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X-WR-CALNAME;VALUE=TEXT:Microwave photons emitted by fractionally charged quasiparticles -- Laboratoire de Physique des Solides - UMR 8502
X-WR-RELCALID:https://www.lps.u-psud.fr/spip.php?article3340
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SUMMARY:Microwave photons emitted by fractionally charged quasiparticles
UID:20191004T221817-a3340-e352@https://www.lps.u-psud.fr
DTSTAMP:20191004T221817
DTSTART:20191009T221500
DTEND:20191009T231500
CREATED:20191004T221817
LAST-MODIFIED:20191004T221825
LOCATION:salle 208a\, aîle sud LPS\, bât 510
ORGANIZER;CN=civelli[:mailto:marcello.civelli@u-psud.fr]
ATTENDEE:Manohar Kumar
DESCRIPTION:In a partially filled Landau Level\, the electron-electron interactions\, for example Coulomb interactions\, become dominant at high magnetic fields. It leads to manifestation of the many-body states like fractional quantum Hall (FQH) states where quasiparticle excitations carry fractional charges (e*=e/m\, m = 3\,5...) ; implying that many electrons acting in concert can create a quasiparticle with a charge smaller than that of an electron[1]. This apparent paradox has been well studied for last three decades using zero-frequency current noise[2\,3]. However\, unambiguous detection of the fractional charge of the quasiparticles is still missing ; which is extremely susceptible to intricate dynamics of the bulk-edge correspondence[4]. Due to this dynamical feature\, the emission and absorption of microwave by these quasiparticles will carries the imprints of fractional excitations. This require a measurement of current fluctuations at very high frequency[5] Here we developed the emission microwave spectroscopy for the FQH states by measuring non-equilibrium current fluctuations at frequency ν (hν > [kB*T\, e*VB]). The microwave photons emitted by FQH states are independent of bias voltage (e*VB < hν) ; but for e*VB > hν\, the current fluctuations cross over to the regular voltage-dependent shot noise. This crossover voltage carries the characteristics of the quasiparticle excitations namely their charge and statistics. Additionally\, we use the non-equilibrium fluctuation dissipation relation [6\,7] to connect the high and low frequency shot noise measurement\, hence unambiguously determining the charge of the quasi-particle excitations which is found to be e*=e/3 for the case of n = 4/3 and 2/3. [8] This measurement can be extended towards the study of non-classicality of these emitted photons in an ac-driven system and can probe the anyonic statistics of FQH systems\, which are not yet experimentally demonstrated. [1] R. B. Laughlin\, Anomalous Quantum Hall Effect : An Incompressible Quantum Fluid with Fractionally Charged Excitations\, Phys. Rev. Lett. 50\, 1395 (1983). [2] R. de Picciotto\, et al. Direct observation of a fractional charge\, Nature 389\, 162 (1997). [3] L. Saminadayar\, D.C. Glattli\, Y. Jin\, and B. Etienne\, Observation of the e/3 fractionally charged Laughlin quasiparticles\, Phys. Rev. Lett. 79\, 2526 (1997). [4] M. Dolev\, Y. Gross\, Y. C. Chung\, M. Heiblum\, V. Umansky\, and D. Mahalu\, Dependence of the tunneling quasiparticle charge determined via shot noise measurements on the tunneling barrier and energetics\, Phys. Rev. B 81\, 161303(R) (2010). [5] R. J. Schoelkopf\, P. J. Burke\, A. A. Kozhevnikov\, D. E. Prober\, and M. J. Rooks\, Frequency Dependence of Shot Noise in a Diffusive Mesoscopic Conductor\, Phys. Rev. Lett. 78\, 3370 (1997). [6] I Safi and P. Joyez\, Time-dependent theory of nonlinear response and current fluctuations\, Phys. Rev. B. 84\, 205129 (2011). [7] I. Safi\, Time-dependent transport in arbitrary extended driven tunnel junctions\, arxiv:1401.5950 ; see also B. Roussel\, P. Degiovanni and I. Safi\, Perturbative fluctuation dissipation relation for nonequilibrium finite-frequency noise in quantum circuits\, Phys. Rev. B 93\, 045102 (2016). [8] R. Bisognin\, H. Bartolomei\, M. Kumar\, I. Safi2\, J.-M. Berroir\, E. Bocquillon \, B. Plaçais \, A. Cavanna 3\, U. Gennser\, Y. Jin and G. Fève\, Microwave photons emitted by fractionally charged quasiparticles\, Nature Communications 10\, 1708 (2019). Also see : M. Kapfer\, P. Roulleau\, M. Santin\, I. Farrer\, D. A. Ritchie and D. C. Glattli\, A Josephson relation for fractionally charged anyons\, Science\, 363\, 846\, (2019).
CATEGORIES:Microwave photons emitted by fractionally charged quasiparticles
URL:https://www.lps.u-psud.fr/spip.php?article3340&id_evenement=352
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STATUS:CONFIRMED
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