Quantum synchronization in nanoscale heat engines.
Physical review. E 101:2-1 (2020) 020201
Abstract:
Owing to the ubiquity of synchronization in the classical world, it is interesting to study its behavior in quantum systems. Though quantum synchronization has been investigated in many systems, a clear connection to quantum technology applications is lacking. We bridge this gap and show that nanoscale heat engines are a natural platform to study quantum synchronization and always possess a stable limit cycle. Furthermore, we demonstrate an intimate relationship between the power of a coherently driven heat engine and its phase-locking properties by proving that synchronization places an upper bound on the achievable steady-state power of the engine. We also demonstrate that such an engine exhibits finite steady-state power if and only if its synchronization measure is nonzero. Finally, we show that the efficiency of the engine sets a point in terms of the bath temperatures where synchronization vanishes. We link the physical phenomenon of synchronization with the emerging field of quantum thermodynamics by establishing quantum synchronization as a mechanism of stable phase coherence.Experimental Self-Characterization of Quantum Measurements.
Physical review letters 124:4 (2020) 040402
Abstract:
The accurate and reliable description of measurement devices is a central problem in both observing uniquely nonclassical behaviors and realizing quantum technologies from powerful computing to precision metrology. To date quantum tomography is the prevalent tool to characterize quantum detectors. However, such a characterization relies on accurately characterized probe states, rendering reliability of the characterization lost in circular argument. Here we report a self-characterization method of quantum measurements based on reconstructing the response range-the entirety of attainable measurement outcomes, eliminating the reliance on known states. We characterize two representative measurements implemented with photonic setups and obtain fidelities above 99.99% with the conventional tomographic reconstructions. This initiates range-based techniques in characterizing quantum systems and foreshadows novel device-independent protocols of quantum information applications.Phase diffusion and the small-noise approximation in linear amplifiers: Limitations and beyond
Quantum Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften 3 (2019) 200
Is the fermionic exchange phase also acquired locally?
Journal of Physics Communications IOP Publishing 3:11 (2019) 111001
Modular quantum computation in a trapped ion system
Nature Communications Springer Nature 10:1 (2019) ARTN 4692