Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 21: Quantum Dots and Wires: Transport (joint session HL/TT)

TT 21.6: Talk

Tuesday, March 18, 2025, 12:30–12:45, H13

Beyond full counting statistics and Langevin theory: The quantum polyspectra approach to multi-detector measurements — •Armin Ghorbanietemad, Markus Sifft, and Daniel Hägele — Ruhr University Bochum, Faculty of Physics and Astronomy, Experimental Physics VI, Germany

The quantum polyspectra approach to quantum measurements has recently been shown to cover the full range between weak and strong quantum measurements [1 - 3]. It provides thus a more general approach to quantum measurements than the full counting statistics used in nano-electronics or the Langevin-approach used in spin noise spectroscopy. This approach draws its strength from comparing higher order spectra of the measurement record with model spectra calculated from quantum expressions that are calculated on the level of a Lindblad master equation. Here, we generalize the polyspectra approach to include the case of the simultaneous measurements of more than one quantity of a quantum system. The approach regards measurement induced damping, measurement backaction, and the quantum Zeno effect. We give a few examples of multi-detector polyspectra that were calculated by a multi-detector extension of our SignalSnap and QuantumCatch library [4, 5].

[1] Hägele et al., PRB 98, 205143 (2018)

[2] Sifft et al., PRR 3, 033123 (2021)

[3] Sifft et al., PRA 109, 062210 (2024)

[4] https://github.com/MarkusSifft/SignalSnap

[5] https://github.com/MarkusSifft/QuantumCatch

Keywords: Quantum measurements; Polyspectra; Signal analysis