7,642 research outputs found
Slow Vibrations in Transport through Molecules
We show how one can measure the signal from slow jumps of a single molecule
between metastable positions using a setup where the molecule is fixed to one
lead, and one of the coupling strengths is controlled externally. Such a
measurement yields information about slow processes deforming the molecule in
times much longer than the characteristic time scales for the electron
transport process.Comment: 4 pages, 3 figure
Thermalization of hot electrons via interfacial electron-magnon interaction
Recent work on layered structures of superconductors (S) or normal metals (N)
in contact with ferromagnetic insulators (FI) has shown how the properties of
the previous can be strongly affected by the magnetic proximity effect due to
the static FI magnetization. Here we show that such structures can also exhibit
a new electron thermalization mechanism due to the coupling of electrons with
the dynamic magnetization, i.e., magnons in FI. We here study the heat flow
between the two systems and find that in thin films the heat conductance due to
the interfacial electron-magnon collisions can dominate over the well-known
electron-phonon coupling below a certain characteristic temperature that can be
straightforwardly reached with present-day experiments. We also study the role
of the magnon band gap and the induced spin-splitting field induced in S on the
resulting heat conductance and show that heat balance experiments can reveal
information about such quantities in a way quite different from typical magnon
spectroscopy experiments
Quantum detectors for the third cumulant of current fluctuations
We consider the measurement of the third cumulant of current fluctuations
arising from a point contact, employing the transitions that they cause in a
quantum detector connected to the contact. We detail two generic detectors: a
quantum two-level system and a harmonic oscillator. In these systems, for an
arbitrary relation between the voltage driving the point contact and the energy
scales of the detectors, the results can be expressed in terms of an effective
detector temperature T_eff. The third cumulant can be found from the dependence
of T_eff on the sign of the driving voltage. We find that proper ordering of
the fluctuation operators is relevant in the analysis of the transition rates.
This is reflected in the effective Fano factor for the third cumulant measured
in such setups: it depends on the ratio of the voltage and an energy scale
describing the circuit where the fluctuations are produced.Comment: 12+ pages, 8 figure
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