classification results. In particular, we show how to select important features and adapt the network geometry based on information acquired in the learning process. Moreover, the tree tensor network can be adapted for optimal precision or fast response in time without the need for repeating the learning process. This paves the way to high-frequency real-time applications as needed for current and future LHC event classification to trigger events at the tens of MHz scale.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Arceci2022a,

title = {Supplemntary material: Entanglement of Formation of Mixed Many-Body Quantum States via Tree Tensor Operators},

author = {L. Arceci and Pietro Silvi and Simone Montangero},

pages = {1–20},

keywords = {},

pubstate = {published},

tppubtype = {article}

}