arXiv subjects

Jose-Ignacio Izpura

Publications and source records attributed to Jose-Ignacio Izpura.

3 recordsLinked to original sources

arXiv2025

A quantum model for Johnson noise

Johnson noise is a small random voltage that appears between terminals of any resistor interacting with its thermal bath at temperature T. It looks like continuous, but the discreteness of the electrical charge suggests its discrete origin coming from the charge noise due to random translocations of individual electrons between terminals. The capacitance allowing these translocations would quantize the energy entering the resistor in this way, thus acting as the antenna of the resistor to pick up thermal energy in the form of charge unbalances (fluctuations of energy) between its terminals. The subsequent relaxations of these fluctuations by the conductance G=1/R of the resistor (the collective reaction of all its carriers) would give rise to its Johnson noise. This collective reaction to dissipate fluctuations of energy caused by individual electrons, agrees with the Fluctuation-Dissipation framework that Callen and Welton proposed in 1951 for noisy processes.

cond-mat.stat-mech↗

arXiv2025

Particle-wave duality in electrical noise

Though electrical noise and conduction current are assigned to corpuscle-like electrons drifting in solid matter, this model hardly fits in the Fluctuation-Dissipation framework. However, fluctuations of energy due to displacements of single electrons between two close conductors lead to a discrete noise model looking like continuous in practice. The complex Admittance it uses for the displacement and conduction currents between such conductors, allows a treatment of fluctuations and dissipations of electrical energy that excels the example of Callen and Welton using the complex Impedance of resistors. The new model thus obtained not only unifies the phase noise of electronic oscillators with the linewidth of lasers, but also explains why the shot noise that the drift theory assigns to conduction currents is not observed.

cond-mat.other↗

arXiv2019

Learning to measure resistance noise demystifies the ubiquitous 1/f excess noise

To study resistance noise (DeltaR) by a spectrum analyzer we must convert this noise into a noise voltage (DeltaV) at the reach of such generalized voltmeter. Whenever a current Iconv is set in a resistor to convert its resistance noise into noise voltage by Ohm's Law: DeltaV=DeltaR*Iconv, the converted noise thus obtained does not track DeltaRte (its resistance noise in Thermal Equilibrium, TE) but DeltaR, that is: a resistance noise out of TE due to Iconv itself. Thus, backgating noises in the channel of resistors (i. e. Field-Induced Resistance Noise, FIRN) found by this method always are noises out of TE. The way the Lorentzian DeltaRte of a resistor is converted by Iconv into nine decades of resistance noise DeltaR with 1/f spectrum is the lesson we give on this unexpected spectral change that we could express as: "To measure is to disturb, particularly in resistance noise measurements".

cond-mat.other↗