Equation 19 · Part 2 · The Corner of the Equivalence Principle No Experiment Has Touched
subscript
subscript
What this part means
The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.
Its job in the formula
A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.
Full expression→subscript→Article meaning
The passage around this formula
Run the actual experimental record against that basis and a pattern appears fast. Dennis Schlippert and colleagues’ 2014 dual-species atom interferometer, dropping laser-cooled rubidium and potassium together, reported an Eötvös ratio of (0.3 ± 5.4) × 10⁻⁷ between the two species [ 5 ] , and the same collaboration’s improved 2020 apparatus tightened that to η(Rb,K) = (−1.9 ± 3.2) × 10⁻⁷ [ 6 ] . Because rubidium and potassium differ in composition rather than internal quantum state, these bound a combination of and , not the coherence or entanglement pieces. Peter Asenbaum and colleagues pushed a single-species version of the same idea further, interfering two…
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
Sources cited in the surrounding passage
- [5] Quantum Test of the Universality of Free Fall ↗
- [6] Quantum test of the Universality of Free Fall using rubidium and potassium ↗
- [4] Atom-Interferometric Test of the Equivalence Principle at the 10⁻¹² Level ↗
- [7] Quantum test of the equivalence principle for atoms in superpositions of internal energy eigenstates ↗
- [10] Observation of a gravitational Aharonov-Bohm effect ↗
These citations provide research context; check each source for the exact claim it supports.