Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 64: Quantum Information Systems: Mostly Concepts (jointly with HL)

TT 64.3: Talk

Wednesday, March 18, 2015, 11:30–11:45, EW 202

Creating and controlling entanglement using coherent time-delayed feedback — •Sven Moritz Hein, Franz Schulze, Alexander Carmele, and Andreas Knorr — Technische Universität Berlin, Institut für theoretische Physik, Nichtlineare Optik und Quantenelektronik, Hardenbergstraße 36, 10623 Berlin, Germany

Entanglement is a quantum-mechanical property interesting from a fundamental point of view as well as for future applications in quantum information science. We propose to use time-delayed quantum-coherent feedback to create and control entanglement between quantum-mechanical objects.

In classical physics, feedback schemes with a distinct feedback delay[1] are successfully applied to control unstable states and periodic orbits. We demonstrate by numerical simulations that this concept can be transferred to the quantum regime. Here, it can be used to enhance the entanglement of photons from a biexciton cascade[2] and also entangle cavities and other quantum nodes in a quantum network. To preserve quantum coherence, the feedback will be modeled in a fully quantum-mechanical way without the use of measurements.

[1] K. Pyragas, Phys. Lett. A 170, 421--428 (1992)

[2] S. M. Hein, et al., Phys. Rev. Lett. 113, 027401 (2014)