I would like to see experimental results for repeated measurement of a single-particle, quantum system that is approximately either particle-in-a-box or simple harmonic oscillator. If particle-in-a-box, then ideally in a limit that is approximately "infinite" square well. Can someone point me to such results, ideally with a reference to a paper?
In response to feedback in the comments that seem to have misinterpreted the question while also, helpfully, suggesting that some context might narrow scope, here's some context for the question:
- From theory we expect that each measurement will cause the wavefunction to collapse. It will then evolve according to the Schrodinger equation until the next measurement, when it will collapse again.
- In theory if we push the measurements closer and closer together in time, we expect to find the particle in approximately the same place each time due to the collapse of the wavefunction from the prior measurement, which, if the measurements are sufficiently frequent, will not have much time to spread before the next measurement.
- In theory, we also tend to assume that the measurement is instantaneous and of potentially infinite precision, whereas in practice neither is true: The measurement will take finite time to complete and have finite spatial precision.
- Experimental results may be subject to both quantum uncertainties (due to the method of measurement itself being subject to quantum effects) and classical uncertainties, which presumably have different impact on how the wavefunction collapses.
- Ensemble experiments, while useful, do not directly probe these aspects of quantum measurement because they typically have the "collapse" but then no direct measurement of the subsequent "evolve" and "collapse" that you'd have in repeated measurements of a specific particle.
I'm interested in experimental data that probes a system subject to repeated measurement and how that empirically does (or doesn't, if that's the case) match expectations from the ad-hoc theoretical procedure of repeated cycles of collapsing and evolving the wavefunction, especially in presence of finite-precision measurements.
Within that context, I'm trying to keep the question open-ended enough to avoid eliminating "closely" related experimental results but not completely open.
Examples of desired characteristics of a relevant experiment:
- Takes multiple (finite-precision) position measurements of the same particle repeatedly over time.
- Is a quantum system that is "approximately" particle-in-a-box or simple harmonic oscillator.
- Constitutes an experimental measurement.
- May be, but doesn't need to be, in multiple dimensions, e.g., it doesn't need to be a one-dimensional box.
Examples of things that are not of interest at this point:
- Theoretical discussion of the Schrodinger equation in general or in the specific cases of the problems identified.
- Theoretical discussion of quantum measurement, including collapse of wave functions.
- Experimental results for systems that are not approximately particle-in-a-box or simple harmonic oscillator, including but not limited to discussion of the two-slit experiment or atomic orbitals.
- Experimental measurements of ensembles rather than repeated measurements of a specific, single-particle system. (This also eliminates the two-slit experiment since each particle hitting the screen is a different particle.)
Examples of questions that are similar but that do not meet the specifications above:
- References on experimental realization of quantum one-dimensional infinite-well model (Focuses on one-dimension, particle-in-a-box only, and does not include repeated measurement of a single system. Answer, likewise, applies to ensemble results rather than repeated measurements of individual particles.)
- Quantum measurement in experiment (Theoretical discussion only.)
Restating the question from the first paragraph, what experimental results exist within the constraints listed above, ideally with a reference to a paper?