Negativity of the excess noise in a quantum wire capacitively coupled to a gate

Abstract

The electrical current noise of a quantum wire is expected to increase with increasing applied voltage. We show that this intuition can be wrong. Specifically, we consider a single channel quantum wire with impurities and with a capacitive coupling to nearby metallic gates and find that its excess noise, defined as the change in the noise caused by the finite voltage, can be negative at zero temperature. This feature is present both for large ($c\gg c_q$) and small ($c\ll c_q$) capacitive coupling, where $c$ is the geometrical and $c_q$ the quantum capacitance of the wire. In particular, for $c\gg c_q$, negativity of the excess noise can occur at finite frequency when the transmission coefficients are energy dependent, i.e. in the presence of Fabry-Pérot resonances or band curvature. In the opposite regime $c\lesssim c_q$, a non trivial voltage dependence of the noise arises even for energy independent transmission coefficients: at zero frequency the noise decreases with voltage as a power law when $c<c_q/3$, while, at finite frequency, regions of negative excess noise are present due to Andreev-type resonances.

11 pages, 5 figures. Revised version, references and technical details added, typos corrected

References in corpus (4)

• Using a quantum dot as a high-frequency shot noise detector
• Transport properties of single channel quantum wires with an impurity: Influence of finite length and temperature on average current and noise
• Asymmetric Quantum Shot Noise in Quantum Dots
• Oscillatory non-linear conductance of an interacting quantum wire with an impurity

Cited by in corpus (4)

• Emission and absorption noise in the fractional quantum Hall effect
• Finite frequency noise of a superconductor/ferromagnet quantum point contact
• AC driven strongly correlated quantum circuits and Hall edge states: Unified photo-assisted noise and revisited minimal excitations
• Tuning Excess Noise by Aharonov-Bohm Interferometry