Unsharpness in the Stern-Gerlach device via stochastic perturbation in the Hamiltonian

Unsolvability of the Halting Problem in Quantum Dynamics

Unsolved Problems in Solar Polarization

Unspeakable quantum information

Unstable particles as open quantum systems

Unstable Semiclassical Trajectories in Tunneling

Unstable systems and quantum Zeno phenomena in quantum field theory

Unstructured Randomness, Small Gaps and Localization

Untangling Quantum Entanglement

Unusual bound or localized states

Unusual Bound States in Quantum Chains

Unusual decoherence in qubit measurements with a Bose-Einstein condensate

Unusual light spectra from a two-level atom in squeezed vacuum

Unusual Properties of Superoscillating Particles

Unusual quantum states: nonlocality, entropy, Maxwell's daemon, and fractals

Unusual scalar products in Hilbert space of Quantum Mechanics: non-Hermitian square-well model with two coupled channels

Unveiled reality: comment on d'Espagnat's note on measurement

Unveiling optical hidden correlations: the illusionist game

Unveiling quantum entanglement degradation near a Schwarzschild black hole

Unversality of decoherence in the macroworld