204 results on '"Naddeo, Adele"'
Search Results
2. Interaction between Everett worlds and fundamental decoherence in Non-unitary Newtonian Gravity
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Maimone, Filippo., Naddeo, Adele, and Scelza, Giovanni
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Quantum Physics ,Condensed Matter - Strongly Correlated Electrons ,General Relativity and Quantum Cosmology - Abstract
It is shown that Non-unitary Newtonian Gravity (NNG) model admits a simple interpretation in terms of Feynman path integral, in which the sum over all possible histories is replaced by a summation over pairs of paths. Correlations between different paths are allowed by a fundamental decoherence mechanism of gravitational origin and can be interpreted as a kind of communication between different branches of the wave function. The ensuing formulation could be used in turn as a motivation to introduce Non-unitary Gravity itself.
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- 2023
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3. A glimpse into Feynman's contributions to the debate on the foundations of quantum mechanics
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Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,General Relativity and Quantum Cosmology ,Quantum Physics - Abstract
The broad debate on foundational issues in quantum mechanics, which took place at the famous 1957 Chapel Hill conference on \textit{The Role of Gravitation in Physics}, is here critically analyzed with an emphasis on Richard Feynman's contributions. One of the most debated questions at Chapel Hill was whether the gravitational field had to be quantized and its possible role in wave function collapse. Feynman's arguments in favor of the quantization of the gravitational field, based essentially on a series of gedanken experiments, are here discussed. Then the related problem of the wave function collapse, for which Feynman hints to decoherence as a possible solution, is discussed. Finally, another topic is analyzed, concerning the role of the observer in a closed Universe. In this respect, Feynman's many-worlds characterization of Everett's approach at Chapel Hill is discussed, together with later contributions of his, including a kind of Schr\"{o}dinger's cat paradox, which are scattered throughout the 1962-63 Lectures on Gravitation. Philosophical implications of Feynman's ideas in relation to foundational issues are also discussed., Comment: 14 pages, no figures. Based on the talk given by AN at the 16th Marcel Grossmann Conference, parallel session HR3 (Time and Philosophy in Physics). arXiv admin note: substantial text overlap with arXiv:2102.11220
- Published
- 2021
4. A look inside Feynman's route to gravitation
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Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
- Subjects
Physics - History and Philosophy of Physics ,General Relativity and Quantum Cosmology - Abstract
In this contribution we report about Feynman's approach to gravitation, starting from the records of his interventions at the Chapel Hill Conference of 1957. As well known, Feynman was concerned about the relation of gravitation with the rest of physics. Probably for this reason, he promoted an unusual, field theoretical approach to general relativity, in which, after the recognition that the interaction must be mediated by the quanta of a massless spin-$2$ field, Einstein's field equations should follow from the general properties of Lorentz-invariant quantum field theory, plus self-consistency requirements. Quantum corrections would then be included by considering loop diagrams. These ideas were further developed by Feynman in his famous lectures on gravitation, delivered at Caltech in 1962-63, and in a handful of published papers, where he also introduced some field theoretical tools which were soon recognized to be of general interest, such as ghosts and the tree theorem. Some original pieces of Feynman's work on gravity are also present in a set of unpublished lectures delivered at Hughes Aircraft Company in 1966-67 and devoted primarily to astrophysics and cosmology. Some comments on the relation between Feynman's approach to gravity and his ideas on the quantum foundations of the fundamental interactions are included., Comment: 13 pages, no figures. Based on the talk given by AN at the 16th Marcel Grossmann Conference, parallel session HR2 (History of Relativity, Gravitation and Cosmology). arXiv admin note: text overlap with arXiv:2102.11220
- Published
- 2021
5. Towards detecting gravitational waves: a contribution by Richard Feynman
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Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
- Subjects
Physics - History and Philosophy of Physics ,General Relativity and Quantum Cosmology - Abstract
An account of Richard Feynman's work on gravitational waves is given. Feynman's involvement with this subject can be traced backto 1957, when he attended the famous Chapel Hill conference on the Role of Gravitation in Physics. At that conference, he presented in particular the celebrated sticky bead argument, which was devised to intuitively argue that gravitational waves must carry energy, if they exist at all. While giving a simple argument in favor of the existence of gravitational waves, Feynman's thought experiment paved the way for their detection and stimulated subsequent efforts in building a practical detecting device. Feynman's contributions were systematically developed in a letter to Victor Weisskopf, completed in February 1961, as well as in his Caltech Lectures on Gravitation, delivered in 1962-63. There, a detailed calculation of the power radiated as gravitational radiation was performed, using both classical and quantum field theoretical tools, leading to a derivation of the quadrupole formula and its application to gravitational radiation by a binary star system. A comparison between the attitudes of Feynman and of the general relativity community to the problems of gravitational wave physics is drawn as well., Comment: 20 pages, 1 figure. Based on the talk given by MD at the 16th Marcel Grossmann Conference, parallel session HR2 (History of Relativity, Gravitation and Cosmology)
- Published
- 2021
6. A road map for Feynman's adventures in the land of gravitation
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Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,General Relativity and Quantum Cosmology ,Quantum Physics - Abstract
Richard P. Feynman's work on gravitation, as can be inferred from several published and unpublished sources, is reviewed. Feynman was involved with this subject at least from late 1954 to the late 1960s, giving several pivotal contributions to it. Even though he published only three papers, much more material is available, beginning with the records of his many interventions at the Chapel Hill conference in 1957, which are here analyzed in detail, and show that he had already considerably developed his ideas on gravity. In addition he expressed deep thoughts about fundamental issues in quantum mechanics which were suggested by the problem of quantum gravity, such as superpositions of the wave functions of macroscopic objects and the role of the observer. Feynman also lectured on gravity several times. Besides the famous lectures given at Caltech in 1962-63, he extensively discussed this subject in a series of lectures delivered at the Hughes Aircraft Company in 1966-67, whose focus was on astronomy and astrophysics. All this material allows to reconstruct a detailed picture of Feynman's ideas on gravity and of their evolution until the late sixties. According to him, gravity, like electromagnetism, has quantum foundations, therefore general relativity has to be regarded as the classical limit of an underlying quantum theory; this quantum theory should be investigated by computing physical processes, as if they were experimentally accessible. The same attitude is shown with respect to gravitational waves, as is evident also from an unpublished letter addressed to Victor F. Weisskopf. In addition, an original approach to gravity, which closely mimics (and probably was inspired by) the derivation of the Maxwell equations given by Feynman in that period, is sketched in the unpublished Hughes lectures., Comment: 47 pages, no figures, final version. Dedicated to the Memory of Erasmo Recami
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- 2021
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7. Einstein, Planck and Vera Rubin: relevant encounters between the Cosmological and the Quantum Worlds
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Salucci, Paolo, Esposito, Giampiero, Lambiase, Gaetano, Battista, Emmanuele, Benetti, Micol, Bini, Donato, Boco, Lumen, Sharma, Gauri, Bozza, Valerio, Buoninfante, Luca, Capolupo, Antonio, Capozziello, Salvatore, Covone, Giovanni, D'Agostino, Rocco, DeLaurentis, Mariafelicia, De Martino, Ivan, De Somma, Giulia, Di Grezia, Elisabetta, Di Paolo, Chiara, Fatibene, Lorenzo, Gammaldi, Viviana, Geralico, Andrea, Ingoglia, Lorenzo, Lapi, Andrea, Luciano, Giuseppe G., Mastrototaro, Leonardo, Naddeo, Adele, Pantoni, Lara, Petruzziello, Luciano, Piedipalumbo, Ester, Pietroni, Silvia, Quaranta, Aniello, Rota, Paolo, Sarracino, Giuseppe, Sorge, Francesco, Stabile, Antonio, Stornaiolo, Cosimo, Tedesco, Antonio, Valdarnini, Riccardo, Viaggiu, Stefano, and Yunge, Andy A. V.
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General Relativity and Quantum Cosmology ,Astrophysics - Astrophysics of Galaxies ,High Energy Physics - Phenomenology ,High Energy Physics - Theory - Abstract
In Cosmology and in Fundamental Physics there is a crucial question like: where the elusive substance that we call Dark Matter is hidden in the Universe and what is it made of?, that, even after 40 years from the Vera Rubin seminal discovery does not have a proper answer. Actually, the more we have investigated, the more this issue has become strongly entangled with aspects that go beyond the established Quantum Physics, the Standard Model of Elementary particles and the General Relativity and related to processes like the Inflation, the accelerated expansion of the Universe and High Energy Phenomena around compact objects. Even Quantum Gravity and very exotic DM particle candidates may play a role in framing the Dark Matter mystery that seems to be accomplice of new unknown Physics. Observations and experiments have clearly indicated that the above phenomenon cannot be considered as already theoretically framed, as hoped for decades. The Special Topic to which this review belongs wants to penetrate this newly realized mystery from different angles, including that of a contamination of different fields of Physics apparently unrelated. We show with the works of this ST that this contamination is able to guide us into the required new Physics. This review wants to provide a good number of these "paths or contamination" beyond/among the three worlds above; in most of the cases, the results presented here open a direct link with the multi-scale dark matter phenomenon, enlightening some of its important aspects. Also in the remaining cases, possible interesting contacts emerges., Comment: 64 pages 16 Figures. In print on Frontiers in Astronomy and Space Sciences, for the Research Topic: "When Planck, Einstein and Vera Rubin Meet. Dark Matter: What is it ? Where is it?"
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- 2020
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8. Microscopic foundation of thermodynamics, transition to classicality and regularization of gravitational-collapse singularities within Non-unitary $4$-th Derivative Gravity classically equivalent to Einstein gravity and its Newtonian limit
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De Filippo, Sergio and Naddeo, Adele
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General Relativity and Quantum Cosmology - Abstract
A detailed and updated review is given of De Filippo's Non-unitary $4$-th Derivative Gravity and its Newtonian limit, by pointing out the crucial role of non-unitarity in addressing transition to classicality and specifically localization of macroscopic bodies, microscopic foundation of the second law of thermodynamics, measurement problem; furthermore it provides a quantum field theory of gravity possibly not only renormalizable but even finite, with a cancelation mechanism analogous to supersymmetric field theories where cancelations are due to superpartners whereas here to negative energy fields. Finally this non-unitary proposal addresses the longstanding black hole information loss problem and this according to an unorthodox view at variance with the mainstream endeavors to save unitarity at the expense of changing General Relativity in vague unspecified ways. Last but not least motivations and conceptual framework are given, as the author could not present them in his first papers written in a hurry since he was aware that in a little time he would be unable to use pc keyboard or to write on paper due to the progressing of motor neuron disease.
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- 2020
9. Some insight into Feynman's approach to electromagnetism
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Di Mauro, Marco, De Luca, Roberto, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,High Energy Physics - Theory ,Physics - Classical Physics - Abstract
We retrace an ab initio relativistic derivation of Maxwell's equations that was developed by Feynman in unpublished notes, clarifying the analogies and the differences with analogous treatments present in the literature. Unlike the latter, Feynman's approach stands out because it considers electromagnetic potentials as primary, reflecting his ideas about the quantum foundations of electromagnetism. Some considerations about the foundations of special relativity, which are naturally suggested by this approach, are given in appendix., Comment: 17 pages, no figures, submitted for publication
- Published
- 2020
10. Searching for a response: the intriguing mystery of Feynman's theoretical reference amplifier
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d'Alessandro, Vincenzo, Daliento, Santolo, Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,Physics - Popular Physics - Abstract
We analyze Feynman's work on the response of an amplifier performed at Los Alamos and described in a technical report of 1946, as well as lectured on at the Cornell University in 1946-47 during his course on Mathematical Methods. The motivation for such a work was Feynman's involvement in the Manhattan Project, for which the necessity emerged of feeding the output pulses of counters into amplifiers or several other circuits, with the risk of introducing distortion at each step. In order to deal with such a problem, Feynman designed a theoretical "reference amplifier", thus enabling a characterization of the distortion by means of a benchmark relationship between phase and amplification for each frequency, and providing a standard tool for comparing the operation of real devices. A general theory was elaborated, from which he was able to deduce the basic features of an amplifier just from its response to a pulse or to a sine wave of definite frequency. Moreover, in order to apply such a theory to practical problems, a couple of remarkable examples were worked out, both for high-frequency cutoff amplifiers and for low-frequency ones. A special consideration deserves a mysteriously exceptional amplifier with best stability behavior introduced by Feynman, for which different physical interpretations are here envisaged. Feynman's earlier work then later flowed in the Hughes lectures on Mathematical Methods in Physics and Engineering of 1970-71, where he also remarked on causality properties of an amplifier, that is on certain relations between frequency and phase shift that a real amplifier has to satisfy in order not to allow output signals to appear before input ones. Quite interestingly, dispersion relations to be satisfied by the response function were introduced., Comment: 19 pages, 6 figures
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- 2019
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11. Microscopic foundations of the Second Law of Thermodynamics within Nonunitary Newtonian Gravity
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De Filippo, Sergio, Maimone, Filippo, Naddeo, Adele, and Scelza, Giovanni
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Condensed Matter - Statistical Mechanics ,Quantum Physics - Abstract
The quest for a microscopic foundation of Thermodynamics is addressed within the Nonunitary Newtonian Gravity model through the study of a specific closed system, namely a three-dimensional harmonic nanocrystal. A numerical calculation of the nanocrystal von Neumann entropy as a function of time is performed, showing a sharp monotonic increase, followed by a stabilization at late times. This behavior is consistent with the emergence of a micro-canonical ensemble within the initial energy levels, signaling, in this way, the establishment of a non-unitary gravity-induced thermal equilibrium., Comment: 2 figures, 8 pages. arXiv admin note: text overlap with arXiv:1801.02500
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- 2019
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12. Feynman's different approach to electromagnetism
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De Luca, Roberto, Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,High Energy Physics - Theory ,Physics - Classical Physics - Abstract
We discuss a previously unpublished description of electromagnetism outlined by Richard P. Feynman in the 1960s in five handwritten pages, recently uncovered among his papers, and partly developed in later lectures. Though similar to the existing approaches deriving electromagnetism from special relativity, the present one extends a long way towards the derivation of Maxwell's equations with minimal physical assumptions. In particular, without postulating Coulomb's law, homogeneous Maxwell's equations are written down by following a route different from the standard one, i.e. first introducing electromagnetic potentials in order to write down a relativistic invariant action, which is just the inverse approach to the usual one. Also, Feynman's derivation of the Lorentz force exclusively follows from its linearity in the charge velocity and from relativistic invariance. Going further, i.e. adding the inhomogeneous Maxwell's equations, requires some more physical input, and can be done by just following conventional lines, hence this task was not pursued here. Despite its incompleteness, this way of proceeding is of great historical and epistemological significance. We also comment about its possible relevance to didactics, as an interesting supplement to usual treatments., Comment: 17 pages, no figures
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- 2019
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13. On Stanley Deser’s role in the development of quantum gravity
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Di Mauro, Marco, additional and Naddeo, Adele, additional
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- 2023
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14. A glimpse into Feynman's contributions to the debate on the foundations of quantum mechanics
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Di Mauro, Marco, additional, Esposito, Salvatore, additional, and Naddeo, Adele, additional
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- 2023
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15. A natural cure for causality violations in Newton-Schr\'odinger equation
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Maimone, Filippo, Scelza, Giovanni, and Naddeo, Adele
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Quantum Physics ,Condensed Matter - Other Condensed Matter - Abstract
It is explicitly shown that a one-family parameter model reproducing the nonlinear Newton-Schr\"odinger equation as the parameter goes to infinity is free from any causality violation problem for any finite value of it. This circumstance arises from the intrinsic mechanism of spontaneous state reduction of the model, absent in the Newton-Schr\"odinger limit. A specific ideal EPR experiment involving a superposition of two distinct CM's position states of a massive lump is analyzed, showing recovered compatibility with QM. Besides, the new framework suggests a soft version of the Many Worlds Interpretation, in which the typical indiscriminate proliferation of Everett branches, together with the bizarre inter-branches communications made possible by nonlinearity, are strongly suppressed in the macroscopic world by the same mechanism of state reduction., Comment: 11 pages, 2 figures
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- 2018
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16. When physics meets biology: a less known Feynman
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Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
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Physics - History and Philosophy of Physics ,Physics - Biological Physics ,Physics - Popular Physics ,Quantitative Biology - Other Quantitative Biology - Abstract
We discuss a less known aspect of Feynman's multifaceted scientific work, centered about his interest in molecular biology, which came out around 1959 and lasted for several years. After a quick historical reconstruction about the birth of molecular biology, we focus on Feynman's work on genetics with Robert S. Edgar in the laboratory of Max Delbruck, which was later quoted by Francis Crick and others in relevant papers, as well as in Feynman's lectures given at the Hughes Aircraft Company on biology, organic chemistry and microbiology, whose notes taken by the attendee John Neer are available. An intriguing perspective comes out about one of the most interesting scientists of the XX century., Comment: On the centenary of the birth of Richard P. Feynman (May 11, 1918 - February 15, 1988)
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- 2018
17. A two-particle simulation of Nonunitary Newtonian Gravity
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Scelza, Giovanni, Maimone, Filippo, and Naddeo, Adele
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Quantum Physics ,Condensed Matter - Other Condensed Matter - Abstract
The result of a numerical simulation of two interacting particles in the framework of Nonunitary Newtonian Gravity is presented here. Particles are held close together by a 3-d harmonic trap and interact with each other via an `electrical' delta-like potential and via the ordinary Newtonian term, together with a fluctuational nonunitary counterpart of the latter. Fundamental nonunitarity can be seen as arising from the interaction of the physical degrees of freedom with (gravitational) hidden copies of them. Starting from an energy eigenstate within the ordinary setting, it is shown that, while energy expectation remains constant, a slow net variation of the von Neumann entropy for the system as a whole takes place, with a small modulation induced on the relative entanglement entropy of the two particles. Besides, the simulation shows explicitly how fundamental gravity-induced entropy can be clearly distinguished from the subjective notion of coarse-grained entropy, i.e. from the entropy of one particle with respect to the `environment' of the other., Comment: 10 pages, 3 figures
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- 2018
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18. A hydrodynamic model for cooperating solidary countries
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De Luca, Roberto, Di Mauro, Marco, Falzarano, Angelo, and Naddeo, Adele
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Quantitative Finance - General Finance ,Physics - Physics and Society ,Quantitative Finance - Economics - Abstract
The goal of international trade theories is to explain the exchange of goods and services between different countries, aiming to benefit from it. Albeit the idea is very simple and known since ancient history, smart policy and business strategies need to be implemented by each subject, resulting in a complex as well as not obvious interplay. In order to understand such a complexity, different theories have been developed since the sixteenth century and today new ideas still continue to enter the game. Among them, the so called classical theories are country-based and range from Absolute and Comparative Advantage theories by A. Smith and D. Ricardo to Factor Proportions theory by E. Heckscher and B. Ohlin. In this work we build a simple hydrodynamic model, able to reproduce the main conclusions of Comparative Advantage theory in its simplest setup, i.e. a two-country world with country A and country B exchanging two goods within a genuine exchange-based economy and a trade flow ruled only by market forces. The model is further generalized by introducing money in order to discuss its role in shaping trade patterns. Advantages and drawbacks of the model are also discussed together with perspectives for its improvement., Comment: 8 pages, 2 figures
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- 2017
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19. Propensity to spending of an average consumer over a brief period
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De Luca, Roberto, Di Mauro, Marco, Falzarano, Angelo, and Naddeo, Adele
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Quantitative Finance - General Finance - Abstract
Understanding consumption dynamics and its impact on the whole economy and welfare within the present economic crisis is not an easy task. Indeed the level of consumer demand for different goods varies with the prices, consumer incomes and demographic factors. Furthermore crisis may trigger different behaviors which result in distortions and amplification effects. In the present work we propose a simple model to quantitatively describe the time evolution over a brief period of the amount of money an average consumer decides to spend, depending on his/her available budget. A simple hydrodynamical analog of the model is discussed. Finally, perspectives of this work are briefly outlined., Comment: 5 pages, 7 figures
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- 2017
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20. The effect of the behavior of an average consumer on the public debt dynamics
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De Luca, Roberto, Di Mauro, Marco, Falzarano, Angelo, and Naddeo, Adele
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Quantitative Finance - Economics - Abstract
An important issue within the present economic crisis is understanding the dynamics of the public debt of a given country, and how the behavior of average consumers and tax payers in that country affects it. Starting from a model of the average consumer behavior introduced earlier by the authors, we propose a simple model to quantitatively address this issue. The model is then studied and analytically solved under some reasonable simplifying assumptions. In this way we obtain a condition under which the public debt steadily decreases., Comment: 4 pages, 1 figures, submitted for publication to Physica A
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- 2017
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21. Measuring a Mass: The Puzzling History of an Elusive Particle.
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Di Grezia, Elisabetta, Esposito, Salvatore, and Naddeo, Adele
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NEUTRINOLESS double beta decay ,COLLISIONS (Nuclear physics) ,COSMIC rays ,NEUTRINOS ,NEUTRINO mass ,STANDARD model (Nuclear physics) ,NEUTRINO oscillation - Abstract
Since Pauli's hypothesis of their existence in 1930, neutrinos never ceased to bring into play novel ideas and to add new pieces of physics in the whole picture of fundamental interactions. They are only weakly interacting and, at odds with Standard Model's predictions, have a mass less than one millionth of the electron mass, which makes the investigation of their properties very challenging. The issue of the measurement of neutrino's rest mass gained a wider and wider consensus since its discovery through neutrino oscillations in 1998. Various neutrino sources are available for experiments, ranging from nuclear collisions of cosmic rays in the Earth atmosphere and supernova explosions to neutrino beams produced by accelerators and power reactors. These suggest different approaches to the experimental detection and measurement of the absolute value of the neutrino mass. In this paper, we retrace the intriguing story of this endeavor, focusing mainly on direct mass determination methods. The puzzling issue of the nature of massive neutrinos is addressed as well with explicit reference to the phenomenon of double beta-decay as a viable experimental tool to discriminate between Dirac's and Majorana's nature. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Achilles Overtakes the Turtle: Experiments and Theory Addressing Students' Difficulties with Infinite Processes
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De Luca, Roberto, Di Mauro, Marco, Naddeo, Adele, Onorato, Pasquale, and Rosi, Tommaso
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The difficulties students have in blending mathematics and physics are here analyzed, by focusing on the issue of a convergent series. We present an experimental and a theoretical analysis of some phenomena which can be investigated employing series, as the bouncing marble and Zeno's paradox of Achilles and the turtle. Measurements were carried out by students employing ICT instruments, such as the smartphone microphone, the smartphone camera or online motion sensors and results were the grounds for a deep discussion about the apparent paradox and the sources of students' misunderstanding. The activities were designed for students on introductory university courses or in advanced high-school classes and was implemented with 90 students of mathematics and physics who are interested in a curriculum addressed to the teaching of mathematics and physics at high school level. Results about their preconceptions before the sequence and some quotes of their metacognitive thinking after the activities are reported.
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- 2020
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23. A Look Inside Feynman’s Approach to Gravitation
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Di Mauro, Marco, additional, Esposito, Salvatore, additional, and Naddeo, Adele, additional
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- 2022
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24. SU(N) Multi-Skyrmions at Finite Volume
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Canfora, Fabrizio, Di Mauro, Marco, Kurkov, Maxim A., and Naddeo, Adele
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High Energy Physics - Theory ,High Energy Physics - Phenomenology ,Mathematical Physics ,Nuclear Theory - Abstract
We study multi-soliton solutions of the four-dimensional SU(N) Skyrme model by combining the hedgehog ansatz for SU(N) based on the harmonic maps of $S^{2}$ into $CP^{N-1}$ and a geometrical trick which allows to analyze explicitly finite-volume effects without breaking the relevant symmetries of the ansatz. The geometric setup allows to introduce a parameter which is related to the 't Hooft coupling of a suitable large $N$ limit, in which $N\rightarrow\infty$ and the curvature of the background metric approaches zero, in such a way that their product is constant. The relevance of such a parameter to the physics of the system is pointed out. In particular, we discuss how the discrete symmetries of the configurations depend on it., Comment: 29 pages, 7 figures, minor changes, matches published version
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- 2015
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25. Microscopic foundation of thermodynamics, transition to classicality and regularization of gravitational collapse singularities within non-unitary fourth-derivative gravity and its Newtonian limit
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Filippo, Sergio De and Naddeo, Adele
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- 2022
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26. Spin-orbit coupled Bose-Einstein condensates in a double well
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Citro, Roberta and Naddeo, Adele
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Condensed Matter - Quantum Gases - Abstract
We study the quantum dynamics of a spin-orbit (SO) coupled Bose-Einstein condensate (BEC) in a double-well potential inspired by the experimental protocol recently developed by NIST group. We focus on the regime where the number of atoms is very large and perform a two-mode approximation. An analytical solution of the two-site Bose-Hubbard-like Hamiltonian is found for several limiting cases, which range from a strong Raman coupling to a strong Josephson coupling, ending with the complete model in the presence of weak nonlinear interactions. Depending on the particular limit, different approaches are chosen: a mapping onto an SU(2) spin problem together with a Holstein-Primakoff transformation in the first two cases and a rotating wave approximation (RWA) when dealing with the complete model. The quantum evolution of the number difference of bosons with equal or different spin between the two wells is investigated in a wide range of parameters; finally the corresponding total atomic current and the spin current are computed. We show a spin Josephson effect which could be detected in experiments and employed to build up realistic devices., Comment: 18 pages
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- 2014
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27. Quantum Hall fluids in the presence of topological defects
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Iacomino, Patrizia, Marotta, Vincenzo, and Naddeo, Adele
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High Energy Physics - Theory - Abstract
We review our recent results on the physics of quantum Hall fluids at Jain and non conventional fillings within a general field theoretic framework. We focus on a peculiar conformal field theory (CFT), the one obtained by means of the m-reduction technique, and stress its power in describing strongly correlated low dimensional condensed matter systems in the presence of localized impurities or topological defects. By exploiting the notion of Morita equivalence for field theories on noncommutative two-tori and choosing rational values of the noncommutativity parameter, we find a general one-to-one correspondence between the m-reduced conformal field theory describing the quantum Hall fluid and an Abelian noncommutative field theory. As an example of application of the formalism, we study a quantum Hall bilayer at nonconventional fillings in the presence of a localized topological defect and briefly recall its boundary state structure corresponding to two different boundary conditions, the periodic as well as the twisted boundary conditions respectively, which give rise to different topological sectors on a torus. Then we introduce generalized magnetic translation operators as tensor products, which act on the quantum Hall fluid and defect space respectively, and compute their action on the boundary partition functions: in this way their role as boundary condition changing operators is fully evidenced. From such results we infer the general structure of generalized magnetic translations in our model and clarify the deep relation between noncommutativity and non-Abelian statistics of quasi-hole excitations, which is crucial for physical implementations of topological quantum computing., Comment: 38 pages, 3 figures, review article
- Published
- 2013
28. Searching for a response: the intriguing mystery of Feynman’s theoretical reference amplifier
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d’Alessandro, Vincenzo, Daliento, Santolo, Di Mauro, Marco, Esposito, Salvatore, and Naddeo, Adele
- Published
- 2019
- Full Text
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29. Nonequilibrium properties of an atomic quantum dot coupled to a Bose-Einstein condensate
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Citro, Roberta, Naddeo, Adele, and Romeo, Francesco
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Condensed Matter - Quantum Gases - Abstract
We study nonequilibrium properties of an atomic quantum dot (AQD) coupled to a Bose-Einstein condensate (BEC) within Keldysh-Green's function formalism when the AQD level is varied harmonically in time. Nonequilibrium features in the AQD energy absorption spectrum are the side peaks that develop as an effect of photon absorption and emission. We show that atoms can be efficiently transferred from the BEC into the AQD for the parameter regime of current experiments with cold atoms., Comment: 8 pages, 2 figures, to appear in the special issue "Novel Quantum Phases and Mesoscopic Physics in Quantum Gases" of The European Physical Journal - Special Topics
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- 2013
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30. Some insights into Feynman's approach to electrodynamics
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Di Mauro, Marco, additional, Esposito, Salvatore, additional, and Naddeo, Adele, additional
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- 2021
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31. Reduction of two theories by means of a mathematical limit : a historical review of past debates
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Di Mauro, Marco, additional, Drago, Antonino, additional, and Naddeo, Adele, additional
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- 2021
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32. Dissipative quantum mechanics and Kondo-like impurities on noncommutative two-tori
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Iacomino, Patrizia, Marotta, Vincenzo, and Naddeo, Adele
- Subjects
High Energy Physics - Theory ,Condensed Matter - Strongly Correlated Electrons - Abstract
In a recent paper, by exploiting the notion of Morita equivalence for field theories on noncommutative tori and choosing rational values of the noncommutativity parameter $\theta $ (in appropriate units), a general one-to-one correspondence between the $m$-reduced conformal field theory (CFT) describing a quantum Hall fluid (QHF) at paired states fillings $\nu =% \frac{m}{pm+2}$ and an Abelian noncommutative field theory (NCFT) has been established . That allowed us to add new evidence to the relationship between noncommutativity and quantum Hall fluids\cite% {ncmanybody}. On the other hand, the $m$-reduced CFT is equivalent to a system of two massless scalar bosons with a magnetic boundary interaction as introduced by Callan et al., at the so called ``magic''\ points. We are then able to describe, within such a framework, the dissipative quantum mechanics of a particle confined to a plane and subject to an external magnetic field normal to it. Here we develop such a point of view by focusing on the case $m=2$ which corresponds to a quantum Hall bilayer. The key role of a localized impurity which couples the two layers is emphasized and the effect of noncommutativity in terms of generalized magnetic translations (GMT) is fully exploited. As a result, general GMT operators are introduced, in the form of a tensor product, which act on the QHF and defect space respectively, and a comprehensive study of their rich structure is performed., Comment: 18 pages, 1 figure, accepted for publication in International Journal of Modern Physics A
- Published
- 2011
- Full Text
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33. Quantum dynamics of a binary mixture of BECs in a double well potential: an Holstein-Primakoff approach
- Author
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Citro, Roberta, Naddeo, Adele, and Orignac, Edmond
- Subjects
Condensed Matter - Quantum Gases ,Physics - Atomic Physics - Abstract
We study the quantum dynamics of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. Focussing on the regime where the number of atoms is very large, a mapping onto a SU(2) spin problem together with a Holstein-Primakoff transformation is performed. The quantum evolution of the number difference of bosons between the two wells is investigated for different initial conditions, which range from the case of a small imbalance between the two wells to a coherent spin state. The results show an instability towards a phase-separation above a critical positive value of the interspecies interaction while the system evolves towards a coherent tunneling regime for negative interspecies interactions. A comparison with a semiclassical approach is discussed together with some implications on the experimental realization of phase separation with cold atoms., Comment: 12 pages, 7 figures, accepted for publication in J. Phys. B
- Published
- 2011
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34. Quantum superpositions of a mirror for experimental tests for nonunitary Newtonian gravity
- Author
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Maimone, Filippo, Scelza, Giovanni, Naddeo, Adele, and Pelino, Vinicio
- Subjects
Condensed Matter - Other Condensed Matter ,Quantum Physics - Abstract
Aim of this work is to calculate explicitly the result of the experiment of superposition of a mirror in the Michelson photon cavities interferometric device proposed by Marshall, Simon, Penrose and Bownmeester, as expected within a recently proposed model of non-unitary self-gravity inducing localization. As for other proposals of modifications of Quantum Mechanics in a non-unitary sense, aimed to account for both unitary evolution and irreversible collapse, like in the famous Ghirardi-Rimini-Weber and Pearle's models, it turns out that, for the experimental parameters proposed, no effect is detectable at all. It is pointed out that the enhancing properties of matter granularity does not substantially change this conclusion. Parameters have also been exploratively varied in a certain range beyond the proposed values. It is shown that within `sensible' parameters, that are not yet attainable within current technology, the model exhibits a peculiar signature with respect to other collapse models as far as parameters space is explored. Besides, the calculation offers a way to see non-unitary gravity at work in a quasi-realistic setting., Comment: 16 pages, 3 figures
- Published
- 2011
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35. Paired quantum Hall states on noncommutative two-tori
- Author
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Marotta, Vincenzo and Naddeo, Adele
- Subjects
High Energy Physics - Theory - Abstract
By exploiting the notion of Morita equivalence for field theories on noncommutative tori and choosing rational values of the noncommutativity parameter theta (in appropriate units), a one-to-one correspondence between an abelian noncommutative field theory (NCFT) and a non-abelian theory of twisted fields on ordinary space can be established. Starting from this general result, we focus on the conformal field theory (CFT) describing a quantum Hall fluid (QHF) at paired states fillings nu =m/pm+2, recently obtained by means of m-reduction procedure, and show that it is the Morita equivalent of a NCFT. In this way we extend the construction proposed in a previous work (V. Marotta, A. Naddeo, Nucl. Phys. B 810(2009) 575) for the Jain series nu =m/2pm+1. The case m=2 is explicitly discussed and the role of noncommutativity in the physics of quantum Hall bilayers is emphasized. Our results represent a step forward the construction of a new effective low energy description of certain condensed matter phenomena and help to clarify the relationship between noncommutativity and quantum Hall fluids., Comment: 20 pages, 1 figure; Nuclear Physics B (2010), in print
- Published
- 2010
- Full Text
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36. Quantum Bose Josephson Junction with binary mixtures of BECs
- Author
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Naddeo, Adele and Citro, Roberta
- Subjects
Condensed Matter - Quantum Gases - Abstract
We study the quantum behaviour of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. We focus on the small tunneling amplitude regime and apply perturbation theory up to second order. Analytical expressions for the energy eigenvalues and eigenstates are obtained. Then the quantum evolution of the number difference of bosons between the two potential wells is fully investigated for two different initial conditions: completely localized states and coherent spin states. In the first case both the short and the long time dynamics is studied and a rich behaviour is found, ranging from small amplitude oscillations and collapses and revivals to coherent tunneling. In the second case the short-time scale evolution of number difference is determined and a more irregular dynamics is evidenced. Finally, the formation of Schroedinger cat states is considered and shown to affect the momentum distribution., Comment: 14 pages, 4 figures
- Published
- 2010
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37. Twisted Conformal Field Theories and Morita equivalence
- Author
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Marotta, Vincenzo and Naddeo, Adele
- Subjects
High Energy Physics - Theory - Abstract
The Morita equivalence for field theories on noncommutative two-tori is analysed in detail for rational values of the noncommutativity parameter theta (in appropriate units): an isomorphism is established between an abelian noncommutative field theory (NCFT) and a non-abelian theory of twisted fields on ordinary space. We focus on a particular conformal field theory (CFT), the one obtained by means of the m-reduction procedure (V. Marotta, J. Phys. A 26 (1993) 3481; V. Marotta, Mod. Phys. Lett. A 13} (1998) 853; V. Marotta, Nucl. Phys. B 527 (1998) 717; V. Marotta, A. Sciarrino, Mod. Phys. Lett. A 13 (1998) 2863), and show that it is the Morita equivalent of a NCFT. Finally, the whole m-reduction procedure is shown to be the image in the ordinary space of the Morita duality. An application to the physics of a quantum Hall fluid at Jain fillings nu =m/2pm+1 is explicitly discussed in order to further elucidate such a correspondence and to clarify its role in the physics of strongly correlated systems. A new picture emerges, which is very different from the existing relationships between noncommutativity and many body systems (A. P. Polychronakos, arXiv:0706.1095v2)., Comment: 16 pages, 2 figures
- Published
- 2009
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38. Introducing General Relativity in High Schools: a proposal for a Teaching-Learning Module.
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Mauro, Marco Di and Naddeo, Adele
- Published
- 2024
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39. A general CFT model for antiferromagnetic spin-1/2 ladders with Mobius boundary conditions
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
We show how the low-energy properties of the 2-leg XXZ spin-1/2 ladders with general anisotropy parameter $\Delta $ on closed geometries can be accounted for in the framework of the m-reduction procedure developed in [1]. In the limit of quasi-decoupled chains, a conformal field theory (CFT) with central charge c=2 is derived and its ability to describe the model with different boundary conditions is shown. Special emphasis is given to the Mobius boundary conditions which generate a topological defect corresponding to non trivial single-spinon excitations. Then, in the case of the 2-leg XXX ladders we discuss in detail the role of various perturbations in determining the renormalization group flow starting from the ultraviolet (UV) critical point with c=2., Comment: 23 pages, 5 figures; J. Stat. Mech.: Theory Exp. (2008), in print
- Published
- 2008
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40. The m-reduction in Conformal Field Theory as the Morita equivalence on two-tori
- Author
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Marotta, Vincenzo and Naddeo, Adele
- Subjects
High Energy Physics - Theory - Abstract
We study the Morita equivalence for field theories on noncommutative two-tori. For rational values of the noncommutativity parameter $\theta $ (in appropriate units) we show the equivalence between an abelian noncommutative field theory and a nonabelian theory of twisted fields on ordinary space. We concentrate on a particular conformal field theory (CFT), the one obtained by means of the m-reduction procedure (V. Marotta, J. Phys. A 26 (1993) 3481; Mod. Phys. Lett. A 13 (1998) 853; Nucl. Phys. B 527 (1998) 717), and show that the Morita equivalence also holds at this level. An application to the physics of a quantum Hall fluid at Jain fillings \nu =m/2pm+1 is explicitly considered in order to further elucidate such a correspondence., Comment: 12 pages, 1 figure
- Published
- 2008
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41. Topologically protected qubits as minimal Josephson junction arrays with non trivial boundary conditions: a proposal
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory ,Quantum Physics - Abstract
Recently a one-dimensional closed ladder of Josephson junctions has been studied (G. Cristofano et al., Phys. Lett. A 372 (2008) 2464) within a twisted conformal field theory (CFT) approach (G. Cristofano et al., Mod. Phys. Lett. A 15 (2000) 1679; Nucl. Phys. B 641 (2002) 547) and shown to develop the phenomenon of flux fractionalization (G. Cristofano et al., Eur. Phys. J. B 49 (2006) 83). That led us to predict the emergence of a topological order in such a system (G. Cristofano et al., JSTAT (2005) P03006). In this letter we analyze the ground states and the topological properties of fully frustrated Josephson junction arrays (JJA) arranged in a Corbino disk geometry for a variety of boundary conditions. In particular minimal configurations of fully frustrated JJA are considered and shown to exhibit the properties needed in order to build up a solid state qubit, protected from decoherence. The stability and transformation properties of the ground states of the JJA under adiabatic magnetic flux changes are analyzed in detail in order to provide a tool for the manipulation of the proposed qubit., Comment: 24 pages, 4 figures
- Published
- 2008
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42. Fully frustrated Josephson junction ladders with Mobius boundary conditions as topologically protected qubits
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
Quantum Physics ,Condensed Matter - Statistical Mechanics ,High Energy Physics - Theory - Abstract
We show how to realize a ``protected'' qubit by using a fully frustrated Josephson Junction ladder (JJL) with Mobius boundary conditions. Such a system has been recently studied within a twisted conformal field theory (CFT) approach (Mod. Phys. Lett. A 15 (2000) 1679; Nucl. Phys. B 641 (2002) 547) and shown to develop the phenomenon of flux fractionalization (Eur. Phys. J. B 49 (2006) 83). The relevance of a ``closed'' geometry has been fully exploited in relating the topological properties of the ground state of the system to the presence of half flux quanta and the emergence of a topological order has been predicted (JSTAT (2005) P03006). In this letter the stability and transformation properties of the ground states under adiabatic magnetic flux change are analyzed and the deep consequences on the realization of a solid state qubit, protected from decoherence, are presented., Comment: 21 pages, 2 figures, in print in Phys. Lett. A
- Published
- 2007
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43. Fermionic systems with charge correlations on the Bethe lattice
- Author
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Mancini, Ferdinando and Naddeo, Adele
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Statistical Mechanics - Abstract
A fermionic model, built up of q species of localized Fermi particles, interacting by charge correlations, is isomorphic to a spin-q/2 Ising model. However, the equivalence is only formal and the two systems exhibit a different physical behavior. By considering a Bethe lattice with q=1, we have exactly solved the models. There exists a critical temperature below which there is a spontaneous breakdown of the particle-hole symmetry for the first model, and of the spin symmetry for the second. While the spin system is always stable and exhibits a homogeneous ferromagnetic phase below T_{c}, the fermionic system for T
- Published
- 2007
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44. Inhomogeneous charge ordering of a spinless fermionic system on the Bethe lattice
- Author
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Mancini, Ferdinando, Mancini, Francesco Paolo, and Naddeo, Adele
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Statistical Mechanics - Abstract
We show that a system of spinless Fermi particles, localized on the sites of the Bethe lattice with coordination number z and interacting through a repulsive nearest-neighbor interaction, exhibits a phase transition to a charge-ordered state. The phase diagram in the n-T plane is derived. Relevant thermodynamic quantities, such as the free energy, the specific heat, the entropy and the compressibility are analyzed in detail., Comment: 7 pages, 9 figures
- Published
- 2007
45. Equations of motion approach to the spin-1/2 Ising model on the Bethe lattice
- Author
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Mancini, Ferdinando and Naddeo, Adele
- Subjects
Condensed Matter - Statistical Mechanics ,Condensed Matter - Strongly Correlated Electrons - Abstract
We exactly solve the ferromagnetic spin-1/2 Ising model on the Bethe lattice in the presence of an external magnetic field by means of the equations of motion method within the Green's function formalism. In particular, such an approach is applied to an isomorphic model of localized Fermi particles interacting via an intersite Coulomb interaction. A complete set of eigenoperators is found together with the corresponding eigenvalues. The Green's functions and the correlation functions are written in terms of a finite set of parameters to be self-consistently determined. A procedure is developed, that allows us to exactly fix the unknown parameters in the case of a Bethe lattice with any coordination number z. Non-local correlation functions up to four points are also provided together with a study of the relevant thermodynamic quantities., Comment: RevTex, 29 pages, 13 figures
- Published
- 2007
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46. Transport properties in bilayer Quantum Hall systems in the presence of a topological defect
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
Following a suggestion given in Phys. Lett. B 571(2003) 621, we show how a bilayer Quantum Hall system at fillings nu =1/p+1 can exhibit a point-like topological defect in its edge state structure. Indeed our CFT theory for such a system, the Twisted Model (TM), gives rise in a natural way to such a feature in the twisted sector. Our results are in agreement with recent experimental findings (Phys. Rev. B 72 (2005) 041305) which evidence the presence of a topological defect in the transport properties of the bilayer system., Comment: 10 pages, 4 figures; talk given by A. Naddeo at "X Training Course in the Physics of Correlated Electron Systems and High-Tc Superconductors, Vietri sul Mare (SA),Italy, 3-14 October 2005
- Published
- 2006
- Full Text
- View/download PDF
47. CFT description of the Fully Frustrated XY model and phase diagram analysis
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Minnhagen, Petter, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
Following a suggestion given in Nucl. Phys. B 300 (1988)611,we show how the U(1)*Z_{2} symmetry of the fully frustrated XY (FFXY) model on a square lattice can be accounted for in the framework of the m-reduction procedure developed for a Quantum Hall system at "paired states" fillings nu =1 (cfr. Cristofano et al.,Mod. Phys. Lett. A 15 (2000)1679;Nucl. Phys. B 641 (2002)547). The resulting twisted conformal field theory (CFT) with central charge c=2 is shown to well describe the physical properties of the FFXY model. In particular the whole phase diagram is recovered by analyzing the flow from the Z_{2} degenerate vacuum of the c=2 CFT to the infrared fixed point unique vacuum of the c=3/2 CFT. The last theory is known to successfully describe the critical behavior of the system at the overlap temperature for the Ising and vortex-unbinding transitions., Comment: 18 pages, 1 figure, to appear in JSTAT
- Published
- 2006
- Full Text
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48. Topological order and magnetic flux fractionalization in Josephson junction ladders with Mobius boundary conditions: a twisted CFT description
- Author
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Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
We propose a CFT description for a closed one-dimensional fully frustrated ladder of quantum Josephson junctions with Mobius boundary conditions (see cond-mat/0503555; we show how such a system can develop topological order thanks to flux fractionalization. Such a property is crucial for its implementation as a "protected" solid state qubit., Comment: 19 pages, 3 figures, to appear in Proceedings of PI-2005, 8-th International Conference on Path Integrals. From Quantum Information to Cosmology
- Published
- 2005
49. A Unifying Conformal Field Theory Approach to the Quantum Hall Effect
- Author
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Cristofano, Gerardo, Maiella, Giuseppe, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
We review the main results of the effective description of the Quantum Hall fluid for the Jain fillings, nu=m/2pm+1, and the non-standard ones nu=m/pm+2 by a conformal field theory (CFT) in two dimensions. It is stressed the unifying character of the m-reduction procedure to construct appropriate twisted CFT models, called Twisted Models (TM), which by construction reproduce the Quantum Hall topological properties at those fillings. Indeed for the Jain plateaux we find that the different descriptions given in the literature fall into different sectors of the TM for the torus topology. Other interesting aspects are explicitly seen for the m=2 non standard filling nu=1/p+1 (the pairing case) as the merging of non-Abelian statistics or the instability of the TM model (c=2) versus the Moore-Read one (c=3/2). Furthermore by using Boundary CFT techniques the presence of localized impurities and/or dissipation is shown to be closely connected with the twisted sector of the TM, whose presence assures the consistency of the construction and whose role in describing non trivial global properties of 2D quantum condensed matter systems is still under study., Comment: Review article to appear on Recent Research Developments in Physics-Transworld Research Network, Kerala, India (2005)
- Published
- 2005
50. Point-like topological defects in bilayer quantum Hall systems
- Author
-
Cristofano, Gerardo, Marotta, Vincenzo, Naddeo, Adele, and Niccoli, Giuliano
- Subjects
High Energy Physics - Theory - Abstract
Following a suggestion given in Phys. Lett. B 571 (2003) 250, we show how a bilayer Quantum Hall system at fillings nu =m/pm+2 can exhibit a point-like topological defect in its edge state structure. Indeed our CFT theory for such a system, the Twisted Model (TM), gives rise in a natural way to such a feature in the twisted sector. Our results are in agreement with recent experimental findings (cond-mat/0503478) which evidence the presence of a topological defect in the bilayer system., Comment: 9 pages, 3 figures
- Published
- 2005
- Full Text
- View/download PDF
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