Vienna Center for Quantum Science and Technology

A thorium-229 optical nuclear clock with feedback loop

Abstract The laser-accessible nuclear transition in the thorium-229 isotope has been identified as a candidate for realizing an optical nuclear clock 1 that might outperform current optical clocks based on electron-shell transitions in atoms or ions 2 . It is expected to be more...

Plasmon‐Enhanced Second‐Harmonic Generation in Atomically Thin Crystalline Silver Nanostructures

ABSTRACT The intrinsically weak nonlinear optical response of existing materials, further constrained by symmetry‐forbidden second‐order processes in centrosymmetric media, severely limits efficient frequency conversion in deeply subwavelength, ultrathin volumes. Addressing this...

Anomalous weak values in a generalized Mach–Zehnder interferometer extracted directly from intensity measurements

Abstract Weak values provide a powerful framework for characterizing quantum systems. Their experimental extraction conventionally relies on weak conditioned von Neumann measurements, involving weak interactions and meter states that increase experimental complexity and often lim...

Continuous-wave laser absorption spectroscopy of the thorium-229 nucleus

Abstract The low-energy nuclear transition in thorium-229 (Th-229) has been excited in thorium-doped crystals with laser light 1–3 , opening the path towards a highly stable and robust solid-state optical nuclear clock 4 . The required laser radiation at 148-nm wavelength has so...

Quantum Interference and the Limits of Separability

Abstract Quantum theory implies, and empirical evidence confirms, that while particles can exhibit wave-like behavior in interferometric experiments, this behavior is so limited as not to allow for third- and higher-order interference. The article at hand shows that this possibil...