Experiments Testing Quantum Foundations
Foundations experiments test quantitative predictions and model assumptions. They do not usually decide an interpretation merely by displaying interference or entanglement. This index identifies the measured object and the inference each experiment can support; it is not a current ranking of experimental records.
Correlation and compatibility tests
Section titled “Correlation and compatibility tests”| Class | Measured quantity | Model comparison | Main caution |
|---|---|---|---|
| Bell tests | Joint outcome correlations for chosen settings | Local models under setting and sampling assumptions | A violation is not a signaling channel |
| Contextuality scenarios | Compatible-context probabilities or operational equivalences | The specified noncontextual model | Compatibility and equivalence need experimental support |
| Leggett–Garg tests | Temporal correlations | Macrorealist premises with noninvasive-measurement assumptions | Measurement disturbance can mimic a violation |
| No-signaling tests | Dependence of local marginals on remote settings | Operational signaling alternatives and apparatus consistency | Finite fluctuations and systematic cross-talk require separation |
Superposition and modified-dynamics tests
Section titled “Superposition and modified-dynamics tests”Matter-wave interferometry measures contrast, phase, and the dependence of interference on path separation, propagation time, and environmental coupling. It tests coherence in the realized system; translating the result into a collapse constraint needs a specific model. See Matter-Wave Interferometry.
Superconducting cat states characterize superpositions in controlled circuit degrees of freedom. “Macroscopic” must be tied to a stated measure, such as distinguishability of branches or a collective observable. Particle number alone is not a universal measure. See Superconducting Cat States.
Optomechanical tests probe motion, force noise, and potentially coherent mechanical states. Ordinary thermal and technical noise must be separated from any proposed extra diffusion. See Optomechanical Tests.
Collapse-model tests compare interference loss, heating, radiation, or force noise with predictions of a named model variant. A constraint is conditional on the coupling and noise assumptions. See Collapse Model Tests.
Tests of probability, linearity, and interaction
Section titled “Tests of probability, linearity, and interaction”Born-rule tests compare observed probabilities with the standard rule under a specified apparatus model. A multi-path interference test can constrain particular deviations, but imperfections in opening and closing paths may change the dynamics being compared. See Precision Tests of the Born Rule.
Linearity tests constrain a parametrized departure from linear dynamics. A null result for one modification does not establish every possible nonlinear theory is excluded. See Tests of Linearity.
Gravity-mediated entanglement proposals seek a nonclassical correlation attributed to gravitational coupling. The inference about a mediator depends on locality, initial correlations, alternative interactions, and the model class. See Gravity-Mediated Entanglement Interface.
Comparing evidence responsibly
Section titled “Comparing evidence responsibly”Record the preparation, relevant scale, measured observable, uncertainty, null model, and alternative. Distinguish an apparatus demonstration, a parameter exclusion, and an interpretation-dependent claim.
Use Experimental Foundations Roadmap for a learning sequence and frontier bridges for stable criteria for evaluating new results.
References
Section titled “References”- Brunner, Nicolas, Daniel Cavalcanti, Stefano Pironio, Valerio Scarani, and Stephanie Wehner, “Bell nonlocality,” Reviews of Modern Physics 86, 419–478 (2014). Review.
- Budroni, Costantino, Adán Cabello, Otfried Gühne, Matthias Kleinmann, and Jan-Åke Larsson, “Kochen–Specker contextuality,” Reviews of Modern Physics 94, 045007 (2022). Review.
- Carlesso, Matteo, Sandro Donadi, Luca Ferialdi, Mauro Paternostro, Hendrik Ulbricht, and Angelo Bassi, “Present status and future challenges of non-interferometric tests of collapse models,” Nature Physics 18, 243–250 (2022). Review.