### Conveners

#### Tests of Quantum Mechanics: Session 1

- David Kaplan

#### Tests of Quantum Mechanics: Session 2

- Surjeet Rajendran

Kaplan and Rajendran have recently demonstrated that non-linear and state-dependent terms can be consistently added to quantum field theory to yield causal non-linear time evolution in quantum mechanics. Causal non-linear theories have the unavoidable feature that their quantum effects are dramatically sensitive to the full physical spread of the quantum state of the system. As a result, such...

Long-baseline light-pulse atom interferometry (LPAI) is a powerful tool for performing tests of fundamental physics (see [1] and reference therein). Using state-of-the-art technology for coherent manipulation of ultracold (picoKelvin) atoms, LPAI is capable of creating quantum superpositions over tens of meters. Moreover, due to acceleration sensitivities close to 10-14 m/s2, using (say) a 100...

We provide the optimal measurement strategy for a class of noisy channels that reduce to the identity channel for a specific value of a parameter (spreading channels). We provide an example that is physically relevant: the estimation of the absolute value of the displacement in the presence of phase randomizing noise. This channel is useful to model axion dark matter search.

Surprisingly,...