1,786,413 research outputs found
Temperature and magnetic field dependence of a Kondo system in the weak coupling regime
Get PDFThe Kondo effect arises due to the interaction between a localized spin and the electrons of a surrounding host. Studies of individual magnetic impurities by scanning tunneling spectroscopy have renewed interest in Kondo physics; however, a quantitative comparison with theoretical predictions remained challenging. Here we show that the zero-bias anomaly detected on an organic radical weakly coupled to a Au (111) surface can be described with astonishing agreement by perturbation theory as originally developed by Kondo 60 years ago. Our results demonstrate that Kondo physics can only be fully conceived by studying both temperature and magnetic field dependence of the resonance. The identification of a spin 1/2 Kondo system is of relevance not only as a benchmark for predictions for Kondo physics but also for correlated electron materials in general.Peer reviewe
Quantum dot Josephson junctions in the Kondo regime
Get PDFIn this thesis, we study quantum dots (QD) fabricated from single-wall carbon nanotubes (SWCNT). The SWCNT are connected to source (S) and drain (D) leads by tunnelling contacts whose transparency is characterized by their respective coupling parameters, S and D. The leads consist of a Ti/Al double layer and become superconducting below the critical temperatureTC ~ 1K. By application of an external magnetic field B, we can suppress superconductivity and drive the leads into the normal state.
We measure the electrical transport through these QD systems at temperatures well below 1K. The differential conductivity G in dependency of a bias voltage VSD and a backgate voltage VBG reflects the successive filling of electron states on the QD, revealing whether the occupation is odd or even. For an odd occupation and normal metal leads, the Kondo effect will dominate transport when the coupling of the QD to the leads, = S + D, is large enough. The associated energy scale is parameterized by the Kondo temperature TK. In the presence of a BCS density of states (DOS) in the leads, a competition sets in between superconductivity and the Kondo effect. Both processes rely on the formation of opposing spin singlet states involving electrons in the leads. For TC > TK, the Kondo effect is suppressed, whereas it persists in the opposite regime, TC < TK. Both regimes have previously been studied in similar samples by electrical transport spectroscopy (PRL 89, 256801 (2002); NJP 9, 124 (2007)).
In chapter III, we report on the discovery of a third regime by studying a QD with highly asymmetrical coupling, S / D ~ 50. With superconducting leads, this asymmetry gives rise to a Kondo effect pinned to one lead only, illustrating the fact that TK dominates over TC at one contact, whereas TC > TK at the other. As a result, we observe a significant enhancement of a particular feature in non-equilibrium transport, the Andreev reflection, in states with this kind of asymmetrical Kondo effect.
In chapter IV, we expand our scope of investigation by comparing Kondo physics to the supercurrent IC that is transported through the QD. We extract the full supercurrent by following a fitting procedure based on the `extended resistively and capacitively shunted junction model' for overdamped Josephson junctions (Nature 439, 953 (2006); Nano Lett. 7, 2441 (2007)). Using VBG to tune T within one odd charge state, we drive the QD from
one regime (TK > TC) to the other (TC > TK). Since IC is very sensitive to the Kondo effect, it acts as a probe for the transition that occurs at the crossing between the two regimes (Nature Nanotech. 1, 53 (2006)). In a second odd charge state with larger , TK is always larger than TC, and consequently no transition is observed.
Chapters V and VI document our efforts to gain more direct control over the Kondo effect by means of topgates (TG). Ideally, such TG would allow us to tune S
and D individually, thus greatly increasing the possibilities for comprehension and manipulation of these complex systems. In chapter VI, we report on a TG dependent Kondo effect in the presence of an effective ferromagnetic field (Science 306, 86 (2004); Nature Physics 4, 373 (2008)). Albeit not based on direct control over S,D, this result has caught our interest and might stimulate further research in the same direction
Foldilecanium Kondo 2011
No full textKey to separate the known species of Foldilecanium Kondo 1. Stigmatic setae bulbose and/or spinose with sharp or rounded tips, totaling 3 (rarely 2 or 4) per stigmatic cleft; marginal setae bluntly to sharply spinose................................................................................................................................................. F. amazonensis Foldi, comb. nov. –- Stigmatic setae spinose with rounded tips, totaling 5-7 per stigmatic cleft; marginal setae bluntly spinose, with parallel sides................................................. F. multisetosus Kondo, sp. nov.Published as part of Kondo, Takumasa, 2011, Transfer of the myrmecophilous soft scale insect Neolecanium amazonensis Foldi to Foldilecanium gen. nov. (Hemiptera: Coccidae), with description of a new species from Colombia., pp. 1-10 in Insecta Mundi 2011 (167) on page 4, DOI: 10.5281/zenodo.516058
George Kondo Oral History Interview
No full textOral History Interview by Ken Verdoia with George Kondo. A business graduate of the University of California, Mr. Kondo was involved with an import-export business with Japan prior to the freezing of assets in advance of the war. Relocated to Topaz, Mr. Kondo was in the camp for only a few months before accepting a domestic job in the midwest, eventually working for the Japanese American Citizens League in San Francisco, California
Neotoumeyella Kondo and Williams 2009
No full textKey to adult females of Neotoumeyella species (adapted from Kondo and Williams 2009) 1. Dorsal microducts of two types: i) very large sclerotic pores (up to 43 μm in diameter) with a central microduct scattered throughout, in groups of 3–6 pores “like in a rosette” around body margin; plus, ii) smaller microducts, of the normal type (not associated with a sclerotized plate) present. Ventral tubular ducts without a terminal filament....... N. ferum (Hempel), comb. nov. — Dorsal microducts of one type: i) small, normal type of microduct (not associated with a large sclerotized plate) present. Ventral tubular ducts with a terminal filament............... 2 2(1). Ventral tubular ducts scarce, of one type............................................ 3 — Ventral tubular ducts abundant, of more than one type................................ 5 3(2). Ventral tubular ducts present around mouthparts and often near antennae. Spiracular pore band abruptly broadening just before stigmatic areas (up to 30 pores wide). Anal ring with six setae.................................. N. sonorensis (Cockerell and Parrott) — Ventral tubular ducts absent from around mouthparts and antennae. Spiracular pore band narrow throughout (2–6 pores wide). Anal ring with 8–10 setae............................. 4 4(3). Multilocular pores abundant in mid-ventral region of mesothorax. Stigmatic setae subequal in length..................................... N. cephalanthi Kondo and Williams — Multilocular pores absent from mid-ventral region of mesothorax. Stigmatic setae not subequal in length, median setae much longer than lateral setae. N. caliensis Kondo and Williams 5(2). Discoidal pores widespread over entire dorsum, except for a narrow submarginal band. Ventral tubular ducts present only up to area around posterior spiracular pore band. N. cerifera (Ferris) — Discoidal pores present around anal plates and extending only to mid-dorsum. Ventral tubular ducts present submarginally up to areas of anterior spiracular pore band.................................................................... N. leucaenae (Cockerell)Published as part of Kondo, Takumasa, 2018, A new combination and an update of Neotoumeyella Kondo and Williams, 2009 (Hemiptera: Coccomorpha: Coccidae), pp. 1-5 in Insecta Mundi 616 on page 4, DOI: 10.5281/zenodo.369939
Austrotachardiella colombiana Kondo and Gullan
No full textAustrotachardiella colombiana Kondo and Gullan Material studied. Colombia, Valle del Cauca: Alcalá: Finca La Pastora, 04°39 ′ 41.6 ″ N, 75°47 ′ 46.6 ″ W, 1240 m, 27.iv.2009, coll. J. Muñoz, ex avocado cv. 'Papelillo' ('Lorena'), 1 (UVCO). Distribution. Colombia (Kondo and Gullan 2005). Remarks. We found a single specimen of A. colombiana on the twig of a tree of the 'Lorena' cultivar. Austrotachardiella colombiana was originally described by Kondo and Gullan (2005) based on specimens collected on two cultivars of guava, Psidium guajava L. (Myrtaceae). This is the first record of this species on avocado worldwide. It is not considered a species of economic importance on avocados.Published as part of Kondo, Takumasa & Muñoz, Jazmín Adriana, 2016, Scale insects (Hemiptera: Coccoidea) associated with avocado crop, Persea americana Mill. (Lauraceae) in Valle del Cauca and neighboring departments of Colombia, pp. 1-24 in Insecta Mundi 2016 (465) on page 13, DOI: 10.5281/zenodo.464580
Local Kondo temperatures in atomic chains
No full textWe study the effect of disorder in strongly interacting small atomic chains. Using the Kotliar-Ruckenstein slave-boson approach, we diagonalize the Hamiltonian via scattering matrix theory. We numerically solve the Kondo transmission and the slave-boson parameters that allow us to calculate the Kondo temperature. We demonstrate that in the weak disorder regime, disorder in the energy levels of the dopants induces a nonscreened disorder in the Kondo couplings of the atoms. We show that disorder increases the Kondo temperature of a perfect chain. We find that this disorder in the couplings comes from a local distribution of Kondo temperatures along the chain. We propose two experimental setups where the impact of local Kondo temperatures can be observed.QN/Quantum NanoscienceApplied Science
‘It’s a-me, Mario!’ Exploring dynamic changes and similarities in the composition of early Nintendo video game music
Get PDFAs with films, a thoughtfully composed video game soundtrack has the ability to dramatically enhance and elevate the experience for the audience or player. This article explores the potential issues and difficulties of composing for video game systems by studying the sound-producing hardware and music for two popular systems from one manufacturer. By comparing two of Nintendo’s Super Mario titles, which appeared on both 8-bit and 16-bit systems, through an analysis of the technology, audio, visual (audiovisual), music, and gameplay elements, it is shown that the musical composition was affected by the limitations of processing power. The discussion shows how the composer, Koji Kondo, overcame the issues of limited computing power by using layers of repetition while applying various functions of music for film to enhance player immersion.
Kondo composed theme music that has become engrained in popular culture and is synonymous with one of Nintendo’s flagship franchises (Greening, 2014). By attempting to understand the method or approach behind the composition for earlier systems, it is possible to investigate and discuss the evolution of video game music while acknowledging and contributing to the study of music for games. A musical analysis of the Castle and Underwater themes on each system allows for a direct comparison of the compositional approach, while an audiovisual analysis reveals the presence of existing cinematic tropes and identifies potential influences on the creation of effective musical soundtracks for video games.
Applying audiovisual theory to games will require the use of existing literature from Lissa (1965), Gorbman (1987), Chion (1994) and Tagg (2004), along with the work of Collins (2005; 2007a; 2007b; 2008a; 2008b), which adapts and applies audiovisual analysis to video games
Description of a new species of Toumeyella Cockerell (Hemiptera: Coccidae) from Mexico, with a taxonomic key to Mexican species. Revista Brasileira de Entomologia 55 (2):229-233.
No full textABSTRACT. Description of a new species of Toumeyella Cockerell (Hemiptera, Coccidae) from Mexico, with a taxonomic key
to Mexican species. A new species of soft scale insect from Mexico, Toumeyella fontanai Kondo & Pellizzari sp. nov. is described and illustrated. A taxonomic key to the species of scale insects of the genus Toumeyella Cockerell known in Mexico is provided
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