Articulating values to scaffold diverse approaches to physics theories
Jer Steeger and Rachel E. Scherr
Why not talk about measurement?
Jer Steeger and Rachel E. Scherr
Why not talk about measurement?
1. For some physics, measurement doesn't matter
2. Talking about measurement has led to new physics
3. It might help students learn that new physics
1. For some physics, measurement doesn't matter
\psi
1. For some physics, measurement doesn't matter
\psi
[...] you have to prepare a whole ensemble of particles, each in the same state \( \psi \) [to measure expectation values].
Griffiths (2005, p. 15)
1. For some physics, measurement doesn't matter
Although we believe that after [measurement] we know the state completely, nevertheless, only statistical statements can be made on the values of the physical quantities involved.
von Neumann (1955, p. 207)
1. For some physics, measurement doesn't matter
On this approach, Schrödinger's cat is no weirder than a coin.
Q: When do the details of a measurement of a single particle not matter for the physics?
A: When we only care about the statistics of measurement outcomes.
1. For some physics, measurement doesn't matter
1. For some physics, measurement doesn't matter
But talking about the measurement of a single particle has generated useful physics—even for folks taking von Neumann's approach!
Why not talk about measurement?
1. For some physics, measurement doesn't matter
2. Talking about measurement has led to new physics
3. It might help students learn that new physics
2. Talking about measurement has led to new physics
2. Talking about measurement has led to new physics
2.0. The coin
\longrightarrow
+
+
2. Talking about measurement has led to new physics
2.1. Decoherence
2. Talking about measurement has led to new physics
2.1. Decoherence
2. Talking about measurement has led to new physics
2.2. Bell inequalities
2. Talking about measurement has led to new physics
2.2. Bell inequalities
2. Talking about measurement has led to new physics
2.3. State estimation
\psi?
2. Talking about measurement has led to new physics
2.3. State estimation (ask me if interested!)
2. Talking about measurement has led to new physics
Historical claims:
- Many worlds resources helped physicists do decoherence.
- Hidden variable resources helped physicists do Bell inequalities.
- Epistemic resources helped physicists do state estimation.
Why not talk about measurement?
1. For some physics, measurement doesn't matter
2. Talking about measurement has led to new physics
3. It might help students learn that new physics
3. It might help students learn that new physics
Pedagogical hypotheses:
- Many worlds resources help students learn decoherence.
- Hidden variable resources help students learn Bell inequalities.
- Epistemic resources help students learn state estimation.
Historically-grounded and constructivist-friendly.
Historical claims:
- Many worlds resources helped physicists do decoherence.
- Hidden variable resources helped physicists do Bell inequalities.
- Epistemic resources helped physicists do state estimation.
We should start testing them!
3. It might help students learn that new physics
Resources for teaching
Why not talk about measurement?
By Jer Steeger
Why not talk about measurement?
Conventional wisdom suggests we should not teach physics undergraduates about different approaches to measurement in quantum mechanics. We challenge this wisdom by demonstrating that different interpretations were central to key breakthroughs in the second quantum revolution: namely, decoherence, non-locality, and state estimation. Thus, teaching measurement might bring students' epistemologies closer to those of experts.
