Y. Sun, W. Tan, L. Liang, H. Jiang, Z. Wang, F. Liu, H. Chen
{"title":"Metamaterial analog of quantum interference: From electromagnetically induced transparency to absorption","authors":"Y. Sun, W. Tan, L. Liang, H. Jiang, Z. Wang, F. Liu, H. Chen","doi":"10.1209/0295-5075/98/64007","DOIUrl":"https://doi.org/10.1209/0295-5075/98/64007","url":null,"abstract":"With a metamaterial structure, the phenomenology observed in quantum electromagnetically induced transparency is reproduced. Through the parametric comparison between quantum and classical systems, the physical mechanism of this novel phenomenon has been explained directly in our analysis. In addition, we use another metamaterial structure to mimic a tripod four-level atom and reveal the analog of electromagnetically induced absorption. Our theoretical and experimental studies may not only bring an intuitive understanding of quantum interference in atomic system, but also provide useful guidelines for the design of microwave devices based on metamaterials.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126254622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Ouahrani, J. M. Menéndez, M. Marques, J. Contreras‐García, V. Baonza, J. Recio
{"title":"Local pressures in Zn chalcogenide polymorphs","authors":"T. Ouahrani, J. M. Menéndez, M. Marques, J. Contreras‐García, V. Baonza, J. Recio","doi":"10.1209/0295-5075/98/56002","DOIUrl":"https://doi.org/10.1209/0295-5075/98/56002","url":null,"abstract":"Using the rich polymorphism of ZnX (X: S, Se, Te) compounds, we show how local pressures can be unequivocally determined from i) first-principles total energy calculations, and ii) atomic volumes derived by means of topological analysis of crystalline electron densities. An analogy between atoms and mechanical resistors is put forward since these local pressures lead to the inverse of the thermodynamic pressure once their respective inverses are added up. Accordingly, we define the atomic-like mechanical conductance as a measure of the atomic volume reduction for energy unit under pressure, and prove that, in agreement with chemical hardness expectations, Zn has lower values than S, Se, and Te in all the polymorphs of the chalcogenide crystal family.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131959915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Cabibbo-Kobayashi-Maskawa density matrices","authors":"M. Fiolhais","doi":"10.1209/0295-5075/98/51001","DOIUrl":"https://doi.org/10.1209/0295-5075/98/51001","url":null,"abstract":"The flavor changing charged currents of the weak sector of the Standard Model are studied in the framework of a quantum statistical approach. The quantum superposition of same-type quarks, generated by the Cabibbo-Kobayashi-Maskawa matrix, is used to define three density matrices, one for each quark family. The properties of such density matrices are analyzed, in particular, the associated von Neumann entropy. It is proven that, due to the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, the quantum mixtures of quarks resulting from the weak interaction do not increase entropy and, therefore, the violation of CP and T symmetries cannot be related to the second law of thermodynamics.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134494262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stable states of E″ defects in α-quartz","authors":"R. Mashkovtsev, Y. Pan","doi":"10.1209/0295-5075/98/56005","DOIUrl":"https://doi.org/10.1209/0295-5075/98/56005","url":null,"abstract":"Several new radiation defects in triplet states occurring in electron-irradiated, synthetic α-quartz have been observed by using electron paramagnetic resonance (EPR) spectroscopy. These defects are stable at room temperature and above for years. The primary spin Hamiltonian parameter matrices g and D have now been determined for four stable triplet defects, which herein are labeled , and . Inter-electron distances estimated by using the magnetic dipole model suggest that the structures of new centers involve the unpaired electrons located in the orbitals of two silicon atoms next to one oxygen vacancy each. Our results suggest that the optical band at 5.67 eV is related to these triplet defects.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134326012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Word sense disambiguation via high order of learning in complex networks","authors":"T. C. Silva, D. R. Amancio","doi":"10.1209/0295-5075/98/58001","DOIUrl":"https://doi.org/10.1209/0295-5075/98/58001","url":null,"abstract":"Complex networks have been employed to model many real systems and as a modeling tool in a myriad of applications. In this paper, we use the framework of complex networks to the problem of supervised classification in the word disambiguation task, which consists in deriving a function from the supervised (or labeled) training data of ambiguous words. Traditional supervised data classification takes into account only topological or physical features of the input data. On the other hand, the human (animal) brain performs both low- and high-level orders of learning and it has facility to identify patterns according to the semantic meaning of the input data. In this paper, we apply a hybrid technique which encompasses both types of learning in the field of word sense disambiguation and show that the high-level order of learning can really improve the accuracy rate of the model. This evidence serves to demonstrate that the internal structures formed by the words do present patterns that, generally, cannot be correctly unveiled by only traditional techniques. Finally, we exhibit the behavior of the model for different weights of the low- and high-level classifiers by plotting decision boundaries. This study helps one to better understand the effectiveness of the model.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132210973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Turbulent patterns in wall-bounded flows: A Turing instability?","authors":"P. Manneville","doi":"10.1209/0295-5075/98/64001","DOIUrl":"https://doi.org/10.1209/0295-5075/98/64001","url":null,"abstract":"In their way to/from turbulence, plane wall-bounded flows display an interesting transitional regime where laminar and turbulent oblique bands alternate, the origin of which is still mysterious. In line with Barkley's recent work about the pipe flow transition involving reaction-diffusion concepts, we consider plane Couette flow in the same perspective and transform Waleffe's classical four-variable model of self-sustaining process into a reaction-diffusion model. We show that, upon fulfillment of a condition on the relative diffusivities of its variables, the featureless turbulent regime becomes unstable against patterning as the result of a Turing instability. A reduced two-variable model helps us to delineate the appropriate region of parameter space. An intrinsic status is therefore given to the pattern's wavelength for the first time. Virtues and limitations of the model are discussed, calling for a microscopic support of the phenomenological approach.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117119605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Strain and amorphization under light-ion implantation in SiC","authors":"S. Leclerc, M. Beaufort, J. Barbot, A. Déclemy","doi":"10.1209/0295-5075/98/46001","DOIUrl":"https://doi.org/10.1209/0295-5075/98/46001","url":null,"abstract":"Consequences of ion implantation on the strain build-up and the crystalline-to-amorphous transition have been studied in SiC as a function of the energy of the incident He ions. The ratio of strain to displacements per atom (dpa) determined from X-ray diffraction (XRD) measurements and simulations decreases with ion energy whilst a significant recombination of defects is ruled out. Transmission electron microscopy (TEM) experiments show that this resistance to strain occurring with increasing energy of implantation is concomitant with a resistance to amorphization. The crystalline-to-amorphous transition is not correlated with a threshold deposited nuclear energy or defect concentration as calculated by ion implantation computer codes but occurs once a critical strain estimated at about 10% is reached.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134056765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Earth rotation prevents exact solid-body rotation of fluids in the laboratory","authors":"P. Cortet, J. Boisson, D. C. 'ebron, F. Moisy","doi":"10.1209/0295-5075/98/59002","DOIUrl":"https://doi.org/10.1209/0295-5075/98/59002","url":null,"abstract":"We report direct evidence of a secondary flow excited by the Earth rotation in a water-filled spherical container spinning at constant rotation rate. This so-called tilt-over flow essentially consists in a rotation around an axis which is slightly tilted with respect to the rotation axis of the sphere. In the astrophysical context, it corresponds to the flow in the liquid cores of planets forced by precession of the planet rotation axis, and it has been proposed to contribute to the generation of planetary magnetic fields. We detect this weak secondary flow using a particle image velocimetry system mounted in the rotating frame. This secondary flow consists in a weak rotation, thousand times smaller than the sphere rotation, around a horizontal axis which is stationary in the laboratory frame. Its amplitude and orientation are in quantitative agreement with the theory of the tilt-over flow excited by precession. These results show that setting a fluid in a perfect solid-body rotation in a laboratory experiment is impossible —unless by tilting the rotation axis of the experiment parallel to the Earth rotation axis.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123766716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reply to comment by G. Geloni et al.","authors":"G. Robb, R. Bonifacio","doi":"10.1209/0295-5075/98/44002","DOIUrl":"https://doi.org/10.1209/0295-5075/98/44002","url":null,"abstract":"Gordon Robb and Rodolfo Bonifacio respond to G. Geloni's comments on \"Quantum effects in spontaneous emission by a relativistic, undulating electron beam\" by Robb G. R. M. and Bonifacio R.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126103986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Antchev, P. Aspell, I. Atanassov, I. Atanassov, V. Avati, J. Baechler, V. Berardi, M. Berretti, E. Bossini, M. Bozzo, P. Brogi, E. Brücken, A. Buzzo, F. Cafagna, M. Calicchio, M. Catanesi, C. Covault, M. Csanád, T. Csörgő, M. Deile, K. Eggert, V. Eremin, R. Ferretti, F. Ferro, A. Fiergolski, F. García, S. Giani, V. Greco, V. Greco, L. Grzanka, L. Grzanka, J. Heino, T. Hildén, M. Intonti, J. Kašpar, J. Kopal, V. Kundr'at, K. Kurvinen, S. Lami, G. Latino, R. Lauhakangas, T. Leszko, É. Lippmaa, M. Lokajicek, M. Vetere, F. L. Rodríguez, M. Macr'i, L. Magaletti, T. Mäki, A. Mercadante, N. Minafra, S. Minutoli, F. Nemes, F. Nemes, H. Niewiadomski, E. Oliveri, F. Oljemark, R. Orava, M. Oriunno, M. Oriunno, K. Osterberg, P. Palazzi, J. Proch'azka, M. Quinto, E. Radermacher, E. Radicioni, F. Ravotti, E. Robutti, L. Ropelewski, G. Ruggiero, H. Saarikko, A. Santroni, A. Scribano, W. Snoeys, J. Sziklai, C. Taylor, N. Turini, V. Vacek, M. Vitek, J. Welti, J. Whitmore
{"title":"Measurement of the forward charged-particle pseudorapidity density in pp collisions at √s = 7 TeV with the TOTEM experiment","authors":"G. Antchev, P. Aspell, I. Atanassov, I. Atanassov, V. Avati, J. Baechler, V. Berardi, M. Berretti, E. Bossini, M. Bozzo, P. Brogi, E. Brücken, A. Buzzo, F. Cafagna, M. Calicchio, M. Catanesi, C. Covault, M. Csanád, T. Csörgő, M. Deile, K. Eggert, V. Eremin, R. Ferretti, F. Ferro, A. Fiergolski, F. García, S. Giani, V. Greco, V. Greco, L. Grzanka, L. Grzanka, J. Heino, T. Hildén, M. Intonti, J. Kašpar, J. Kopal, V. Kundr'at, K. Kurvinen, S. Lami, G. Latino, R. Lauhakangas, T. Leszko, É. Lippmaa, M. Lokajicek, M. Vetere, F. L. Rodríguez, M. Macr'i, L. Magaletti, T. Mäki, A. Mercadante, N. Minafra, S. Minutoli, F. Nemes, F. Nemes, H. Niewiadomski, E. Oliveri, F. Oljemark, R. Orava, M. Oriunno, M. Oriunno, K. Osterberg, P. Palazzi, J. Proch'azka, M. Quinto, E. Radermacher, E. Radicioni, F. Ravotti, E. Robutti, L. Ropelewski, G. Ruggiero, H. Saarikko, A. Santroni, A. Scribano, W. Snoeys, J. Sziklai, C. Taylor, N. Turini, V. Vacek, M. Vitek, J. Welti, J. Whitmore","doi":"10.1209/0295-5075/98/31002","DOIUrl":"https://doi.org/10.1209/0295-5075/98/31002","url":null,"abstract":"The TOTEM experiment has measured the charged-particle pseudorapidity density dNch/dη in pp collisions at for 5.3<|η|<6.4 in events with at least one charged particle with transverse momentum above 40 MeV/c in this pseudorapidity range. This extends the analogous measurement performed by the other LHC experiments to the previously unexplored forward η region. The measurement refers to more than 99% of non-diffractive processes and to single and double diffractive processes with diffractive masses above ∼3.4 GeV/c2, corresponding to about 95% of the total inelastic cross-section. The dNch/dη has been found to decrease with |η|, from 3.84 ± 0.01(stat) ± 0.37(syst) at |η|=5.375 to 2.38±0.01(stat)±0.21(syst) at |η|=6.375. Several MC generators have been compared to data; none of them has been found to fully describe the measurement.","PeriodicalId":171520,"journal":{"name":"EPL (Europhysics Letters)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114994164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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