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243 results on '"Longobardi, L."'

4. Breakdown of the escape dynamics in Josephson junctions

Author

Massarotti, D., Stornaiuolo, D., Lucignano, P., Galletti, L., Born, D., Rotoli, G., Lombardi, F., Longobardi, L., Tagliacozzo, A., and Tafuri, F.

Subjects
Condensed Matter - Superconductivity
Abstract

We have identified anomalous behavior of the escape rate out of the zero-voltage state in Josephson junctions with a high critical current density Jc. For this study we have employed YBa2Cu3O7-x grain boundary junctions, which span a wide range of Jc and have appropriate electrodynamical parameters. Such high Jc junctions, when hysteretic, do not switch from the superconducting to the normal state following the expected stochastic Josephson distribution, despite having standard Josephson properties such as a Fraunhofer magnetic field pattern. The switching current distributions (SCDs) are consistent with nonequilibrium dynamics taking place on a local rather than a global scale. This means that macroscopic quantum phenomena seem to be practically unattainable for high Jc junctions. We argue that SCDs are an accurate means to measure nonequilibrium effects. This transition from global to local dynamics is of relevance for all kinds of weak links, including the emergent family of nanohybrid Josephson junctions. Therefore caution should be applied in the use of such junctions in, for instance, the search for Majorana fermions., Comment: 8 pages, 4 figures

Published
2015
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5. Macroscopic quantum tunneling in spin filter ferromagnetic Josephson junctions

Author

Massarotti, D., Pal, A., Rotoli, G., Longobardi, L., Blamire, M. G., and Tafuri, F.

Subjects
Condensed Matter - Superconductivity
Abstract

The interfacial coupling of two materials with different ordered phases, such as a superconductor (S) and a ferromagnet (F) is driving new fundamental physics and innovative applications. For example, the creation of spin-filter Josephson junctions and the demonstration of triplet supercurrents have suggested the potential of a dissipationless version of spintronics based on unconventional superconductivity. Here we demonstrate evidence for active quantum applications of S-F-S junctions, through the observation of macroscopic quantum tunneling in Josephson junctions with GdN ferromagnetic insulator barriers. We prove a clear transition from thermal to quantum regime at a crossover temperature of about 100 mK at zero magnetic field in junctions which demonstrate a clear signature of unconventional superconductivity. Following previous demonstration of passive S-F-S phase shifters in a phase qubit, our result paves the way to the active use of spin filter Josephson systems in quantum hybrid circuits., Comment: 16 pages, 4 figures

Published
2015
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6. Resolving the effects of frequency dependent damping and quantum phase diffusion in YBa$_2$Cu$_3$O$_{7-x}$ Josephson junctions

Author

Stornaiuolo, D., Rotoli, G., Massarotti, D., Carillo, F., Longobardi, L., Beltram, F., and Tafuri, F.

Subjects
Condensed Matter - Superconductivity
Abstract

We report on the study of the phase dynamics of high critical temperature superconductor Josephson junctions. We realized YBa$_2$Cu$_3$O$_{7-x}$ (YBCO) grain boundary (GB) biepitaxial junctions in the submicron scale, using low loss substrates, and analyzed their dissipation by comparing the transport measurements with Monte Carlo simulations. The behavior of the junctions can be fitted using a model based on two quality factors, which results in a frequency dependent damping. Moreover, our devices can be designed to have Josephson energy of the order of the Coulomb energy. In this unusual energy range, phase delocalization strongly influences the device's dynamics, promoting the transition to a quantum phase diffusion regime. We study the signatures of such a transition by combining the outcomes of Monte Carlo simulations with the analysis of the device's parameters, the critical current and the temperature behavior of the low voltage resistance $R_0$., Comment: 8 pages, 4 figures

Published
2013
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7. High critical-current density and scaling of phase-slip processes in YBaCuO nanowires

Author

Papari, G., Carillo, F., Stornaiuolo, D., Longobardi, L., Beltram, F., and Tafuri, F.

Subjects
Condensed Matter - Superconductivity
Abstract

YBaCuO nanowires were reproducibly fabricated down to widths of 50 nm. A Au/Ti cap layer on YBCO yielded high electrical performance up to temperatures above 80 K in single nanowires. Critical current density of tens of MA/cm2 at T = 4.2 K and of 10 MA/cm2 at 77 K were achieved that survive in high magnetic fields. Phase-slip processes were tuned by choosing the size of the nanochannels and the intensity of the applied external magnetic field. Data indicate that YBCO nanowires are rather attractive system for the fabrication of efficient sensors, supporting the notion of futuristic THz devices., Comment: 8 pages, 3 figures. Accepted for publication in Superconductor Science and Technology

Published
2012
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20. Phenological segregation suggests speciation by time in the planktonic diatom Pseudo-nitzschia allochrona sp. nov

Author

Rachele Rossi, Longobardi L, Adriana Zingone, Roberta Piredda, Maria Valeria Ruggiero, Isabella Percopo, and Diana Sarno

Subjects
0106 biological sciences, Sympatry, Ecological niche, 0303 health sciences, biology, Phenology, Ecology, media_common.quotation_subject, Reproductive isolation, Plankton, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, 03 medical and health sciences, Speciation, Diatom, 14. Life underwater, Pseudo-nitzschia, 030304 developmental biology, media_common
Abstract

The emergence of new species is poorly understood in marine plankton, where the lack of physical barriers and homogeneous environmental conditions limit spatial and ecological segregation. Here we combine molecular and ecological information from a long term time series and propose Pseudo-nitzschia allochrona, a new cryptic diatom, as a possible case of speciation by temporal segregation. The new species differs in several genetic markers (18S, LSU and ITS rDNA fragments and rbcL) and is reproductively isolated from its closest relative, which is morphologically identical. Data from a long term plankton time series show Pseudo-nitzschia allochrona invariably occurring in summer-autumn in the Gulf of Naples, where its sister species are instead found in winter-spring. Temperature and nutrients are the main factors associated with the occurrence of P. allochrona, which could have evolved in sympatry by switching its phenology and occupying a new ecological niche. This case of possible speciation by time shows the relevance of combining ecological time series with molecular information to shed light on the eco-evolutionary dynamics of marine microorganisms.

Published
2021
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31. Bias current ramp rate dependence of the crossover temperature from Kramers to phase diffusion switching in moderately damped NbN/AlN/NbN Josephson junctions.

Author

Lisitskiy, M., Massarotti, D., Galletti, L., Longobardi, L., Rotoli, G., Russo, M., Tafuri, F., and Ruggiero, B.

Subjects
JOSEPHSON junctions, PHASE transitions, TEMPERATURE effect, DAMPING capacity, DIFFUSION
Abstract

We investigate the phase dynamics of moderately damped NbN/AlN/NbN Josephson junctions and we present experimental results on detailed aspects of phase diffusion processes. We measure both single escape and multiple escape and retrapping events obtaining a crossover temperature T* from Kramers to phase diffusion switching. We observe a clear dependence of the crossover temperature T* by the bias current ramp rate, while the damping factor Q remains the same. The measured effect is in strong agreement with theoretical predictions reported by Fenton and Warburton. [ABSTRACT FROM AUTHOR]

Published
2014
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32. Plankton dynamics across the freshwater, transitional 1 and marine research sites of the LTER-Italy Network. Patterns, fluctuations, drivers

Author

Morabito, G, Mazzocchi, Mg, Salmaso, N, Zingone, A, Bergami, C, Flaim, G., Accoroni, S, Basset, A, Bastianini, M, Belmonte, G, F Bernardi Aubry, Bertani, I, Bresciani, M, Buzzi, F, Cabrini, M, Camatti, E, Caroppo, C, Cataletto, B, Castellano, M, P Del Negro, A de Olazabal, I Di Capua, Elia, Ac, Fornasaro, D, Giallain, M, Grilli, F, Leoni, B, Lipizer, M, Longobardi, L, Ludovisi, A, Lugliè, A, Manca, M, Margiotta, F, A Mariani, M, Marini, M, Marzocchi, M, Obertegger, U, Oggioni, A, Mario, B, Padedda, Pansera, M, Piscia, R, Povero, P, Pulina, S, Romagnoli, T, Rosati, I, Rossetti, G, Rubino, F, Sarno, D, T Satta, C, Sechi, N, Stanca, E, Tirelli, V, Totti, C, and Pugnetti, A

Subjects
Aquatic ecosystems LTER-Italy Mesozooplankton Phytoplankton
Published
2018

34. Escape dynamics in moderately damped Josephson junctions

Author

MASSAROTTI D, LONGOBARDI L, GALLETTI L, STORNAIUOLO D, MONTEMURRO D, PEPE G, BARONE A, ROTOLI, Giacomo, TAFURI, Francesco, Massarotti, Davide, Longobardi, L., Galletti, L., Stornaiuolo, Daniela, Montemurro, D., Pepe, GIOVANNI PIERO, Rotoli, G., Barone, A., Tafuri, Francesco, Massarotti, D, Longobardi, L, Galletti, L, Stornaiuolo, D, Montemurro, D, Pepe, G, Rotoli, Giacomo, and Barone, A

Subjects
Superconductivity phase diagram, Condensed Matter::Superconductivity, Critical currents, Josephson device
Abstract

"The Josephson effect is a privileged access to the macroscopic quantum nature of superconductors. We review some ideas and experimental techniques on macroscopic quantum decay phenomena occurring in Josephson structures. The attention is mainly addressed to intermediate levels of dissipation which characterize a large majority of low critical currentJosephson devices and are therefore an avoidable consequence of nanotechnology applied more and more to Josephson devices. Phase diffusion phenomena take over thermal activation in some temperature ranges also affecting the transition to macroscopic quantum tunneling, enriching the phase diagram mostly defined by the Josephson energy, the temperature and the level of dissipation."

Published
2012

35. Plankton dynamics across the freshwater, transitional and marine research sites of the LTER-Italy Network. Patterns, fluctuations, drivers

Author

Morabito, G, Mazzocchi, M, Salmaso, N, Zingone, A, Bergami, C, Flaim, G, Accoroni, S, Basset, A, Bastianini, M, Belmonte, G, Bernardi Aubry, F, Bertani, I, Bresciani, M, Buzzi, F, Cabrini, M, Camatti, E, Caroppo, C, Cataletto, B, Castellano, M, Del Negro, P, de Olazabal, A, Di Capua, I, Elia, A, Fornasaro, D, Giallain, M, Grilli, F, Leoni, B, Lipizer, M, Longobardi, L, Ludovisi, A, Lugliè, A, Manca, M, Margiotta, F, Mariani, M, Marini, M, Marzocchi, M, Obertegger, U, Oggioni, A, Padedda, B, Pansera, M, Piscia, R, Povero, P, Pulina, S, Romagnoli, T, Rosati, I, Rossetti, G, Rubino, F, Sarno, D, Satta, C, Sechi, N, Stanca, E, Tirelli, V, Totti, C, Pugnetti, A, Mazzocchi, MG, Elia, AC, Mariani, MA, Padedda, BM, Satta, CT, Morabito, G, Mazzocchi, M, Salmaso, N, Zingone, A, Bergami, C, Flaim, G, Accoroni, S, Basset, A, Bastianini, M, Belmonte, G, Bernardi Aubry, F, Bertani, I, Bresciani, M, Buzzi, F, Cabrini, M, Camatti, E, Caroppo, C, Cataletto, B, Castellano, M, Del Negro, P, de Olazabal, A, Di Capua, I, Elia, A, Fornasaro, D, Giallain, M, Grilli, F, Leoni, B, Lipizer, M, Longobardi, L, Ludovisi, A, Lugliè, A, Manca, M, Margiotta, F, Mariani, M, Marini, M, Marzocchi, M, Obertegger, U, Oggioni, A, Padedda, B, Pansera, M, Piscia, R, Povero, P, Pulina, S, Romagnoli, T, Rosati, I, Rossetti, G, Rubino, F, Sarno, D, Satta, C, Sechi, N, Stanca, E, Tirelli, V, Totti, C, Pugnetti, A, Mazzocchi, MG, Elia, AC, Mariani, MA, Padedda, BM, and Satta, CT

Abstract

A first synoptic and trans-domain overviewof plankton dynamics was conducted across the aquatic sites belonging to the Italian Long-Term Ecological Research Network (LTER-Italy). Based on published studies, checked and complemented with unpublished information, we investigated phytoplankton and zooplankton annual dynamics and long-term changes across domains: from the large subalpine lakes to mountain lakes and artificial lakes, from lagoons to marine coastal ecosystems. This study permitted identifying common and unique environmental drivers and ecological functional processes controlling seasonal and long-termtemporal course. The most relevant patterns of plankton seasonal succession were revealed, showing that the driving factors were nutrient availability, stratification regime, and freshwater inflow. Phytoplankton and mesozooplankton displayed a wide interannual variability at most sites. Unidirectional or linear long-term trends were rarely detected but all sites were impacted across the years by at least one, but in many case several major stressor(s): nutrient inputs, meteo-climatic variability at the local and regional scale, and direct human activities at specific sites. Different climatic and anthropic forcings frequently co-occurred, whereby the responses of plankton communities were the result of this environmental complexity. Overall, the LTER investigations are providing an unparalleled framework of knowledge to evaluate changes in the aquatic pelagic systems and management options

Published
2018

37. What happens in Josephson junctions at high critical current densities

Author

Massarotti, D., primary, Stornaiuolo, D., additional, Lucignano, P., additional, Caruso, R., additional, Galletti, L., additional, Montemurro, D., additional, Jouault, B., additional, Campagnano, G., additional, Arani, H. F., additional, Longobardi, L., additional, Parlato, L., additional, Pepe, G. P., additional, Rotoli, G., additional, Tagliacozzo, A., additional, Lombardi, F., additional, and Tafuri, F., additional

Published
2017
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39. Resolving the effects of frequency-dependent damping and quantum phase diffusion in YBa2Cu3O7-x Josephson junctions

Author

Stornaiuolo D., Rotoli G., Massarotti D., Longobardi L., Tafuri F., CARILLO, Franco, BELTRAM, Fabio, Stornaiuolo, Daniela, G., Rotoli, Massarotti, Davide, F., Carillo, L., Longobardi, F., Beltram, Tafuri, Francesco, Stornaiuolo, D., Rotoli, G., Massarotti, D., Carillo, Franco, Longobardi, L., Beltram, Fabio, and Tafuri, F.

Subjects
Superconductivity (cond-mat.supr-con), Condensed Matter - Superconductivity, Condensed Matter::Superconductivity, FOS: Physical sciences
Abstract

We report on the study of the phase dynamics of high critical temperature superconductor Josephson junctions. We realized YBa$_2$Cu$_3$O$_{7-x}$ (YBCO) grain boundary (GB) biepitaxial junctions in the submicron scale, using low loss substrates, and analyzed their dissipation by comparing the transport measurements with Monte Carlo simulations. The behavior of the junctions can be fitted using a model based on two quality factors, which results in a frequency dependent damping. Moreover, our devices can be designed to have Josephson energy of the order of the Coulomb energy. In this unusual energy range, phase delocalization strongly influences the device's dynamics, promoting the transition to a quantum phase diffusion regime. We study the signatures of such a transition by combining the outcomes of Monte Carlo simulations with the analysis of the device's parameters, the critical current and the temperature behavior of the low voltage resistance $R_0$., Comment: 8 pages, 4 figures

Published
2013

43. Paroxetine and fluoxetine effects on mood and cognitive functions in depressed nondemented elderly patients

Author

Cassano G, B, Puca F, Scapicchio P, L, Trabucchi M, Aguglia E, Albano C, Bruzzone G, Antico L, Guidi L, Tricerfi A, Cappa C, Smerieri G, Simonini E, Tilli C, Caserta F, Varia S, Cerqua R, Califano M, Cerqua G, Chioma V, Bertuzzi D, Menetti M, Corsonello F, Zottola C, Pranno L, De Candia R, Di Fiorino M, Cerfi A, Bani A, Fichera G, Bonomol G, Giberti G, Cassis S, Grumelli B, Galetti G, Anni G, Guala A, Lancia U, Saponaro A, Longobardi L, Bruni A, Macchione C, Fantò F, Baietto T, Martucci M, Faronl J, Calandriello L, Meduri M, Di Rosa A, E, Cacciola M, Mordechai M, Zuccaro S, M, Palummeri E, Cella A, Trasciatti S, Paolucci S, Coiro R, Pedone V, Angelini A, Piani F, Righini D, Puca E, Brancasi B, Rengo F, Cacciatore F, Robotti C, A, Bilone F, Nicotra M, C, Rotolo V, Salsi A, De Carolis S, Scarpino O, Del Gobbo M, Sdanganelli F, Di Biase A, Pontrelli B, Spilimbergo P, G, Di Costanzo E, Matranga M, Stocchi E, Grassini P, Valenti G, Fontana V, Venuta M, Guaraldi G, P, Zanni L, Verrienti P, Stoppelli N, Scardino V, Vischia F, Pirfo E., ABETE, PASQUALE, Cassano, G, B, Puca, F, Scapicchio, P, L, Trabucchi, M, Aguglia, E, Albano, C, Bruzzone, G, Antico, L, Guidi, L, Tricerfi, A, Cappa, C, Smerieri, G, Simonini, E, Tilli, C, Caserta, F, Varia, S, Cerqua, R, Califano, M, Cerqua, G, Chioma, V, Bertuzzi, D, Menetti, M, Corsonello, F, Zottola, C, Pranno, L, De Candia, R, Di Fiorino, M, Cerfi, A, Bani, A, Fichera, G, Bonomol, G, Giberti, G, Cassis, S, Grumelli, B, Galetti, G, Anni, G, Guala, A, Lancia, U, Saponaro, A, Longobardi, L, Bruni, A, Macchione, C, Fantò, F, Baietto, T, Martucci, M, Faronl, J, Calandriello, L, Meduri, M, Di Rosa, A, E, Cacciola, M, Mordechai, M, Zuccaro, S, M, Palummeri, E, Cella, A, Trasciatti, S, Paolucci, S, Coiro, R, Pedone, V, Angelini, A, Piani, F, Righini, D, Puca, E, Brancasi, B, Rengo, F, Abete, Pasquale, Cacciatore, F, Robotti, C, A, Bilone, F, Nicotra, M, Rotolo, V, Salsi, A, De Carolis, S, Scarpino, O, Del Gobbo, M, Sdanganelli, F, Di Biase, A, Pontrelli, B, Spilimbergo, P, G, Di Costanzo, E, Matranga, M, Stocchi, E, Grassini, P, Valenti, G, Fontana, V, Venuta, M, Guaraldi, G, P, Zanni, L, Verrienti, P, Stoppelli, N, Scardino, V, Vischia, F, and Pirfo, E.

Published
2002

49. Development and testing of a persistent flux bias for qubits

Author

Longobardi, L., Pottorf, S., Patel, V., and Lukens, J.E.

Subjects
Quantum electronics -- Research, Niobium -- Electric properties, Electric circuits -- Design and construction, Business, Electronics, Electronics and electrical industries
Abstract

The development and testing of an on-chip persistent flux bias for flux qubit by adding an aluminum shunt to the niobium bias coil is reported.

Published
2007

50. Breakdown of the escape dynamics in Josephson junctions

Author

Massarotti, D., primary, Stornaiuolo, D., additional, Lucignano, P., additional, Galletti, L., additional, Born, D., additional, Rotoli, G., additional, Lombardi, F., additional, Longobardi, L., additional, Tagliacozzo, A., additional, and Tafuri, F., additional

Published
2015
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