2017/11/30 by Gernot Schaller, Javier Cerrillo, Georg Engelhardt +1 · 48 citations
Computer Science · Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Coupling (piping) #Limit (mathematics) #Mathematical analysis #Mathematics #Maxwell's demon #Physics #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1103/physrevb.97.195104
published in Physical review. B./Physical review. B 97(19) (American Physical Society) · to appear in PRB, side-by-side with arXiv:1711.08914
arxiv created 2018/03/27 · openalex publication_date 2018/05/03 · arxiv updated 2018/05/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider an external feedback control loop implementing the action of a Maxwell demon. Applying control actions that are conditioned on measurement outcomes, the demon may transport electrons against a bias voltage and thereby effectively converts information into electric power. While the underlying model---a feedback-controlled quantum dot that is coupled to two electronic leads---is well explored in the limit of small tunnel couplings, we can address the strong-coupling regime with a fermionic reaction-coordinate mapping. This exact mapping transforms the setup into a serial triple quantum dot coupled to two leads. We find that a continuous projective measurement of the central dot occupation would lead to a complete suppression of electronic transport due to the quantum Zeno effect. In contrast, by using a microscopic detector model we can implement a weak measurement, which allows for closure of the control loop without transport blockade. Then, in the weak-coupling regime, the energy flows associated with the feedback loop are negligible, and dominantly the information gained in the measurement induces a bound for the generated electric power. In the strong coupling limit, the protocol may require more energy for operating the control loop than electric power produced, such that the whole device is no longer information dominated and can thus not be interpreted as a Maxwell demon.