What is model collapse in physics?

Short answer

In physics, “collapse models” are theories proposing that quantum wavefunction collapse is a real physical process, not merely an update of knowledge or a mathematical rule. They modify Schrödinger’s equation with nonlinear, stochastic terms that are negligible for microscopic systems but increasingly localize macroscopic ones. These theories aim to explain why measurements produce definite classical outcomes, but they make experimentally testable predictions and remain debated: increasingly precise experiments have found no evidence for some simple versions, without ruling out every collapse model.

The views on this question

Two lenses on the same evidence. Source weight and the primary source ratio show what each rests on.

Alternative

Source weight 33%

The main alternative is to reject adding a new physical collapse mechanism. On this view, standard quantum mechanics may be retained while the measurement problem is addressed through another interpretation or account of measurement. Collapse models remain possible, but their extra dynamics face increasingly stringent experimental tests and are not yet established as a physical fact.

Some approaches treat collapse as an interpretive or measurement-related issue rather than a new physical process governed by modified dynamics.
The standard quantum framework has extraordinary empirical success, even though its interpretation raises questions about what physically exists.
Experimental null results challenge at least the simplest objective-collapse proposals, so the evidence does not currently establish physical collapse.
The alternative is not a single competing collapse theory: it is a family of non-collapse interpretations and conventional readings of quantum mechanics.

Short answer

The deeper question

The views on this question

Follow the white rabbit

What is model collapse in physics?

Short answer

The views on this question

Alternative

Follow the white rabbit