Large-scale quantum effects have always played an important role in the foundations of
quantum theory. With recent experimental progress and the aspiration for quantum …

Spacetime curvature induces tidal forces on the wave function of a single quantum system.
Using a dual light-pulse atom interferometer, we measure a phase shift associated with such …

We show that an interaction between a harmonic oscillator and a two-level test mass (TLTM)
mediated by a local operations and classical communication (LOCC) channel produces a …

We assess the most macroscopic matter-wave experiments to date as to the extent to which
they probe the quantum-classical boundary by demonstrating interference of heavy …

We study how matter-wave interferometry with Bose–Einstein condensates is affected by
hypothetical collapse models and by environmental decoherence processes. Motivated by …

The theory of general relativity is based on the equivalence principle, which states that all
gravitational effects vanish in any local measurement. This principle is the best-understood …

In this thesis I present a universal scheme to assess the macroscopicity of experimentally
fabricated quantum superposition states based on the degree to which they probe the …

We show that an interaction between a harmonic oscillator and a two-level test mass (TLTM)
mediated by a local operations and classical communication (LOCC) channel produces a …

Trapped and guided matterwave interferometry holds the promise of a step-change in the
sensitivity of measurements such as gravity or rotation. This thesis studies the proposal of a …