633 research outputs found
Squeezing light with Majorana fermions
Coupling a semiconducting nanowire to a microwave cavity provides a powerfull
means to assess the presence or absence of isolated Majorana fermions in the
nanowire. These exotic bound states can cause a significant cavity frequency
shift but also a strong cavity nonlinearity leading for instance to light
squeezing. The dependence of these effects on the nanowire gate voltages gives
direct signatures of the unique properties of Majorana fermions, such as their
self-adjoint character and their exponential confinement.Comment: long version: 11 pages, 5 figure
Direct cavity detection of Majorana pairs
No experiment could directly test the particle/antiparticle duality of
Majorana fermions, so far. However, this property represents a necessary
ingredient towards the realization of topological quantum computing schemes.
Here, we show how to complete this task by using microwave techniques. The
direct coupling between a pair of overlapping Majorana bound states and the
electric field from a microwave cavity is extremely difficult to detect due to
the self-adjoint character of Majorana fermions which forbids direct energy
exchanges with the cavity. We show theoretically how this problem can be
circumvented by using photo-assisted tunneling to fermionic reservoirs. The
absence of direct microwave transition inside the Majorana pair in spite of the
light-Majorana coupling would represent a smoking gun for the Majorana
self-adjoint character.Comment: 6 pages, 4 figure
Mise en place dâinterventions explicites adaptĂ©es visant Ă favoriser lâapprentissage des correspondances graphĂšmes-phonĂšmes
Dans cette recherche, des interventions explicites adaptées tenant compte d'études probantes seront expérimentées auprÚs d'élÚves de premiÚre année du primaire à risque d'avoir des difficultés en lecture, plus particuliÚrement en ce qui concerne l'acquisition des correspondances graphÚmes-phonÚmes
La construction discursive du sexe par le genre : une question matérialiste ?
En 1990, la fĂ©ministe amĂ©ricaine Judith Butler dĂ©fend une thĂšse constructiviste radicale sur la production discursive du sexe par le genre qui lie le sort des combats fĂ©ministes et queer dans une union contre le pouvoir des normes hĂ©tĂ©rosexistes. Mais cette singuliĂšre convergence des luttes a-t-elle un sens matĂ©rialiste ? Nous proposons ici de partir de la rĂ©ception problĂ©matique de Butler par le fĂ©minisme matĂ©rialiste français, afin de mettre au jour ce qui, dans la tradition marxiste, a pu faire obstacle Ă lâintĂ©gration dâune perspective queer. Faut-il maintenir la distinction des aspects symboliques et des aspects matĂ©riels de lâexistence sociale, qui place les questions de genre Ă lâextrĂ©mitĂ© culturelle de lâĂ©ventail des luttes ? Point dâachoppement central pour les critiques de Butler, la matiĂšre demande Ă ĂȘtre redĂ©finie, au prisme de la lecture althussĂ©rienne de Marx, comme matĂ©rialitĂ© discursive
Lâ« espace public » Ă lâĂ©preuve de la critique fĂ©ministe
Cet article fait partie dâun ensemble de contributions prĂ©sentĂ©es lors des Ă©changes annuels organisĂ©s entre lâĂ©cole doctorale de philosophie de lâuniversitĂ© Paris 1 PanthĂ©onâSorbonne et les Ă©coles doctorales de sciences politiques des universitĂ©s de Rome 3 et Rome 1. En 2013, le thĂšme de ces Ă©changes concernait « Lâespace public ». Ils eurent lieu successivement Ă Â Rome (mars 2013) et Ă Â Paris 1 (juin 2013). On trouvera donc rassemblĂ©s dans ce mĂȘme numĂ©ro les articles de Audrey Benoit (Paris 1), Francesca Di Lascio (Rome 3), Laura Fotia (Rome 3), Annick Jaulin (Paris 1), Clotilde NouĂ«t (Paris 1), Luca Scuccimarra (Rome 1), Diana Tasini (Rome 3) et Tommaso Visone (Rome 3). Pour donner une idĂ©e complĂšte des dĂ©bats de ces journĂ©es, il faudrait encore y ajouter la contribution de Bertrand Binoche : « Opinion publique, IdĂ©ologie et idĂ©ologie », publiĂ©e dans Scienza & Politica, vol. XXV, n° 47, 2012, p. 33â42 (http://scienzaepolitica.unibo.it/article/view/3837/3243)
Le matérialisme discursif. Pour une critique féministe de la construction idéologique du « sexe »
Le point de dĂ©part du travail est un constat : la thĂšse fĂ©ministe, que Judith Butler dĂ©fend en 1990 dans Trouble dans le genre, selon laquelle la catĂ©gorie de « sexe » ne dĂ©crit pas la rĂ©alitĂ© naturelle de la diffĂ©rence de lâhomme et de la femme, mais relĂšve dâune construction discursive produite par les normes hĂ©tĂ©rosexistes du genre, a rencontrĂ© dâimportantes rĂ©sistances thĂ©oriques, jusque dans certains cercles fĂ©ministes et/ou matĂ©rialistes. Le parti pris qui est celui de Butler en 1990, d..
Finite frequency noise of a superconductor/ferromagnet quantum point contact
We have calculated the finite-frequency current noise of a
superconductor-ferromagnet quantum point contact (SF QPC). This signal is
qualitatively affected by the spin-dependence of interfacial phase shifts
(SDIPS) acquired by electrons upon reflection on the QPC. For a weakly
transparent QPC, noise steps appear at frequencies or voltages determined
directly by the SDIPS. These steps can occur at experimentally accessible
temperatures and frequencies. Finite frequency noise is thus a promising tool
to characterize the scattering properties of a SF QPC.Comment: 5 pages, 3 figures, revised version, to appear in Phys. Rev. Let
Modulation of drug sensitivity in yeast cells by the ATPâbinding domain of human DNA topoisomerase IIα
Epipodophyllotoxins are effective antitumour drugs that trap eukaryotic DNA topoisomerase II in a covalent complex with DNA. Based on DNA cleavage assays, the mode of interaction of these drugs was proposed to involve amino acid residues of the catalytic site. An in vitro binding study, however, revealed two potential binding sites for etoposide within human DNA topoisomerase IIα (htopoIIα), one in the catalytic core of the enzyme and one in the ATPâbinding Nâterminal domain. Here we have tested how Nâterminal mutations that reduce the affinity of the site for etoposide or ATP affect the sensitivity of yeast cells to etoposide. Surprisingly, when introduced into fullâlength enzymes, mutations that lower the drug binding capacity of the Nâterminal domain in vitro render yeast more sensitive to epipodophyllotoxins. Consistently, when the htopoIIα Nâterminal domain alone is overexpressed in the presence of yeast topoII, cells become more resistant to etoposide. Point mutations that weaken etoposide binding eliminate this resistance phenotype. We argue that the Nâterminal ATPâbinding pocket competes with the active site of the holoenzyme for binding etoposide both in cis and in trans with different outcomes, suggesting that each topoisomerase II monomer has two nonâequivalent drugâbinding site
Classroom anxiety and enjoyment in CLIL and non-CLIL: Does the target language matter?
This study investigates pupilsâ anxiety and enjoyment in the classroom when learning a second or foreign language. The particularity of this study lies in the comparison of two target languages (English and Dutch) in two educational contexts (CLIL and non-CLIL) at different instruction levels (primary and secondary education). While most research on content and language integrated learning (CLIL) focuses on English as a target language, the Belgian context calls for a comparison with the language of the âotherâ community, in this case Dutch. Data were collected from 896 pupils in French-speaking Belgium through a self-report questionnaire measuring pupilsâ anxiety and enjoyment in the classroom, along with background characteristics. Results indicate that while CLIL pupils experience significantly less anxiety than their non-CLIL counterparts, English learners report significantly less anxiety and more enjoyment than Dutch learners. This suggests an important role of the target language for emotional engagement in the classroom and calls for further investigation into the role of target language perceptions. Finally, the interactions with instruction level reveal that while primary school pupils report stronger emotions, the effects of CLIL and English are much larger at secondary level
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