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Inès Safi Home Page / Page personnelle

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Research activities

During her PhD in Orsay (defended in 96) under the direction of the late H. J. Schulz, Ines Safi has predicted the charge fractionalization in quantum wires, by introducing chiral plasmonic density operators and proposing uni-directional injection of electrons. This study was further investigated by K. V. Pham and collaborators two years later. Attempts were recently performed to test experimentally the phenomena by the group of A. Yacoby in Harvard. Nevertheless, it holds in an infinite wire, and can be modified by connection to charge reservoirs. In order to take into account the latter, Inès Safi proposed an original model, simultanously with D. Maslov (his paper was submitted one week after!). The prediction of DC conductance was confirmed very soon by the group of Tarucha in Japan, and by others later on. This gave rise to a fruitful debate, and the model was finally recognized as the most suited to study quantum transport in quantum wires and carbon nanotubes, as confirmed by other approaches. In particular, Inès Safi has discovered a new crucial phenomena, a momentum-conserving reflection of an electron impinging on an interacting wire, which can also be extended to edge states in the fractional quantum Hall regime. During her postdoctoral period in CEA (96-98, Orme des Merisiers, France), revisiting the results of Kane and Fisher close to resonance, Inès Safi has explained some of the features of the experimental observation of fractional charge through shot noise measurement by the group of C. Glattli, cited in the Nobel lecture of Laughlin. After getting a permanent position in CNRS in 1998, she moved to CPT in Marseille where she has proposed for the first time to use noise correlations to detect fractional statistics, through a three-terminal set-up (coll. T. Martin). She has also started to develop a general Keldysh approach to treat both DC and AC current and finite-frequency noise in chiral and non-chiral systems, and for general Hamiltonians depending on both conjugate bosonic fields, a situation not treated before. This field has been pursued by the group of Marseille after she returned to LPS in Orsay (in 2000). She has been an expert in out-of equilibrium transport in one dimensional systems, studying non-linear current and high-frequency noise in those systems, in particular with her two previous post-doctorates Bjoern Trauzettel and Cristina Bena (colls. F. Dolcini, H. Grabert and A. Crépieux). Inès Safi has worked on coherent conductors embedded in an ohmic circuit, and was able for the first time to treat the case of a good transmitting channel in series with an arbitrary resistance, yielding exact predictions not only for current average, its fluctuations (noise), but also higher cumulants (coll. H. Saleur). Those works give a very interesting possibility to distinguish the role of intrinsic interactions from that of an external resistance of the circuit.

Inès Safi est chargée de recherches au CNRS en physique théorique de la matière condensée à Orsay.

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PUBLICATIONS

Peer reviewed publications / Publications dans des revues avec comité de lecture

I. Safi, C. Bena and A. Crépieux, ”The AC conductance and nonsymmetrized noise at finite frequency in quantum wires and carbon nanotubes”, soumis à Phys. Rev. B (2008). http://arxiv.org/abs/0805.3932v1

C. Bena and I. Safi,”Emission and absorption noise in the fractional quantum Hall effect”, Phys. Rev. B 76, 125317 (2007). http://arxiv.org/abs/0705.0156

F. Dolcini, B. Trauzettel, I. Safi and H. Grabert, ”Negativity of the excess noise of a quantum wire capacitively coupled to a gate”, Phys. Rev. B. 75, 045332 (2007). http://arxiv.org/abs/cond-mat/0609227

F. Dolcini, B. Trauzettel, I. Safi and H. Grabert, ” Transport properties of single channel quantum wires with an impurity: influence of finite length and temperature on average current and noise”, Phys. Rev. B, 71, 165309 − 1 (2005). http://arxiv.org/abs/cond-mat?papernum=0409320

I. Safi and H. Saleur ”One-channel conductor in an ohmic environment: mapping to a Tomonaga-Luttinger liquid and full counting statistics”, Phys. Rev. Letters 93, 126602 − 1 (2004). http://arxiv.org/PS_cache/cond-mat/pdf/0312/0312477v1.pdf

B. Trauzettel, I. Safi, F. Dolcini and H. Grabert, ”Appearance of fractional charge in the noise of nonchiral Luttinger liquids”, Phys. Rev. Letters 92, 226405 (2004). http://arxiv.org/abs/cond-mat/0402479

F. Dolcini, H. Grabert, I. Safi and B. Trauzettel, ” Oscillatory nonlinear conductance of interacting one-dimensional quantum wires”, Phys. Rev. Letters 91, 266402 (2003). http://arxiv.org/abs/cond-mat/0311168

R. Guyon, T. Martin, I. Safi and P. Devillard, ”Fractional Statistics, Hanbury-Brown and Twiss correlations and the quantum Hall effect ”, C.R. Physique 3, 1 − 11 (2002). http://prola.aps.org/abstract/PRL/v86/i20/p4628_1 P. Devillard, R. Guyon, T. Martin, I. Safi and B. K. Chakravarty, ”Andreev Reflection off a fluctuating superconductor in the absence of equilibrium”, Phys. Rev. B 66, 165413 (2002). http://arxiv.org/abs/cond-mat/0202446

R. Guyon, P. Devillard, T. Martin and I. Safi, ”Klein Factors in Multiple Fractional Quantum Hall Effect tunneling ”, Phys. Rev. B. 65, 153304 (2002). http://arxiv.org/abs/cond-mat/0109340v2

I. Safi, P. Devillard and T. Martin, ”Partition noise and statistics in the fractional quantum Hall effect”, Phys. Rev. Letters 86, 4628−4632 (2001). http://arxiv.org/abs/cond-mat/0004244 Inès Safi, “A dynamic scattering approach for a gated interacting wire“, Eur. Phys. J. B. 12, 451 (1999). http://arxiv.org/abs/cond-mat/9807122

Inès Safi and H. J. Schulz, “Interacting electrons with spin in a onedimensional dirty wire connected to leads“, Phys. Rev. B, 59, 3040 (1999). http://arxiv.org/abs/cond-mat/9803326 Inès Safi, “Propriétés d’un fil quantique connecté à des réservoirs“, Ann. Phys. (France) 22, 463 (1997).

Inès Safi, “Resonance in a Tomonaga-Luttinger liquid“, Phys. Rev. B 56, R 12 691 (1997).http://arxiv.org/abs/cond-mat/9708179

Inès Safi, “Conductance of a quantum wire: Landauer’s approach versus Kubo formula“, Phys. Rev. B 55, 7331 (1997 II). http://arxiv.org/abs/cond-mat/9701027

I. Safi and H. J. Schulz, “Transport in an inhomogenous Luttinger liquid”, Phys. Rev. B 52, R17040 (1995).http://arxiv.org/abs/cond-mat/9505079

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PUBLICATIONS

Proceedings / Actes de colloques

B. Trauzettel, I. Safi, F. Dolcini and H. Grabert ” Fractional charge in the noise of Luttinger liquid systems, Proc. SPIE Int. Soc. Opt. Eng. 5843, 115 (2005).

B. Trauzettel, I. Safi, F. Dolcini and H. Grabert, ”Current noise in non-chiral Luttinger Liquids: Appearance of fractional charge”, AIP Conf. Proc. 780, 421 (2005).

I. Safi and H. Saleur, ”A one-channel conductor in an ohmic environment: mapping to a TLL and full counting statistics”, dans ”Quantum information and decoherence in nanosystems”, D.C. Glattli, M.Sanquer, et J. Tran Thanh Van, eds., EDPSciences, (2005).

F. Dolcini, B. Trauzettel, I. Safi and H. Grabert, ”Transport properties of an interacting quantum wire with an impurity: Effects of the finite length” dans ”Quantum information and decoherence in nanosystems”, D.C. Glattli, M.Sanquer, et J. Tran Thanh Van, eds (2005).

I. Safi, P. Devillard and T. Martin, ”Fractional statistics and noise correlations in the FQHE”, dans “Electronic Correlations: From mesoto nano-physics”, ´editeurs T. Martin, G. Montambaux et J. Trân Thanh Vˆan, EDPSciences (2001).

I. Safi, “A dynamic transmission approach for a gated interacting one dimensional wire”, Quantum Physics at the mesoscopic scale, ´editeurs C. Glattli, Marc Sanquer et J. Tran Thanh Van (Editions Frontières, France) (1999).

I. Safi and H. J. Schulz, ”Transport in an interacting wire connected to measuring leads and proximity effects in Correlated Fermions and Transport in Mesoscopic Systems”, edited by T. Martin, G. Montambaux, and J. T. T. Van (Editions Frontières, Gif-sur-Yvette, 1996). http://arxiv.org/abs/cond-mat/9711082

I. Safi and H. J. Schulz, ”Transport in an interacting wire connected to measuring leads” in Quantum Transport in Semiconductor Submicron Structures, edited by B. Kramer (Kluwer Academic Press, Dordrecht, 1995), Chap. 3, p. 159. http://arxiv.org/abs/cond-mat/9605014

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Presentations

Samples of talks

Finite Frequency Non-Symmetrized Noise in interacting one-dimensional systems, talk in the colloquium for the ”60 th birthday of Hermann Grabert”, Freiburg, Germany, March 2007. (PDF / Powerpoint / PPS) Tomonaga-Luttinger Liquid versus Dynamical Coulomb Blockade, talk in the Vth Rencontres de Moriond ”Quantum Information and Decoherence in nanosystems ”, La Thuile, Italy, January 2004. (PDF / Powerpoint / PPS)

1 D strongly correlated fermions in a mesoscopic context, talk in the Symposium for the memory of Heinz Schulz, Orsay, May 1999. (HTML & Audio)

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Links / Liens

Laboratoire de Physique des Solides

Equipe scientifique : Théorie 1

Université Paris-Sud

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Inès Safi (safi@lps.u-psud.fr), Laboratoire de Physique des Solides, Université Paris-Sud, Orsay (France)