Single photons and the foundations of quantum mechanics
The interest in the foundations of quantum mechanics led to the invention of quantum technologies and return, the tools we have been developing for applications now enable us to make ever more precise tests of the foundations and potential limitations of quantum theory.
In our research we develop sources of nonclassical light, single photons and entangled photon pairs and then apply them towards quantum communication and in testing the foundations of quantum mechanics. Recently we have been working on coherent control of semiconductor quantum dots so that they deliver high fidelity single photons and entangled photon pairs [1,2]. We have tested the quality of the single photons with novel quantum optical assessment tools, for example non-Gaussianity witnesses .
As an unconventional application I will present our tests for potential higher-order interferences that would go beyond quantum mechanics  and interference tests that could reveal the necessity for a quaternion-based quantum mechanical description of nature. Even if these tests only yield null results, they are able to rule out alternative theories and thus give us tighter bounds on where to look for possible extensions and modifications of quantum theory.
- H. Jayakumar, A. Predojević, T. Huber, T. Kauten, G. S. Solomon, and G. Weihs, Deterministic Photon Pairs and Coherent Optical Control of a Single Quantum Dot, Phys. Rev. Lett. 110, 135505 (2013), DOI: 10.1103/PhysRevLett.110.135505
- H. Jayakumar, A. Predojević, T. Kauten, T. Huber, G. S. Solomon, and G. Weihs, Time-bin entangled photons from a quantum dot, Nature Communications 5, 4251 (2014). DOI: 10.1038/ncomms5251
- Predojević, M. Ježek, T. Huber, H. Jayakumar, T. Kauten, G. Solomon, R. Filip, and G. Weihs, Efficiency vs. multi-photon contribution test for quantum dots, Opt. Express 22, 4789-4798 (2014). DOI: 10.1364/OE.22.004789
U. Sinha, C. Couteau, T. Jennewein, R. Laflamme, and G. Weihs, Ruling out multi-order interference in quantum mechanics, Science 329, 418-421 (2010). DOI: 10.1126/science.1190545
Host: Glenn Solomon