ترغب بنشر مسار تعليمي؟ اضغط هنا

Detection of finite frequency photo-assisted shot noise with a resonant circuit

146   0   0.0 ( 0 )
 نشر من قبل Thierry Martin
 تاريخ النشر 2010
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Denis Chevallier




اسأل ChatGPT حول البحث

Photo-assisted transport through a mesoscopic conductor occurs when an oscillatory (AC) voltage is superposed to the constant (DC) bias which is imposed on this conductor. Of particular interest is the photo assisted shot noise, which has been investigated theoretically and experimentally for several types of samples. For DC biased conductors, a detection scheme for finite frequency noise using a dissipative resonant circuit, which is inductively coupled to the mesoscopic device, was developped recently. We argue that the detection of the finite frequency photo-assisted shot noise can be achieved with the same setup, despite the fact that time translational invariance is absent here. We show that a measure of the photo-assisted shot noise can be obtained through the charge correlator associated with the resonant circuit, where the latter is averaged over the AC drive frequency. We test our predictions for a point contact placed in the fractional quantum Hall effect regime, for the case of weak backscattering. The Keldysh elements of the photo-assisted noise correlator are computed. For simple Laughlin fractions, the measured photo-assisted shot noise displays peaks at the frequency corresponding to the DC bias voltage, as well as satellite peaks separated by the AC drive frequency.



قيم البحث

اقرأ أيضاً

71 - Alex Zazunov 2007
We consider the measurement of higher current moments with a dissipative resonant circuit, which is coupled inductively to a mesoscopic device in the coherent regime. Information about the higher current moments is coded in the histograms of the char ge on the capacitor plates of the resonant circuit. Dissipation is included via the Caldeira-Leggett model, and it is essential to include it in order for the charge fluctuations (or the measured noise) to remain finite. We identify which combination of current correlators enter the measurement of the third moment. The latter remains stable for zero damping. Results are illustrated briefly for a quantum point contact.
We study the finite frequency (F.F.) noise properties of edge states in the Laughlin state. We investigate the model of a resonant detector coupled to a quantum point contact in the weak-backscattering limit. In particular we discuss the impact of po ssible renormalization of the Luttinger exponent, due to environmental effects, on the measured quantities and we propose a simple way to extract such non-universal parameters from noise measurements.
We consider the fluctuations of the electrical current (shot noise) in the presence of a voltage time-modulation. For a non-interacting metal, it is known that the derivative of the photo-assisted noise has a staircase behavior. In the presence of Co ulomb interactions, we show that the photo-assisted noise presents a more complex profile, in particular for the two following systems: 1) a two-dimensional electron gas in the fractional quantum Hall regime for which we have obtained evenly spaced singularities in the noise derivative, with a spacing related to the filling factor and, 2) a carbon nanotube for which a smoothed staircase in the noise derivative is obtained.
59 - A. Crepieux , P. Devillard , 2003
The effect of an AC perturbation on the shot noise of a fractional quantum Hall fluid is studied both in the weak and the strong backscattering regimes. It is known that the zero-frequency current is linear in the bias voltage, while the noise deriva tive exhibits steps as a function of bias. In contrast, at Laughlin fractions, the backscattering current and the backscattering noise both exhibit evenly spaced singularities, which are reminiscent of the tunneling density of states singularities for quasiparticles. The spacing is determined by the quasiparticle charge $ u e$ and the ratio of the DC bias with respect to the drive frequency. Photo--assisted transport can thus be considered as a probe for effective charges at such filling factors, and could be used in the study of more complicated fractions of the Hall effect. A non-perturbative method for studying photo--assisted transport at $ u=1/2$ is developed, using a refermionization procedure.
By coupling a quantum detector, a superconductor-insulator-superconductor junction, to a Josephson junction textit{via} a resonant circuit we probe the high frequency properties, namely the ac complex admittance and the current fluctuations of the Jo sephson junction at the resonant frequencies. The admittance components show frequency dependent singularities related to the superconducting density of state while the noise exhibits a strong frequency dependence, consistent with theoretical predictions. The circuit also allows to probe separately the emission and absorption noise in the quantum regime of the superconducting resonant circuit at equilibrium. At low temperature the resonant circuit exhibits only absorption noise related to zero point fluctuations, whereas at higher temperature emission noise is also present.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا