With the development of photonic quantum technologies, single photons have become key
for various applications including quantum communication and quantum computing …

Quantum theory is the foundation of modern physics. Some of its basic principles, such as
Born's rule, however, are based on postulates which require experimental testing. Any …

Bohr's complementarity is one central tenet of quantum physics. The paradoxical wave-
particle duality of quantum matters and photons has been tested in Young's double-slit …

Modern quantum technologies have matured such that they can now be used in space
applications, eg, long‐distance quantum communication. Here, the design of a compact true …

These lecture notes provide a basic introduction to the framework of generalized
probabilistic theories (GPTs) and a sketch of a reconstruction of quantum theory (QT) from …

Many experiments in the field of quantum foundations seek to adjudicate between quantum
theory and speculative alternatives to it. This requires one to analyze the experimental data …

Macroscopic realism (MR) is the notion that a time-evolving system possesses definite
properties, irrespective of past or future measurements. Quantum-mechanical theories can …

Quantum theory permits interference between indistinguishable paths but, at the same time,
restricts its order. Single-particle interference, for instance, is limited to the second order, that …

Quantum information technology requires bright and stable single-photon emitters (SPEs).
As a promising single-photon source, SPEs in layered hexagonal boron nitride (hBN) have …

Despite its enormous empirical success, the formalism of quantum theory still raises
fundamental questions: why is nature described in terms of complex Hilbert spaces, and …