arXiv subjects

Edouard Pinsolle

Publications and source records attributed to Edouard Pinsolle.

8 recordsLinked to original sources

arXiv2025

Higgs mode in superconducting Titanium nanostructures

We report observations of Higgs modes in superconducting Titanium nanostructures at very low temperature. They appear as anomalies in the microwave complex impedance of the samples revealed by the presence of a dc supercurrent. By varying the sample geometry and contact material, we probe how the Higgs modes are sensitive to the dimensionality of superconductivity, the penetration of the dc and ac current densities in the sample and the dissipation in the contacts.

cond-mat.supr-con↗

arXiv2025

Sensing Quantum Vacuum Fluctuations with Non-Gaussian Electronic Noise

The statistics of electron transport in a quantum conductor is affected by fluctuations of its voltage bias. Here we show experimentally how a third order correlation in the electromagnetic field arises from the noise of a tunnel junction in the microwave domain being modulated by the vacuum fluctuations generated by a resistor at ultralow temperature. This provides a way to measure the vacuum fluctuations experienced by the junction, not offset by the unavoidable noise added by the detection setup.

cond-mat.mes-hall↗

arXiv2024

Counting statistics of ultra-broadband microwave photons

We report measurements of counting statistics, average and variance, of microwave photons of ill-defined frequency : bichromatic photons, i.e. photons involving two well separated frequencies, and "white" broadband photons. Our setup allows for the analysis of single photonic modes of arbitrary waveform over the 1-10 GHz frequency range. The photon statistics are obtained by on-the-fly numerical calculation from the sampled time-dependent voltage. Using an ac+dc biased tunnel junction as a source of quantum microwave, we report an ultra-wide squeezing spectrum representing a competitive source for entanglement generation (up to 0.9 billion measured entangled bits per second) easily achievable experimentally. We also report the observation of quantum steering by the tunnel junction, and show how the presence of squeezing of a broadband mode implies the existence of entanglement between two modes it encompasses.

quant-ph↗

arXiv2023

Noise Dynamics in the Quantum Regime

A time-dependent bias voltage on a tunnel junction generates a time-dependent modulation of its current fluctuations, and in particular of its variance. This translates into an excitation at frequency $\tilde{f}$ generating correlations between current fluctuating at any frequency $f$ and at frequency $\pm$ $\tilde{f} -f$. We report the measurement of such a correlation in the fully quantum regime, i.e. when both frequencies are much greater than $k_BT/h$ with $T$ the temperature. Such a correlator, usually referred to as the noise susceptibility, is involved in corrections to the measurements of higher-order moments and in the squeezing of noise.

cond-mat.mes-hall↗

arXiv2020

Quantitative Measurements of Giant and Quantized Microwave Faraday Rotation

We report {\it quantitative} microwave Faraday rotation measurements conducted with a high-mobility two-dimensional electron gas (2DEG) in a GaAs/AlGaAs semiconductor heterostructure. In a magnetic field, the Hall effect and the Faraday effect arise from the action of Lorentz force on electrons in the 2DEG. As with the Hall effect, a classical Faraday effect is observed at low magnetic field as well as a quantized Faraday effect at high magnetic field. The high electron mobility of the 2DEG enables a giant single-pass Faraday rotation of $θ_F^{max} \simeq 45^\circ$ $(\simeq0.8$~rad) to be achieved at a modest magnetic field of $B \simeq 100$~mT. In the quantum regime, we find that the Faraday rotation $θ_F$ is quantized in units of $α^*= 2.80(4)α$, where $α\simeq 1/137$ is the fine structure constant. The enhancement in rotation quantum $α^* > α$ is attributed to electromagnetic confinement within a waveguide structure.

cond-mat.mes-hall↗

arXiv2020

Shot Noise of a Temperature-Biased Tunnel Junction

We report the measurement of the current noise of a tunnel junction driven out-of-equilibrium by a temperature and/or voltage difference, i.e. the charge noise of heat and/or electrical current. This is achieved by a careful control of electron temperature below 1 K at the nanoscale, and a sensitive measurement of noise with wide bandwidth, from 0.1 to 1 GHz. An excellent agreement between experiment and theory with no fitting parameter is obtained. In particular, we find that the current noise of the junction of resistance R when one electrode is at temperature T and the other one at zero temperature is given by S = 2 ln2 kB T /R.

cond-mat.mes-hall↗

arXiv2018

Non-Gaussian Current Fluctuations in a Short Diffusive Conductor

We report the measurement of the third moment of current fluctuations in a short metallic wire at low temperature. The data are deduced from the statistics of voltage fluctuations across the conductor using a careful determination of environmental contributions. Our results at low bias agree very well with theoretical predictions for coherent transport with no fitting parameter. By increasing the bias voltage we explore the cross-over from elastic to inelastic transport.

cond-mat.mes-hall↗

arXiv2016

Direct measurement of the electron energy relaxation dynamics in metallic wires

We present measurements of the dynamical response of thermal noise to an ac excitation in conductors at low temperature. From the frequency dependence of this response function - the noise thermal impedance - in the range 1 kHz-1 GHz we obtain direct determinations of the inelastic relaxation times relevant in metallic wires at low temperature: the electron-phonon scattering time and the diffusion time of electrons along the wires. Combining these results with that of resistivity provides a measurement of heat capacity of samples made of thin film. The simplicity and reliability of this technique makes it very promising for future applications in other systems.

cond-mat.mes-hall↗